Mojo: Implement plumbing to support passing handles over 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 {
 namespace system {
 
 MojoResult Dispatcher::Close() {
   base::AutoLock locker(lock_);
   if (is_closed_)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
   is_closed_ = true;
   CancelAllWaitersNoLock();
   return CloseImplNoLock();
 }
 
-MojoResult Dispatcher::WriteMessage(const void* bytes,
-                                    uint32_t num_bytes,
-                                    const MojoHandle* handles,
-                                    uint32_t num_handles,
+MojoResult Dispatcher::WriteMessage(const void* bytes, uint32_t num_bytes,
+                                    const std::vector<Dispatcher*>* dispatchers,
                                     MojoWriteMessageFlags flags) {
+  DCHECK(!dispatchers || (dispatchers->size() > 0 &&
+                          dispatchers->size() < kMaxMessageNumHandles));
+
   base::AutoLock locker(lock_);
   if (is_closed_)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
-  return WriteMessageImplNoLock(bytes, num_bytes, handles, num_handles, flags);
+  return WriteMessageImplNoLock(bytes, num_bytes, dispatchers, flags);
 }
 
-MojoResult Dispatcher::ReadMessage(void* bytes,
-                                   uint32_t* num_bytes,
-                                   MojoHandle* handles,
-                                   uint32_t* num_handles,
-                                   MojoReadMessageFlags flags) {
+MojoResult Dispatcher::ReadMessage(
+    void* bytes, uint32_t* num_bytes,
+    uint32_t max_num_dispatchers,
+    std::vector<scoped_refptr<Dispatcher> >* dispatchers,
+    MojoReadMessageFlags flags) {
+  DCHECK(max_num_dispatchers == 0 || !!dispatchers);
+
   base::AutoLock locker(lock_);
   if (is_closed_)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
-  return ReadMessageImplNoLock(bytes, num_bytes, handles, num_handles, flags);
+  return ReadMessageImplNoLock(bytes, num_bytes,
+                               max_num_dispatchers, dispatchers,
+                               flags);
 }
 
 MojoResult Dispatcher::AddWaiter(Waiter* waiter,
                                  MojoWaitFlags flags,
                                  MojoResult wake_result) {
   DCHECK_GE(wake_result, 0);
 
   base::AutoLock locker(lock_);
   if (is_closed_)
     return MOJO_RESULT_INVALID_ARGUMENT;
@@ skipping 25 matching lines @@
 }
 
 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 MojoHandle* handles,
-                                              uint32_t num_handles,
-                                              MojoWriteMessageFlags flags) {
+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,
-                                             MojoHandle* handles,
-                                             uint32_t* num_handles,
-                                             MojoReadMessageFlags flags) {
+MojoResult Dispatcher::ReadMessageImplNoLock(
+    void* bytes, uint32_t* num_bytes,
+    uint32_t max_num_dispatchers,
+    std::vector<scoped_refptr<Dispatcher> >* 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