content/common/throttling_url_loader.cc - chromium/src - Git at Google

 // Copyright 2017 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 "content/common/throttling_url_loader.h"

 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/public/common/browser_side_navigation_policy.h"

 namespace content {

 class ThrottlingURLLoader::ForwardingThrottleDelegate
     : public URLLoaderThrottle::Delegate {
  public:
   ForwardingThrottleDelegate(ThrottlingURLLoader* loader,
                              URLLoaderThrottle* throttle)
       : loader_(loader), throttle_(throttle) {}
   ~ForwardingThrottleDelegate() override = default;

   // URLLoaderThrottle::Delegate:
   void CancelWithError(int error_code,
                        base::StringPiece custom_reason) override {
     if (!loader_)
       return;

     ScopedDelegateCall scoped_delegate_call(this);
     loader_->CancelWithError(error_code, custom_reason);
   }

   void Resume() override {
     if (!loader_)
       return;

     ScopedDelegateCall scoped_delegate_call(this);
     loader_->StopDeferringForThrottle(throttle_);
   }

   void SetPriority(net::RequestPriority priority) override {
     if (!loader_)
       return;

     ScopedDelegateCall scoped_delegate_call(this);
     loader_->SetPriority(priority);
   }

   void PauseReadingBodyFromNet() override {
     if (!loader_)
       return;

     ScopedDelegateCall scoped_delegate_call(this);
     loader_->PauseReadingBodyFromNet(throttle_);
   }

   void ResumeReadingBodyFromNet() override {
     if (!loader_)
       return;

     ScopedDelegateCall scoped_delegate_call(this);
     loader_->ResumeReadingBodyFromNet(throttle_);
   }

   void InterceptResponse(
       network::mojom::URLLoaderPtr new_loader,
       network::mojom::URLLoaderClientRequest new_client_request,
       network::mojom::URLLoaderPtr* original_loader,
       network::mojom::URLLoaderClientRequest* original_client_request)
       override {
     if (!loader_)
       return;

     ScopedDelegateCall scoped_delegate_call(this);
     loader_->InterceptResponse(std::move(new_loader),
                                std::move(new_client_request), original_loader,
                                original_client_request);
   }
   void Detach() { loader_ = nullptr; }

  private:
   // This class helps ThrottlingURLLoader to keep track of whether it is being
   // called by its throttles.
   // If ThrottlingURLLoader is destoyed while any of the throttles is calling
   // into it, it delays destruction of the throttles. That way throttles don't
   // need to worry about any delegate calls may destory them synchronously.
   class ScopedDelegateCall {
    public:
     explicit ScopedDelegateCall(ForwardingThrottleDelegate* owner)
         : owner_(owner) {
       DCHECK(owner_->loader_);

       owner_->loader_->inside_delegate_calls_++;
     }

     ~ScopedDelegateCall() {
       // The loader may have been detached and destroyed.
       if (owner_->loader_)
         owner_->loader_->inside_delegate_calls_--;
     }

    private:
     ForwardingThrottleDelegate* const owner_;
     DISALLOW_COPY_AND_ASSIGN(ScopedDelegateCall);
   };

   ThrottlingURLLoader* loader_;
   URLLoaderThrottle* const throttle_;

   DISALLOW_COPY_AND_ASSIGN(ForwardingThrottleDelegate);
 };

 ThrottlingURLLoader::StartInfo::StartInfo(
     scoped_refptr<network::SharedURLLoaderFactory> in_url_loader_factory,
     int32_t in_routing_id,
     int32_t in_request_id,
     uint32_t in_options,
     network::ResourceRequest* in_url_request,
     scoped_refptr<base::SingleThreadTaskRunner> in_task_runner)
     : url_loader_factory(std::move(in_url_loader_factory)),
       routing_id(in_routing_id),
       request_id(in_request_id),
       options(in_options),
       url_request(*in_url_request),
       task_runner(std::move(in_task_runner)) {}

 ThrottlingURLLoader::StartInfo::~StartInfo() = default;

 ThrottlingURLLoader::ResponseInfo::ResponseInfo(
     const network::ResourceResponseHead& in_response_head)
     : response_head(in_response_head) {}

 ThrottlingURLLoader::ResponseInfo::~ResponseInfo() = default;

 ThrottlingURLLoader::RedirectInfo::RedirectInfo(
     const net::RedirectInfo& in_redirect_info,
     const network::ResourceResponseHead& in_response_head)
     : redirect_info(in_redirect_info), response_head(in_response_head) {}

 ThrottlingURLLoader::RedirectInfo::~RedirectInfo() = default;

 ThrottlingURLLoader::PriorityInfo::PriorityInfo(
     net::RequestPriority in_priority,
     int32_t in_intra_priority_value)
     : priority(in_priority), intra_priority_value(in_intra_priority_value) {}

 ThrottlingURLLoader::PriorityInfo::~PriorityInfo() = default;

 // static
 std::unique_ptr<ThrottlingURLLoader> ThrottlingURLLoader::CreateLoaderAndStart(
     scoped_refptr<network::SharedURLLoaderFactory> factory,
     std::vector<std::unique_ptr<URLLoaderThrottle>> throttles,
     int32_t routing_id,
     int32_t request_id,
     uint32_t options,
     network::ResourceRequest* url_request,
     network::mojom::URLLoaderClient* client,
     const net::NetworkTrafficAnnotationTag& traffic_annotation,
     scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
   std::unique_ptr<ThrottlingURLLoader> loader(new ThrottlingURLLoader(
       std::move(throttles), client, traffic_annotation));
   loader->Start(std::move(factory), routing_id, request_id, options,
                 url_request, std::move(task_runner));
   return loader;
 }

 ThrottlingURLLoader::~ThrottlingURLLoader() {
   if (inside_delegate_calls_ > 0) {
     // A throttle is calling into this object. In this case, delay destruction
     // of the throttles, so that throttles don't need to worry about any
     // delegate calls may destory them synchronously.
     for (auto& entry : throttles_)
       entry.delegate->Detach();

     auto throttles =
         std::make_unique<std::vector<ThrottleEntry>>(std::move(throttles_));
     base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE,
                                                     std::move(throttles));
   }
 }

 void ThrottlingURLLoader::FollowRedirect(
     const base::Optional<net::HttpRequestHeaders>& modified_request_headers) {
   if (url_loader_) {
     if (to_be_removed_request_headers_.empty()) {
       url_loader_->FollowRedirect(base::nullopt, modified_request_headers);
     } else {
       url_loader_->FollowRedirect(to_be_removed_request_headers_,
                                   modified_request_headers);
     }
     to_be_removed_request_headers_.clear();
   }
 }

 void ThrottlingURLLoader::SetPriority(net::RequestPriority priority,
                                       int32_t intra_priority_value) {
   if (!url_loader_) {
     if (!loader_cancelled_) {
       DCHECK_EQ(DEFERRED_START, deferred_stage_);
       priority_info_ =
           std::make_unique<PriorityInfo>(priority, intra_priority_value);
     }
     return;
   }

   url_loader_->SetPriority(priority, intra_priority_value);
 }

 network::mojom::URLLoaderClientEndpointsPtr ThrottlingURLLoader::Unbind() {
   return network::mojom::URLLoaderClientEndpoints::New(
       url_loader_.PassInterface(), client_binding_.Unbind());
 }

 ThrottlingURLLoader::ThrottlingURLLoader(
     std::vector<std::unique_ptr<URLLoaderThrottle>> throttles,
     network::mojom::URLLoaderClient* client,
     const net::NetworkTrafficAnnotationTag& traffic_annotation)
     : forwarding_client_(client),
       client_binding_(this),
       traffic_annotation_(traffic_annotation),
       weak_factory_(this) {
   throttles_.reserve(throttles.size());
   for (auto& throttle : throttles)
     throttles_.emplace_back(this, std::move(throttle));
 }

 void ThrottlingURLLoader::Start(
     scoped_refptr<network::SharedURLLoaderFactory> factory,
     int32_t routing_id,
     int32_t request_id,
     uint32_t options,
     network::ResourceRequest* url_request,
     scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
   DCHECK(!loader_cancelled_);

   if (options & network::mojom::kURLLoadOptionSynchronous)
     is_synchronous_ = true;

   DCHECK(deferring_throttles_.empty());
   if (!throttles_.empty()) {
     bool deferred = false;
     for (auto& entry : throttles_) {
       auto* throttle = entry.throttle.get();
       bool throttle_deferred = false;
       throttle->WillStartRequest(url_request, &throttle_deferred);
       if (!HandleThrottleResult(throttle, throttle_deferred, &deferred))
         return;
     }

     if (deferred) {
       deferred_stage_ = DEFERRED_START;
       start_info_ = std::make_unique<StartInfo>(
           std::move(factory), routing_id, request_id, options, url_request,
           std::move(task_runner));
       return;
     }
   }

   StartNow(factory.get(), routing_id, request_id, options, url_request,
            std::move(task_runner));
 }

 void ThrottlingURLLoader::StartNow(
     network::SharedURLLoaderFactory* factory,
     int32_t routing_id,
     int32_t request_id,
     uint32_t options,
     network::ResourceRequest* url_request,
     scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
   network::mojom::URLLoaderClientPtr client;
   client_binding_.Bind(mojo::MakeRequest(&client), std::move(task_runner));
   client_binding_.set_connection_error_handler(base::BindOnce(
       &ThrottlingURLLoader::OnClientConnectionError, base::Unretained(this)));

   DCHECK(factory);
   factory->CreateLoaderAndStart(
       mojo::MakeRequest(&url_loader_), routing_id, request_id, options,
       *url_request, std::move(client),
       net::MutableNetworkTrafficAnnotationTag(traffic_annotation_));

   if (!pausing_reading_body_from_net_throttles_.empty())
     url_loader_->PauseReadingBodyFromNet();

   if (priority_info_) {
     auto priority_info = std::move(priority_info_);
     url_loader_->SetPriority(priority_info->priority,
                              priority_info->intra_priority_value);
   }

   // Initialize with the request URL, may be updated when on redirects
   response_url_ = url_request->url;
 }

 bool ThrottlingURLLoader::HandleThrottleResult(URLLoaderThrottle* throttle,
                                                bool throttle_deferred,
                                                bool* should_defer) {
   DCHECK(!deferring_throttles_.count(throttle));
   if (loader_cancelled_)
     return false;
   *should_defer |= throttle_deferred;
   if (throttle_deferred)
     deferring_throttles_.insert(throttle);
   return true;
 }

 void ThrottlingURLLoader::StopDeferringForThrottle(
     URLLoaderThrottle* throttle) {
   if (deferring_throttles_.find(throttle) == deferring_throttles_.end())
     return;

   deferring_throttles_.erase(throttle);
   if (deferring_throttles_.empty() && !loader_cancelled_)
     Resume();
 }

 void ThrottlingURLLoader::OnReceiveResponse(
     const network::ResourceResponseHead& response_head) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
   DCHECK(!loader_cancelled_);
   DCHECK(deferring_throttles_.empty());

   if (!throttles_.empty()) {
     bool deferred = false;
     for (auto& entry : throttles_) {
       auto* throttle = entry.throttle.get();
       bool throttle_deferred = false;
       throttle->WillProcessResponse(response_url_, response_head,
                                     &throttle_deferred);
       if (!HandleThrottleResult(throttle, throttle_deferred, &deferred))
         return;
     }

     if (deferred) {
       deferred_stage_ = DEFERRED_RESPONSE;
       response_info_ = std::make_unique<ResponseInfo>(response_head);
       client_binding_.PauseIncomingMethodCallProcessing();
       return;
     }
   }

   forwarding_client_->OnReceiveResponse(response_head);
 }

 void ThrottlingURLLoader::OnReceiveRedirect(
     const net::RedirectInfo& redirect_info,
     const network::ResourceResponseHead& response_head) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
   DCHECK(!loader_cancelled_);
   DCHECK(deferring_throttles_.empty());

   if (!throttles_.empty()) {
     bool deferred = false;
     for (auto& entry : throttles_) {
       auto* throttle = entry.throttle.get();
       bool throttle_deferred = false;
       auto weak_ptr = weak_factory_.GetWeakPtr();
       std::vector<std::string> headers;
       throttle->WillRedirectRequest(redirect_info, response_head,
                                     &throttle_deferred, &headers);
       if (!weak_ptr)
         return;
       if (!HandleThrottleResult(throttle, throttle_deferred, &deferred))
         return;

       to_be_removed_request_headers_.insert(
           to_be_removed_request_headers_.end(), headers.begin(), headers.end());
     }

     if (deferred) {
       deferred_stage_ = DEFERRED_REDIRECT;
       redirect_info_ =
           std::make_unique<RedirectInfo>(redirect_info, response_head);
       client_binding_.PauseIncomingMethodCallProcessing();
       return;
     }
   }

   // TODO(dhausknecht) at this point we do not actually know if we commit to the
   // redirect or if it will be cancelled. FollowRedirect would be a more
   // suitable place to set this URL but there we do not have the data.
   response_url_ = redirect_info.new_url;
   forwarding_client_->OnReceiveRedirect(redirect_info, response_head);
 }

 void ThrottlingURLLoader::OnUploadProgress(
     int64_t current_position,
     int64_t total_size,
     OnUploadProgressCallback ack_callback) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
   DCHECK(!loader_cancelled_);

   forwarding_client_->OnUploadProgress(current_position, total_size,
                                        std::move(ack_callback));
 }

 void ThrottlingURLLoader::OnReceiveCachedMetadata(
     const std::vector<uint8_t>& data) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
   DCHECK(!loader_cancelled_);

   forwarding_client_->OnReceiveCachedMetadata(data);
 }

 void ThrottlingURLLoader::OnTransferSizeUpdated(int32_t transfer_size_diff) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
   DCHECK(!loader_cancelled_);

   forwarding_client_->OnTransferSizeUpdated(transfer_size_diff);
 }

 void ThrottlingURLLoader::OnStartLoadingResponseBody(
     mojo::ScopedDataPipeConsumerHandle body) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
   DCHECK(!loader_cancelled_);

   forwarding_client_->OnStartLoadingResponseBody(std::move(body));
 }

 void ThrottlingURLLoader::OnComplete(
     const network::URLLoaderCompletionStatus& status) {
   DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
   DCHECK(!loader_cancelled_);

   // This is the last expected message. Pipe closure before this is an error
   // (see OnClientConnectionError). After this it is expected and should be
   // ignored.
   DisconnectClient(nullptr);
   forwarding_client_->OnComplete(status);
 }

 void ThrottlingURLLoader::OnClientConnectionError() {
   // TODO(reillyg): Temporary workaround for crbug.com/756751 where without
   // browser-side navigation this error on async loads will confuse the loading
   // of cross-origin iframes.
   if (is_synchronous_ || content::IsBrowserSideNavigationEnabled())
     CancelWithError(net::ERR_ABORTED, nullptr);
 }

 void ThrottlingURLLoader::CancelWithError(int error_code,
                                           base::StringPiece custom_reason) {
   if (loader_cancelled_)
     return;

   network::URLLoaderCompletionStatus status;
   status.error_code = error_code;
   status.completion_time = base::TimeTicks::Now();

   deferred_stage_ = DEFERRED_NONE;
   DisconnectClient(custom_reason);
   forwarding_client_->OnComplete(status);
 }

 void ThrottlingURLLoader::Resume() {
   if (loader_cancelled_ || deferred_stage_ == DEFERRED_NONE)
     return;

   auto prev_deferred_stage = deferred_stage_;
   deferred_stage_ = DEFERRED_NONE;
   switch (prev_deferred_stage) {
     case DEFERRED_START: {
       StartNow(start_info_->url_loader_factory.get(), start_info_->routing_id,
                start_info_->request_id, start_info_->options,
                &start_info_->url_request, std::move(start_info_->task_runner));
       break;
     }
     case DEFERRED_REDIRECT: {
       client_binding_.ResumeIncomingMethodCallProcessing();
       // TODO(dhausknecht) at this point we do not actually know if we commit to
       // the redirect or if it will be cancelled. FollowRedirect would be a more
       // suitable place to set this URL but there we do not have the data.
       response_url_ = redirect_info_->redirect_info.new_url;
       forwarding_client_->OnReceiveRedirect(redirect_info_->redirect_info,
                                             redirect_info_->response_head);
       // Note: |this| may be deleted here.
       break;
     }
     case DEFERRED_RESPONSE: {
       client_binding_.ResumeIncomingMethodCallProcessing();
       forwarding_client_->OnReceiveResponse(response_info_->response_head);
       // Note: |this| may be deleted here.
       break;
     }
     default:
       NOTREACHED();
       break;
   }
 }

 void ThrottlingURLLoader::SetPriority(net::RequestPriority priority) {
   if (url_loader_)
     url_loader_->SetPriority(priority, -1);
 }

 void ThrottlingURLLoader::PauseReadingBodyFromNet(URLLoaderThrottle* throttle) {
   if (pausing_reading_body_from_net_throttles_.empty() && url_loader_)
     url_loader_->PauseReadingBodyFromNet();

   pausing_reading_body_from_net_throttles_.insert(throttle);
 }

 void ThrottlingURLLoader::ResumeReadingBodyFromNet(
     URLLoaderThrottle* throttle) {
   auto iter = pausing_reading_body_from_net_throttles_.find(throttle);
   if (iter == pausing_reading_body_from_net_throttles_.end())
     return;

   pausing_reading_body_from_net_throttles_.erase(iter);
   if (pausing_reading_body_from_net_throttles_.empty() && url_loader_)
     url_loader_->ResumeReadingBodyFromNet();
 }

 void ThrottlingURLLoader::InterceptResponse(
     network::mojom::URLLoaderPtr new_loader,
     network::mojom::URLLoaderClientRequest new_client_request,
     network::mojom::URLLoaderPtr* original_loader,
     network::mojom::URLLoaderClientRequest* original_client_request) {
   response_intercepted_ = true;

   if (original_loader)
     *original_loader = std::move(url_loader_);
   url_loader_ = std::move(new_loader);

   if (original_client_request)
     *original_client_request = client_binding_.Unbind();
   client_binding_.Bind(std::move(new_client_request));
   client_binding_.set_connection_error_handler(base::BindOnce(
       &ThrottlingURLLoader::OnClientConnectionError, base::Unretained(this)));
 }

 void ThrottlingURLLoader::DisconnectClient(base::StringPiece custom_reason) {
   client_binding_.Close();

   if (!custom_reason.empty()) {
     url_loader_.ResetWithReason(
         network::mojom::URLLoader::kClientDisconnectReason,
         custom_reason.as_string());
   } else {
     url_loader_ = nullptr;
   }

   loader_cancelled_ = true;
 }

 ThrottlingURLLoader::ThrottleEntry::ThrottleEntry(
     ThrottlingURLLoader* loader,
     std::unique_ptr<URLLoaderThrottle> the_throttle)
     : delegate(
           std::make_unique<ForwardingThrottleDelegate>(loader,
                                                        the_throttle.get())),
       throttle(std::move(the_throttle)) {
   throttle->set_delegate(delegate.get());
 }

 ThrottlingURLLoader::ThrottleEntry::ThrottleEntry(ThrottleEntry&& other) =
     default;

 ThrottlingURLLoader::ThrottleEntry::~ThrottleEntry() = default;

 ThrottlingURLLoader::ThrottleEntry& ThrottlingURLLoader::ThrottleEntry::
 operator=(ThrottleEntry&& other) = default;

 }  // namespace content
	// Copyright 2017 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 "content/common/throttling_url_loader.h"

	#include "base/single_thread_task_runner.h"
	#include "base/threading/thread_task_runner_handle.h"
	#include "content/public/common/browser_side_navigation_policy.h"

	namespace content {

	class ThrottlingURLLoader::ForwardingThrottleDelegate
	: public URLLoaderThrottle::Delegate {
	public:
	ForwardingThrottleDelegate(ThrottlingURLLoader* loader,
	URLLoaderThrottle* throttle)
	: loader_(loader), throttle_(throttle) {}
	~ForwardingThrottleDelegate() override = default;

	// URLLoaderThrottle::Delegate:
	void CancelWithError(int error_code,
	base::StringPiece custom_reason) override {
	if (!loader_)
	return;

	ScopedDelegateCall scoped_delegate_call(this);
	loader_->CancelWithError(error_code, custom_reason);
	}

	void Resume() override {
	if (!loader_)
	return;

	ScopedDelegateCall scoped_delegate_call(this);
	loader_->StopDeferringForThrottle(throttle_);
	}

	void SetPriority(net::RequestPriority priority) override {
	if (!loader_)
	return;

	ScopedDelegateCall scoped_delegate_call(this);
	loader_->SetPriority(priority);
	}

	void PauseReadingBodyFromNet() override {
	if (!loader_)
	return;

	ScopedDelegateCall scoped_delegate_call(this);
	loader_->PauseReadingBodyFromNet(throttle_);
	}

	void ResumeReadingBodyFromNet() override {
	if (!loader_)
	return;

	ScopedDelegateCall scoped_delegate_call(this);
	loader_->ResumeReadingBodyFromNet(throttle_);
	}

	void InterceptResponse(
	network::mojom::URLLoaderPtr new_loader,
	network::mojom::URLLoaderClientRequest new_client_request,
	network::mojom::URLLoaderPtr* original_loader,
	network::mojom::URLLoaderClientRequest* original_client_request)
	override {
	if (!loader_)
	return;

	ScopedDelegateCall scoped_delegate_call(this);
	loader_->InterceptResponse(std::move(new_loader),
	std::move(new_client_request), original_loader,
	original_client_request);
	}
	void Detach() { loader_ = nullptr; }

	private:
	// This class helps ThrottlingURLLoader to keep track of whether it is being
	// called by its throttles.
	// If ThrottlingURLLoader is destoyed while any of the throttles is calling
	// into it, it delays destruction of the throttles. That way throttles don't
	// need to worry about any delegate calls may destory them synchronously.
	class ScopedDelegateCall {
	public:
	explicit ScopedDelegateCall(ForwardingThrottleDelegate* owner)
	: owner_(owner) {
	DCHECK(owner_->loader_);

	owner_->loader_->inside_delegate_calls_++;
	}

	~ScopedDelegateCall() {
	// The loader may have been detached and destroyed.
	if (owner_->loader_)
	owner_->loader_->inside_delegate_calls_--;
	}

	private:
	ForwardingThrottleDelegate* const owner_;
	DISALLOW_COPY_AND_ASSIGN(ScopedDelegateCall);
	};

	ThrottlingURLLoader* loader_;
	URLLoaderThrottle* const throttle_;

	DISALLOW_COPY_AND_ASSIGN(ForwardingThrottleDelegate);
	};

	ThrottlingURLLoader::StartInfo::StartInfo(
	scoped_refptr<network::SharedURLLoaderFactory> in_url_loader_factory,
	int32_t in_routing_id,
	int32_t in_request_id,
	uint32_t in_options,
	network::ResourceRequest* in_url_request,
	scoped_refptr<base::SingleThreadTaskRunner> in_task_runner)
	: url_loader_factory(std::move(in_url_loader_factory)),
	routing_id(in_routing_id),
	request_id(in_request_id),
	options(in_options),
	url_request(*in_url_request),
	task_runner(std::move(in_task_runner)) {}

	ThrottlingURLLoader::StartInfo::~StartInfo() = default;

	ThrottlingURLLoader::ResponseInfo::ResponseInfo(
	const network::ResourceResponseHead& in_response_head)
	: response_head(in_response_head) {}

	ThrottlingURLLoader::ResponseInfo::~ResponseInfo() = default;

	ThrottlingURLLoader::RedirectInfo::RedirectInfo(
	const net::RedirectInfo& in_redirect_info,
	const network::ResourceResponseHead& in_response_head)
	: redirect_info(in_redirect_info), response_head(in_response_head) {}

	ThrottlingURLLoader::RedirectInfo::~RedirectInfo() = default;

	ThrottlingURLLoader::PriorityInfo::PriorityInfo(
	net::RequestPriority in_priority,
	int32_t in_intra_priority_value)
	: priority(in_priority), intra_priority_value(in_intra_priority_value) {}

	ThrottlingURLLoader::PriorityInfo::~PriorityInfo() = default;

	// static
	std::unique_ptr<ThrottlingURLLoader> ThrottlingURLLoader::CreateLoaderAndStart(
	scoped_refptr<network::SharedURLLoaderFactory> factory,
	std::vector<std::unique_ptr<URLLoaderThrottle>> throttles,
	int32_t routing_id,
	int32_t request_id,
	uint32_t options,
	network::ResourceRequest* url_request,
	network::mojom::URLLoaderClient* client,
	const net::NetworkTrafficAnnotationTag& traffic_annotation,
	scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
	std::unique_ptr<ThrottlingURLLoader> loader(new ThrottlingURLLoader(
	std::move(throttles), client, traffic_annotation));
	loader->Start(std::move(factory), routing_id, request_id, options,
	url_request, std::move(task_runner));
	return loader;
	}

	ThrottlingURLLoader::~ThrottlingURLLoader() {
	if (inside_delegate_calls_ > 0) {
	// A throttle is calling into this object. In this case, delay destruction
	// of the throttles, so that throttles don't need to worry about any
	// delegate calls may destory them synchronously.
	for (auto& entry : throttles_)
	entry.delegate->Detach();

	auto throttles =
	std::make_unique<std::vector<ThrottleEntry>>(std::move(throttles_));
	base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE,
	std::move(throttles));
	}
	}

	void ThrottlingURLLoader::FollowRedirect(
	const base::Optional<net::HttpRequestHeaders>& modified_request_headers) {
	if (url_loader_) {
	if (to_be_removed_request_headers_.empty()) {
	url_loader_->FollowRedirect(base::nullopt, modified_request_headers);
	} else {
	url_loader_->FollowRedirect(to_be_removed_request_headers_,
	modified_request_headers);
	}
	to_be_removed_request_headers_.clear();
	}
	}

	void ThrottlingURLLoader::SetPriority(net::RequestPriority priority,
	int32_t intra_priority_value) {
	if (!url_loader_) {
	if (!loader_cancelled_) {
	DCHECK_EQ(DEFERRED_START, deferred_stage_);
	priority_info_ =
	std::make_unique<PriorityInfo>(priority, intra_priority_value);
	}
	return;
	}

	url_loader_->SetPriority(priority, intra_priority_value);
	}

	network::mojom::URLLoaderClientEndpointsPtr ThrottlingURLLoader::Unbind() {
	return network::mojom::URLLoaderClientEndpoints::New(
	url_loader_.PassInterface(), client_binding_.Unbind());
	}

	ThrottlingURLLoader::ThrottlingURLLoader(
	std::vector<std::unique_ptr<URLLoaderThrottle>> throttles,
	network::mojom::URLLoaderClient* client,
	const net::NetworkTrafficAnnotationTag& traffic_annotation)
	: forwarding_client_(client),
	client_binding_(this),
	traffic_annotation_(traffic_annotation),
	weak_factory_(this) {
	throttles_.reserve(throttles.size());
	for (auto& throttle : throttles)
	throttles_.emplace_back(this, std::move(throttle));
	}

	void ThrottlingURLLoader::Start(
	scoped_refptr<network::SharedURLLoaderFactory> factory,
	int32_t routing_id,
	int32_t request_id,
	uint32_t options,
	network::ResourceRequest* url_request,
	scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
	DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
	DCHECK(!loader_cancelled_);

	if (options & network::mojom::kURLLoadOptionSynchronous)
	is_synchronous_ = true;

	DCHECK(deferring_throttles_.empty());
	if (!throttles_.empty()) {
	bool deferred = false;
	for (auto& entry : throttles_) {
	auto* throttle = entry.throttle.get();
	bool throttle_deferred = false;
	throttle->WillStartRequest(url_request, &throttle_deferred);
	if (!HandleThrottleResult(throttle, throttle_deferred, &deferred))
	return;
	}

	if (deferred) {
	deferred_stage_ = DEFERRED_START;
	start_info_ = std::make_unique<StartInfo>(
	std::move(factory), routing_id, request_id, options, url_request,
	std::move(task_runner));
	return;
	}
	}

	StartNow(factory.get(), routing_id, request_id, options, url_request,
	std::move(task_runner));
	}

	void ThrottlingURLLoader::StartNow(
	network::SharedURLLoaderFactory* factory,
	int32_t routing_id,
	int32_t request_id,
	uint32_t options,
	network::ResourceRequest* url_request,
	scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
	network::mojom::URLLoaderClientPtr client;
	client_binding_.Bind(mojo::MakeRequest(&client), std::move(task_runner));
	client_binding_.set_connection_error_handler(base::BindOnce(
	&ThrottlingURLLoader::OnClientConnectionError, base::Unretained(this)));

	DCHECK(factory);
	factory->CreateLoaderAndStart(
	mojo::MakeRequest(&url_loader_), routing_id, request_id, options,
	*url_request, std::move(client),
	net::MutableNetworkTrafficAnnotationTag(traffic_annotation_));

	if (!pausing_reading_body_from_net_throttles_.empty())
	url_loader_->PauseReadingBodyFromNet();

	if (priority_info_) {
	auto priority_info = std::move(priority_info_);
	url_loader_->SetPriority(priority_info->priority,
	priority_info->intra_priority_value);
	}

	// Initialize with the request URL, may be updated when on redirects
	response_url_ = url_request->url;
	}

	bool ThrottlingURLLoader::HandleThrottleResult(URLLoaderThrottle* throttle,
	bool throttle_deferred,
	bool* should_defer) {
	DCHECK(!deferring_throttles_.count(throttle));
	if (loader_cancelled_)
	return false;
	*should_defer \|= throttle_deferred;
	if (throttle_deferred)
	deferring_throttles_.insert(throttle);
	return true;
	}

	void ThrottlingURLLoader::StopDeferringForThrottle(
	URLLoaderThrottle* throttle) {
	if (deferring_throttles_.find(throttle) == deferring_throttles_.end())
	return;

	deferring_throttles_.erase(throttle);
	if (deferring_throttles_.empty() && !loader_cancelled_)
	Resume();
	}

	void ThrottlingURLLoader::OnReceiveResponse(
	const network::ResourceResponseHead& response_head) {
	DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
	DCHECK(!loader_cancelled_);
	DCHECK(deferring_throttles_.empty());

	if (!throttles_.empty()) {
	bool deferred = false;
	for (auto& entry : throttles_) {
	auto* throttle = entry.throttle.get();
	bool throttle_deferred = false;
	throttle->WillProcessResponse(response_url_, response_head,
	&throttle_deferred);
	if (!HandleThrottleResult(throttle, throttle_deferred, &deferred))
	return;
	}

	if (deferred) {
	deferred_stage_ = DEFERRED_RESPONSE;
	response_info_ = std::make_unique<ResponseInfo>(response_head);
	client_binding_.PauseIncomingMethodCallProcessing();
	return;
	}
	}

	forwarding_client_->OnReceiveResponse(response_head);
	}

	void ThrottlingURLLoader::OnReceiveRedirect(
	const net::RedirectInfo& redirect_info,
	const network::ResourceResponseHead& response_head) {
	DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
	DCHECK(!loader_cancelled_);
	DCHECK(deferring_throttles_.empty());

	if (!throttles_.empty()) {
	bool deferred = false;
	for (auto& entry : throttles_) {
	auto* throttle = entry.throttle.get();
	bool throttle_deferred = false;
	auto weak_ptr = weak_factory_.GetWeakPtr();
	std::vector<std::string> headers;
	throttle->WillRedirectRequest(redirect_info, response_head,
	&throttle_deferred, &headers);
	if (!weak_ptr)
	return;
	if (!HandleThrottleResult(throttle, throttle_deferred, &deferred))
	return;

	to_be_removed_request_headers_.insert(
	to_be_removed_request_headers_.end(), headers.begin(), headers.end());
	}

	if (deferred) {
	deferred_stage_ = DEFERRED_REDIRECT;
	redirect_info_ =
	std::make_unique<RedirectInfo>(redirect_info, response_head);
	client_binding_.PauseIncomingMethodCallProcessing();
	return;
	}
	}

	// TODO(dhausknecht) at this point we do not actually know if we commit to the
	// redirect or if it will be cancelled. FollowRedirect would be a more
	// suitable place to set this URL but there we do not have the data.
	response_url_ = redirect_info.new_url;
	forwarding_client_->OnReceiveRedirect(redirect_info, response_head);
	}

	void ThrottlingURLLoader::OnUploadProgress(
	int64_t current_position,
	int64_t total_size,
	OnUploadProgressCallback ack_callback) {
	DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
	DCHECK(!loader_cancelled_);

	forwarding_client_->OnUploadProgress(current_position, total_size,
	std::move(ack_callback));
	}

	void ThrottlingURLLoader::OnReceiveCachedMetadata(
	const std::vector<uint8_t>& data) {
	DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
	DCHECK(!loader_cancelled_);

	forwarding_client_->OnReceiveCachedMetadata(data);
	}

	void ThrottlingURLLoader::OnTransferSizeUpdated(int32_t transfer_size_diff) {
	DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
	DCHECK(!loader_cancelled_);

	forwarding_client_->OnTransferSizeUpdated(transfer_size_diff);
	}

	void ThrottlingURLLoader::OnStartLoadingResponseBody(
	mojo::ScopedDataPipeConsumerHandle body) {
	DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
	DCHECK(!loader_cancelled_);

	forwarding_client_->OnStartLoadingResponseBody(std::move(body));
	}

	void ThrottlingURLLoader::OnComplete(
	const network::URLLoaderCompletionStatus& status) {
	DCHECK_EQ(DEFERRED_NONE, deferred_stage_);
	DCHECK(!loader_cancelled_);

	// This is the last expected message. Pipe closure before this is an error
	// (see OnClientConnectionError). After this it is expected and should be
	// ignored.
	DisconnectClient(nullptr);
	forwarding_client_->OnComplete(status);
	}

	void ThrottlingURLLoader::OnClientConnectionError() {
	// TODO(reillyg): Temporary workaround for crbug.com/756751 where without
	// browser-side navigation this error on async loads will confuse the loading
	// of cross-origin iframes.
	if (is_synchronous_ \|\| content::IsBrowserSideNavigationEnabled())
	CancelWithError(net::ERR_ABORTED, nullptr);
	}

	void ThrottlingURLLoader::CancelWithError(int error_code,
	base::StringPiece custom_reason) {
	if (loader_cancelled_)
	return;

	network::URLLoaderCompletionStatus status;
	status.error_code = error_code;
	status.completion_time = base::TimeTicks::Now();

	deferred_stage_ = DEFERRED_NONE;
	DisconnectClient(custom_reason);
	forwarding_client_->OnComplete(status);
	}

	void ThrottlingURLLoader::Resume() {
	if (loader_cancelled_ \|\| deferred_stage_ == DEFERRED_NONE)
	return;

	auto prev_deferred_stage = deferred_stage_;
	deferred_stage_ = DEFERRED_NONE;
	switch (prev_deferred_stage) {
	case DEFERRED_START: {
	StartNow(start_info_->url_loader_factory.get(), start_info_->routing_id,
	start_info_->request_id, start_info_->options,
	&start_info_->url_request, std::move(start_info_->task_runner));
	break;
	}
	case DEFERRED_REDIRECT: {
	client_binding_.ResumeIncomingMethodCallProcessing();
	// TODO(dhausknecht) at this point we do not actually know if we commit to
	// the redirect or if it will be cancelled. FollowRedirect would be a more
	// suitable place to set this URL but there we do not have the data.
	response_url_ = redirect_info_->redirect_info.new_url;
	forwarding_client_->OnReceiveRedirect(redirect_info_->redirect_info,
	redirect_info_->response_head);
	// Note: \|this\| may be deleted here.
	break;
	}
	case DEFERRED_RESPONSE: {
	client_binding_.ResumeIncomingMethodCallProcessing();
	forwarding_client_->OnReceiveResponse(response_info_->response_head);
	// Note: \|this\| may be deleted here.
	break;
	}
	default:
	NOTREACHED();
	break;
	}
	}

	void ThrottlingURLLoader::SetPriority(net::RequestPriority priority) {
	if (url_loader_)
	url_loader_->SetPriority(priority, -1);
	}

	void ThrottlingURLLoader::PauseReadingBodyFromNet(URLLoaderThrottle* throttle) {
	if (pausing_reading_body_from_net_throttles_.empty() && url_loader_)
	url_loader_->PauseReadingBodyFromNet();

	pausing_reading_body_from_net_throttles_.insert(throttle);
	}

	void ThrottlingURLLoader::ResumeReadingBodyFromNet(
	URLLoaderThrottle* throttle) {
	auto iter = pausing_reading_body_from_net_throttles_.find(throttle);
	if (iter == pausing_reading_body_from_net_throttles_.end())
	return;

	pausing_reading_body_from_net_throttles_.erase(iter);
	if (pausing_reading_body_from_net_throttles_.empty() && url_loader_)
	url_loader_->ResumeReadingBodyFromNet();
	}

	void ThrottlingURLLoader::InterceptResponse(
	network::mojom::URLLoaderPtr new_loader,
	network::mojom::URLLoaderClientRequest new_client_request,
	network::mojom::URLLoaderPtr* original_loader,
	network::mojom::URLLoaderClientRequest* original_client_request) {
	response_intercepted_ = true;

	if (original_loader)
	*original_loader = std::move(url_loader_);
	url_loader_ = std::move(new_loader);

	if (original_client_request)
	*original_client_request = client_binding_.Unbind();
	client_binding_.Bind(std::move(new_client_request));
	client_binding_.set_connection_error_handler(base::BindOnce(
	&ThrottlingURLLoader::OnClientConnectionError, base::Unretained(this)));
	}

	void ThrottlingURLLoader::DisconnectClient(base::StringPiece custom_reason) {
	client_binding_.Close();

	if (!custom_reason.empty()) {
	url_loader_.ResetWithReason(
	network::mojom::URLLoader::kClientDisconnectReason,
	custom_reason.as_string());
	} else {
	url_loader_ = nullptr;
	}

	loader_cancelled_ = true;
	}

	ThrottlingURLLoader::ThrottleEntry::ThrottleEntry(
	ThrottlingURLLoader* loader,
	std::unique_ptr<URLLoaderThrottle> the_throttle)
	: delegate(
	std::make_unique<ForwardingThrottleDelegate>(loader,
	the_throttle.get())),
	throttle(std::move(the_throttle)) {
	throttle->set_delegate(delegate.get());
	}

	ThrottlingURLLoader::ThrottleEntry::ThrottleEntry(ThrottleEntry&& other) =
	default;

	ThrottlingURLLoader::ThrottleEntry::~ThrottleEntry() = default;

	ThrottlingURLLoader::ThrottleEntry& ThrottlingURLLoader::ThrottleEntry::
	operator=(ThrottleEntry&& other) = default;

	} // namespace content