Make iterators safe in FOREACH_MOD etc macros, so that ModuleManager::Detach() wont...

[user/henk/code/inspircd.git] / include / modules.h

/*       +------------------------------------+
 *       | Inspire Internet Relay Chat Daemon |
 *       +------------------------------------+
 *
 *  InspIRCd: (C) 2002-2007 InspIRCd Development Team
 * See: http://www.inspircd.org/wiki/index.php/Credits
 *
 * This program is free but copyrighted software; see
 *          the file COPYING for details.
 *
 * ---------------------------------------------------
 */

#ifndef __MODULES_H
#define __MODULES_H

#include "globals.h"
#include "dynamic.h"
#include "base.h"
#include "ctables.h"
#include "inspsocket.h"
#include <string>
#include <deque>
#include <sstream>
#include "timer.h"
#include "mode.h"
#include "dns.h"

class XLine;

/** Used with OnAccessCheck() method of modules
 */
enum AccessControlType {
        ACR_DEFAULT,            // Do default action (act as if the module isnt even loaded)
        ACR_DENY,               // deny the action
        ACR_ALLOW,              // allow the action
        AC_KICK,                // a user is being kicked
        AC_DEOP,                // a user is being deopped
        AC_OP,                  // a user is being opped
        AC_VOICE,               // a user is being voiced
        AC_DEVOICE,             // a user is being devoiced
        AC_HALFOP,              // a user is being halfopped
        AC_DEHALFOP,            // a user is being dehalfopped
        AC_INVITE,              // a user is being invited
        AC_GENERAL_MODE         // a channel mode is being changed
};

/** Used to define a set of behavior bits for a module
 */
enum ModuleFlags {
        VF_STATIC = 1,          // module is static, cannot be /unloadmodule'd
        VF_VENDOR = 2,          // module is a vendor module (came in the original tarball, not 3rd party)
        VF_SERVICEPROVIDER = 4, // module provides a service to other modules (can be a dependency)
        VF_COMMON = 8           // module needs to be common on all servers in a network to link
};

/** Used with SendToMode()
 */
enum WriteModeFlags {
        WM_AND = 1,
        WM_OR = 2
};

/** Used to represent an event type, for user, channel or server
 */
enum TargetTypeFlags {
        TYPE_USER = 1,
        TYPE_CHANNEL,
        TYPE_SERVER,
        TYPE_OTHER
};

/** Used to represent wether a message was PRIVMSG or NOTICE
 */
enum MessageType {
        MSG_PRIVMSG = 0,
        MSG_NOTICE = 1
};

/** If you change the module API, change this value.
 * If you have enabled ipv6, the sizes of structs is
 * different, and modules will be incompatible with
 * ipv4 servers, so this value will be ten times as
 * high on ipv6 servers.
 */
#define NATIVE_API_VERSION 12000
#ifdef IPV6
#define API_VERSION (NATIVE_API_VERSION * 10)
#else
#define API_VERSION (NATIVE_API_VERSION * 1)
#endif

class ServerConfig;

/* Forward-delacare module for ModuleMessage etc
 */
class Module;
class InspIRCd;

/** Low level definition of a FileReader classes file cache area -
 * a text file seperated into lines.
 */
typedef std::deque<std::string> file_cache;

/** A set of strings.
 */
typedef file_cache string_list;

/** Holds a list of 'published features' for modules.
 */
typedef std::map<std::string,Module*> featurelist;

/** Holds a list of modules which implement an interface
 */
typedef std::deque<Module*> modulelist;

/** Holds a list of all modules which implement interfaces, by interface name
 */
typedef std::map<std::string, std::pair<int, modulelist> > interfacelist;

/**
 * This #define allows us to call a method in all
 * loaded modules in a readable simple way, e.g.:
 * 'FOREACH_MOD(I_OnConnect,OnConnect(user));'
 */
#define FOREACH_MOD(y,x) do { \
        EventHandlerIter safei; \
        for (EventHandlerIter _i = ServerInstance->Modules->EventHandlers[y].begin(); _i != ServerInstance->Modules->EventHandlers[y].end(); ++_i) \
        { \
                safei = _i; \
                safei++; \
                try \
                { \
                        (*_i)->x ; \
                } \
                catch (CoreException& modexcept) \
                { \
                        ServerInstance->Log(DEFAULT,"Exception caught: %s",modexcept.GetReason()); \
                } \
                _i = safei; \
        } \
} while (0);

/**
 * This #define allows us to call a method in all
 * loaded modules in a readable simple way and pass
 * an instance pointer to the macro. e.g.:
 * 'FOREACH_MOD_I(Instance, OnConnect, OnConnect(user));'
 */
#define FOREACH_MOD_I(z,y,x) do { \
        EventHandlerIter safei; \
        for (EventHandlerIter _i = z->Modules->EventHandlers[y].begin(); _i != z->Modules->EventHandlers[y].end(); ++_i) \
        { \
                safei = _i; \
                safei++; \
                try \
                { \
                        (*_i)->x ; \
                } \
                catch (CoreException& modexcept) \
                { \
                        z->Log(DEFAULT,"Exception caught: %s",modexcept.GetReason()); \
                } \
                _i = safei; \
        } \
} while (0);

/**
 * This define is similar to the one above but returns a result in MOD_RESULT.
 * The first module to return a nonzero result is the value to be accepted,
 * and any modules after are ignored.
 */
#define FOREACH_RESULT(y,x) \
do { \
        EventHandlerIter safei; \
        MOD_RESULT = 0; \
        for (EventHandlerIter _i = ServerInstance->Modules->EventHandlers[y].begin(); _i != ServerInstance->Modules->EventHandlers[y].end(); ++_i) \
        { \
                safei = _i; \
                safei++; \
                try \
                { \
                        int res = (*_i)->x ; \
                        if (res != 0) { \
                                MOD_RESULT = res; \
                                break; \
                        } \
                } \
                catch (CoreException& modexcept) \
                { \
                        ServerInstance->Log(DEFAULT,"Exception caught: %s",modexcept.GetReason()); \
                } \
                _i = safei; \
        } \
} while(0);


/**
 * This define is similar to the one above but returns a result in MOD_RESULT.
 * The first module to return a nonzero result is the value to be accepted,
 * and any modules after are ignored.
 */
#define FOREACH_RESULT_I(z,y,x) \
do { \
        EventHandlerIter safei; \
        MOD_RESULT = 0; \
        for (EventHandlerIter _i = z->Modules->EventHandlers[y].begin(); _i != z->Modules->EventHandlers[y].end(); ++_i) \
        { \
                safei = _i; \
                safei++; \
                try \
                { \
                        int res = (*_i)->x ; \
                        if (res != 0) { \
                                MOD_RESULT = res; \
                                break; \
                        } \
                } \
                catch (CoreException& modexcept) \
                { \
                        z->Log(DEBUG,"Exception caught: %s",modexcept.GetReason()); \
                } \
                _i = safei; \
        } \
} while (0);

/** Represents a non-local user.
 * (in fact, any FD less than -1 does)
 */
#define FD_MAGIC_NUMBER -42

/* Useful macros */
#ifdef WINDOWS
/** Is a local user */
#define IS_LOCAL(x) ((x->GetFd() > -1))
#else
/** Is a local user */
#define IS_LOCAL(x) ((x->GetFd() > -1) && (x->GetFd() <= MAX_DESCRIPTORS))
#endif
/** Is a remote user */
#define IS_REMOTE(x) (x->GetFd() < 0)
/** Is a module created user */
#define IS_MODULE_CREATED(x) (x->GetFd() == FD_MAGIC_NUMBER)
/** Is an oper */
#define IS_OPER(x) (*x->oper)
/** Is away */
#define IS_AWAY(x) (*x->awaymsg)

/** Holds a module's Version information.
 *  The four members (set by the constructor only) indicate details as to the version number
 *  of a module. A class of type Version is returned by the GetVersion method of the Module class.
 *  The flags and API values represent the module flags and API version of the module.
 *  The API version of a module must match the API version of the core exactly for the module to
 *  load successfully.
 */
class CoreExport Version : public classbase
{
 public:
         /** Version numbers, build number, flags and API version
          */
         const int Major, Minor, Revision, Build, Flags, API;

         /** Initialize version class
          */
         Version(int major, int minor, int revision, int build, int flags, int api_ver);
};

/** The ModuleMessage class is the base class of Request and Event
 * This class is used to represent a basic data structure which is passed
 * between modules for safe inter-module communications.
 */
class CoreExport ModuleMessage : public Extensible
{
 public:
        /** Destructor
         */
        virtual ~ModuleMessage() {};
};

/** The Request class is a unicast message directed at a given module.
 * When this class is properly instantiated it may be sent to a module
 * using the Send() method, which will call the given module's OnRequest
 * method with this class as its parameter.
 */
class CoreExport Request : public ModuleMessage
{
 protected:
        /** This member holds a pointer to arbitary data set by the emitter of the message
         */
        char* data;
        /** This should be a null-terminated string identifying the type of request,
         * all modules should define this and use it to determine the nature of the
         * request before they attempt to cast the Request in any way.
         */
        const char* id;
        /** This is a pointer to the sender of the message, which can be used to
         * directly trigger events, or to create a reply.
         */
        Module* source;
        /** The single destination of the Request
         */
        Module* dest;
 public:
        /** Create a new Request
         * This is for the 'old' way of casting whatever the data is
         * to char* and hoping you get the right thing at the other end.
         * This is slowly being depreciated in favor of the 'new' way.
         */
        Request(char* anydata, Module* src, Module* dst);
        /** Create a new Request
         * This is for the 'new' way of defining a subclass
         * of Request and defining it in a common header,
         * passing an object of your Request subclass through
         * as a Request* and using the ID string to determine
         * what to cast it back to and the other end. This is
         * much safer as there are no casts not confirmed by
         * the ID string, and all casts are child->parent and
         * can be checked at runtime with dynamic_cast<>()
         */
        Request(Module* src, Module* dst, const char* idstr);
        /** Fetch the Request data
         */
        char* GetData();
        /** Fetch the ID string
         */
        const char* GetId();
        /** Fetch the request source
         */
        Module* GetSource();
        /** Fetch the request destination (should be 'this' in the receiving module)
         */
        Module* GetDest();
        /** Send the Request.
         * Upon returning the result will be arbitary data returned by the module you
         * sent the request to. It is up to your module to know what this data is and
         * how to deal with it.
         */
        char* Send();
};


/** The Event class is a unicast message directed at all modules.
 * When the class is properly instantiated it may be sent to all modules
 * using the Send() method, which will trigger the OnEvent method in
 * all modules passing the object as its parameter.
 */
class CoreExport Event : public ModuleMessage
{
 protected:
        /** This member holds a pointer to arbitary data set by the emitter of the message
         */
        char* data;
        /** This is a pointer to the sender of the message, which can be used to
         * directly trigger events, or to create a reply.
         */
        Module* source;
        /** The event identifier.
         * This is arbitary text which should be used to distinguish
         * one type of event from another.
         */
        std::string id;
 public:
        /** Create a new Event
         */
        Event(char* anydata, Module* src, const std::string &eventid);
        /** Get the Event data
         */
        char* GetData();
        /** Get the event Source
         */
        Module* GetSource();
        /** Get the event ID.
         * Use this to determine the event type for safe casting of the data
         */
        std::string GetEventID();
        /** Send the Event.
         * The return result of an Event::Send() will always be NULL as
         * no replies are expected.
         */
        char* Send(InspIRCd* ServerInstance);
};

/** Priority types which can be returned from Module::Prioritize()
 */
enum Priority { PRIORITY_FIRST, PRIORITY_DONTCARE, PRIORITY_LAST, PRIORITY_BEFORE, PRIORITY_AFTER };

/** Implementation-specific flags which may be set in Module::Implements()
 */
enum Implementation
{
        I_BEGIN,
        I_OnUserConnect, I_OnUserQuit, I_OnUserDisconnect, I_OnUserJoin, I_OnUserPart, I_OnRehash, I_OnServerRaw, 
        I_OnUserPreJoin, I_OnUserPreKick, I_OnUserKick, I_OnOper, I_OnInfo, I_OnWhois, I_OnUserPreInvite,
        I_OnUserInvite, I_OnUserPreMessage, I_OnUserPreNotice, I_OnUserPreNick, I_OnUserMessage, I_OnUserNotice, I_OnMode,
        I_OnGetServerDescription, I_OnSyncUser, I_OnSyncChannel, I_OnSyncChannelMetaData, I_OnSyncUserMetaData,
        I_OnDecodeMetaData, I_ProtoSendMode, I_ProtoSendMetaData, I_OnWallops, I_OnChangeHost, I_OnChangeName, I_OnAddLine,
        I_OnDelLine, I_OnCleanup, I_OnUserPostNick, I_OnAccessCheck, I_On005Numeric, I_OnKill, I_OnRemoteKill, I_OnLoadModule, I_OnUnloadModule,
        I_OnBackgroundTimer, I_OnPreCommand, I_OnCheckReady, I_OnUserRrgister, I_OnCheckInvite,
        I_OnCheckKey, I_OnCheckLimit, I_OnCheckBan, I_OnStats, I_OnChangeLocalUserHost, I_OnChangeLocalUserGecos, I_OnLocalTopicChange,
        I_OnPostLocalTopicChange, I_OnEvent, I_OnRequest, I_OnOperCompre, I_OnGlobalOper, I_OnPostConnect, I_OnAddBan, I_OnDelBan,
        I_OnRawSocketAccept, I_OnRawSocketClose, I_OnRawSocketWrite, I_OnRawSocketRead, I_OnChangeLocalUserGECOS, I_OnUserRegister,
        I_OnOperCompare, I_OnChannelDelete, I_OnPostOper, I_OnSyncOtherMetaData, I_OnSetAway, I_OnCancelAway, I_OnUserList,
        I_OnPostCommand, I_OnPostJoin, I_OnWhoisLine, I_OnBuildExemptList, I_OnRawSocketConnect, I_OnGarbageCollect, I_OnBufferFlushed,
        I_OnText,
        I_END
};

/** Base class for all InspIRCd modules
 *  This class is the base class for InspIRCd modules. All modules must inherit from this class,
 *  its methods will be called when irc server events occur. class inherited from module must be
 *  instantiated by the ModuleFactory class (see relevent section) for the module to be initialised.
 */
class CoreExport Module : public Extensible
{
 protected:
        /** Creator/owner pointer
         */
        InspIRCd* ServerInstance;
 public:

        /** Default constructor.
         * Creates a module class.
         * @param Me An instance of the InspIRCd class which will be saved into ServerInstance for your use
         * \exception ModuleException Throwing this class, or any class derived from ModuleException, causes loading of the module to abort.
         */
        Module(InspIRCd* Me);

        /** Default destructor.
         * destroys a module class
         */
        virtual ~Module();

        virtual void Prioritize()
        {
        }

        /** Returns the version number of a Module.
         * The method should return a Version object with its version information assigned via
         * Version::Version
         */
        virtual Version GetVersion();

        /** Called when a user connects.
         * The details of the connecting user are available to you in the parameter User *user
         * @param user The user who is connecting
         */
        virtual void OnUserConnect(User* user);

        /** Called when a user quits.
         * The details of the exiting user are available to you in the parameter User *user
         * This event is only called when the user is fully registered when they quit. To catch
         * raw disconnections, use the OnUserDisconnect method.
         * @param user The user who is quitting
         * @param message The user's quit message (as seen by non-opers)
         * @param oper_message The user's quit message (as seen by opers)
         */
        virtual void OnUserQuit(User* user, const std::string &message, const std::string &oper_message);

        /** Called whenever a user's socket is closed.
         * The details of the exiting user are available to you in the parameter User *user
         * This event is called for all users, registered or not, as a cleanup method for modules
         * which might assign resources to user, such as dns lookups, objects and sockets.
         * @param user The user who is disconnecting
         */
        virtual void OnUserDisconnect(User* user);

        /** Called whenever a channel is deleted, either by QUIT, KICK or PART.
         * @param chan The channel being deleted
         */
        virtual void OnChannelDelete(Channel* chan);

        /** Called when a user joins a channel.
         * The details of the joining user are available to you in the parameter User *user,
         * and the details of the channel they have joined is available in the variable Channel *channel
         * @param user The user who is joining
         * @param channel The channel being joined
         * @param silent Change this to true if you want to conceal the JOIN command from the other users
         * of the channel (useful for modules such as auditorium)
         * @param sync This is set to true if the JOIN is the result of a network sync and the remote user is being introduced
         * to a channel due to the network sync.
         */
        virtual void OnUserJoin(User* user, Channel* channel, bool sync, bool &silent);

        /** Called after a user joins a channel
         * Identical to OnUserJoin, but called immediately afterwards, when any linking module has
         * seen the join.
         * @param user The user who is joining
         * @param channel The channel being joined
         */
        virtual void OnPostJoin(User* user, Channel* channel);

        /** Called when a user parts a channel.
         * The details of the leaving user are available to you in the parameter User *user,
         * and the details of the channel they have left is available in the variable Channel *channel
         * @param user The user who is parting
         * @param channel The channel being parted
         * @param partmessage The part message, or an empty string
         * @param silent Change this to true if you want to conceal the PART command from the other users
         * of the channel (useful for modules such as auditorium)
         */
        virtual void OnUserPart(User* user, Channel* channel, const std::string &partmessage, bool &silent);

        /** Called on rehash.
         * This method is called prior to a /REHASH or when a SIGHUP is received from the operating
         * system. You should use it to reload any files so that your module keeps in step with the
         * rest of the application. If a parameter is given, the core has done nothing. The module
         * receiving the event can decide if this parameter has any relevence to it.
         * @param user The user performing the rehash, if any -- if this is server initiated, the
         * value of this variable will be NULL.
         * @param parameter The (optional) parameter given to REHASH from the user.
         */
        virtual void OnRehash(User* user, const std::string &parameter);

        /** Called when a raw command is transmitted or received.
         * This method is the lowest level of handler available to a module. It will be called with raw
         * data which is passing through a connected socket. If you wish, you may munge this data by changing
         * the string parameter "raw". If you do this, after your function exits it will immediately be
         * cut down to 510 characters plus a carriage return and linefeed. For INBOUND messages only (where
         * inbound is set to true) the value of user will be the User of the connection sending the
         * data. This is not possible for outbound data because the data may be being routed to multiple targets.
         * @param raw The raw string in RFC1459 format
         * @param inbound A flag to indicate wether the data is coming into the daemon or going out to the user
         * @param user The user record sending the text, when inbound == true.
         */
        virtual void OnServerRaw(std::string &raw, bool inbound, User* user);

        /** Called whenever a user is about to join a channel, before any processing is done.
         * Returning a value of 1 from this function stops the process immediately, causing no
         * output to be sent to the user by the core. If you do this you must produce your own numerics,
         * notices etc. This is useful for modules which may want to mimic +b, +k, +l etc. Returning -1 from
         * this function forces the join to be allowed, bypassing restrictions such as banlists, invite, keys etc.
         *
         * IMPORTANT NOTE!
         *
         * If the user joins a NEW channel which does not exist yet, OnUserPreJoin will be called BEFORE the channel
         * record is created. This will cause Channel* chan to be NULL. There is very little you can do in form of
         * processing on the actual channel record at this point, however the channel NAME will still be passed in
         * char* cname, so that you could for example implement a channel blacklist or whitelist, etc.
         * @param user The user joining the channel
         * @param chan If the  channel is a new channel, this will be NULL, otherwise it will be a pointer to the channel being joined
         * @param cname The channel name being joined. For new channels this is valid where chan is not.
         * @param privs A string containing the users privilages when joining the channel. For new channels this will contain "@".
         * You may alter this string to alter the user's modes on the channel.
         * @return 1 To prevent the join, 0 to allow it.
         */
        virtual int OnUserPreJoin(User* user, Channel* chan, const char* cname, std::string &privs);
        
        /** Called whenever a user is about to be kicked.
         * Returning a value of 1 from this function stops the process immediately, causing no
         * output to be sent to the user by the core. If you do this you must produce your own numerics,
         * notices etc.
         * @param source The user issuing the kick
         * @param user The user being kicked
         * @param chan The channel the user is being kicked from
         * @param reason The kick reason
         * @return 1 to prevent the kick, 0 to continue normally, -1 to explicitly allow the kick regardless of normal operation
         */
        virtual int OnUserPreKick(User* source, User* user, Channel* chan, const std::string &reason);

        /** Called whenever a user is kicked.
         * If this method is called, the kick is already underway and cannot be prevented, so
         * to prevent a kick, please use Module::OnUserPreKick instead of this method.
         * @param source The user issuing the kick
         * @param user The user being kicked
         * @param chan The channel the user is being kicked from
         * @param reason The kick reason
         * @param silent Change this to true if you want to conceal the PART command from the other users
         * of the channel (useful for modules such as auditorium)
         */
        virtual void OnUserKick(User* source, User* user, Channel* chan, const std::string &reason, bool &silent);

        /** Called whenever a user opers locally.
         * The User will contain the oper mode 'o' as this function is called after any modifications
         * are made to the user's structure by the core.
         * @param user The user who is opering up
         * @param opertype The opers type name
         */
        virtual void OnOper(User* user, const std::string &opertype);

        /** Called after a user opers locally.
         * This is identical to Module::OnOper(), except it is called after OnOper so that other modules
         * can be gauranteed to already have processed the oper-up, for example m_spanningtree has sent
         * out the OPERTYPE, etc.
         * @param user The user who is opering up
         * @param opertype The opers type name
         */
        virtual void OnPostOper(User* user, const std::string &opertype);
        
        /** Called whenever a user types /INFO.
         * The User will contain the information of the user who typed the command. Modules may use this
         * method to output their own credits in /INFO (which is the ircd's version of an about box).
         * It is purposefully not possible to modify any info that has already been output, or halt the list.
         * You must write a 371 numeric to the user, containing your info in the following format:
         *
         * &lt;nick&gt; :information here
         *
         * @param user The user issuing /INFO
         */
        virtual void OnInfo(User* user);
        
        /** Called whenever a /WHOIS is performed on a local user.
         * The source parameter contains the details of the user who issued the WHOIS command, and
         * the dest parameter contains the information of the user they are whoising.
         * @param source The user issuing the WHOIS command
         * @param dest The user who is being WHOISed
         */
        virtual void OnWhois(User* source, User* dest);
        
        /** Called whenever a user is about to invite another user into a channel, before any processing is done.
         * Returning 1 from this function stops the process immediately, causing no
         * output to be sent to the user by the core. If you do this you must produce your own numerics,
         * notices etc. This is useful for modules which may want to filter invites to channels.
         * @param source The user who is issuing the INVITE
         * @param dest The user being invited
         * @param channel The channel the user is being invited to
         * @return 1 to deny the invite, 0 to allow
         */
        virtual int OnUserPreInvite(User* source,User* dest,Channel* channel);
        
        /** Called after a user has been successfully invited to a channel.
         * You cannot prevent the invite from occuring using this function, to do that,
         * use OnUserPreInvite instead.
         * @param source The user who is issuing the INVITE
         * @param dest The user being invited
         * @param channel The channel the user is being invited to
         */
        virtual void OnUserInvite(User* source,User* dest,Channel* channel);
        
        /** Called whenever a user is about to PRIVMSG A user or a channel, before any processing is done.
         * Returning any nonzero value from this function stops the process immediately, causing no
         * output to be sent to the user by the core. If you do this you must produce your own numerics,
         * notices etc. This is useful for modules which may want to filter or redirect messages.
         * target_type can be one of TYPE_USER or TYPE_CHANNEL. If the target_type value is a user,
         * you must cast dest to a User* otherwise you must cast it to a Channel*, this is the details
         * of where the message is destined to be sent.
         * @param user The user sending the message
         * @param dest The target of the message (Channel* or User*)
         * @param target_type The type of target (TYPE_USER or TYPE_CHANNEL)
         * @param text Changeable text being sent by the user
         * @param status The status being used, e.g. PRIVMSG @#chan has status== '@', 0 to send to everyone.
         * @param exempt_list A list of users not to send to. For channel messages, this will usually contain just the sender.
         * It will be ignored for private messages.
         * @return 1 to deny the NOTICE, 0 to allow it
         */
        virtual int OnUserPreMessage(User* user,void* dest,int target_type, std::string &text,char status, CUList &exempt_list);

        /** Called whenever a user is about to NOTICE A user or a channel, before any processing is done.
         * Returning any nonzero value from this function stops the process immediately, causing no
         * output to be sent to the user by the core. If you do this you must produce your own numerics,
         * notices etc. This is useful for modules which may want to filter or redirect messages.
         * target_type can be one of TYPE_USER or TYPE_CHANNEL. If the target_type value is a user,
         * you must cast dest to a User* otherwise you must cast it to a Channel*, this is the details
         * of where the message is destined to be sent.
         * You may alter the message text as you wish before relinquishing control to the next module
         * in the chain, and if no other modules block the text this altered form of the text will be sent out
         * to the user and possibly to other servers.
         * @param user The user sending the message
         * @param dest The target of the message (Channel* or User*)
         * @param target_type The type of target (TYPE_USER or TYPE_CHANNEL)
         * @param text Changeable text being sent by the user
         * @param status The status being used, e.g. PRIVMSG @#chan has status== '@', 0 to send to everyone.
         * @param exempt_list A list of users not to send to. For channel notices, this will usually contain just the sender.
         * It will be ignored for private notices.
         * @return 1 to deny the NOTICE, 0 to allow it
         */
        virtual int OnUserPreNotice(User* user,void* dest,int target_type, std::string &text,char status, CUList &exempt_list);

        /** Called whenever the server wants to build the exemption list for a channel, but is not directly doing a PRIVMSG or NOTICE.
         * For example, the spanningtree protocol will call this event when passing a privmsg on (but not processing it directly).
         * @param message_type The message type, either MSG_PRIVMSG or MSG_NOTICE
         * @param chan The channel to build the exempt list of
         * @param sender The original sender of the PRIVMSG or NOTICE
         * @param status The status char to be used for the channel list
         * @param exempt_list The exempt list to be populated
         * @param text The original message text causing the exempt list to be built
         */
        virtual void OnBuildExemptList(MessageType message_type, Channel* chan, User* sender, char status, CUList &exempt_list, const std::string &text);
        
        /** Called before any nickchange, local or remote. This can be used to implement Q-lines etc.
         * Please note that although you can see remote nickchanges through this function, you should
         * NOT make any changes to the User if the user is a remote user as this may cause a desnyc.
         * check user->server before taking any action (including returning nonzero from the method).
         * If your method returns nonzero, the nickchange is silently forbidden, and it is down to your
         * module to generate some meaninful output.
         * @param user The username changing their nick
         * @param newnick Their new nickname
         * @return 1 to deny the change, 0 to allow
         */
        virtual int OnUserPreNick(User* user, const std::string &newnick);

        /** Called after any PRIVMSG sent from a user.
         * The dest variable contains a User* if target_type is TYPE_USER and a Channel*
         * if target_type is TYPE_CHANNEL.
         * @param user The user sending the message
         * @param dest The target of the message
         * @param target_type The type of target (TYPE_USER or TYPE_CHANNEL)
         * @param text the text being sent by the user
         * @param status The status being used, e.g. PRIVMSG @#chan has status== '@', 0 to send to everyone.
         */
        virtual void OnUserMessage(User* user, void* dest, int target_type, const std::string &text, char status, const CUList &exempt_list);

        /** Called after any NOTICE sent from a user.
         * The dest variable contains a User* if target_type is TYPE_USER and a Channel*
         * if target_type is TYPE_CHANNEL.
         * @param user The user sending the message
         * @param dest The target of the message
         * @param target_type The type of target (TYPE_USER or TYPE_CHANNEL)
         * @param text the text being sent by the user
         * @param status The status being used, e.g. NOTICE @#chan has status== '@', 0 to send to everyone.
         */
        virtual void OnUserNotice(User* user, void* dest, int target_type, const std::string &text, char status, const CUList &exempt_list);

        /** Called immediately before any NOTICE or PRIVMSG sent from a user, local or remote.
         * The dest variable contains a User* if target_type is TYPE_USER and a Channel*
         * if target_type is TYPE_CHANNEL.
         * The difference between this event and OnUserPreNotice/OnUserPreMessage is that delivery is gauranteed,
         * the message has already been vetted. In the case of the other two methods, a later module may stop your
         * message. This also differs from OnUserMessage which occurs AFTER the message has been sent.
         * @param user The user sending the message
         * @param dest The target of the message
         * @param target_type The type of target (TYPE_USER or TYPE_CHANNEL)
         * @param text the text being sent by the user
         * @param status The status being used, e.g. NOTICE @#chan has status== '@', 0 to send to everyone.
         */
        virtual void OnText(User* user, void* dest, int target_type, const std::string &text, char status, CUList &exempt_list);

        /** Called after every MODE command sent from a user
         * The dest variable contains a User* if target_type is TYPE_USER and a Channel*
         * if target_type is TYPE_CHANNEL. The text variable contains the remainder of the
         * mode string after the target, e.g. "+wsi" or "+ooo nick1 nick2 nick3".
         * @param user The user sending the MODEs
         * @param dest The target of the modes (User* or Channel*)
         * @param target_type The type of target (TYPE_USER or TYPE_CHANNEL)
         * @param text The actual modes and their parameters if any
         */
        virtual void OnMode(User* user, void* dest, int target_type, const std::string &text);

        /** Allows modules to alter or create server descriptions
         * Whenever a module requires a server description, for example for display in
         * WHOIS, this function is called in all modules. You may change or define the
         * description given in std::string &description. If you do, this description
         * will be shown in the WHOIS fields.
         * @param servername The servername being searched for
         * @param description Alterable server description for this server
         */
        virtual void OnGetServerDescription(const std::string &servername,std::string &description);

        /** Allows modules to synchronize data which relates to users during a netburst.
         * When this function is called, it will be called from the module which implements
         * the linking protocol. This currently is m_spanningtree.so. A pointer to this module
         * is given in Module* proto, so that you may call its methods such as ProtoSendMode
         * (see below). This function will be called for every user visible on your side
         * of the burst, allowing you to for example set modes, etc. Do not use this call to
         * synchronize data which you have stored using class Extensible -- There is a specialist
         * function OnSyncUserMetaData and OnSyncChannelMetaData for this!
         * @param user The user being syncronized
         * @param proto A pointer to the module handling network protocol
         * @param opaque An opaque pointer set by the protocol module, should not be modified!
         */
        virtual void OnSyncUser(User* user, Module* proto, void* opaque);

        /** Allows modules to synchronize data which relates to channels during a netburst.
         * When this function is called, it will be called from the module which implements
         * the linking protocol. This currently is m_spanningtree.so. A pointer to this module
         * is given in Module* proto, so that you may call its methods such as ProtoSendMode
         * (see below). This function will be called for every user visible on your side
         * of the burst, allowing you to for example set modes, etc. Do not use this call to
         * synchronize data which you have stored using class Extensible -- There is a specialist
         * function OnSyncUserMetaData and OnSyncChannelMetaData for this!
         *
         * For a good example of how to use this function, please see src/modules/m_chanprotect.cpp
         *
         * @param chan The channel being syncronized
         * @param proto A pointer to the module handling network protocol
         * @param opaque An opaque pointer set by the protocol module, should not be modified!
         */
        virtual void OnSyncChannel(Channel* chan, Module* proto, void* opaque);

        /* Allows modules to syncronize metadata related to channels over the network during a netburst.
         * Whenever the linking module wants to send out data, but doesnt know what the data
         * represents (e.g. it is Extensible metadata, added to a User or Channel by a module) then
         * this method is called.You should use the ProtoSendMetaData function after you've
         * correctly decided how the data should be represented, to send the metadata on its way if it belongs
         * to your module. For a good example of how to use this method, see src/modules/m_swhois.cpp.
         * @param chan The channel whos metadata is being syncronized
         * @param proto A pointer to the module handling network protocol
         * @param opaque An opaque pointer set by the protocol module, should not be modified!
         * @param extname The extensions name which is being searched for
         * @param displayable If this value is true, the data is going to be displayed to a user,
         * and not sent across the network. Use this to determine wether or not to show sensitive data.
         */
        virtual void OnSyncChannelMetaData(Channel* chan, Module* proto,void* opaque, const std::string &extname, bool displayable = false);

        /* Allows modules to syncronize metadata related to users over the network during a netburst.
         * Whenever the linking module wants to send out data, but doesnt know what the data
         * represents (e.g. it is Extensible metadata, added to a User or Channel by a module) then
         * this method is called. You should use the ProtoSendMetaData function after you've
         * correctly decided how the data should be represented, to send the metadata on its way if
         * if it belongs to your module.
         * @param user The user whos metadata is being syncronized
         * @param proto A pointer to the module handling network protocol
         * @param opaque An opaque pointer set by the protocol module, should not be modified!
         * @param extname The extensions name which is being searched for
         * @param displayable If this value is true, the data is going to be displayed to a user,
         * and not sent across the network. Use this to determine wether or not to show sensitive data.
         */
        virtual void OnSyncUserMetaData(User* user, Module* proto,void* opaque, const std::string &extname, bool displayable = false);

        /* Allows modules to syncronize metadata not related to users or channels, over the network during a netburst.
         * Whenever the linking module wants to send out data, but doesnt know what the data
         * represents (e.g. it is Extensible metadata, added to a User or Channel by a module) then
         * this method is called. You should use the ProtoSendMetaData function after you've
         * correctly decided how the data should be represented, to send the metadata on its way if
         * if it belongs to your module.
         * @param proto A pointer to the module handling network protocol
         * @param opaque An opaque pointer set by the protocol module, should not be modified!
         * @param displayable If this value is true, the data is going to be displayed to a user,
         * and not sent across the network. Use this to determine wether or not to show sensitive data.
         */
        virtual void OnSyncOtherMetaData(Module* proto, void* opaque, bool displayable = false);

        /** Allows module data, sent via ProtoSendMetaData, to be decoded again by a receiving module.
         * Please see src/modules/m_swhois.cpp for a working example of how to use this method call.
         * @param target_type The type of item to decode data for, TYPE_USER or TYPE_CHANNEL
         * @param target The Channel* or User* that data should be added to
         * @param extname The extension name which is being sent
         * @param extdata The extension data, encoded at the other end by an identical module through OnSyncChannelMetaData or OnSyncUserMetaData
         */
        virtual void OnDecodeMetaData(int target_type, void* target, const std::string &extname, const std::string &extdata);

        /** Implemented by modules which provide the ability to link servers.
         * These modules will implement this method, which allows transparent sending of servermodes
         * down the network link as a broadcast, without a module calling it having to know the format
         * of the MODE command before the actual mode string.
         *
         * More documentation to follow soon. Please see src/modules/m_chanprotect.cpp for examples
         * of how to use this function.
         *
         * @param opaque An opaque pointer set by the protocol module, should not be modified!
         * @param target_type The type of item to decode data for, TYPE_USER or TYPE_CHANNEL
         * @param target The Channel* or User* that modes should be sent for
         * @param modeline The modes and parameters to be sent
         */
        virtual void ProtoSendMode(void* opaque, int target_type, void* target, const std::string &modeline);

        /** Implemented by modules which provide the ability to link servers.
         * These modules will implement this method, which allows metadata (extra data added to
         * user and channel records using class Extensible, Extensible::Extend, etc) to be sent
         * to other servers on a netburst and decoded at the other end by the same module on a
         * different server.
         *
         * More documentation to follow soon. Please see src/modules/m_swhois.cpp for example of
         * how to use this function.
         * @param opaque An opaque pointer set by the protocol module, should not be modified!
         * @param target_type The type of item to decode data for, TYPE_USER or TYPE_CHANNEL
         * @param target The Channel* or User* that metadata should be sent for
         * @param extname The extension name to send metadata for
         * @param extdata Encoded data for this extension name, which will be encoded at the oppsite end by an identical module using OnDecodeMetaData
         */
        virtual void ProtoSendMetaData(void* opaque, int target_type, void* target, const std::string &extname, const std::string &extdata);
        
        /** Called after every WALLOPS command.
         * @param user The user sending the WALLOPS
         * @param text The content of the WALLOPS message
         */
        virtual void OnWallops(User* user, const std::string &text);

        /** Called whenever a user's hostname is changed.
         * This event triggers after the host has been set.
         * @param user The user whos host is being changed
         * @param newhost The new hostname being set
         */
        virtual void OnChangeHost(User* user, const std::string &newhost);

        /** Called whenever a user's GECOS (realname) is changed.
         * This event triggers after the name has been set.
         * @param user The user who's GECOS is being changed
         * @param gecos The new GECOS being set on the user
         */
        virtual void OnChangeName(User* user, const std::string &gecos);

        /** Called whenever an xline is added by a local user.
         * This method is triggered after the line is added.
         * @param source The sender of the line or NULL for local server
         * @param line The xline being added
         */
        virtual void OnAddLine(User* source, XLine* line);

        /** Called whenever an xline is deleted.
         * This method is triggered after the line is deleted.
         * @param source The user removing the line or NULL for local server
         * @param line the line being deleted
         */
        virtual void OnDelLine(User* source, XLine* line);

        /** Called whenever a zline is deleted.
         * This method is triggered after the line is deleted.
         * @param source The user removing the line
         * @param hostmask The hostmask to delete
         */

        /** Called before your module is unloaded to clean up Extensibles.
         * This method is called once for every user and channel on the network,
         * so that when your module unloads it may clear up any remaining data
         * in the form of Extensibles added using Extensible::Extend().
         * If the target_type variable is TYPE_USER, then void* item refers to
         * a User*, otherwise it refers to a Channel*.
         * @param target_type The type of item being cleaned
         * @param item A pointer to the item's class
         */
        virtual void OnCleanup(int target_type, void* item);

        /** Called after any nickchange, local or remote. This can be used to track users after nickchanges
         * have been applied. Please note that although you can see remote nickchanges through this function, you should
         * NOT make any changes to the User if the user is a remote user as this may cause a desnyc.
         * check user->server before taking any action (including returning nonzero from the method).
         * Because this method is called after the nickchange is taken place, no return values are possible
         * to indicate forbidding of the nick change. Use OnUserPreNick for this.
         * @param user The user changing their nick
         * @param oldnick The old nickname of the user before the nickchange
         */
        virtual void OnUserPostNick(User* user, const std::string &oldnick);

        /** Called before an action which requires a channel privilage check.
         * This function is called before many functions which check a users status on a channel, for example
         * before opping a user, deopping a user, kicking a user, etc.
         * There are several values for access_type which indicate for what reason access is being checked.
         * These are:<br><br>
         * AC_KICK (0) - A user is being kicked<br>
         * AC_DEOP (1) - a user is being deopped<br>
         * AC_OP (2) - a user is being opped<br>
         * AC_VOICE (3) - a user is being voiced<br>
         * AC_DEVOICE (4) - a user is being devoiced<br>
         * AC_HALFOP (5) - a user is being halfopped<br>
         * AC_DEHALFOP (6) - a user is being dehalfopped<br>
         * AC_INVITE () - a user is being invited<br>
         * AC_GENERAL_MODE (8) - a user channel mode is being changed<br><br>
         * Upon returning from your function you must return either ACR_DEFAULT, to indicate the module wishes
         * to do nothing, or ACR_DENY where approprate to deny the action, and ACR_ALLOW where appropriate to allow
         * the action. Please note that in the case of some access checks (such as AC_GENERAL_MODE) access may be
         * denied 'upstream' causing other checks such as AC_DEOP to not be reached. Be very careful with use of the
         * AC_GENERAL_MODE type, as it may inadvertently override the behaviour of other modules. When the access_type
         * is AC_GENERAL_MODE, the destination of the mode will be NULL (as it has not yet been determined).
         * @param source The source of the access check
         * @param dest The destination of the access check
         * @param channel The channel which is being checked
         * @param access_type See above
         */
        virtual int OnAccessCheck(User* source,User* dest,Channel* channel,int access_type);

        /** Called when a 005 numeric is about to be output.
         * The module should modify the 005 numeric if needed to indicate its features.
         * @param output The 005 string to be modified if neccessary.
         */
        virtual void On005Numeric(std::string &output);

        /** Called when a client is disconnected by KILL.
         * If a client is killed by a server, e.g. a nickname collision or protocol error,
         * source is NULL.
         * Return 1 from this function to prevent the kill, and 0 from this function to allow
         * it as normal. If you prevent the kill no output will be sent to the client, it is
         * down to your module to generate this information.
         * NOTE: It is NOT advisable to stop kills which originate from servers or remote users.
         * If you do so youre risking race conditions, desyncs and worse!
         * @param source The user sending the KILL
         * @param dest The user being killed
         * @param reason The kill reason
         * @return 1 to prevent the kill, 0 to allow
         */
        virtual int OnKill(User* source, User* dest, const std::string &reason);

        /** Called when an oper wants to disconnect a remote user via KILL
         * @param source The user sending the KILL
         * @param dest The user being killed
         * @param reason The kill reason
         */
        virtual void OnRemoteKill(User* source, User* dest, const std::string &reason, const std::string &operreason);

        /** Called whenever a module is loaded.
         * mod will contain a pointer to the module, and string will contain its name,
         * for example m_widgets.so. This function is primary for dependency checking,
         * your module may decide to enable some extra features if it sees that you have
         * for example loaded "m_killwidgets.so" with "m_makewidgets.so". It is highly
         * recommended that modules do *NOT* bail if they cannot satisfy dependencies,
         * but instead operate under reduced functionality, unless the dependency is
         * absolutely neccessary (e.g. a module that extends the features of another
         * module).
         * @param mod A pointer to the new module
         * @param name The new module's filename
         */
        virtual void OnLoadModule(Module* mod,const std::string &name);

        /** Called whenever a module is unloaded.
         * mod will contain a pointer to the module, and string will contain its name,
         * for example m_widgets.so. This function is primary for dependency checking,
         * your module may decide to enable some extra features if it sees that you have
         * for example loaded "m_killwidgets.so" with "m_makewidgets.so". It is highly
         * recommended that modules do *NOT* bail if they cannot satisfy dependencies,
         * but instead operate under reduced functionality, unless the dependency is
         * absolutely neccessary (e.g. a module that extends the features of another
         * module).
         * @param mod Pointer to the module being unloaded (still valid)
         * @param name The filename of the module being unloaded
         */
        virtual void OnUnloadModule(Module* mod,const std::string &name);

        /** Called once every five seconds for background processing.
         * This timer can be used to control timed features. Its period is not accurate
         * enough to be used as a clock, but it is gauranteed to be called at least once in
         * any five second period, directly from the main loop of the server.
         * @param curtime The current timer derived from time(2)
         */
        virtual void OnBackgroundTimer(time_t curtime);

        /** Called whenever any command is about to be executed.
         * This event occurs for all registered commands, wether they are registered in the core,
         * or another module, and for invalid commands. Invalid commands may only be sent to this
         * function when the value of validated is false. By returning 1 from this method you may prevent the
         * command being executed. If you do this, no output is created by the core, and it is
         * down to your module to produce any output neccessary.
         * Note that unless you return 1, you should not destroy any structures (e.g. by using
         * InspIRCd::QuitUser) otherwise when the command's handler function executes after your
         * method returns, it will be passed an invalid pointer to the user object and crash!)
         * @param command The command being executed
         * @param parameters An array of array of characters containing the parameters for the command
         * @param pcnt The nuimber of parameters passed to the command
         * @param user the user issuing the command
         * @param validated True if the command has passed all checks, e.g. it is recognised, has enough parameters, the user has permission to execute it, etc.
         * @param original_line The entire original line as passed to the parser from the user
         * @return 1 to block the command, 0 to allow
         */
        virtual int OnPreCommand(const std::string &command, const char** parameters, int pcnt, User *user, bool validated, const std::string &original_line);

        /** Called after any command has been executed.
         * This event occurs for all registered commands, wether they are registered in the core,
         * or another module, but it will not occur for invalid commands (e.g. ones which do not
         * exist within the command table). The result code returned by the command handler is
         * provided.
         * @param command The command being executed
         * @param parameters An array of array of characters containing the parameters for the command
         * @param pcnt The nuimber of parameters passed to the command
         * @param user the user issuing the command
         * @param result The return code given by the command handler, one of CMD_SUCCESS or CMD_FAILURE
         * @param original_line The entire original line as passed to the parser from the user
         */
        virtual void OnPostCommand(const std::string &command, const char** parameters, int pcnt, User *user, CmdResult result, const std::string &original_line);

        /** Called to check if a user who is connecting can now be allowed to register
         * If any modules return false for this function, the user is held in the waiting
         * state until all modules return true. For example a module which implements ident
         * lookups will continue to return false for a user until their ident lookup is completed.
         * Note that the registration timeout for a user overrides these checks, if the registration
         * timeout is reached, the user is disconnected even if modules report that the user is
         * not ready to connect.
         * @param user The user to check
         * @return true to indicate readiness, false if otherwise
         */
        virtual bool OnCheckReady(User* user);

        /** Called whenever a user is about to register their connection (e.g. before the user
         * is sent the MOTD etc). Modules can use this method if they are performing a function
         * which must be done before the actual connection is completed (e.g. ident lookups,
         * dnsbl lookups, etc).
         * Note that you should NOT delete the user record here by causing a disconnection!
         * Use OnUserConnect for that instead.
         * @param user The user registering
         * @return 1 to indicate user quit, 0 to continue
         */
        virtual int OnUserRegister(User* user);

        /** Called whenever a user joins a channel, to determine if invite checks should go ahead or not.
         * This method will always be called for each join, wether or not the channel is actually +i, and
         * determines the outcome of an if statement around the whole section of invite checking code.
         * return 1 to explicitly allow the join to go ahead or 0 to ignore the event.
         * @param user The user joining the channel
         * @param chan The channel being joined
         * @return 1 to explicitly allow the join, 0 to proceed as normal
         */
        virtual int OnCheckInvite(User* user, Channel* chan);

        /** Called whenever a user joins a channel, to determine if key checks should go ahead or not.
         * This method will always be called for each join, wether or not the channel is actually +k, and
         * determines the outcome of an if statement around the whole section of key checking code.
         * if the user specified no key, the keygiven string will be a valid but empty value.
         * return 1 to explicitly allow the join to go ahead or 0 to ignore the event.
         * @param user The user joining the channel
         * @param chan The channel being joined
         * @return 1 to explicitly allow the join, 0 to proceed as normal
         */
        virtual int OnCheckKey(User* user, Channel* chan, const std::string &keygiven);

        /** Called whenever a user joins a channel, to determine if channel limit checks should go ahead or not.
         * This method will always be called for each join, wether or not the channel is actually +l, and
         * determines the outcome of an if statement around the whole section of channel limit checking code.
         * return 1 to explicitly allow the join to go ahead or 0 to ignore the event.
         * @param user The user joining the channel
         * @param chan The channel being joined
         * @return 1 to explicitly allow the join, 0 to proceed as normal
         */
        virtual int OnCheckLimit(User* user, Channel* chan);

        /** Called whenever a user joins a channel, to determine if banlist checks should go ahead or not.
         * This method will always be called for each join, wether or not the user actually matches a channel ban, and
         * determines the outcome of an if statement around the whole section of ban checking code.
         * return 1 to explicitly allow the join to go ahead or 0 to ignore the event.
         * @param user The user joining the channel
         * @param chan The channel being joined
         * @return 1 to explicitly allow the join, 0 to proceed as normal
         */
        virtual int OnCheckBan(User* user, Channel* chan);

        /** Called on all /STATS commands
         * This method is triggered for all /STATS use, including stats symbols handled by the core.
         * @param symbol the symbol provided to /STATS
         * @param user the user issuing the /STATS command
         * @param results A string_list to append results into. You should put all your results
         * into this string_list, rather than displaying them directly, so that your handler will
         * work when remote STATS queries are received.
         * @return 1 to block the /STATS from being processed by the core, 0 to allow it
         */
        virtual int OnStats(char symbol, User* user, string_list &results);

        /** Called whenever a change of a local users displayed host is attempted.
         * Return 1 to deny the host change, or 0 to allow it.
         * @param user The user whos host will be changed
         * @param newhost The new hostname
         * @return 1 to deny the host change, 0 to allow
         */
        virtual int OnChangeLocalUserHost(User* user, const std::string &newhost);

        /** Called whenever a change of a local users GECOS (fullname field) is attempted.
         * return 1 to deny the name change, or 0 to allow it.
         * @param user The user whos GECOS will be changed
         * @param newhost The new GECOS
         * @return 1 to deny the GECOS change, 0 to allow
         */
        virtual int OnChangeLocalUserGECOS(User* user, const std::string &newhost); 

        /** Called whenever a topic is changed by a local user.
         * Return 1 to deny the topic change, or 0 to allow it.
         * @param user The user changing the topic
         * @param chan The channels who's topic is being changed
         * @param topic The actual topic text
         * @param 1 to block the topic change, 0 to allow
         */
        virtual int OnLocalTopicChange(User* user, Channel* chan, const std::string &topic);

        /** Called whenever a local topic has been changed.
         * To block topic changes you must use OnLocalTopicChange instead.
         * @param user The user changing the topic
         * @param chan The channels who's topic is being changed
         * @param topic The actual topic text
         */
        virtual void OnPostLocalTopicChange(User* user, Channel* chan, const std::string &topic);

        /** Called whenever an Event class is sent to all module by another module.
         * Please see the documentation of Event::Send() for further information. The Event sent can
         * always be assumed to be non-NULL, you should *always* check the value of Event::GetEventID()
         * before doing anything to the event data, and you should *not* change the event data in any way!
         * @param event The Event class being received
         */
        virtual void OnEvent(Event* event);

        /** Called whenever a Request class is sent to your module by another module.
         * Please see the documentation of Request::Send() for further information. The Request sent
         * can always be assumed to be non-NULL, you should not change the request object or its data.
         * Your method may return arbitary data in the char* result which the requesting module
         * may be able to use for pre-determined purposes (e.g. the results of an SQL query, etc).
         * @param request The Request class being received
         */
        virtual char* OnRequest(Request* request);

        /** Called whenever an oper password is to be compared to what a user has input.
         * The password field (from the config file) is in 'password' and is to be compared against
         * 'input'. This method allows for encryption of oper passwords and much more besides.
         * You should return a nonzero value if you want to allow the comparison or zero if you wish
         * to do nothing.
         * @param password The oper's password
         * @param input The password entered
         * @param tagnumber The tag number (from the configuration file) of this oper's tag
         * @return 1 to match the passwords, 0 to do nothing. -1 to not match, and not continue.
         */
        virtual int OnOperCompare(const std::string &password, const std::string &input, int tagnumber);

        /** Called whenever a user is given usermode +o, anywhere on the network.
         * You cannot override this and prevent it from happening as it is already happened and
         * such a task must be performed by another server. You can however bounce modes by sending
         * servermodes out to reverse mode changes.
         * @param user The user who is opering
         */
        virtual void OnGlobalOper(User* user);

        /** Called after a user has fully connected and all modules have executed OnUserConnect
         * This event is informational only. You should not change any user information in this
         * event. To do so, use the OnUserConnect method to change the state of local users.
         * This is called for both local and remote users.
         * @param user The user who is connecting
         */
        virtual void OnPostConnect(User* user);

        /** Called whenever a ban is added to a channel's list.
         * Return a non-zero value to 'eat' the mode change and prevent the ban from being added.
         * @param source The user adding the ban
         * @param channel The channel the ban is being added to
         * @param banmask The ban mask being added
         * @return 1 to block the ban, 0 to continue as normal
         */
        virtual int OnAddBan(User* source, Channel* channel,const std::string &banmask);

        /** Called whenever a ban is removed from a channel's list.
         * Return a non-zero value to 'eat' the mode change and prevent the ban from being removed.
         * @param source The user deleting the ban
         * @param channel The channel the ban is being deleted from
         * @param banmask The ban mask being deleted
         * @return 1 to block the unban, 0 to continue as normal
         */
        virtual int OnDelBan(User* source, Channel* channel,const std::string &banmask);

        /** Called immediately after any  connection is accepted. This is intended for raw socket
         * processing (e.g. modules which wrap the tcp connection within another library) and provides
         * no information relating to a user record as the connection has not been assigned yet.
         * There are no return values from this call as all modules get an opportunity if required to
         * process the connection.
         * @param fd The file descriptor returned from accept()
         * @param ip The IP address of the connecting user
         * @param localport The local port number the user connected to
         */
        virtual void OnRawSocketAccept(int fd, const std::string &ip, int localport);

        /** Called immediately before any write() operation on a user's socket in the core. Because
         * this event is a low level event no user information is associated with it. It is intended
         * for use by modules which may wrap connections within another API such as SSL for example.
         * return a non-zero result if you have handled the write operation, in which case the core
         * will not call write().
         * @param fd The file descriptor of the socket
         * @param buffer A char* buffer being written
         * @param Number of characters to write
         * @return Number of characters actually written or 0 if you didn't handle the operation
         */
        virtual int OnRawSocketWrite(int fd, const char* buffer, int count);

        /** Called immediately before any socket is closed. When this event is called, shutdown()
         * has not yet been called on the socket.
         * @param fd The file descriptor of the socket prior to close()
         */
        virtual void OnRawSocketClose(int fd);

        /** Called immediately upon connection of an outbound BufferedSocket which has been hooked
         * by a module.
         * @param fd The file descriptor of the socket immediately after connect()
         */
        virtual void OnRawSocketConnect(int fd);

        /** Called immediately before any read() operation on a client socket in the core.
         * This occurs AFTER the select() or poll() so there is always data waiting to be read
         * when this event occurs.
         * Your event should return 1 if it has handled the reading itself, which prevents the core
         * just using read(). You should place any data read into buffer, up to but NOT GREATER THAN
         * the value of count. The value of readresult must be identical to an actual result that might
         * be returned from the read() system call, for example, number of bytes read upon success,
         * 0 upon EOF or closed socket, and -1 for error. If your function returns a nonzero value,
         * you MUST set readresult.
         * @param fd The file descriptor of the socket
         * @param buffer A char* buffer being read to
         * @param count The size of the buffer
         * @param readresult The amount of characters read, or 0
         * @return nonzero if the event was handled, in which case readresult must be valid on exit
         */
        virtual int OnRawSocketRead(int fd, char* buffer, unsigned int count, int &readresult);

        /** Called whenever a user sets away.
         * This method has no parameter for the away message, as it is available in the
         * user record as User::awaymsg.
         * @param user The user setting away
         */
        virtual void OnSetAway(User* user);

        /** Called when a user cancels their away state.
         * @param user The user returning from away
         */
        virtual void OnCancelAway(User* user);

        /** Called whenever a NAMES list is requested.
         * You can produce the nameslist yourself, overriding the current list,
         * and if you do you must return 1. If you do not handle the names list,
         * return 0.
         * @param The user requesting the NAMES list
         * @param Ptr The channel the NAMES list is requested for
         * @param userlist The user list for the channel (you may change this pointer.
         * If you want to change the values, take a copy first, and change the copy, then
         * point the pointer at your copy)
         * @return 1 to prevent the user list being sent to the client, 0 to allow it.
         * Returning -1 allows the names list, but bypasses any checks which check for
         * channel membership before sending the names list.
         */
        virtual int OnUserList(User* user, Channel* Ptr, CUList* &userlist);

        /** Called whenever a line of WHOIS output is sent to a user.
         * You may change the numeric and the text of the output by changing
         * the values numeric and text, but you cannot change the user the
         * numeric is sent to. You may however change the user's User values.
         * @param user The user the numeric is being sent to
         * @param dest The user being WHOISed
         * @param numeric The numeric of the line being sent
         * @param text The text of the numeric, including any parameters
         * @return nonzero to drop the line completely so that the user does not
         * receive it, or zero to allow the line to be sent.
         */
        virtual int OnWhoisLine(User* user, User* dest, int &numeric, std::string &text);

        /** Called at intervals for modules to garbage-collect any hashes etc.
         * Certain data types such as hash_map 'leak' buckets, which must be
         * tidied up and freed by copying into a new item every so often. This
         * method is called when it is time to do that.
         */
        virtual void OnGarbageCollect();

        /** Called whenever a user's write buffer has been completely sent.
         * This is called when the user's write buffer is completely empty, and
         * there are no more pending bytes to be written and no pending write events
         * in the socket engine's queue. This may be used to refill the buffer with
         * data which is being spooled in a controlled manner, e.g. LIST lines.
         * @param user The user who's buffer is now empty.
         */
        virtual void OnBufferFlushed(User* user);
};


#define CONF_NO_ERROR           0x000000
#define CONF_NOT_A_NUMBER       0x000010
#define CONF_INT_NEGATIVE       0x000080
#define CONF_VALUE_NOT_FOUND    0x000100
#define CONF_FILE_NOT_FOUND     0x000200


/** Allows reading of values from configuration files
 * This class allows a module to read from either the main configuration file (inspircd.conf) or from
 * a module-specified configuration file. It may either be instantiated with one parameter or none.
 * Constructing the class using one parameter allows you to specify a path to your own configuration
 * file, otherwise, inspircd.conf is read.
 */
class CoreExport ConfigReader : public classbase
{
  protected:
        InspIRCd* ServerInstance;
        /** The contents of the configuration file
         * This protected member should never be accessed by a module (and cannot be accessed unless the
         * core is changed). It will contain a pointer to the configuration file data with unneeded data
         * (such as comments) stripped from it.
         */
        ConfigDataHash* data;
        /** Used to store errors
         */
        std::ostringstream* errorlog;
        /** If we're using our own config data hash or not
         */
        bool privatehash;
        /** True if an error occured reading the config file
         */
        bool readerror;
        /** Error code
         */
        long error;
        
  public:
        /** Default constructor.
         * This constructor initialises the ConfigReader class to read the inspircd.conf file
         * as specified when running ./configure.
         */
        ConfigReader(InspIRCd* Instance);
        /** Overloaded constructor.
         * This constructor initialises the ConfigReader class to read a user-specified config file
         */
        ConfigReader(InspIRCd* Instance, const std::string &filename);
        /** Default destructor.
         * This method destroys the ConfigReader class.
         */
        ~ConfigReader();

        /** Retrieves a value from the config file.
         * This method retrieves a value from the config file. Where multiple copies of the tag
         * exist in the config file, index indicates which of the values to retrieve.
         */
        std::string ReadValue(const std::string &tag, const std::string &name, int index, bool allow_linefeeds = false);
        /** Retrieves a value from the config file.
         * This method retrieves a value from the config file. Where multiple copies of the tag
         * exist in the config file, index indicates which of the values to retrieve. If the
         * tag is not found the default value is returned instead.
         */
        std::string ReadValue(const std::string &tag, const std::string &name, const std::string &default_value, int index, bool allow_linefeeds = false);

        /** Retrieves a boolean value from the config file.
         * This method retrieves a boolean value from the config file. Where multiple copies of the tag
         * exist in the config file, index indicates which of the values to retrieve. The values "1", "yes"
         * and "true" in the config file count as true to ReadFlag, and any other value counts as false.
         */
        bool ReadFlag(const std::string &tag, const std::string &name, int index);
        /** Retrieves a boolean value from the config file.
         * This method retrieves a boolean value from the config file. Where multiple copies of the tag
         * exist in the config file, index indicates which of the values to retrieve. The values "1", "yes"
         * and "true" in the config file count as true to ReadFlag, and any other value counts as false.
         * If the tag is not found, the default value is used instead.
         */
        bool ReadFlag(const std::string &tag, const std::string &name, const std::string &default_value, int index);

        /** Retrieves an integer value from the config file.
         * This method retrieves an integer value from the config file. Where multiple copies of the tag
         * exist in the config file, index indicates which of the values to retrieve. Any invalid integer
         * values in the tag will cause the objects error value to be set, and any call to GetError() will
         * return CONF_INVALID_NUMBER to be returned. need_positive is set if the number must be non-negative.
         * If a negative number is placed into a tag which is specified positive, 0 will be returned and GetError()
         * will return CONF_INT_NEGATIVE. Note that need_positive is not suitable to get an unsigned int - you
         * should cast the result to achieve that effect.
         */
        int ReadInteger(const std::string &tag, const std::string &name, int index, bool need_positive);
        /** Retrieves an integer value from the config file.
         * This method retrieves an integer value from the config file. Where multiple copies of the tag
         * exist in the config file, index indicates which of the values to retrieve. Any invalid integer
         * values in the tag will cause the objects error value to be set, and any call to GetError() will
         * return CONF_INVALID_NUMBER to be returned. needs_unsigned is set if the number must be unsigned.
         * If a signed number is placed into a tag which is specified unsigned, 0 will be returned and GetError()
         * will return CONF_NOT_UNSIGNED. If the tag is not found, the default value is used instead.
         */
        int ReadInteger(const std::string &tag, const std::string &name, const std::string &default_value, int index, bool need_positive);

        /** Returns the last error to occur.
         * Valid errors can be found by looking in modules.h. Any nonzero value indicates an error condition.
         * A call to GetError() resets the error flag back to 0.
         */
        long GetError();
        /** Counts the number of times a given tag appears in the config file.
         * This method counts the number of times a tag appears in a config file, for use where
         * there are several tags of the same kind, e.g. with opers and connect types. It can be
         * used with the index value of ConfigReader::ReadValue to loop through all copies of a
         * multiple instance tag.
         */
        int Enumerate(const std::string &tag);
        /** Returns true if a config file is valid.
         * This method is partially implemented and will only return false if the config
         * file does not exist or could not be opened.
         */
        bool Verify();
        /** Dumps the list of errors in a config file to an output location. If bail is true,
         * then the program will abort. If bail is false and user points to a valid user
         * record, the error report will be spooled to the given user by means of NOTICE.
         * if bool is false AND user is false, the error report will be spooled to all opers
         * by means of a NOTICE to all opers.
         */
        void DumpErrors(bool bail,User* user);

        /** Returns the number of items within a tag.
         * For example if the tag was &lt;test tag="blah" data="foo"&gt; then this
         * function would return 2. Spaces and newlines both qualify as valid seperators
         * between values.
         */
        int EnumerateValues(const std::string &tag, int index);
};



/** Caches a text file into memory and can be used to retrieve lines from it.
 * This class contains methods for read-only manipulation of a text file in memory.
 * Either use the constructor type with one parameter to load a file into memory
 * at construction, or use the LoadFile method to load a file.
 */
class CoreExport FileReader : public classbase
{
        InspIRCd* ServerInstance;
        /** The file contents
         */
        file_cache fc;

        /** Content size in bytes
         */
        unsigned long contentsize;

        /** Calculate content size in bytes
         */
        void CalcSize();

 public:
        /** Default constructor.
         * This method does not load any file into memory, you must use the LoadFile method
         * after constructing the class this way.
         */
        FileReader(InspIRCd* Instance);

        /** Secondary constructor.
         * This method initialises the class with a file loaded into it ready for GetLine and
         * and other methods to be called. If the file could not be loaded, FileReader::FileSize
         * returns 0.
         */
        FileReader(InspIRCd* Instance, const std::string &filename);

        /** Default destructor.
         * This deletes the memory allocated to the file.
         */
        ~FileReader();

        /** Used to load a file.
         * This method loads a file into the class ready for GetLine and
         * and other methods to be called. If the file could not be loaded, FileReader::FileSize
         * returns 0.
         */
        void LoadFile(const std::string &filename);

        /** Returns the whole content of the file as std::string
         */
        std::string Contents();

        /** Returns the entire size of the file as std::string
         */
        unsigned long ContentSize();

        /** Returns true if the file exists
         * This function will return false if the file could not be opened.
         */
        bool Exists();
 
        /** Retrieve one line from the file.
         * This method retrieves one line from the text file. If an empty non-NULL string is returned,
         * the index was out of bounds, or the line had no data on it.
         */
        std::string GetLine(int x);

        /** Returns the size of the file in lines.
         * This method returns the number of lines in the read file. If it is 0, no lines have been
         * read into memory, either because the file is empty or it does not exist, or cannot be
         * opened due to permission problems.
         */
        int FileSize();
};

/** A DLLFactory (designed to load shared objects) containing a
 * handle to a module's init_module() function. Unfortunately,
 * due to the design of shared object systems we must keep this
 * hanging around, as if we remove this handle, we remove the
 * shared object file from memory (!)
 */
typedef DLLFactory<Module> ircd_module;

/** A list of modules
 */
typedef std::vector<Module*> IntModuleList;

/** An event handler iterator
 */
typedef IntModuleList::iterator EventHandlerIter;

/** Module priority states
 */
enum PriorityState
{
        PRIO_DONTCARE,
        PRIO_FIRST,
        PRIO_LAST,
        PRIO_AFTER,
        PRIO_BEFORE
};

/** ModuleManager takes care of all things module-related
 * in the core.
 */
class CoreExport ModuleManager : public classbase
{
 private:
        /** Holds a string describing the last module error to occur
         */
        std::string LastModuleError;
 
        /** The feature names published by various modules
         */
        featurelist Features;

        /** The interface names published by various modules
         */
        interfacelist Interfaces;
 
        /** Total number of modules loaded into the ircd
         */
        int ModCount; 
        
        /** Our pointer to the main insp instance
         */
        InspIRCd* Instance;

        /** List of loaded modules and shared object/dll handles
         * keyed by module name
         */
        std::map<std::string, std::pair<ircd_module*, Module*> > Modules;

 public:

        /** Event handler hooks.
         * This needs to be public to be used by FOREACH_MOD and friends.
         */
        IntModuleList EventHandlers[I_END];

        /** Simple, bog-standard, boring constructor.
         */
        ModuleManager(InspIRCd* Ins);

        /** Destructor
         */
        ~ModuleManager(); 

        /** Change the priority of one event in a module.
         * Each module event has a list of modules which are attached to that event type.
         * If you wish to be called before or after other specific modules, you may use this
         * method (usually within void Module::Prioritize()) to set your events priority.
         * You may use this call in other methods too, however, this is not supported behaviour
         * for a module.
         * @param mod The module to change the priority of
         * @param i The event to change the priority of
         * @param s The state you wish to use for this event. Use one of
         * PRIO_FIRST to set the event to be first called, PRIO_LAST to
         * set it to be the last called, or PRIO_BEFORE and PRIO_AFTER
         * to set it to be before or after one or more other modules.
         * @param modules If PRIO_BEFORE or PRIO_AFTER is set in parameter 's',
         * then this contains a list of one or more modules your module must be 
         * placed before or after. Your module will be placed before the highest
         * priority module in this list for PRIO_BEFORE, or after the lowest
         * priority module in this list for PRIO_AFTER.
         * @param sz The number of modules being passed for PRIO_BEFORE and PRIO_AFTER.
         * Defaults to 1, as most of the time you will only want to prioritize your module
         * to be before or after one other module.
         */
        bool SetPriority(Module* mod, Implementation i, PriorityState s, Module** modules = NULL, size_t sz = 1);

        /** Change the priority of all events in a module.
         * @param mod The module to set the priority of
         * @param s The priority of all events in the module.
         * Note that with this method, it is not possible to effectively use
         * PRIO_BEFORE or PRIO_AFTER, you should use the more fine tuned
         * SetPriority method for this, where you may specify other modules to
         * be prioritized against.
         */
        bool SetPriority(Module* mod, PriorityState s);

        /** Attach an event to a module.
         * You may later detatch the event with ModuleManager::Detach().
         * If your module is unloaded, all events are automatically detatched.
         * @param i Event type to attach
         * @param mod Module to attach event to
         * @return True if the event was attached
         */
        bool Attach(Implementation i, Module* mod);

        /** Detatch an event from a module.
         * This is not required when your module unloads, as the core will
         * automatically detatch your module from all events it is attached to.
         * @param i Event type to detach
         * @param mod Module to detach event from
         * @param Detach true if the event was detached
         */
        bool Detach(Implementation i, Module* mod);

        /** Attach an array of events to a module
         * @param i Event types (array) to attach
         * @param mod Module to attach events to
         */
        void Attach(Implementation* i, Module* mod, size_t sz);

        /** Detach all events from a module (used on unload)
         * @param mod Module to detach from
         */
        void DetachAll(Module* mod);
 
        /** Returns text describing the last module error
         * @return The last error message to occur
         */
        std::string& LastError();

        /** Load a given module file
         * @param filename The file to load
         * @return True if the module was found and loaded
         */
        bool Load(const char* filename);

        /** Unload a given module file
         * @param filename The file to unload
         * @return True if the module was unloaded
         */
        bool Unload(const char* filename);
        
        /** Called by the InspIRCd constructor to load all modules from the config file.
         */
        void LoadAll();
        
        /** Get the total number of currently loaded modules
         * @return The number of loaded modules
         */
        int GetCount()
        {
                return this->ModCount;
        }
        
        /** Find a module by name, and return a Module* to it.
         * This is preferred over iterating the module lists yourself.
         * @param name The module name to look up
         * @return A pointer to the module, or NULL if the module cannot be found
         */
        Module* Find(const std::string &name);
 
        /** Publish a 'feature'.
         * There are two ways for a module to find another module it depends on.
         * Either by name, using InspIRCd::FindModule, or by feature, using this
         * function. A feature is an arbitary string which identifies something this
         * module can do. For example, if your module provides SSL support, but other
         * modules provide SSL support too, all the modules supporting SSL should
         * publish an identical 'SSL' feature. This way, any module requiring use
         * of SSL functions can just look up the 'SSL' feature using FindFeature,
         * then use the module pointer they are given.
         * @param FeatureName The case sensitive feature name to make available
         * @param Mod a pointer to your module class
         * @returns True on success, false if the feature is already published by
         * another module.
         */
        bool PublishFeature(const std::string &FeatureName, Module* Mod);

        /** Publish a module to an 'interface'.
         * Modules which implement the same interface (the same way of communicating
         * with other modules) can publish themselves to an interface, using this
         * method. When they do so, they become part of a list of related or
         * compatible modules, and a third module may then query for that list
         * and know that all modules within that list offer the same API.
         * A prime example of this is the hashing modules, which all accept the
         * same types of Request class. Consider this to be similar to PublishFeature,
         * except for that multiple modules may publish the same 'feature'.
         * @param InterfaceName The case sensitive interface name to make available
         * @param Mod a pointer to your module class
         * @returns True on success, false on failure (there are currently no failure
         * cases)
         */
        bool PublishInterface(const std::string &InterfaceName, Module* Mod);

        /** Return a pair saying how many other modules are currently using the
         * interfaces provided by module m.
         * @param m The module to count usage for
         * @return A pair, where the first value is the number of uses of the interface,
         * and the second value is the interface name being used.
         */
        std::pair<int,std::string> GetInterfaceInstanceCount(Module* m);

        /** Mark your module as using an interface.
         * If you mark your module as using an interface, then that interface
         * module may not unload until your module has unloaded first.
         * This can be used to prevent crashes by ensuring code you depend on
         * is always in memory while your module is active.
         * @param InterfaceName The interface to use
         */
        void UseInterface(const std::string &InterfaceName);

        /** Mark your module as finished with an interface.
         * If you used UseInterface() above, you should use this method when
         * your module is finished with the interface (usually in its destructor)
         * to allow the modules which implement the given interface to be unloaded.
         * @param InterfaceName The interface you are finished with using.
         */
        void DoneWithInterface(const std::string &InterfaceName);

        /** Unpublish a 'feature'.
         * When your module exits, it must call this method for every feature it
         * is providing so that the feature table is cleaned up.
         * @param FeatureName the feature to remove
         */
        bool UnpublishFeature(const std::string &FeatureName);

        /** Unpublish your module from an interface
         * When your module exits, it must call this method for every interface
         * it is part of so that the interfaces table is cleaned up. Only when
         * the last item is deleted from an interface does the interface get
         * removed.
         * @param InterfaceName the interface to be removed from
         * @param Mod The module to remove from the interface list
         */
        bool UnpublishInterface(const std::string &InterfaceName, Module* Mod);

        /** Find a 'feature'.
         * There are two ways for a module to find another module it depends on.
         * Either by name, using InspIRCd::FindModule, or by feature, using the
         * InspIRCd::PublishFeature method. A feature is an arbitary string which
         * identifies something this module can do. For example, if your module
         * provides SSL support, but other modules provide SSL support too, all
         * the modules supporting SSL should publish an identical 'SSL' feature.
         * To find a module capable of providing the feature you want, simply
         * call this method with the feature name you are looking for.
         * @param FeatureName The feature name you wish to obtain the module for
         * @returns A pointer to a valid module class on success, NULL on failure.
         */
        Module* FindFeature(const std::string &FeatureName);

        /** Find an 'interface'.
         * An interface is a list of modules which all implement the same API.
         * @param InterfaceName The Interface you wish to obtain the module
         * list of.
         * @return A pointer to a deque of Module*, or NULL if the interface
         * does not exist.
         */
        modulelist* FindInterface(const std::string &InterfaceName);

        /** Given a pointer to a Module, return its filename
         * @param m The module pointer to identify
         * @return The module name or an empty string
         */
        const std::string& GetModuleName(Module* m);

        /** Return a list of all modules matching the given filter
         * @param filter This int is a bitmask of flags set in Module::Flags,
         * such as VF_VENDOR or VF_STATIC. If you wish to receive a list of
         * all modules with no filtering, set this to 0.
         * @return The list of module names
         */
        const std::vector<std::string> GetAllModuleNames(int filter);
};

/** This definition is used as shorthand for the various classes
 * and functions needed to make a module loadable by the OS.
 * It defines the class factory and external init_module function.
 */
#define MODULE_INIT(y) \
        extern "C" DllExport Module * init_module(InspIRCd* Me) \
        { \
                return new y(Me); \
        }

#endif