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, 96 insertions, 0 deletions

diff --git a/ipc/ipc_sync_message.h b/ipc/ipc_sync_message.h
new file mode 100644
index 0000000..5d072a7
--- /dev/null
+++ b/ipc/ipc_sync_message.h
@@ -0,0 +1,96 @@
+// 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_SYNC_MESSAGE_H__
+#define IPC_IPC_SYNC_MESSAGE_H__
+
+#if defined(OS_WIN)
+#include <windows.h>
+#endif
+#include <string>
+#include "base/basictypes.h"
+#include "ipc/ipc_message.h"
+
+namespace base {
+class WaitableEvent;
+}
+
+namespace IPC {
+
+class MessageReplyDeserializer;
+
+class SyncMessage : public Message {
+ public:
+  SyncMessage(int32 routing_id, uint16 type, PriorityValue priority,
+              MessageReplyDeserializer* deserializer);
+
+  // Call this to get a deserializer for the output parameters.
+  // Note that this can only be called once, and the caller is responsible
+  // for deleting the deserializer when they're done.
+  MessageReplyDeserializer* GetReplyDeserializer();
+
+  // If this message can cause the receiver to block while waiting for user
+  // input (i.e. by calling MessageBox), then the caller needs to pump window
+  // messages and dispatch asynchronous messages while waiting for the reply.
+  // If this event is passed in, then window messages will start being pumped
+  // when it's set.  Note that this behavior will continue even if the event is
+  // later reset.  The event must be valid until after the Send call returns.
+  void set_pump_messages_event(base::WaitableEvent* event) {
+    pump_messages_event_ = event;
+    if (event) {
+      header()->flags |= PUMPING_MSGS_BIT;
+    } else {
+      header()->flags &= ~PUMPING_MSGS_BIT;
+    }
+  }
+
+  // Call this if you always want to pump messages.  You can call this method
+  // or set_pump_messages_event but not both.
+  void EnableMessagePumping();
+
+  base::WaitableEvent* pump_messages_event() const {
+    return pump_messages_event_;
+  }
+
+  // Returns true if the message is a reply to the given request id.
+  static bool IsMessageReplyTo(const Message& msg, int request_id);
+
+  // Given a reply message, returns an iterator to the beginning of the data
+  // (i.e. skips over the synchronous specific data).
+  static void* GetDataIterator(const Message* msg);
+
+  // Given a synchronous message (or its reply), returns its id.
+  static int GetMessageId(const Message& msg);
+
+  // Generates a reply message to the given message.
+  static Message* GenerateReply(const Message* msg);
+
+ private:
+  struct SyncHeader {
+    // unique ID (unique per sender)
+    int message_id;
+  };
+
+  static bool ReadSyncHeader(const Message& msg, SyncHeader* header);
+  static bool WriteSyncHeader(Message* msg, const SyncHeader& header);
+
+  MessageReplyDeserializer* deserializer_;
+  base::WaitableEvent* pump_messages_event_;
+
+  static uint32 next_id_;  // for generation of unique ids
+};
+
+// Used to deserialize parameters from a reply to a synchronous message
+class MessageReplyDeserializer {
+ public:
+  bool SerializeOutputParameters(const Message& msg);
+ private:
+  // Derived classes need to implement this, using the given iterator (which
+  // is skipped past the header for synchronous messages).
+  virtual bool SerializeOutputParameters(const Message& msg, void* iter) = 0;
+};
+
+}  // namespace IPC
+
+#endif  // IPC_IPC_SYNC_MESSAGE_H__