Split the IPC code into ipc/

This splits the ipc code from the common project.  The 'common' project pulls in
all of webkit, the v8 bindings, skia, googleurl, and a number of other projects
which makes it very difficult to deal with especially for external projects
wanting just to use some of Chromium's infrastructure.  This puts the ipc code
into its top-level ipc/ directory with a dependency only on base.  The common
project depends on the new ipc/ipc.gyp:ipc target so that all projects currently
pulling common in to get the IPC code still have it available.  This mostly
follows agl's pre-gyp attempt to do this which was r13062.

Known issues:
- Currently a number of projects depend on chrome/chrome.gyp:common in order to
use the IPC infrastructure.  Rather than fixing all of these dependencies I have
made common depend on ipc/ipc.gyp:ipc and added "ipc" to the include_rules
section of DEPS so that checkdeps.py doesn't complain.  Over time projects that
need IPC should depend on the IPC project themselves and dependencies on common
removed, although I don't think many projects that need IPC will be able to get
away without common currently.
- ipc/ipc_message_macros.h still has #include "chrome/common/..." inside of a
ipc/ should not refer to files in chrome/... now.  I'm not sure how to resolve
this since it's really an IDE bug
- the named pipe name (windows+linux) and the logging event name (all) + env
variable (posix) refer explicitly to 'Chrome' which somewhat hurts the illusion
of ipc/ being an independent library.  I think this should be examined in a
subsequent, much smaller patch.
- I've eliminated the IPC.SendMsgCount counter since it was implemented in a way
to create a dependency from ipc/ to chrome/common/chrome_counters. This is the
same approach that r13062 took.

http://codereview.chromium.org/155905

(Patch from James Robinson)


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@21342 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 118 insertions, 0 deletions

diff --git a/ipc/ipc_channel.h b/ipc/ipc_channel.h
new file mode 100644
index 0000000..a7a9a34
--- /dev/null
+++ b/ipc/ipc_channel.h
@@ -0,0 +1,118 @@
+// 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 IPC_IPC_CHANNEL_H_
+#define IPC_IPC_CHANNEL_H_
+
+#include "ipc/ipc_message.h"
+
+namespace IPC {
+
+//------------------------------------------------------------------------------
+
+class Channel : public Message::Sender {
+  // Security tests need access to the pipe handle.
+  friend class ChannelTest;
+
+ public:
+  // Implemented by consumers of a Channel to receive messages.
+  class Listener {
+   public:
+    virtual ~Listener() {}
+
+    // Called when a message is received.
+    virtual void OnMessageReceived(const Message& message) = 0;
+
+    // Called when the channel is connected and we have received the internal
+    // Hello message from the peer.
+    virtual void OnChannelConnected(int32 peer_pid) {}
+
+    // Called when an error is detected that causes the channel to close.
+    // This method is not called when a channel is closed normally.
+    virtual void OnChannelError() {}
+  };
+
+  enum Mode {
+    MODE_SERVER,
+    MODE_CLIENT
+  };
+
+  enum {
+    // The maximum message size in bytes. Attempting to receive a
+    // message of this size or bigger results in a channel error.
+    kMaximumMessageSize = 256 * 1024 * 1024,
+
+    // Ammount of data to read at once from the pipe.
+    kReadBufferSize = 4 * 1024
+  };
+
+  // Initialize a Channel.
+  //
+  // |channel_id| identifies the communication Channel.
+  // |mode| specifies whether this Channel is to operate in server mode or
+  // client mode.  In server mode, the Channel is responsible for setting up the
+  // IPC object, whereas in client mode, the Channel merely connects to the
+  // already established IPC object.
+  // |listener| receives a callback on the current thread for each newly
+  // received message.
+  //
+  Channel(const std::string& channel_id, Mode mode, Listener* listener);
+
+  ~Channel();
+
+  // Connect the pipe.  On the server side, this will initiate
+  // waiting for connections.  On the client, it attempts to
+  // connect to a pre-existing pipe.  Note, calling Connect()
+  // will not block the calling thread and may complete
+  // asynchronously.
+  bool Connect();
+
+  // Close this Channel explicitly.  May be called multiple times.
+  void Close();
+
+  // Modify the Channel's listener.
+  void set_listener(Listener* listener);
+
+  // Send a message over the Channel to the listener on the other end.
+  //
+  // |message| must be allocated using operator new.  This object will be
+  // deleted once the contents of the Message have been sent.
+  //
+  //  FIXME bug 551500: the channel does not notice failures, so if the
+  //    renderer crashes, it will silently succeed, leaking the parameter.
+  //    At least the leak will be fixed by...
+  //
+  virtual bool Send(Message* message);
+
+#if defined(OS_POSIX)
+  // On POSIX an IPC::Channel wraps a socketpair(), this method returns the
+  // FD # for the client end of the socket.
+  // This method may only be called on the server side of a channel.
+  //
+  // If the kTestingChannelID flag is specified on the command line then
+  // a named FIFO is used as the channel transport mechanism rather than a
+  // socketpair() in which case this method returns -1.
+  int GetClientFileDescriptor() const;
+#endif  // defined(OS_POSIX)
+
+ private:
+  // PIMPL to which all channel calls are delegated.
+  class ChannelImpl;
+  ChannelImpl *channel_impl_;
+
+  // The Hello message is internal to the Channel class.  It is sent
+  // by the peer when the channel is connected.  The message contains
+  // just the process id (pid).  The message has a special routing_id
+  // (MSG_ROUTING_NONE) and type (HELLO_MESSAGE_TYPE).
+  enum {
+    HELLO_MESSAGE_TYPE = kuint16max  // Maximum value of message type (uint16),
+                                     // to avoid conflicting with normal
+                                     // message types, which are enumeration
+                                     // constants starting from 0.
+  };
+};
+
+}  // namespace IPC
+
+#endif  // IPC_IPC_CHANNEL_H_