The Tor Browser: comparison ipc/chromium/src/base/message_pump

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+:dc3db254fb53
+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+#ifndef BASE_MESSAGE_PUMP_LIBEVENT_H_
+#define BASE_MESSAGE_PUMP_LIBEVENT_H_
+#include "base/message_pump.h"
+#include "base/time.h"
+#include "nsAutoPtr.h"
+// Declare structs we need from libevent.h rather than including it
+struct event_base;
+struct event;
+class nsDependentCSubstring;
+namespace base {
+// Class to monitor sockets and issue callbacks when sockets are ready for I/O
+// TODO(dkegel): add support for background file IO somehow
+class MessagePumpLibevent : public MessagePump {
+public:
+// Object returned by WatchFileDescriptor to manage further watching.
+class FileDescriptorWatcher {
+public:
+FileDescriptorWatcher();
+~FileDescriptorWatcher();  // Implicitly calls StopWatchingFileDescriptor.
+// NOTE: These methods aren't called StartWatching()/StopWatching() to
+// avoid confusion with the win32 ObjectWatcher class.
+// Stop watching the FD, always safe to call.  No-op if there's nothing
+// to do.
+bool StopWatchingFileDescriptor();
+private:
+// Called by MessagePumpLibevent, ownership of |e| is transferred to this
+// object.
+void Init(event* e, bool is_persistent);
+// Used by MessagePumpLibevent to take ownership of event_.
+event *ReleaseEvent();
+friend class MessagePumpLibevent;
+private:
+bool is_persistent_;  // false if this event is one-shot.
+event* event_;
+DISALLOW_COPY_AND_ASSIGN(FileDescriptorWatcher);
+};
+// Used with WatchFileDescptor to asynchronously monitor the I/O readiness of
+// a File Descriptor.
+class Watcher {
+public:
+virtual ~Watcher() {}
+// Called from MessageLoop::Run when an FD can be read from/written to
+// without blocking
+virtual void OnFileCanReadWithoutBlocking(int fd) = 0;
+virtual void OnFileCanWriteWithoutBlocking(int fd) = 0;
+};
+MessagePumpLibevent();
+virtual ~MessagePumpLibevent();
+enum Mode {
+WATCH_READ = 1 << 0,
+WATCH_WRITE = 1 << 1,
+WATCH_READ_WRITE = WATCH_READ | WATCH_WRITE
+};
+// Have the current thread's message loop watch for a a situation in which
+// reading/writing to the FD can be performed without Blocking.
+// Callers must provide a preallocated FileDescriptorWatcher object which
+// can later be used to manage the Lifetime of this event.
+// If a FileDescriptorWatcher is passed in which is already attached to
+// an event, then the effect is cumulative i.e. after the call |controller|
+// will watch both the previous event and the new one.
+// If an error occurs while calling this method in a cumulative fashion, the
+// event previously attached to |controller| is aborted.
+// Returns true on success.
+// TODO(dkegel): switch to edge-triggered readiness notification
+bool WatchFileDescriptor(int fd,
+bool persistent,
+Mode mode,
+FileDescriptorWatcher *controller,
+Watcher *delegate);
+// This is analagous to FileDescriptorWatcher above, which really is
+// just a wrapper around libevent's |struct event|.  This class acts
+// as a sort of "scoped event watcher" in that it guarantees that
+// when this class is out of scope, the signal-event it wraps is
+// removed from libevent's guts.
+//
+// XXX/cjones: this isn't my favorite API, but preserving it in
+// order to match code above
+class SignalEvent {
+friend class MessagePumpLibevent;
+public:
+SignalEvent();
+~SignalEvent();             // implicitly calls StopCatching()
+// Have libevent forget this event.
+bool StopCatching();
+private:
+void Init(event* e);
+event* ReleaseEvent();
+event* event_;
+DISALLOW_COPY_AND_ASSIGN(SignalEvent);
+};
+class SignalWatcher {
+public:
+virtual ~SignalWatcher() {}
+// Called from MessageLoop::Run when |sig| has been delivered to
+// this process
+virtual void OnSignal(int sig) = 0;
+};
+// Have the current thread's message loop catch the signal |sig|.
+// Multiple watchers can catch the same signal; they're all notified
+// upon its delivery.  Callers must provide a preallocated
+// SignalEvent object which can be used to manage the lifetime of
+// this event.  Returns true on success.
+bool CatchSignal(int sig,
+SignalEvent* sigevent,
+SignalWatcher* delegate);
+// MessagePump methods:
+virtual void Run(Delegate* delegate);
+virtual void Quit();
+virtual void ScheduleWork();
+virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time);
+private:
+// Risky part of constructor.  Returns true on success.
+bool Init();
+// This flag is set to false when Run should return.
+bool keep_running_;
+// This flag is set when inside Run.
+bool in_run_;
+// The time at which we should call DoDelayedWork.
+TimeTicks delayed_work_time_;
+// Libevent dispatcher.  Watches all sockets registered with it, and sends
+// readiness callbacks when a socket is ready for I/O.
+event_base* event_base_;
+// Called by libevent to tell us a registered FD can be read/written to.
+static void OnLibeventNotification(int fd, short flags,
+void* context);
+// Called by libevent upon receiving a signal
+static void OnLibeventSignalNotification(int sig, short flags,
+void* context);
+// Unix pipe used to implement ScheduleWork()
+// ... callback; called by libevent inside Run() when pipe is ready to read
+static void OnWakeup(int socket, short flags, void* context);
+// ... write end; ScheduleWork() writes a single byte to it
+int wakeup_pipe_in_;
+// ... read end; OnWakeup reads it and then breaks Run() out of its sleep
+int wakeup_pipe_out_;
+// ... libevent wrapper for read end
+event* wakeup_event_;
+DISALLOW_COPY_AND_ASSIGN(MessagePumpLibevent);
+};
+/**
+*  LineWatcher overrides OnFileCanReadWithoutBlocking. It separates the read
+*  data by mTerminator and passes each line to OnLineRead.
+*/
+class LineWatcher : public MessagePumpLibevent::Watcher
+{
+public:
+LineWatcher(char aTerminator, int aBufferSize) : mReceivedIndex(0),
+mBufferSize(aBufferSize),
+mTerminator(aTerminator)
+{
+mReceiveBuffer = new char[mBufferSize];
+}
+~LineWatcher() {}
+protected:
+/**
+* OnError will be called when |read| returns error. Derived class should
+* implement this function to handle error cases when needed.
+*/
+virtual void OnError() {}
+virtual void OnLineRead(int aFd, nsDependentCSubstring& aMessage) = 0;
+virtual void OnFileCanWriteWithoutBlocking(int /* aFd */) {}
+private:
+virtual void OnFileCanReadWithoutBlocking(int aFd) MOZ_FINAL;
+nsAutoPtr<char> mReceiveBuffer;
+int mReceivedIndex;
+int mBufferSize;
+char mTerminator;
+};
+}  // namespace base
+#endif  // BASE_MESSAGE_PUMP_LIBEVENT_H_

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comparison: ipc/chromium/src/base/message_pump_libevent.h

ipc/chromium/src/base/message_pump_libevent.h