Index: mojo/public/cpp/bindings/lib/sync_handle_watcher.h |
diff --git a/mojo/public/cpp/bindings/lib/sync_handle_watcher.h b/mojo/public/cpp/bindings/lib/sync_handle_watcher.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..734a21289a5890f61fc6dfeb4bf30d2a059f95de |
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+++ b/mojo/public/cpp/bindings/lib/sync_handle_watcher.h |
@@ -0,0 +1,73 @@ |
+// Copyright 2016 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. |
+ |
+#ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_SYNC_HANDLE_WATCHER_H_ |
+#define MOJO_PUBLIC_CPP_BINDINGS_LIB_SYNC_HANDLE_WATCHER_H_ |
+ |
+#include <unordered_map> |
+ |
+#include "base/callback.h" |
+#include "base/macros.h" |
+#include "base/message_loop/message_loop.h" |
+#include "base/threading/thread_checker.h" |
+#include "mojo/public/cpp/system/core.h" |
+ |
+namespace mojo { |
+namespace internal { |
+ |
+// SyncHandleWatcher is used to support sync methods. While a sync call is |
+// waiting for response, we would like incoming sync method requests on the same |
+// thread to be able to reenter. We also would like master endpoints to continue |
+// dispatching messages for associated endpoints on different threads. |
+// Therefore, SyncHandleWatcher is used as thread-local storage to register all |
+// handles that need to be watched while waiting for sync call responses. |
+// |
+// This class is not thread safe. |
+class SyncHandleWatcher : public base::MessageLoop::DestructionObserver { |
+ public: |
+ // Returns a thread-local object. |
+ static SyncHandleWatcher* current(); |
+ |
+ using HandleCallback = base::Callback<void(MojoResult)>; |
+ bool RegisterHandle(const Handle& handle, |
+ MojoHandleSignals handle_signals, |
+ const HandleCallback& callback); |
+ |
+ void UnregisterHandle(const Handle& handle); |
+ |
+ // Waits on all the registered handles and runs callbacks synchronously for |
+ // those ready handles. |
+ // The method: |
+ // - returns true when |*should_stop| is set to true; |
+ // - returns false when either |caller_handle| is unregistered or any error |
+ // occurs. |
+ bool WatchAllHandles(const Handle& caller_handle, const bool* should_stop); |
+ |
+ private: |
+ struct HandleHasher { |
+ size_t operator()(const Handle& handle) const { |
+ return std::hash<uint32_t>()(static_cast<uint32_t>(handle.value())); |
+ } |
+ }; |
+ using HandleMap = std::unordered_map<Handle, HandleCallback, HandleHasher>; |
+ |
+ SyncHandleWatcher(); |
+ ~SyncHandleWatcher() override; |
+ |
+ // base::MessageLoop::DestructionObserver implementation: |
+ void WillDestroyCurrentMessageLoop() override; |
+ |
+ HandleMap handles_; |
+ |
+ ScopedHandle wait_set_handle_; |
+ |
+ base::ThreadChecker thread_checker_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(SyncHandleWatcher); |
+}; |
+ |
+} // namespace internal |
+} // namespace mojo |
+ |
+#endif // MOJO_PUBLIC_CPP_BINDINGS_LIB_SYNC_HANDLE_WATCHER_H_ |