DevToolsNetworkController: support "limit throughput" network condition.

chrome/browser/devtools/devtools_network_transaction.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 "chrome/browser/devtools/devtools_network_transaction.h"
 
 #include "chrome/browser/devtools/devtools_network_controller.h"
 #include "net/base/net_errors.h"
 #include "net/base/upload_progress.h"
 #include "net/http/http_network_transaction.h"
 #include "net/http/http_request_info.h"
 
 DevToolsNetworkTransaction::DevToolsNetworkTransaction(
     DevToolsNetworkController* controller,
     scoped_ptr<net::HttpTransaction> network_transaction)
     : controller_(controller),
       network_transaction_(network_transaction.Pass()),
       request_(NULL),
       failed_(false),
+      callback_type_(NONE),
       proxy_callback_(base::Bind(&DevToolsNetworkTransaction::OnCallback,
                                  base::Unretained(this))) {
   DCHECK(controller);
   controller->AddTransaction(this);
 }
 
 DevToolsNetworkTransaction::~DevToolsNetworkTransaction() {
   controller_->RemoveTransaction(this);
 }
 
+void DevToolsNetworkTransaction::Throttle(int result) {
+  throttled_result_ = result;
+  int64_t penalty = 0;
+  if (callback_type_ == START)
+    penalty += network_transaction_->GetTotalReceivedBytes();
+  if (result > 0)
+    penalty += result;
+  // Ensure that callback won't fire synchronously.
+  // TODO(eustas): Improve penalty calculation.
+  if (penalty == 0)
+    penalty = 1;
+  controller_->ThrottleTransaction(this, penalty);
+}
+
 void DevToolsNetworkTransaction::OnCallback(int rv) {
   if (failed_)
     return;
   DCHECK(!callback_.is_null());
+  if (callback_type_ == START || callback_type_ == READ) {
+    if (controller_->ShouldThrottle(request_)) {
+      Throttle(rv);
+      return;
+    }
+  }
   net::CompletionCallback callback = callback_;
   callback_.Reset();
+  callback_type_ = NONE;
   callback.Run(rv);
 }
 
+int DevToolsNetworkTransaction::SetupCallback(
+    net::CompletionCallback callback,
+    int result,
+    CallbackType callback_type) {
+  DCHECK(callback_type_ == NONE);
+
+  if (result == net::ERR_IO_PENDING) {
+    callback_type_ = callback_type;
+    callback_ = callback;
+    return result;
+  }
+
+  if (!controller_->ShouldThrottle(request_))
+    return result;
+
+  // In case of read error we can't calculate penalty.

[vsevik, 2014/06/11 12:08:51]

What about if (callback_type == START && result < 0) case?

[eustas, 2014/06/11 13:18:48]

Done.

+  if (callback_type == READ && result < 0)
+    return result;
+
+  // URLRequestJob relies on synchronous end-of-stream notification.
+  if (callback_type == READ && result == 0)
+    return result;
+
+  callback_type_ = callback_type;

[vsevik, 2014/06/11 12:08:52]

Does it mean we also throttle requests of types other than START and READ now?

[eustas, 2014/06/11 13:18:48]

Done.

+  callback_ = callback;
+  Throttle(result);
+  return net::ERR_IO_PENDING;
+}
+
 void DevToolsNetworkTransaction::Fail() {
   DCHECK(request_);
   DCHECK(!failed_);
   failed_ = true;
   network_transaction_->SetBeforeNetworkStartCallback(
       BeforeNetworkStartCallback());
   if (callback_.is_null())
     return;
   net::CompletionCallback callback = callback_;
   callback_.Reset();
+  callback_type_ = NONE;
   callback.Run(net::ERR_INTERNET_DISCONNECTED);
 }
 
 int DevToolsNetworkTransaction::Start(
     const net::HttpRequestInfo* request,
     const net::CompletionCallback& callback,
     const net::BoundNetLog& net_log) {
   DCHECK(request);
   request_ = request;
 
   if (controller_->ShouldFail(request_)) {
     failed_ = true;
     network_transaction_->SetBeforeNetworkStartCallback(
         BeforeNetworkStartCallback());
     return net::ERR_INTERNET_DISCONNECTED;
   }
   int rv = network_transaction_->Start(request, proxy_callback_, net_log);
-  if (rv == net::ERR_IO_PENDING)
-    callback_ = callback;
-  return rv;
+  return SetupCallback(callback, rv, START);
 }
 
 int DevToolsNetworkTransaction::RestartIgnoringLastError(
     const net::CompletionCallback& callback) {
   if (failed_)
     return net::ERR_INTERNET_DISCONNECTED;
   int rv = network_transaction_->RestartIgnoringLastError(proxy_callback_);
-  if (rv == net::ERR_IO_PENDING)
-    callback_ = callback;
-  return rv;
+  return SetupCallback(callback, rv, RESTART_IGNORING_LAST_ERROR);
 }
 
 int DevToolsNetworkTransaction::RestartWithCertificate(
     net::X509Certificate* client_cert,
     const net::CompletionCallback& callback) {
   if (failed_)
     return net::ERR_INTERNET_DISCONNECTED;
   int rv = network_transaction_->RestartWithCertificate(
       client_cert, proxy_callback_);
-  if (rv == net::ERR_IO_PENDING)
-    callback_ = callback;
-  return rv;
+  return SetupCallback(callback, rv, RESTART_WITH_CERTIFICATE);
 }
 
 int DevToolsNetworkTransaction::RestartWithAuth(
     const net::AuthCredentials& credentials,
     const net::CompletionCallback& callback) {
   if (failed_)
     return net::ERR_INTERNET_DISCONNECTED;
   int rv = network_transaction_->RestartWithAuth(credentials, proxy_callback_);
-  if (rv == net::ERR_IO_PENDING)
-    callback_ = callback;
-  return rv;
+  return SetupCallback(callback, rv, RESTART_WITH_AUTH);
 }
 
 bool DevToolsNetworkTransaction::IsReadyToRestartForAuth() {
   return network_transaction_->IsReadyToRestartForAuth();
 }
 
 int DevToolsNetworkTransaction::Read(
     net::IOBuffer* buf,
     int buf_len,
     const net::CompletionCallback& callback) {
   if (failed_)
     return net::ERR_INTERNET_DISCONNECTED;
   int rv = network_transaction_->Read(buf, buf_len, proxy_callback_);
-  if (rv == net::ERR_IO_PENDING)
-    callback_ = callback;
-  return rv;
+  return SetupCallback(callback, rv, READ);
 }
 
 void DevToolsNetworkTransaction::StopCaching() {
   network_transaction_->StopCaching();
 }
 
 bool DevToolsNetworkTransaction::GetFullRequestHeaders(
     net::HttpRequestHeaders* headers) const {
   return network_transaction_->GetFullRequestHeaders(headers);
 }
@@ skipping 41 matching lines @@
 void DevToolsNetworkTransaction::SetBeforeNetworkStartCallback(
     const BeforeNetworkStartCallback& callback) {
   network_transaction_->SetBeforeNetworkStartCallback(callback);
 }
 
 int DevToolsNetworkTransaction::ResumeNetworkStart() {
   if (failed_)
     return net::ERR_INTERNET_DISCONNECTED;
   return network_transaction_->ResumeNetworkStart();
 }
+
+void DevToolsNetworkTransaction::FireThrottledCallback() {
+  DCHECK(!callback_.is_null());
+  DCHECK(callback_type_ == READ || callback_type_ == START);

[vsevik, 2014/06/11 12:08:52]

Looks like we can get here from RestartWithAuth now.

[eustas, 2014/06/11 13:18:48]

Done.

+  net::CompletionCallback callback = callback_;
+  callback_.Reset();
+  callback_type_ = NONE;
+  callback.Run(throttled_result_);
+}