Mojo: share code between SyncDispatcher and Connector

R=piman@chromium.org

Review URL: https://codereview.chromium.org/185723003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254952 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 55 insertions, 57 deletions

diff --git a/mojo/public/bindings/lib/connector.cc b/mojo/public/bindings/lib/connector.cc
index 076e30b..ccdee5c 100644
--- a/mojo/public/bindings/lib/connector.cc
+++ b/mojo/public/bindings/lib/connector.cc
@@ -107,44 +107,18 @@ void Connector::WaitToReadMore() {
 }
 
 void Connector::ReadMore() {
-  for (;;) {
+  while (true) {
     MojoResult rv;
 
-    uint32_t num_bytes = 0, num_handles = 0;
-    rv = ReadMessageRaw(message_pipe_.get(),
-                        NULL,
-                        &num_bytes,
-                        NULL,
-                        &num_handles,
-                        MOJO_READ_MESSAGE_FLAG_NONE);
+    rv = ReadAndDispatchMessage(message_pipe_.get(), incoming_receiver_, NULL);
     if (rv == MOJO_RESULT_SHOULD_WAIT) {
       WaitToReadMore();
       break;
     }
-    if (rv != MOJO_RESULT_RESOURCE_EXHAUSTED) {
-      error_ = true;
-      break;
-    }
-
-    Message message;
-    message.AllocUninitializedData(num_bytes);
-    message.mutable_handles()->resize(num_handles);
-
-    rv = ReadMessageRaw(
-        message_pipe_.get(),
-        message.mutable_data(),
-        &num_bytes,
-        message.mutable_handles()->empty() ? NULL :
-            reinterpret_cast<MojoHandle*>(&message.mutable_handles()->front()),
-        &num_handles,
-        MOJO_READ_MESSAGE_FLAG_NONE);
     if (rv != MOJO_RESULT_OK) {
       error_ = true;
       break;
     }
-
-    if (incoming_receiver_)
-      incoming_receiver_->Accept(&message);
   }
 }
 
diff --git a/mojo/public/bindings/lib/message.cc b/mojo/public/bindings/lib/message.cc
index f33f250a..b57061d 100644
--- a/mojo/public/bindings/lib/message.cc
+++ b/mojo/public/bindings/lib/message.cc
@@ -44,4 +44,41 @@ void Message::Swap(Message* other) {
   std::swap(handles_, other->handles_);
 }
 
+MojoResult ReadAndDispatchMessage(MessagePipeHandle handle,
+                                  MessageReceiver* receiver,
+                                  bool* receiver_result) {
+  MojoResult rv;
+
+  uint32_t num_bytes = 0, num_handles = 0;
+  rv = ReadMessageRaw(handle,
+                      NULL,
+                      &num_bytes,
+                      NULL,
+                      &num_handles,
+                      MOJO_READ_MESSAGE_FLAG_NONE);
+  if (rv != MOJO_RESULT_RESOURCE_EXHAUSTED)
+    return rv;
+
+  Message message;
+  message.AllocUninitializedData(num_bytes);
+  message.mutable_handles()->resize(num_handles);
+
+  rv = ReadMessageRaw(handle,
+                      message.mutable_data(),
+                      &num_bytes,
+                      message.mutable_handles()->empty()
+                          ? NULL
+                          : reinterpret_cast<MojoHandle*>(
+                                &message.mutable_handles()->front()),
+                      &num_handles,
+                      MOJO_READ_MESSAGE_FLAG_NONE);
+  if (receiver && rv == MOJO_RESULT_OK) {
+    bool result = receiver->Accept(&message);
+    if (receiver_result)
+      *receiver_result = result;
+  }
+
+  return rv;
+}
+
 }  // namespace mojo
diff --git a/mojo/public/bindings/lib/sync_dispatcher.cc b/mojo/public/bindings/lib/sync_dispatcher.cc
index f27fc17..4c3c6d6 100644
--- a/mojo/public/bindings/lib/sync_dispatcher.cc
+++ b/mojo/public/bindings/lib/sync_dispatcher.cc
@@ -11,39 +11,17 @@
 namespace mojo {
 
 bool WaitForMessageAndDispatch(MessagePipeHandle handle,
-                               mojo::MessageReceiver* receiver) {
-  uint32_t num_bytes = 0, num_handles = 0;
+                               MessageReceiver* receiver) {
   while (true) {
-    MojoResult rv = ReadMessageRaw(handle,
-                                   NULL,
-                                   &num_bytes,
-                                   NULL,
-                                   &num_handles,
-                                   MOJO_READ_MESSAGE_FLAG_NONE);
-    if (rv == MOJO_RESULT_RESOURCE_EXHAUSTED)
-      break;
-    if (rv != MOJO_RESULT_SHOULD_WAIT)
-      return false;
-    rv = Wait(handle, MOJO_WAIT_FLAG_READABLE, MOJO_DEADLINE_INDEFINITE);
+    bool result;
+    MojoResult rv = ReadAndDispatchMessage(handle, receiver, &result);
+    if (rv == MOJO_RESULT_OK)
+      return result;
+    if (rv == MOJO_RESULT_SHOULD_WAIT)
+      rv = Wait(handle, MOJO_WAIT_FLAG_READABLE, MOJO_DEADLINE_INDEFINITE);
     if (rv != MOJO_RESULT_OK)
       return false;
   }
-
-  Message message;
-  message.AllocUninitializedData(num_bytes);
-  message.mutable_handles()->resize(num_handles);
-
-  MojoResult rv = ReadMessageRaw(
-      handle,
-      message.mutable_data(),
-      &num_bytes,
-      message.mutable_handles()->empty() ? NULL :
-          reinterpret_cast<MojoHandle*>(&message.mutable_handles()->front()),
-      &num_handles,
-      MOJO_READ_MESSAGE_FLAG_NONE);
-  if (rv != MOJO_RESULT_OK)
-    return false;
-  return receiver->Accept(&message);
 }
 
 }  // namespace mojo
diff --git a/mojo/public/bindings/message.h b/mojo/public/bindings/message.h
index 7b058b8..3198f459 100644
--- a/mojo/public/bindings/message.h
+++ b/mojo/public/bindings/message.h
@@ -79,6 +79,15 @@ class MessageReceiver {
                                    MessageReceiver* responder) = 0;
 };
 
+// Read a single message from the pipe and dispatch to the given receiver.  The
+// receiver may be null, in which case the message is simply discarded.
+// Returns MOJO_RESULT_SHOULD_WAIT if the caller should wait on the handle to
+// become readable. Returns MOJO_RESULT_OK if a message was dispatched and
+// otherwise returns an error code if something went wrong.
+MojoResult ReadAndDispatchMessage(MessagePipeHandle handle,
+                                  MessageReceiver* receiver,
+                                  bool* receiver_result);
+
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_BINDINGS_MESSAGE_H_