Mojo: Implement plumbing to support passing handles over MessagePipes.

mojo/system/message_pipe_dispatcher.cc

Index: mojo/system/message_pipe_dispatcher.cc
diff --git a/mojo/system/message_pipe_dispatcher.cc b/mojo/system/message_pipe_dispatcher.cc
index ab84def4d3b0ceee8bb87ca03d23a74cafb11d53..df4def127dcb777724af4a2fd0b983b7e71f6921 100644
--- a/mojo/system/message_pipe_dispatcher.cc
+++ b/mojo/system/message_pipe_dispatcher.cc
@@ -43,7 +43,7 @@ MojoResult MessagePipeDispatcher::CloseImplNoLock() {
 
 MojoResult MessagePipeDispatcher::WriteMessageImplNoLock(
     const void* bytes, uint32_t num_bytes,
-    const MojoHandle* handles, uint32_t num_handles,
+    const std::vector<Dispatcher*>* dispatchers,
     MojoWriteMessageFlags flags) {
   lock().AssertAcquired();
 
@@ -52,40 +52,38 @@ MojoResult MessagePipeDispatcher::WriteMessageImplNoLock(
   if (num_bytes > kMaxMessageNumBytes)
     return MOJO_RESULT_RESOURCE_EXHAUSTED;
 
-  if (!VerifyUserPointer<MojoHandle>(handles, num_handles))
-    return MOJO_RESULT_INVALID_ARGUMENT;
-  if (num_handles > kMaxMessageNumHandles)
-    return MOJO_RESULT_RESOURCE_EXHAUSTED;
-  if (num_handles > 0) {
-    // TODO(vtl): Verify each handle.
+  if (dispatchers) {
+    DCHECK_GT(dispatchers->size(), 0u);
+    DCHECK_LE(dispatchers->size(), kMaxMessageNumHandles);
+
+    // TODO(vtl)
     NOTIMPLEMENTED();
     return MOJO_RESULT_UNIMPLEMENTED;
   }
 
   return message_pipe_->WriteMessage(port_,
                                      bytes, num_bytes,
-                                     handles, num_handles,
+                                     dispatchers,
                                      flags);
 }
 
 MojoResult MessagePipeDispatcher::ReadMessageImplNoLock(
     void* bytes, uint32_t* num_bytes,
-    MojoHandle* handles, uint32_t* num_handles,
+    uint32_t max_num_dispatchers,
+    std::vector<scoped_refptr<Dispatcher> >* dispatchers,
     MojoReadMessageFlags flags) {
   lock().AssertAcquired();
 
-  // TODO(vtl): I suppose we should verify |num_bytes| and |num_handles| (i.e.,
-  // those pointers themselves). Hmmm.
-
-  if (num_bytes && !VerifyUserPointer<void>(bytes, *num_bytes))
-    return MOJO_RESULT_INVALID_ARGUMENT;
-
-  if (num_handles && !VerifyUserPointer<MojoHandle>(handles, *num_handles))
-    return MOJO_RESULT_INVALID_ARGUMENT;
+  if (num_bytes) {
+    if (!VerifyUserPointer<uint32_t>(num_bytes, 1))
+      return MOJO_RESULT_INVALID_ARGUMENT;
+    if (!VerifyUserPointer<void>(bytes, *num_bytes))
+      return MOJO_RESULT_INVALID_ARGUMENT;
+  }
 
   return message_pipe_->ReadMessage(port_,
                                     bytes, num_bytes,
-                                    handles, num_handles,
+                                    max_num_dispatchers, dispatchers,
                                     flags);
 }