Add an event provider class for the event/messagetag event.

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

/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2016 Attila Molnar <attilamolnar@hush.com>
 *
 * This file is part of InspIRCd.  InspIRCd is free software: you can
 * redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation, version 2.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#pragma once

#include "event.h"

namespace ClientProtocol
{
        class EventHook;
        class MessageSource;
        struct RFCEvents;
        struct ParseOutput;
        class TagSelection;
}

/** Contains a message parsed from wire format.
 * Used by Serializer::Parse().
 */
struct ClientProtocol::ParseOutput
{
        /** Command name, must not be empty.
         */
        std::string cmd;

        /** Parameter list, may be empty.
         */
        ClientProtocol::ParamList params;

        /** Message tags, may be empty.
         */
        ClientProtocol::TagMap tags;
};

/** A selection of zero or more tags in a TagMap.
 */
class ClientProtocol::TagSelection
{
        std::bitset<64> selection;

 public:
        /** Check if a tag is selected.
         * @param tags TagMap the tag is in. The TagMap must contain the same tags as it had when the tag
         * was selected with Select(), otherwise the result is not meaningful.
         * @param it Iterator to the tag to check.
         * @return True if the tag is selected, false otherwise.
         */
        bool IsSelected(const TagMap& tags, TagMap::const_iterator it) const
        {
                const size_t index = std::distance(tags.begin(), it);
                return ((index < selection.size()) && (selection[index]));
        }

        /** Select a tag.
         * @param tags TagMap the tag is in. This parameter must be the same every time the method is called.
         * The TagMap must not be altered otherwise the results of IsSelected() is not meaningful.
         * @param it Iterator to the tag to mark as selected.
         */
        void Select(const TagMap& tags, TagMap::const_iterator it)
        {
                const size_t index = std::distance(tags.begin(), it);
                if (index < selection.size())
                        selection[index] = true;
        }

        /** Check if a TagSelection is equivalent to this object.
         * @param other Other TagSelection object to compare this with.
         * @return True if the objects are equivalent, false if they aren't.
         */
        bool operator==(const TagSelection& other) const
        {
                return (this->selection == other.selection);
        }
};

class ClientProtocol::MessageSource
{
        User* sourceuser;
        const std::string* sourcestr;

 public:
        /** Constructor, sets the source to be the full host of a user or sets it to be nothing.
         * The actual source string when serializing will be obtained from User::GetFullHost() if the user is non-NULL.
         * @param Sourceuser User to set as source of the message. If NULL, the message won't have a source when serialized.
         * Optional, defaults to NULL.
         */
        MessageSource(User* Sourceuser = NULL)
        {
                SetSourceUser(Sourceuser);
        }

        /** Constructor, sets the source to the supplied string and optionally sets the source user.
         * @param Sourcestr String to use as message source for serialization purposes. Must remain valid
         * as long as this object is alive.
         * @param Sourceuser User to set as source. Optional, defaults to NULL. It will not be used for serialization but
         * if provided it may be used internally, for example to create message tags.
         * Useful when the source string is synthesized but it is still related to a User.
         */
        MessageSource(const std::string& Sourcestr, User* Sourceuser = NULL)
        {
                SetSource(Sourcestr, Sourceuser);
        }

        /** Get the source of this message as a string.
         * @return Pointer to the message source string or NULL if there is no source.
         */
        const std::string* GetSource() const
        {
                // Return string if there's one explicitly set
                if (sourcestr)
                        return sourcestr;
                if (sourceuser)
                        return &sourceuser->GetFullHost();
                return NULL;
        }

        /** Get the source User.
         * This shouldn't be used for serialization, use GetSource() for that.
         * @return User pointer if the message has a source user, NULL otherwise.
         */
        User* GetSourceUser() const { return sourceuser; }

        /** Set the source of this message to a User.
         * See the one parameter constructor for a more detailed description.
         * @param Sourceuser User to set as source.
         */
        void SetSourceUser(User* Sourceuser)
        {
                sourceuser = Sourceuser;
                sourcestr = NULL;
        }

        /** Set the source string and optionally source user.
         * See the two parameter constructor for a more detailed description.
         * @param Sourcestr String source, to be used for serialization purposes. Must remain valid as long
         * as this object is alive.
         * @param Sourceuser Source user to set, optional.
         */
        void SetSource(const std::string& Sourcestr, User* Sourceuser = NULL)
        {
                sourcestr = &Sourcestr;
                sourceuser = Sourceuser;
        }

        /** Copy the source from a MessageSource object.
         * @param other MessageSource object to copy from.
         */
        void SetSource(const MessageSource& other)
        {
                sourcestr = other.sourcestr;
                sourceuser = other.sourceuser;
        }
};

/** Outgoing client protocol message.
 * Represents a high level client protocol message which is turned into raw or wire format
 * by a Serializer. Messages can be serialized into different format by different serializers.
 *
 * Messages are created on demand and are disposed of after they have been sent.
 *
 * All messages have a command name, a list of parameters and a map of tags, the last two can be empty.
 * They also always have a source, see class MessageSource.
 */
class ClientProtocol::Message : public ClientProtocol::MessageSource
{
 public:
        /** Contains information required to identify a specific version of a serialized message.
         */
        struct SerializedInfo
        {
                const Serializer* serializer;
                TagSelection tagwl;

                /** Constructor.
                 * @param Ser Serializer used to serialize the message.
                 * @param Tagwl Tag whitelist used to serialize the message.
                 */
                SerializedInfo(const Serializer* Ser, const TagSelection& Tagwl)
                        : serializer(Ser)
                        , tagwl(Tagwl)
                {
                }

                /** Check if a SerializedInfo object is equivalent to this object.
                 * @param other Other SerializedInfo object.
                 * @return True if other is equivalent to this object, false otherwise.
                 */
                bool operator==(const SerializedInfo& other) const
                {
                        return ((serializer == other.serializer) && (tagwl == other.tagwl));
                }
        };

        class Param
        {
                const std::string* ptr;
                insp::aligned_storage<std::string> str;
                bool owned;

                void InitFrom(const Param& other)
                {
                        owned = other.owned;
                        if (owned)
                                new(str) std::string(*other.str);
                        else
                                ptr = other.ptr;
                }

         public:
                operator const std::string&() const { return (owned ? *str : *ptr); }

                Param()
                        : ptr(NULL)
                        , owned(false)
                {
                }

                Param(const std::string& s)
                        : ptr(&s)
                        , owned(false)
                {
                }

                Param(int, const char* s)
                        : owned(true)
                {
                        new(str) std::string(s);
                }

                Param(int, const std::string& s)
                        : owned(true)
                {
                         new(str) std::string(s);
                }

                Param(const Param& other)
                {
                        InitFrom(other);
                }

                ~Param()
                {
                        using std::string;
                        if (owned)
                                str->~string();
                }

                Param& operator=(const Param& other)
                {
                        if (&other == this)
                                return *this;

                        using std::string;
                        if (owned)
                                str->~string();
                        InitFrom(other);
                        return *this;
                }

                bool IsOwned() const { return owned; }
        };

        typedef std::vector<Param> ParamList;

 private:
        typedef std::vector<std::pair<SerializedInfo, SerializedMessage> > SerializedList;

        ParamList params;
        TagMap tags;
        std::string command;
        bool msginit_done;
        mutable SerializedList serlist;
        bool sideeffect;

 protected:
        /** Set command string.
         * @param cmd Command string to set.
         */
        void SetCommand(const char* cmd)
        {
                command.clear();
                if (cmd)
                        command = cmd;
        }

 public:
        /** Constructor.
         * @param cmd Command name, e.g. "JOIN", "NICK". May be NULL. If NULL, the command must be set
         * with SetCommand() before the message is serialized.
         * @param Sourceuser See the one parameter constructor of MessageSource for description.
         */
        Message(const char* cmd, User* Sourceuser = NULL)
                : ClientProtocol::MessageSource(Sourceuser)
                , command(cmd ? cmd : std::string())
                , msginit_done(false)
                , sideeffect(false)
        {
                params.reserve(8);
                serlist.reserve(8);
        }

        /** Constructor.
         * @param cmd Command name, e.g. "JOIN", "NICK". May be NULL. If NULL, the command must be set
         * with SetCommand() before the message is serialized.
         * @param Sourcestr See the two parameter constructor of MessageSource for description.
         * Must remain valid as long as this object is alive.
         * @param Sourceuser See the two parameter constructor of MessageSource for description.
         */
        Message(const char* cmd, const std::string& Sourcestr, User* Sourceuser = NULL)
                : ClientProtocol::MessageSource(Sourcestr, Sourceuser)
                , command(cmd ? cmd : std::string())
                , msginit_done(false)
                , sideeffect(false)
        {
                params.reserve(8);
                serlist.reserve(8);
        }

        /** Get the parameters of this message.
         * @return List of parameters.
         */
        const ParamList& GetParams() const { return params; }

        /** Get a map of tags attached to this message.
         * The map contains the tag providers that attached the tag to the message.
         * @return Map of tags.
         */
        const TagMap& GetTags() const { return tags; }

        /** Get the command string.
         * @return Command string, e.g. "NICK", "001".
         */
        const char* GetCommand() const { return command.c_str(); }

        /** Add a parameter to the parameter list.
         * @param str String to add, will be copied.
         */
        void PushParam(const char* str) { params.push_back(Param(0, str)); }

        /** Add a parameter to the parameter list.
         * @param str String to add, will be copied.
         */
        void PushParam(const std::string& str) { params.push_back(Param(0, str)); }

        /** Add a parameter to the parameter list.
         * @param str String to add.
         * The string will NOT be copied, it must remain alive until ClearParams() is called or until the object is destroyed.
         */
        void PushParamRef(const std::string& str) { params.push_back(str); }

        /** Add a placeholder parameter to the parameter list.
         * Placeholder parameters must be filled in later with actual parameters using ReplaceParam() or ReplaceParamRef().
         */
        void PushParamPlaceholder() { params.push_back(Param()); }

        /** Replace a parameter or a placeholder that is already in the parameter list.
         * @param index Index of the parameter to replace. Must be less than GetParams().size().
         * @param str String to replace the parameter or placeholder with, will be copied.
         */
        void ReplaceParam(unsigned int index, const char* str) { params[index] = Param(0, str); }

        /** Replace a parameter or a placeholder that is already in the parameter list.
         * @param index Index of the parameter to replace. Must be less than GetParams().size().
         * @param str String to replace the parameter or placeholder with, will be copied.
         */
        void ReplaceParam(unsigned int index, const std::string& str) { params[index] = Param(0, str); }

        /** Replace a parameter or a placeholder that is already in the parameter list.
         * @param index Index of the parameter to replace. Must be less than GetParams().size().
         * @param str String to replace the parameter or placeholder with.
         * The string will NOT be copied, it must remain alive until ClearParams() is called or until the object is destroyed.
         */
        void ReplaceParamRef(unsigned int index, const std::string& str) { params[index] = Param(str); }

        /** Add a tag.
         * @param tagname Raw name of the tag to use in the protocol.
         * @param tagprov Provider of the tag.
         * @param val Tag value. If empty no value will be sent with the tag.
         * @param tagdata Tag provider specific data, will be passed to MessageTagProvider::ShouldSendTag(). Optional, defaults to NULL.
         */
        void AddTag(const std::string& tagname, MessageTagProvider* tagprov, const std::string& val, void* tagdata = NULL)
        {
                tags.insert(std::make_pair(tagname, MessageTagData(tagprov, val, tagdata)));
        }

        /** Add all tags in a TagMap to the tags in this message. Existing tags will not be overwritten.
         * @param newtags New tags to add.
         */
        void AddTags(const ClientProtocol::TagMap& newtags)
        {
                tags.insert(newtags.begin(), newtags.end());
        }

        /** Get the message in a serialized form.
         * @param serializeinfo Information about which exact serialized form of the message is the caller asking for
         * (which serializer to use and which tags to include).
         * @return Serialized message according to serializeinfo. The returned reference remains valid until the
         * next call to this method.
         */
        const SerializedMessage& GetSerialized(const SerializedInfo& serializeinfo) const;

        /** Clear the parameter list and tags.
         */
        void ClearParams()
        {
                msginit_done = false;
                params.clear();
                tags.clear();
                InvalidateCache();
        }

        /** Remove all serialized messages.
         * If a parameter is changed after the message has been sent at least once, this method must be called before
         * serializing the message again to ensure the cache won't contain stale data.
         */
        void InvalidateCache()
        {
                serlist.clear();
        }

        void CopyAll()
        {
                size_t j = 0;
                for (ParamList::iterator i = params.begin(); i != params.end(); ++i, j++)
                {
                        Param& curr = *i;
                        if (!curr.IsOwned())
                                ReplaceParam(j, curr);
                }
        }

        void SetSideEffect(bool Sideeffect) { sideeffect = Sideeffect; }
        bool IsSideEffect() const { return sideeffect; }

        friend class Serializer;
};

/** Client protocol event class.
 * All messages sent to a user must be part of an event. A single event may result in more than one protocol message
 * being sent, for example a join event may result in a JOIN and a MODE protocol message sent to members of the channel
 * if the joining user has some prefix modes set.
 *
 * Event hooks attached to a specific event can alter the messages sent for that event.
 */
class ClientProtocol::Event
{
        EventProvider* event;
        Message* initialmsg;
        const MessageList* initialmsglist;
        bool eventinit_done;

 public:
        /** Constructor.
         * @param protoeventprov Protocol event provider the event is an instance of.
         */
        Event(EventProvider& protoeventprov)
                : event(&protoeventprov)
                , initialmsg(NULL)
                , initialmsglist(NULL)
                , eventinit_done(false)
        {
        }

        /** Constructor.
         * @param protoeventprov Protocol event provider the event is an instance of.
         * @param msg Message to include in this event by default.
         */
        Event(EventProvider& protoeventprov, ClientProtocol::Message& msg)
                : event(&protoeventprov)
                , initialmsg(&msg)
                , initialmsglist(NULL)
                , eventinit_done(false)
        {
        }

        /** Set a single message as the initial message in the event.
         * Modules may alter this later.
         */
        void SetMessage(Message* msg)
        {
                initialmsg = msg;
                initialmsglist = NULL;
        }

        /** Set a list of messages as the initial messages in the event.
         * Modules may alter this later.
         */
        void SetMessageList(const MessageList& msglist)
        {
                initialmsg = NULL;
                initialmsglist = &msglist;
        }

        /** Get a list of messages to send to a user.
         * The exact messages sent to a user are determined by the initial message(s) set and hooks.
         * @param user User to get the messages for.
         * @param messagelist List to fill in with messages to send to the user for the event
         */
        void GetMessagesForUser(LocalUser* user, MessageList& messagelist);
};

class ClientProtocol::MessageTagEvent
        : public Events::ModuleEventProvider
{
 public:
        MessageTagEvent(Module* mod)
                : ModuleEventProvider(mod, "event/messagetag")
        {
        }
};

/** Base class for message tag providers.
 * All message tags belong to a message tag provider. Message tag providers can populate messages
 * with tags before the message is sent and they have the job of determining whether a user should
 * get a message tag or be allowed to send one.
 */
class ClientProtocol::MessageTagProvider : public Events::ModuleEventListener
{
 public:
        /** Constructor.
         * @param mod Module owning the provider.
         */
        MessageTagProvider(Module* mod)
                : Events::ModuleEventListener(mod, "event/messagetag")
        {
        }

        /** Called when a message is ready to be sent to give the tag provider a chance to add tags to the message.
         * To add tags call Message::AddTag(). If the provided tag or tags have been added already elsewhere or if the
         * provider doesn't want its tag(s) to be on the message, the implementation doesn't have to do anything special.
         * The default implementation does nothing.
         * @param msg Message to be populated with tags.
         */
        virtual void OnPopulateTags(ClientProtocol::Message& msg)
        {
        }

        /** Called for each tag that the server receives from a client in a message.
         * @param user User that sent the tag.
         * @param tagname Name of the tag.
         * @param tagvalue Value of the tag, empty string if the tag has no value. May be modified.
         * @return MOD_RES_ALLOW to accept the tag with the value in 'value', MOD_RES_DENY to reject the tag and act as if it wasn't sent,
         * MOD_RES_PASSTHRU to make no decision. If no hooks accept a tag, the tag is rejected.
         * The default implementation returns MOD_RES_PASSTHRU.
         */
        virtual ModResult OnProcessTag(User* user, const std::string& tagname, std::string& tagvalue)
        {
                return MOD_RES_PASSTHRU;
        }

        /** Called whenever a user is about to receive a message that has a tag attached which is provided by this provider
         * to determine whether or not the user should get the tag.
         * @param user User in question.
         * @param tagdata Tag in question.
         * @return True if the tag should be sent to the user, false otherwise.
         */
        virtual bool ShouldSendTag(LocalUser* user, const MessageTagData& tagdata) = 0;
};

/** Base class for client protocol event hooks.
 * A protocol event hook is attached to a single event type. It has the ability to alter or block messages
 * sent to users which belong to the event the hook is attached to.
 */
class ClientProtocol::EventHook : public Events::ModuleEventListener
{
 public:
        static std::string GetEventName(const std::string& name)
        {
                return "event/protoevent_" + name;
        }

        /** Constructor.
         * @param mod Owner of the hook.
         * @param name Name of the event to hook.
         * @param priority Priority of the hook. Determines the order in which hooks for the same event get called.
         * Optional.
         */
        EventHook(Module* mod, const std::string& name, unsigned int priority = Events::ModuleEventListener::DefaultPriority)
                : Events::ModuleEventListener(mod, GetEventName(name), priority)
        {
        }

        /** Called exactly once before an event is sent to any user.
         * The default implementation doesn't do anything.
         * @param ev Event being sent to one or more users.
         */
        virtual void OnEventInit(const ClientProtocol::Event& ev)
        {
        }

        /** Called for each user that may receive the event.
         * The hook may alter the messages sent to the user and decide whether further hooks should be executed.
         * @param user User the message list is being prepared to be sent to.
         * @param ev Event associated with the messages.
         * @param messagelist List of messages to send to the user. The hook can alter this in any way it sees fit, for example it can replace messages,
         * add new messages, etc. The list must not be empty when the method returns.
         * @return MOD_RES_PASSTHRU to run hooks after the called hook or if no hooks are after the called hook, send the messages in messagelist to the user.
         * MOD_RES_DENY to not send any messages to the user and to not run other hooks,
         * MOD_RES_ALLOW to send the messages in messagelist to the user and to not run other hooks.
         */
        virtual ModResult OnPreEventSend(LocalUser* user, const ClientProtocol::Event& ev, ClientProtocol::MessageList& messagelist) = 0;
};

/** Event provider for client protocol events.
 * Protocol event hooks can be attached to the instances of these providers. The core has event
 * providers for most common IRC events defined in RFC1459.
 */
class ClientProtocol::EventProvider : public Events::ModuleEventProvider
{
 public:
        /** Constructor.
         * @param Mod Module that owns the event provider.
         * @param eventname Name of the event this provider is for, e.g. "JOIN", "PART", "NUMERIC".
         * Should match command name if applicable.
         */
        EventProvider(Module* Mod, const std::string& eventname)
                : Events::ModuleEventProvider(Mod, ClientProtocol::EventHook::GetEventName(eventname))
        {
        }
};

/** Commonly used client protocol events.
 * Available via InspIRCd::GetRFCEvents().
 */
struct ClientProtocol::RFCEvents
{
        EventProvider numeric;
        EventProvider join;
        EventProvider part;
        EventProvider kick;
        EventProvider quit;
        EventProvider nick;
        EventProvider mode;
        EventProvider topic;
        EventProvider privmsg;
        EventProvider invite;
        EventProvider ping;
        EventProvider pong;
        EventProvider error;

        RFCEvents()
                : numeric(NULL, "NUMERIC")
                , join(NULL, "JOIN")
                , part(NULL, "PART")
                , kick(NULL, "KICK")
                , quit(NULL, "QUIT")
                , nick(NULL, "NICK")
                , mode(NULL, "MODE")
                , topic(NULL, "TOPIC")
                , privmsg(NULL, "PRIVMSG")
                , invite(NULL, "INVITE")
                , ping(NULL, "PING")
                , pong(NULL, "PONG")
                , error(NULL, "ERROR")
        {
        }
};

/** Base class for client protocol serializers.
 * A serializer has to implement serialization and parsing of protocol messages to/from wire format.
 */
class CoreExport ClientProtocol::Serializer : public DataProvider
{
 private:
        ClientProtocol::MessageTagEvent evprov;

        /** Make a white list containing which tags a user should get.
         * @param user User in question.
         * @param tagmap Tag map that contains all possible tags.
         * @return Whitelist of tags to send to the user.
         */
        TagSelection MakeTagWhitelist(LocalUser* user, const TagMap& tagmap) const;

 public:
        /** Constructor.
         * @param mod Module owning the serializer.
         * @param Name Name of the serializer, e.g. "rfc".
         */
        Serializer(Module* mod, const char* Name);

        /** Handle a tag in a message being parsed. Call this method for each parsed tag.
         * @param user User sending the tag.
         * @param tagname Name of the tag.
         * @param tagvalue Tag value, may be empty.
         * @param tags TagMap to place the tag into, if it gets accepted.
         * @return True if no error occured, false if the tag name is invalid or if this tag already exists.
         */
        bool HandleTag(LocalUser* user, const std::string& tagname, std::string& tagvalue, TagMap& tags) const;

        /** Serialize a message for a user.
         * @param user User to serialize the message for.
         * @param msg Message to serialize.
         * @return Raw serialized message, only containing the appropriate tags for the user.
         * The reference is guaranteed to be valid as long as the Message object is alive and until the same
         * Message is serialized for another user.
         */
        const SerializedMessage& SerializeForUser(LocalUser* user, Message& msg);

        /** Serialize a high level protocol message into wire format.
         * @param msg High level message to serialize. Contains all necessary information about the message, including all possible tags.
         * @param tagwl Message tags to include in the serialized message. Tags attached to the message but not included in the whitelist must not
         * appear in the output. This is because each user may get a different set of tags for the same message.
         * @return Protocol message in wire format. Must contain message delimiter as well, if any (e.g. CRLF for RFC1459).
         */
        virtual std::string Serialize(const Message& msg, const TagSelection& tagwl) const = 0;

        /** Parse a protocol message from wire format.
         * @param user Source of the message.
         * @param line Raw protocol message.
         * @param parseoutput Output of the parser.
         * @return True if the message was parsed successfully into parseoutput and should be processed, false to drop the message.
         */
        virtual bool Parse(LocalUser* user, const std::string& line, ParseOutput& parseoutput) = 0;
};

inline ClientProtocol::MessageTagData::MessageTagData(MessageTagProvider* prov, const std::string& val, void* data)
        : tagprov(prov)
        , value(val)
        , provdata(data)
{
}