content/common/throttling_url_loader.h

// 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.

#ifndef CONTENT_COMMON_THROTTLING_URL_LOADER_H_
#define CONTENT_COMMON_THROTTLING_URL_LOADER_H_

#include <memory>

#include "content/common/content_export.h"
#include "content/common/url_loader.mojom.h"
#include "content/common/url_loader_factory.mojom.h"
#include "content/public/common/url_loader_throttle.h"
#include "mojo/public/cpp/bindings/binding.h"

namespace content {

namespace mojom {
class URLLoaderFactory;
}

// ThrottlingURLLoader is a wrapper around the mojom::URLLoader[Factory]
// interfaces. It applies a list of URLLoaderThrottle instances which could
// defer, resume or cancel the URL loading.
class CONTENT_EXPORT ThrottlingURLLoader : public mojom::URLLoaderClient,
                                           public URLLoaderThrottle::Delegate {
 public:
  // |factory| and |client| must stay alive during the lifetime of the returned
  // object.
  static std::unique_ptr<ThrottlingURLLoader> CreateLoaderAndStart(
      mojom::URLLoaderFactory* factory,
      std::vector<std::unique_ptr<URLLoaderThrottle>> throttles,
      int32_t routing_id,
      int32_t request_id,
      uint32_t options,
      std::unique_ptr<ResourceRequest> url_request,
      mojom::URLLoaderClient* client);

  ~ThrottlingURLLoader() override;

  void FollowRedirect();
  void SetPriority(net::RequestPriority priority, int32_t intra_priority_value);

 private:
  ThrottlingURLLoader(std::vector<std::unique_ptr<URLLoaderThrottle>> throttles,
                      mojom::URLLoaderClient* client);

  void Start(mojom::URLLoaderFactory* factory,
             int32_t routing_id,
             int32_t request_id,
             uint32_t options,
             std::unique_ptr<ResourceRequest> url_request);

  // mojom::URLLoaderClient implementation:
  void OnReceiveResponse(const ResourceResponseHead& response_head,
                         const base::Optional<net::SSLInfo>& ssl_info,
                         mojom::DownloadedTempFilePtr downloaded_file) override;
  void OnReceiveRedirect(const net::RedirectInfo& redirect_info,
                         const ResourceResponseHead& response_head) override;
  void OnDataDownloaded(int64_t data_len, int64_t encoded_data_len) override;
  void OnUploadProgress(int64_t current_position,
                        int64_t total_size,
                        OnUploadProgressCallback ack_callback) override;
  void OnReceiveCachedMetadata(const std::vector<uint8_t>& data) override;
  void OnTransferSizeUpdated(int32_t transfer_size_diff) override;
  void OnStartLoadingResponseBody(
      mojo::ScopedDataPipeConsumerHandle body) override;
  void OnComplete(const ResourceRequestCompletionStatus& status) override;

  // URLLoaderThrottle::Delegate:
  void CancelWithError(int error_code) override;
  void Resume() override;

  enum DeferredStage {
    DEFERRED_NONE,
    DEFERRED_START,
    DEFERRED_REDIRECT,
    DEFERRED_RESPONSE
  };
  DeferredStage deferred_stage_ = DEFERRED_NONE;
  bool cancelled_by_throttle_ = false;

  std::unique_ptr<URLLoaderThrottle> throttle_;

  mojom::URLLoaderClient* forwarding_client_;
  mojo::Binding<mojom::URLLoaderClient> client_binding_;

  mojom::URLLoaderAssociatedPtr url_loader_;

  // Set if start is deferred.
  mojom::URLLoaderFactory* url_loader_factory_ = nullptr;
  int32_t routing_id_ = -1;
  int32_t request_id_ = -1;
  uint32_t options_ = mojom::kURLLoadOptionNone;
  std::unique_ptr<ResourceRequest> url_request_;

  // Set if either response or redirect is deferred.
  ResourceResponseHead response_head_;

  // Set if response is deferred.
  base::Optional<net::SSLInfo> ssl_info_;
  mojom::DownloadedTempFilePtr downloaded_file_;

  // Set if redirect is deferred.
  net::RedirectInfo redirect_info_;

  // Set if request is deferred and SetPriority() is called.
  bool set_priority_cached_ = false;
  net::RequestPriority priority_ = net::MINIMUM_PRIORITY;
  int32_t intra_priority_value_ = 0;

  DISALLOW_COPY_AND_ASSIGN(ThrottlingURLLoader);
};

}  // namespace content

#endif  // CONTENT_COMMON_THROTTLING_URL_LOADER_H_