Mojo: Implement local passing of MessagePipes.

mojo/system/dispatcher.cc

 // Copyright 2013 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.
 
 #include "mojo/system/dispatcher.h"
 
 #include "base/logging.h"
 #include "mojo/system/limits.h"
 
 namespace mojo {
@@ skipping 17 matching lines @@
 
   base::AutoLock locker(lock_);
   if (is_closed_)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
   return WriteMessageImplNoLock(bytes, num_bytes, dispatchers, flags);
 }
 
 MojoResult Dispatcher::ReadMessage(
     void* bytes, uint32_t* num_bytes,
-    uint32_t max_num_dispatchers,
     std::vector<scoped_refptr<Dispatcher> >* dispatchers,
+    uint32_t* num_dispatchers,

[DaveMoore, 2013/11/13 02:54:02]

Nit: Why do you need an output var for num_dispatchers? Isn't dispatchers
enough?

     MojoReadMessageFlags flags) {
-  DCHECK(max_num_dispatchers == 0 || (dispatchers && dispatchers->empty()));
+  DCHECK(!num_dispatchers || *num_dispatchers == 0 ||
+         (dispatchers && dispatchers->empty()));
 
   base::AutoLock locker(lock_);
   if (is_closed_)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
   return ReadMessageImplNoLock(bytes, num_bytes,
-                               max_num_dispatchers, dispatchers,
+                               dispatchers, num_dispatchers,
                                flags);
 }
 
 MojoResult Dispatcher::AddWaiter(Waiter* waiter,
                                  MojoWaitFlags flags,
                                  MojoResult wake_result) {
   DCHECK_GE(wake_result, 0);
 
   base::AutoLock locker(lock_);
   if (is_closed_)
@@ skipping 11 matching lines @@
 
 Dispatcher::Dispatcher()
     : is_closed_(false) {
 }
 
 Dispatcher::~Dispatcher() {
   // Make sure that |Close()| was called.
   DCHECK(is_closed_);
 }
 
+scoped_refptr<Dispatcher>
+Dispatcher::CreateEquivalentDispatcherAndCloseNoLock() {
+  lock_.AssertAcquired();
+  DCHECK(!is_closed_);
+
+  is_closed_ = true;
+  CancelAllWaitersNoLock();
+  return CreateEquivalentDispatcherAndCloseImplNoLock();
+}
+
 void Dispatcher::CancelAllWaitersNoLock() {
   lock_.AssertAcquired();
   DCHECK(is_closed_);
   // By default, waiting isn't supported. Only dispatchers that can be waited on
   // will do something nontrivial.
 }
 
 MojoResult Dispatcher::CloseImplNoLock() {
   lock_.AssertAcquired();
   DCHECK(is_closed_);
   // This may not need to do anything. Dispatchers should override this to do
   // any actual close-time cleanup necessary.
   return MOJO_RESULT_OK;
 }
 
 MojoResult Dispatcher::WriteMessageImplNoLock(
     const void* bytes, uint32_t num_bytes,
     const std::vector<Dispatcher*>* dispatchers,
     MojoWriteMessageFlags flags) {
   lock_.AssertAcquired();
   DCHECK(!is_closed_);
   // By default, this isn't supported. Only dispatchers for message pipes (with
   // whatever implementation, possibly a proxy) will do something nontrivial.
   return MOJO_RESULT_INVALID_ARGUMENT;
 }
 
 MojoResult Dispatcher::ReadMessageImplNoLock(
-    void* bytes, uint32_t* num_bytes,
-    uint32_t max_num_dispatchers,
-    std::vector<scoped_refptr<Dispatcher> >* dispatchers,
-    MojoReadMessageFlags flags) {
+    void* /*bytes*/, uint32_t* /*num_bytes*/,
+    std::vector<scoped_refptr<Dispatcher> >* /*dispatchers*/,
+    uint32_t* /*num_dispatchers*/,
+    MojoReadMessageFlags /*flags*/) {
   lock_.AssertAcquired();
   DCHECK(!is_closed_);
   // By default, this isn't supported. Only dispatchers for message pipes (with
   // whatever implementation, possibly a proxy) will do something nontrivial.
   return MOJO_RESULT_INVALID_ARGUMENT;
 }
 
 MojoResult Dispatcher::AddWaiterImplNoLock(Waiter* waiter,
                                            MojoWaitFlags flags,
                                            MojoResult wake_result) {
   lock_.AssertAcquired();
   DCHECK(!is_closed_);
   // By default, waiting isn't supported. Only dispatchers that can be waited on
   // will do something nontrivial.
   return MOJO_RESULT_FAILED_PRECONDITION;
 }
 
 void Dispatcher::RemoveWaiterImplNoLock(Waiter* waiter) {
   lock_.AssertAcquired();
   DCHECK(!is_closed_);
   // By default, waiting isn't supported. Only dispatchers that can be waited on
   // will do something nontrivial.
 }
 
 }  // namespace system
 }  // namespace mojo