Make tcp_client_socket_unittest pass on Linux.

Requires another changeset that puts libevent in third_party;
I'll upload that next.
This is not the final word; it makes too many syscalls
per read.  But it's a start.  
Review URL: http://codereview.chromium.org/3202

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@2346 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 89 insertions, 0 deletions

diff --git a/base/message_pump_libevent.h b/base/message_pump_libevent.h
new file mode 100644
index 0000000..7534e50
--- /dev/null
+++ b/base/message_pump_libevent.h
@@ -0,0 +1,89 @@
+// 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"
+
+// Declare structs we need from libevent.h rather than including it
+struct event_base;
+struct event;
+
+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:
+  // Used with WatchObject to asynchronously monitor the I/O readiness of a
+  // socket.
+  class Watcher {
+   public:
+    virtual ~Watcher() {}
+    // Called from MessageLoop::Run when a ready socket is detected.
+    virtual void OnSocketReady(short eventmask) = 0;
+  };
+
+  MessagePumpLibevent();
+  virtual ~MessagePumpLibevent();
+
+  // Have the current thread's message loop watch for a ready socket.
+  // Caller must provide a struct event for this socket for libevent's use.
+  // The event and interest_mask fields are defined in libevent.
+  // Returns true on success.  
+  // TODO(dkegel): hide libevent better; abstraction still too leaky
+  // TODO(dkegel): better error handing
+  // TODO(dkegel): switch to edge-triggered readiness notification
+  void WatchSocket(int socket, short interest_mask, event* e, Watcher*);
+
+  // Stop watching a socket.
+  // Event was previously initialized by WatchSocket.
+  void UnwatchSocket(event* e);
+
+  // MessagePump methods:
+  virtual void Run(Delegate* delegate);
+  virtual void Quit();
+  virtual void ScheduleWork();
+  virtual void ScheduleDelayedWork(const Time& 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.
+  Time 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 socket is ready
+  static void OnReadinessNotification(int socket, 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);
+};
+
+}  // namespace base
+
+#endif  // BASE_MESSAGE_PUMP_LIBEVENT_H_
+