Initial implementation of Cronet Async API.

components/cronet/android/cronet_url_request_adapter.cc

Index: components/cronet/android/cronet_url_request_adapter.cc
diff --git a/components/cronet/android/cronet_url_request_adapter.cc b/components/cronet/android/cronet_url_request_adapter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1d3413060da185a4257a0f07092ad275111c58e6
--- /dev/null
+++ b/components/cronet/android/cronet_url_request_adapter.cc
@@ -0,0 +1,191 @@
+// 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 "cronet_url_request_adapter.h"
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "components/cronet/android/cronet_url_request_context_adapter.h"
+#include "components/cronet/android/wrapped_channel_upload_element_reader.h"
+#include "net/base/io_buffer.h"
+#include "net/base/load_flags.h"
+#include "net/http/http_status_code.h"
+#include "net/url_request/redirect_info.h"
+#include "net/url_request/url_request_context.h"
+
+namespace cronet {
+
+static const int kReadBufferSize = 32768;
+
+CronetURLRequestAdapter::CronetURLRequestAdapter(
+    CronetURLRequestContextAdapter* context,
+    CronetURLRequestAdapterDelegate* delegate,
+    const GURL& url,
+    net::RequestPriority priority)
+    : context_(context),
+      delegate_(delegate),
+      initial_url_(url),
+      initial_priority_(priority),
+      initial_method_("GET"),
+      read_buffer_(new net::IOBufferWithSize(kReadBufferSize)) {
+
+}
+
+CronetURLRequestAdapter::~CronetURLRequestAdapter() {
+}
+
+void CronetURLRequestAdapter::AddRequestHeader(const std::string& name,
+                                               const std::string& value) {
+  initial_request_headers_.SetHeader(name, value);
+}
+
+net::HttpResponseHeaders* CronetURLRequestAdapter::GetResponseHeaders() const {
+  DCHECK(IsOnNetworkThread());
+  return url_request_->response_headers();
+}
+
+const std::string& CronetURLRequestAdapter::GetNegotiatedProtocol() const {
+  DCHECK(IsOnNetworkThread());
+  return url_request_->response_info().npn_negotiated_protocol;
+}
+
+bool CronetURLRequestAdapter::GetWasCached() const {
+  DCHECK(IsOnNetworkThread());
+  return url_request_->response_info().was_cached;
+}
+
+int64 CronetURLRequestAdapter::GetTotalReceivedBytes() const {
+  DCHECK(IsOnNetworkThread());
+  return url_request_->GetTotalReceivedBytes();
+}
+
+void CronetURLRequestAdapter::Start() {
+  DCHECK(!IsOnNetworkThread());
+  context_->GetNetworkTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&CronetURLRequestAdapter::StartOnNetworkThread,
+                 base::Unretained(this)));
+}
+
+void CronetURLRequestAdapter::FollowDeferredRedirect() {
+  DCHECK(!IsOnNetworkThread());
+  context_->GetNetworkTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(
+          &CronetURLRequestAdapter::FollowDeferredRedirectOnNetworkThread,
+          base::Unretained(this)));
+}
+
+// Receive more data.
+void CronetURLRequestAdapter::ReadData() {
+  DCHECK(!IsOnNetworkThread());
+  context_->GetNetworkTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&CronetURLRequestAdapter::ReadDataOnNetworkThread,
+                 base::Unretained(this)));
+}
+
+void CronetURLRequestAdapter::Destroy() {
+  DCHECK(!IsOnNetworkThread());
+  context_->GetNetworkTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&CronetURLRequestAdapter::DestroyOnNetworkThread,
+                 base::Unretained(this)));
+}
+
+// net::URLRequest::Delegate overrides (called on network thread).
+
+void CronetURLRequestAdapter::OnReceivedRedirect(
+    net::URLRequest* request,
+    const net::RedirectInfo& redirect_info,
+    bool* defer_redirect) {
+  DCHECK(IsOnNetworkThread());
+  DCHECK(request->status().is_success());
+  delegate_->OnRedirect(redirect_info.new_url, redirect_info.status_code);
+  *defer_redirect = true;
+}
+
+void CronetURLRequestAdapter::OnResponseStarted(net::URLRequest* request) {
+  DCHECK(IsOnNetworkThread());
+  if (!MaybeReportError(request))
+    return;
+  delegate_->OnResponseStarted(request->GetResponseCode());
+}
+
+void CronetURLRequestAdapter::OnReadCompleted(net::URLRequest* request,
+                                              int bytes_read) {
+  DCHECK(IsOnNetworkThread());
+  if (!MaybeReportError(request))
+    return;
+  if (bytes_read != 0) {
+    delegate_->OnBytesRead(Data(), bytes_read);
+  } else {
+    delegate_->OnRequestFinished();
+  }
+}
+
+bool CronetURLRequestAdapter::IsOnNetworkThread() const {
+  return context_->GetNetworkTaskRunner()->BelongsToCurrentThread();
+}
+
+void CronetURLRequestAdapter::StartOnNetworkThread() {
+  DCHECK(IsOnNetworkThread());
+  VLOG(1) << "Starting chromium request: "
+          << initial_url_.possibly_invalid_spec().c_str()
+          << " priority: " << RequestPriorityToString(initial_priority_);
+  url_request_ = context_->GetURLRequestContext()->CreateRequest(
+      initial_url_, net::DEFAULT_PRIORITY, this, NULL);
+  url_request_->SetLoadFlags(net::LOAD_DISABLE_CACHE |
+                             net::LOAD_DO_NOT_SAVE_COOKIES |
+                             net::LOAD_DO_NOT_SEND_COOKIES);
+  url_request_->set_method(initial_method_);
+  url_request_->SetExtraRequestHeaders(initial_request_headers_);
+  url_request_->SetPriority(initial_priority_);
+  url_request_->Start();
+}
+
+void CronetURLRequestAdapter::FollowDeferredRedirectOnNetworkThread() {
+  DCHECK(IsOnNetworkThread());
+
+  url_request_->FollowDeferredRedirect();
+}
+
+// Reads all available data or starts an asynchronous read.
+void CronetURLRequestAdapter::ReadDataOnNetworkThread() {
+  DCHECK(IsOnNetworkThread());
+  int bytes_read = 0;
+  // If read completes synchronously, pass data to delegate.
+  if (url_request_->Read(
+          read_buffer_.get(), read_buffer_->size(), &bytes_read)) {
+    OnReadCompleted(url_request_.get(), bytes_read);
+  } else if (url_request_->status().status() !=
+             net::URLRequestStatus::IO_PENDING) {
+    OnReadCompleted(url_request_.get(), -1);
+  }
+}
+
+void CronetURLRequestAdapter::DestroyOnNetworkThread() {
+  DCHECK(IsOnNetworkThread());
+  VLOG(1) << "Destroy chromium request: " <<
+      initial_url_.possibly_invalid_spec();
+  delete this;
+}
+
+bool CronetURLRequestAdapter::MaybeReportError(net::URLRequest* request) const {

[xunjieli, 2014/10/31 21:01:51]

nit: I often find "Maybe*" methods hard to reason about. Perhaps add a comment
to this method? Sth along the line of "Returns whether |request| has an error,
and propagates the error to the delegate if there is one."

[mef, 2014/10/31 21:43:15]

Acknowledged. There is a comment in the .h file, is it not clear enough?

[xunjieli, 2014/11/03 14:26:05]

Sorry, I didn't see it. I don't like how c++ separates comments to header file,
so hard to find. I don't think anyone reads header files except compilers :)
okay thanks.

[mmenke, 2014/11/03 16:26:10]

The style is for function level comments to go with function declarations. The
theory is that that's where consumers should look - people that use an API
should never have to open up the source files where it's actually implemented in
order to use it.

+  DCHECK_NE(net::URLRequestStatus::IO_PENDING, url_request_->status().status());
+  DCHECK_EQ(request, url_request_);
+  if (url_request_->status().is_success())
+    return true;
+  VLOG(1) << "Error " << url_request_->status().error()
+          << " on chromium request: " << initial_url_.possibly_invalid_spec();
+  delegate_->OnError(url_request_->status().error());
+  return false;
+}
+
+unsigned char* CronetURLRequestAdapter::Data() const {
+  return reinterpret_cast<unsigned char*>(read_buffer_->data());
+}
+
+}  // namespace cronet