Mojo: First stab at making MessagePipes work across OS pipes.

mojo/system/message_pipe.cc

Index: mojo/system/message_pipe.cc
diff --git a/mojo/system/message_pipe.cc b/mojo/system/message_pipe.cc
index bfb06466efedc59b6e1a20c7d12f02e0d9231841..857cdbcd2ba019221160e244eede76e8f3f2e8ea 100644
--- a/mojo/system/message_pipe.cc
+++ b/mojo/system/message_pipe.cc
@@ -6,22 +6,15 @@
 
 #include "base/logging.h"
 #include "base/stl_util.h"
+#include "mojo/system/channel.h"
 #include "mojo/system/local_message_pipe_endpoint.h"
 #include "mojo/system/message_in_transit.h"
 #include "mojo/system/message_pipe_endpoint.h"
+#include "mojo/system/proxy_message_pipe_endpoint.h"
 
 namespace mojo {
 namespace system {
 
-namespace {
-
-unsigned DestinationPortFromSourcePort(unsigned port) {
-  DCHECK(port == 0 || port == 1);
-  return port ^ 1;
-}
-
-}  // namespace
-
 MessagePipe::MessagePipe(scoped_ptr<MessagePipeEndpoint> endpoint_0,
                          scoped_ptr<MessagePipeEndpoint> endpoint_1) {
   endpoints_[0].reset(endpoint_0.release());
@@ -33,6 +26,12 @@ MessagePipe::MessagePipe() {
   endpoints_[1].reset(new LocalMessagePipeEndpoint());
 }
 
+// static
+unsigned MessagePipe::GetPeerPort(unsigned port) {
+  DCHECK(port == 0 || port == 1);
+  return port ^ 1;
+}
+
 void MessagePipe::CancelAllWaiters(unsigned port) {
   DCHECK(port == 0 || port == 1);
 
@@ -44,38 +43,36 @@ void MessagePipe::CancelAllWaiters(unsigned port) {
 void MessagePipe::Close(unsigned port) {
   DCHECK(port == 0 || port == 1);
 
-  unsigned destination_port = DestinationPortFromSourcePort(port);
+  unsigned destination_port = GetPeerPort(port);
 
   base::AutoLock locker(lock_);
   DCHECK(endpoints_[port].get());
 
   endpoints_[port]->Close();
-  if (endpoints_[destination_port].get())
-    endpoints_[destination_port]->OnPeerClose();
+  bool should_destroy_destination = endpoints_[destination_port].get() ?
+      !endpoints_[destination_port]->OnPeerClose() : false;
 
   endpoints_[port].reset();
+  if (should_destroy_destination) {
+    endpoints_[destination_port]->Close();
+    endpoints_[destination_port].reset();
+  }
 }
 
+// TODO(vtl): Support sending handles.
 // TODO(vtl): Handle flags.
 MojoResult MessagePipe::WriteMessage(
     unsigned port,
     const void* bytes, uint32_t num_bytes,
-    const MojoHandle* handles, uint32_t num_handles,
+    const MojoHandle* /*handles*/, uint32_t /*num_handles*/,
     MojoWriteMessageFlags flags) {
   DCHECK(port == 0 || port == 1);
-
-  unsigned destination_port = DestinationPortFromSourcePort(port);
-
-  base::AutoLock locker(lock_);
-  DCHECK(endpoints_[port].get());
-
-  // The destination port need not be open, unlike the source port.
-  if (!endpoints_[destination_port].get())
-    return MOJO_RESULT_FAILED_PRECONDITION;
-
-  return endpoints_[destination_port]->EnqueueMessage(bytes, num_bytes,
-                                                      handles, num_handles,
-                                                      flags);
+  return EnqueueMessage(
+      GetPeerPort(port),
+      MessageInTransit::Create(
+          MessageInTransit::kTypeMessagePipeEndpoint,
+          MessageInTransit::kSubtypeMessagePipeEndpointData,
+          bytes, num_bytes));
 }
 
 MojoResult MessagePipe::ReadMessage(unsigned port,
@@ -113,6 +110,54 @@ void MessagePipe::RemoveWaiter(unsigned port, Waiter* waiter) {
   endpoints_[port]->RemoveWaiter(waiter);
 }
 
+MojoResult MessagePipe::EnqueueMessage(unsigned port,
+                                       MessageInTransit* message) {
+  DCHECK(port == 0 || port == 1);
+  DCHECK(message);
+
+  if (message->type() == MessageInTransit::kTypeMessagePipe)
+    return HandleControlMessage(port, message);
+
+  DCHECK_EQ(message->type(), MessageInTransit::kTypeMessagePipeEndpoint);
+
+  base::AutoLock locker(lock_);
+  DCHECK(endpoints_[GetPeerPort(port)].get());
+
+  // The destination port need not be open, unlike the source port.
+  if (!endpoints_[port].get()) {
+    message->Destroy();
+    return MOJO_RESULT_FAILED_PRECONDITION;
+  }
+
+  return endpoints_[port]->EnqueueMessage(message);
+}
+
+void MessagePipe::Attach(unsigned port,
+                         scoped_refptr<Channel> channel,
+                         MessageInTransit::EndpointId local_id) {
+  DCHECK(port == 0 || port == 1);
+  DCHECK(channel.get());
+  DCHECK_NE(local_id, MessageInTransit::kInvalidEndpointId);
+
+  base::AutoLock locker(lock_);
+  DCHECK(endpoints_[port].get());
+
+  endpoints_[port]->Attach(channel, local_id);
+}
+
+void MessagePipe::Run(unsigned port, MessageInTransit::EndpointId remote_id) {
+  DCHECK(port == 0 || port == 1);
+  DCHECK_NE(remote_id, MessageInTransit::kInvalidEndpointId);
+
+  base::AutoLock locker(lock_);
+  DCHECK(endpoints_[port].get());
+
+  if (!endpoints_[port]->Run(remote_id)) {
+    endpoints_[port]->Close();
+    endpoints_[port].reset();
+  }
+}
+
 MessagePipe::~MessagePipe() {
   // Owned by the dispatchers. The owning dispatchers should only release us via
   // their |Close()| method, which should inform us of being closed via our
@@ -121,5 +166,37 @@ MessagePipe::~MessagePipe() {
   DCHECK(!endpoints_[1].get());
 }
 
+MojoResult MessagePipe::HandleControlMessage(unsigned port,
+                                             MessageInTransit* message) {
+  DCHECK(port == 0 || port == 1);
+  DCHECK(message);
+  DCHECK_EQ(message->type(), MessageInTransit::kTypeMessagePipe);
+
+  MojoResult rv = MOJO_RESULT_OK;
+  switch (message->subtype()) {
+    case MessageInTransit::kSubtypeMessagePipePeerClosed: {
+      unsigned source_port = GetPeerPort(port);
+
+      base::AutoLock locker(lock_);
+      DCHECK(endpoints_[source_port].get());
+
+      endpoints_[source_port]->Close();
+      if (endpoints_[port].get())
+        endpoints_[port]->OnPeerClose();
+
+      endpoints_[source_port].reset();
+      break;
+    }
+    default:
+      LOG(WARNING) << "Unrecognized MessagePipe control message subtype "
+                   << message->subtype();
+      rv = MOJO_RESULT_UNKNOWN;
+      break;
+  }
+
+  message->Destroy();
+  return rv;
+}
+
 }  // namespace system
 }  // namespace mojo