Move JS support code from //mojo/edk/js to //services/js/system
This code lived in //mojo/edk/js to facilitate sharing it with chromium
but since that's no longer a consideration for //mojo/edk this moves it
to live with its only dependency //services/js (the JS content runner).
This makes //mojo/edk's dependencies much clearer.
R=hansmuller@chromium.org, vtl@google.com
Review URL: https://codereview.chromium.org/1374023002 .
diff --git a/services/js/system/drain_data.h b/services/js/system/drain_data.h
new file mode 100644
index 0000000..3632aab
--- /dev/null
+++ b/services/js/system/drain_data.h
@@ -0,0 +1,64 @@
+// 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.
+
+#ifndef SERVICES_JS_SYSTEM_DRAIN_DATA_H_
+#define SERVICES_JS_SYSTEM_DRAIN_DATA_H_
+
+#include "base/memory/scoped_vector.h"
+#include "gin/runner.h"
+#include "mojo/public/c/environment/async_waiter.h"
+#include "mojo/public/cpp/system/core.h"
+#include "v8/include/v8.h"
+
+namespace mojo {
+namespace js {
+
+// This class is the implementation of the Mojo JavaScript core module's
+// drainData() method. It is not intended to be used directly. The caller
+// allocates a DrainData on the heap and returns GetPromise() to JS. The
+// implementation deletes itself after reading as much data as possible
+// and rejecting or resolving the Promise.
+
+class DrainData {
+ public:
+ // Starts waiting for data on the specified data pipe consumer handle.
+ // See WaitForData(). The constructor does not block.
+ DrainData(v8::Isolate* isolate, mojo::Handle handle);
+
+ // Returns a Promise that will be settled when no more data can be read.
+ // Should be called just once on a newly allocated DrainData object.
+ v8::Handle<v8::Value> GetPromise();
+
+ private:
+ ~DrainData();
+
+ // Registers an "async waiter" that calls DataReady() via WaitCompleted().
+ void WaitForData();
+ static void WaitCompleted(void* self, MojoResult result) {
+ static_cast<DrainData*>(self)->DataReady(result);
+ }
+
+ // Use ReadData() to read whatever is availble now on handle_ and save
+ // it in data_buffers_.
+ void DataReady(MojoResult result);
+ MojoResult ReadData();
+
+ // When the remote data pipe handle is closed, or an error occurs, deliver
+ // all of the buffered data to the JS Promise and then delete this.
+ void DeliverData(MojoResult result);
+
+ using DataBuffer = std::vector<char>;
+
+ v8::Isolate* isolate_;
+ ScopedDataPipeConsumerHandle handle_;
+ MojoAsyncWaitID wait_id_;
+ base::WeakPtr<gin::Runner> runner_;
+ v8::UniquePersistent<v8::Promise::Resolver> resolver_;
+ ScopedVector<DataBuffer> data_buffers_;
+};
+
+} // namespace js
+} // namespace mojo
+
+#endif // SERVICES_JS_SYSTEM_DRAIN_DATA_H_
