Mojo: AsyncWaiter and mojo/public/environment

mojo/public/environment/standalone/default_async_waiter.cc

+// Copyright 2014 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.
+
+#include "mojo/public/environment/default_async_waiter.h"
+
+#include <assert.h>
+
+#include "mojo/public/utility/run_loop.h"
+#include "mojo/public/utility/run_loop_handler.h"
+
+namespace mojo {
+namespace {
+
+// RunLoopHandler implementation used for a request to AsyncWait(). There are
+// two ways RunLoopHandlerImpl is deleted:
+// . when the handle is ready (or errored).
+// . when CancelWait() is invoked.
+class RunLoopHandlerImpl : public RunLoopHandler {
+ public:
+  RunLoopHandlerImpl(const Handle& handle,
+                     MojoAsyncWaitCallback callback,
+                     void* closure)
+      : handle_(handle),
+        callback_(callback),
+        closure_(closure) {
+  }
+
+  virtual ~RunLoopHandlerImpl() {
+    RunLoop::current()->RemoveHandler(handle_);
+  }
+
+  // RunLoopHandler:
+  virtual void OnHandleReady(const Handle& handle) MOJO_OVERRIDE {
+    NotifyCallback(MOJO_RESULT_OK);
+  }
+
+  virtual void OnHandleError(const Handle& handle,
+                             MojoResult result) MOJO_OVERRIDE {
+    NotifyCallback(result);
+  }
+
+ private:
+  void NotifyCallback(MojoResult result) {
+    // Delete this to unregister the handle. That way if the callback
+    // reregisters everything is ok.
+    MojoAsyncWaitCallback callback = callback_;
+    void* closure = closure_;
+    delete this;
+
+    callback(closure, result);
+  }
+
+  const Handle handle_;
+  MojoAsyncWaitCallback callback_;
+  void* closure_;
+
+  MOJO_DISALLOW_COPY_AND_ASSIGN(RunLoopHandlerImpl);
+};
+
+MojoAsyncWaitID AsyncWait(MojoAsyncWaiter* waiter,
+                          MojoHandle handle,
+                          MojoWaitFlags flags,
+                          MojoDeadline deadline,
+                          MojoAsyncWaitCallback callback,
+                          void* closure) {
+  RunLoop* run_loop = RunLoop::current();
+  assert(run_loop);
+
+  // |run_loop_handler| is destroyed either when the handle is ready or if
+  // CancelWait is invoked.
+  RunLoopHandlerImpl* run_loop_handler =
+      new RunLoopHandlerImpl(Handle(handle), callback, closure);
+  run_loop->AddHandler(run_loop_handler, Handle(handle), flags, deadline);
+  return reinterpret_cast<MojoAsyncWaitID>(run_loop_handler);
+}
+
+void CancelWait(MojoAsyncWaiter* waiter, MojoAsyncWaitID wait_id) {
+  delete reinterpret_cast<RunLoopHandlerImpl*>(wait_id);
+}
+
+MojoAsyncWaiter s_default_async_waiter = {
+  AsyncWait,
+  CancelWait
+};
+
+}  // namespace
+
+MojoAsyncWaiter* GetDefaultAsyncWaiter() {
+  return &s_default_async_waiter;
+}
+
+}  // namespace mojo