[Cronet] Upload support for async APIs

components/cronet/android/cronet_upload_data_stream_delegate.h

+// Copyright 2015 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 COMPONENTS_CRONET_ANDROID_CRONET_UPLOAD_DATA_STREAM_DELEGATE_H_
+#define COMPONENTS_CRONET_ANDROID_CRONET_UPLOAD_DATA_STREAM_DELEGATE_H_
+
+#include <jni.h>
+
+#include "base/android/scoped_java_ref.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "components/cronet/android/cronet_upload_data_stream_adapter.h"
+#include "net/base/io_buffer.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}  // namespace base
+
+namespace cronet {
+
+// The Delegate holds onto a reference to the IOBuffer that is currently being
+// written to in Java, so may not be deleted until any read operation in Java
+// has completed.
+//
+// The Delegate is owned by the Java CronetUploadDataStream, and also owns a
+// reference to it. The Delegate is only destroyed after the URLRequest
+// destroys the adapter and the CronetUploadDataStream has no read operation
+// pending, at which point it also releases its reference to the
+// CronetUploadDataStream.
+//
+// Failures don't go through the delegate, but directly to the Java request
+// object, since normally reads aren't allowed to fail during an upload.
+class CronetUploadDataStreamDelegate
+    : public CronetUploadDataStreamAdapter::Delegate {
+ public:
+  CronetUploadDataStreamDelegate(JNIEnv* env, jobject jupload_data_stream);
+  ~CronetUploadDataStreamDelegate() override;
+
+  // CronetUploadDataStreamAdapter::Delegate implementation.  Called on network
+  // thread.
+  void InitializeOnNetworkThread(
+      base::WeakPtr<CronetUploadDataStreamAdapter> adapter) override;
+  void Read(net::IOBuffer* buffer, int buf_len) override;
+  void Rewind() override;
+  void OnAdapterDestroyed() override;
+
+  // Callbacks from Java, called on some Java thread.
+  void OnReadSucceeded(JNIEnv* env,
+                       jobject obj,
+                       int bytes_read,
+                       bool final_chunk);
+  void OnRewindSucceeded(JNIEnv* env, jobject obj);
+
+ private:
+  // Initialized on construction, effectively constant.
+  base::android::ScopedJavaGlobalRef<jobject> jupload_data_stream_;
+
+  // These are initialized in InitializeOnNetworkThread, so are safe to access
+  // during Java callbacks, which all happen after initialization.
+  scoped_refptr<base::SingleThreadTaskRunner> network_task_runner_;
+  base::WeakPtr<CronetUploadDataStreamAdapter> adapter_;
+
+  // Used to keep the read buffer alive until the callback from Java has been
+  // received.
+  scoped_refptr<net::IOBuffer> buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(CronetUploadDataStreamDelegate);
+};
+
+// Explicitly register static JNI functions.
+bool CronetUploadDataStreamDelegateRegisterJni(JNIEnv* env);
+
+}  // namespace cronet
+
+#endif  // COMPONENTS_CRONET_ANDROID_CRONET_UPLOAD_DATA_STREAM_DELEGATE_H_