Factor DrainDataPipeJob out of MojoLoader

sky/engine/platform/fetcher/DrainDataPipeJob.cpp

+// 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 "config.h"
+#include "platform/fetcher/DrainDataPipeJob.h"
+
+#include "base/bind.h"
+
+namespace blink {
+
+DrainDataPipeJob::DrainDataPipeJob(Client* client,
+                                   mojo::ScopedDataPipeConsumerHandle source)
+    : client_(client),
+      source_(source.Pass()),
+      weak_factory_(this) {
+  DCHECK(client_);
+  ReadData();
+}
+
+DrainDataPipeJob::~DrainDataPipeJob() {
+}
+
+void DrainDataPipeJob::ReadData() {
+  const void* buffer = nullptr;
+  uint32_t num_bytes = 0;
+  MojoResult rv = BeginReadDataRaw(source_.get(),
+      &buffer, &num_bytes, MOJO_READ_DATA_FLAG_NONE);
+  if (rv == MOJO_RESULT_OK) {
+    client_->OnDataAvailable(buffer, num_bytes);
+    EndReadDataRaw(source_.get(), num_bytes);
+    WaitForData();
+  } else if (rv == MOJO_RESULT_SHOULD_WAIT) {
+    WaitForData();
+  } else if (rv == MOJO_RESULT_FAILED_PRECONDITION) {
+    client_->OnDataComplete();
+  } else {
+    DCHECK(false);
+  }
+}
+
+void DrainDataPipeJob::WaitForData() {
+  handle_watcher_.Start(source_.get(),
+      MOJO_HANDLE_SIGNAL_READABLE, MOJO_DEADLINE_INDEFINITE,
+      base::Bind(&DrainDataPipeJob::WaitComplete, weak_factory_.GetWeakPtr()));
+}
+
+void DrainDataPipeJob::WaitComplete(MojoResult result) {
+  ReadData();
+}
+
+}  // namespace blink