Mojo C++ bindings: support sync methods - part 2

mojo/public/cpp/bindings/lib/connector.cc

Index: mojo/public/cpp/bindings/lib/connector.cc
diff --git a/mojo/public/cpp/bindings/lib/connector.cc b/mojo/public/cpp/bindings/lib/connector.cc
index ceccaa9a109128d0d64d13c82165702beccec1aa..4eff31d2acef7230ee289064735223d7e3e63919 100644
--- a/mojo/public/cpp/bindings/lib/connector.cc
+++ b/mojo/public/cpp/bindings/lib/connector.cc
@@ -7,9 +7,11 @@
 #include <stdint.h>
 #include <utility>
 
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/synchronization/lock.h"
+#include "mojo/public/cpp/bindings/lib/sync_handle_watcher.h"
 
 namespace mojo {
 namespace internal {
@@ -52,8 +54,11 @@ Connector::Connector(ScopedMessagePipeHandle message_pipe,
       drop_writes_(false),
       enforce_errors_from_incoming_receiver_(true),
       paused_(false),
-      destroyed_flag_(nullptr),
-      lock_(config == MULTI_THREADED_SEND ? new base::Lock : nullptr) {
+      lock_(config == MULTI_THREADED_SEND ? new base::Lock : nullptr),
+      register_sync_handle_watch_count_(0),
+      registered_with_sync_handle_watcher_(false),
+      sync_handle_watcher_callback_count_(0),
+      weak_factory_(this) {
   // Even though we don't have an incoming receiver, we still want to monitor
   // the message pipe to know if is closed or encounters an error.
   WaitToReadMore();
@@ -62,9 +67,6 @@ Connector::Connector(ScopedMessagePipeHandle message_pipe,
 Connector::~Connector() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  if (destroyed_flag_)
-    *destroyed_flag_ = true;
-
   CancelWait();
 }
 
@@ -191,17 +193,76 @@ bool Connector::Accept(Message* message) {
   return true;
 }
 
+bool Connector::RegisterSyncHandleWatch() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (error_)
+    return false;
+
+  register_sync_handle_watch_count_++;
+
+  if (!registered_with_sync_handle_watcher_ && !paused_) {
+    registered_with_sync_handle_watcher_ =
+        SyncHandleWatcher::current()->RegisterHandle(
+            message_pipe_.get(), MOJO_HANDLE_SIGNAL_READABLE,
+            base::Bind(&Connector::OnSyncHandleWatcherHandleReady,
+                       base::Unretained(this)));
+  }
+  return true;
+}
+
+void Connector::UnregisterSyncHandleWatch() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (register_sync_handle_watch_count_ == 0) {
+    NOTREACHED();
+    return;
+  }
+
+  register_sync_handle_watch_count_--;
+  if (register_sync_handle_watch_count_ > 0)
+    return;
+
+  if (registered_with_sync_handle_watcher_) {
+    SyncHandleWatcher::current()->UnregisterHandle(message_pipe_.get());
+    registered_with_sync_handle_watcher_ = false;
+  }
+}
+
+bool Connector::RunSyncHandleWatch(const bool* should_stop) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK_GT(register_sync_handle_watch_count_, 0u);
+
+  if (error_)
+    return false;
+
+  ResumeIncomingMethodCallProcessing();
+
+  return SyncHandleWatcher::current()->WatchAllHandles(message_pipe_.get(),
+                                                       should_stop);
+}
+
 // static
 void Connector::CallOnHandleReady(void* closure, MojoResult result) {
   Connector* self = static_cast<Connector*>(closure);
-  self->OnHandleReady(result);
+  CHECK(self->async_wait_id_ != 0);
+  self->async_wait_id_ = 0;
+  self->OnHandleReadyInternal(result);
 }
 
-void Connector::OnHandleReady(MojoResult result) {
+void Connector::OnSyncHandleWatcherHandleReady(MojoResult result) {
+  base::WeakPtr<Connector> weak_self(weak_factory_.GetWeakPtr());
+
+  sync_handle_watcher_callback_count_++;
+  OnHandleReadyInternal(result);
+  // At this point, this object might have been deleted.
+  if (weak_self)
+    sync_handle_watcher_callback_count_--;
+}
+
+void Connector::OnHandleReadyInternal(MojoResult result) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  CHECK(async_wait_id_ != 0);
-  async_wait_id_ = 0;
   if (result != MOJO_RESULT_OK) {
     HandleError(result != MOJO_RESULT_FAILED_PRECONDITION, false);
     return;
@@ -218,6 +279,15 @@ void Connector::WaitToReadMore() {
                                       MOJO_DEADLINE_INDEFINITE,
                                       &Connector::CallOnHandleReady,
                                       this);
+
+  if (register_sync_handle_watch_count_ > 0 &&
+      !registered_with_sync_handle_watcher_) {
+    registered_with_sync_handle_watcher_ =
+        SyncHandleWatcher::current()->RegisterHandle(
+            message_pipe_.get(), MOJO_HANDLE_SIGNAL_READABLE,
+            base::Bind(&Connector::OnSyncHandleWatcherHandleReady,
+                       base::Unretained(this)));
+  }
 }
 
 bool Connector::ReadSingleMessage(MojoResult* read_result) {
@@ -227,9 +297,7 @@ bool Connector::ReadSingleMessage(MojoResult* read_result) {
 
   // Detect if |this| was destroyed during message dispatch. Allow for the
   // possibility of re-entering ReadMore() through message dispatch.
-  bool was_destroyed_during_dispatch = false;
-  bool* previous_destroyed_flag = destroyed_flag_;
-  destroyed_flag_ = &was_destroyed_during_dispatch;
+  base::WeakPtr<Connector> weak_self = weak_factory_.GetWeakPtr();
 
   Message message;
   const MojoResult rv = ReadMessage(message_pipe_.get(), &message);
@@ -247,13 +315,8 @@ bool Connector::ReadSingleMessage(MojoResult* read_result) {
         incoming_receiver_ && incoming_receiver_->Accept(&message);
   }
 
-  if (was_destroyed_during_dispatch) {
-    if (previous_destroyed_flag)
-      *previous_destroyed_flag = true;  // Propagate flag.
+  if (!weak_self)
     return false;
-  }
-
-  destroyed_flag_ = previous_destroyed_flag;
 
   if (rv == MOJO_RESULT_SHOULD_WAIT)
     return true;
@@ -295,11 +358,15 @@ void Connector::ReadAllAvailableMessages() {
 }
 
 void Connector::CancelWait() {
-  if (!async_wait_id_)
-    return;
+  if (async_wait_id_) {
+    waiter_->CancelWait(async_wait_id_);
+    async_wait_id_ = 0;
+  }
 
-  waiter_->CancelWait(async_wait_id_);
-  async_wait_id_ = 0;
+  if (registered_with_sync_handle_watcher_) {
+    SyncHandleWatcher::current()->UnregisterHandle(message_pipe_.get());
+    registered_with_sync_handle_watcher_ = false;
+  }
 }
 
 void Connector::HandleError(bool force_pipe_reset, bool force_async_handler) {