From 939cb0ba987f927f1ad900d45f98ba6d8e03e9d4 Mon Sep 17 00:00:00 2001 From: danieldg Date: Sat, 26 Sep 2009 01:43:09 +0000 Subject: Clean up SocketEngine interface to allow edge-triggered I/O and sockets that do not force readability. git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@11760 e03df62e-2008-0410-955e-edbf42e46eb7 --- include/socketengine.h | 175 ++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 137 insertions(+), 38 deletions(-) (limited to 'include/socketengine.h') diff --git a/include/socketengine.h b/include/socketengine.h index 4e87f7494..9c45bcf21 100644 --- a/include/socketengine.h +++ b/include/socketengine.h @@ -37,6 +37,97 @@ enum EventType EVENT_ERROR = 2 }; +/** + * Event mask for SocketEngine events + */ +enum EventMask +{ + /** Do not test this socket for readability + */ + FD_WANT_NO_READ = 0x1, + /** Give a read event at all times when reads will not block. + */ + FD_WANT_POLL_READ = 0x2, + /** Give a read event when there is new data to read. + * + * An event MUST be sent if there is new data to be read, and the most + * recent read/recv() on this FD returned EAGAIN. An event MAY be sent + * at any time there is data to be read on the socket. + */ + FD_WANT_FAST_READ = 0x4, + /** Give an optional read event when reads begin to unblock + * + * This state is useful if you want to leave data in the OS receive + * queue but not get continuous event notifications about it, because + * it may not require a system call to transition from FD_WANT_FAST_READ + */ + FD_WANT_EDGE_READ = 0x8, + + /** Mask for all read events */ + FD_WANT_READ_MASK = 0x0F, + + /** Do not test this socket for writeability + */ + FD_WANT_NO_WRITE = 0x10, + /** Give a write event at all times when writes will not block. + * + * You probably don't need to use this state; try your write first, and + * then use FD_WANT_FAST_WRITE. + */ + FD_WANT_POLL_WRITE = 0x20, + /** Give a write event when writes don't block any more + * + * An event MUST be sent if writes will not block, and the most recent + * write/send() on this FD returned EAGAIN, or connect() returned + * EINPROGRESS. An event MAY be sent at any time that writes will not + * block. + * + * Before calling HandleEvent, a socket engine MAY change the state of + * the FD back to FD_WANT_EDGE_WRITE if it is simpler (for example, if a + * one-shot notification was registered). If further writes are needed, + * it is the responsibility of the event handler to change the state to + * one that will generate the required notifications + */ + FD_WANT_FAST_WRITE = 0x40, + /** Give an optional write event on edge-triggered write unblock. + * + * This state is useful to avoid system calls when moving to/from + * FD_WANT_FAST_WRITE when writing data to a mostly-unblocked socket. + */ + FD_WANT_EDGE_WRITE = 0x80, + + /** Mask for all write events */ + FD_WANT_WRITE_MASK = 0xF0, + + /** Add a trial read. During the next DispatchEvents invocation, this + * will call HandleEvent with EVENT_READ unless reads are known to be + * blocking. Useful for edge-triggered reads; does nothing if + * FD_READ_WILL_BLOCK has been set on this EventHandler. + */ + FD_ADD_TRIAL_READ = 0x100, + /** Assert that reads are known to block. This cancels FD_ADD_TRIAL_READ. + */ + FD_READ_WILL_BLOCK = 0x200, + + /** Add a trial write. During the next DispatchEvents invocation, this + * will call HandleEvent with EVENT_WRITE unless writes are known to be + * blocking. + * + * This could be used to group several writes together into a single + * send() syscall, or to ensure that writes are blocking when attempting + * to use FD_WANT_FAST_WRITE. + */ + FD_ADD_TRIAL_WRITE = 0x1000, + /** Assert that writes are known to block. This cancels FD_ADD_TRIAL_WRITE. + */ + FD_WRITE_WILL_BLOCK = 0x2000, + + /** Mask for trial read/write items */ + FD_TRIAL_NOTE_MASK = 0x1100, + /** Mask for read/write blocking notifications */ + FD_BLOCK_NOTE_MASK = 0x2200 +}; + class InspIRCd; class Module; @@ -60,13 +151,15 @@ class Module; */ class CoreExport EventHandler : public Extensible { + private: + /** Private state maintained by socket engine */ + int event_mask; protected: /** File descriptor. - * All events which can be handled - * must have a file descriptor. - * This allows you to add events for - * sockets, fifo's, pipes, and various - * other forms of IPC. + * All events which can be handled must have a file descriptor. This + * allows you to add events for sockets, fifo's, pipes, and various + * other forms of IPC. Do not change this while the object is + * registered with the SocketEngine */ int fd; public: @@ -75,10 +168,11 @@ class CoreExport EventHandler : public Extensible */ inline int GetFd() const { return fd; } + inline int GetEventMask() const { return event_mask; } + /** Set a new file desciptor - * @param FD The new file descriptor. Do not - * call this method without first deleting the - * object from the SocketEngine if you have + * @param FD The new file descriptor. Do not call this method without + * first deleting the object from the SocketEngine if you have * added it to a SocketEngine instance. */ void SetFd(int FD); @@ -99,6 +193,8 @@ class CoreExport EventHandler : public Extensible * and EVENT_WRITE for write events. */ virtual void HandleEvent(EventType et, int errornum = 0) = 0; + + friend class SocketEngine; }; /** Provides basic file-descriptor-based I/O support. @@ -121,16 +217,16 @@ class CoreExport EventHandler : public Extensible */ class CoreExport SocketEngine { -protected: - /** Handle to socket engine, where needed. - */ - int EngineHandle; + protected: /** Current number of descriptors in the engine */ int CurrentSetSize; /** Reference table, contains all current handlers */ EventHandler** ref; + /** List of handlers that want a trial read/write + */ + std::set trials; int MAX_DESCRIPTORS; @@ -139,6 +235,9 @@ protected: time_t lastempty; void UpdateStats(size_t len_in, size_t len_out); + + virtual void OnSetEvent(EventHandler* eh, int old_mask, int new_mask) = 0; + void SetEventMask(EventHandler* eh, int value); public: double TotalEvents; @@ -167,9 +266,9 @@ public: * must provide an object derived from EventHandler which implements * HandleEvent(). * @param eh An event handling object to add - * @param writeFirst Wait for a write event instead of a read + * @param event_mask The initial event mask for the object */ - virtual bool AddFd(EventHandler* eh, bool writeFirst = false) = 0; + virtual bool AddFd(EventHandler* eh, int event_mask) = 0; /** If you call this function and pass it an * event handler, that event handler will @@ -179,22 +278,20 @@ public: * an eventhandler in the writeable state, * as this will consume large amounts of * CPU time. - * @param eh An event handler which wants to - * receive the next writeability event. + * @param eh The event handler to change + * @param event_mask The changes to make to the wait state */ - virtual void WantWrite(EventHandler* eh) = 0; + void ChangeEventMask(EventHandler* eh, int event_mask); - /** Returns the maximum number of file descriptors - * you may store in the socket engine at any one time. + /** Returns the highest file descriptor you may store in the socket engine * @return The maximum fd value */ - virtual int GetMaxFds(); + inline int GetMaxFds() const { return MAX_DESCRIPTORS; } - /** Returns the number of file descriptor slots - * which are available for storing fds. - * @return The number of remaining fd's + /** Returns the number of file descriptors being queried + * @return The set size */ - virtual int GetRemainingFds(); + inline int GetUsedFds() const { return CurrentSetSize; } /** Delete an event handler from the engine. * This function call deletes an EventHandler @@ -229,27 +326,29 @@ public: */ virtual EventHandler* GetRef(int fd); - /** Waits for events and dispatches them to handlers. - * Please note that this doesnt wait long, only - * a couple of milliseconds. It returns the number of - * events which occured during this call. - * This method will dispatch events to their handlers - * by calling their EventHandler::HandleEvent() - * methods with the neccessary EventType value. + /** Waits for events and dispatches them to handlers. Please note that + * this doesn't wait long, only a couple of milliseconds. It returns the + * number of events which occurred during this call. This method will + * dispatch events to their handlers by calling their + * EventHandler::HandleEvent() methods with the necessary EventType + * value. * @return The number of events which have occured. */ - virtual int DispatchEvents(); + virtual int DispatchEvents() = 0; + + /** Dispatch trial reads and writes. This causes the actual socket I/O + * to happen when writes have been pre-buffered. + */ + virtual void DispatchTrialWrites(); - /** Returns the socket engines name. - * This returns the name of the engine for use - * in /VERSION responses. + /** Returns the socket engines name. This returns the name of the + * engine for use in /VERSION responses. * @return The socket engine name */ virtual std::string GetName() = 0; - /** Returns true if the file descriptors in the - * given event handler are within sensible ranges - * which can be handled by the socket engine. + /** Returns true if the file descriptors in the given event handler are + * within sensible ranges which can be handled by the socket engine. */ virtual bool BoundsCheckFd(EventHandler* eh); -- cgit v1.2.3