text: // Copyright (c) 2012 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.
  
  // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
  
  #ifndef CONTENT_CHILD_RESOURCE_DISPATCHER_H_
  #define CONTENT_CHILD_RESOURCE_DISPATCHER_H_
  
  #include <deque>
  #include <string>
  
  #include "base/containers/hash_tables.h"
  #include "base/memory/linked_ptr.h"
  #include "base/memory/shared_memory.h"
  #include "base/memory/weak_ptr.h"
  #include "base/time/time.h"
  #include "content/common/content_export.h"
  #include "content/public/common/resource_type.h"
  #include "ipc/ipc_listener.h"
  #include "ipc/ipc_sender.h"
  #include "net/base/request_priority.h"
  #include "url/gurl.h"
  
  struct ResourceMsg_RequestCompleteData;
  
  namespace blink {
  class WebThreadedDataReceiver;
  }
  
  namespace net {
  struct RedirectInfo;
  }
  
  namespace content {
  class RequestPeer;
  class ResourceDispatcherDelegate;
  class ResourceLoaderBridge;
  class ThreadedDataProvider;
  struct ResourceResponseInfo;
  struct RequestInfo;
  struct ResourceResponseHead;
  struct SiteIsolationResponseMetaData;
  
  // This class serves as a communication interface between the
  // ResourceDispatcherHost in the browser process and the ResourceLoaderBridge in
  // the child process.  It can be used from any child process.
  class CONTENT_EXPORT ResourceDispatcher : public IPC::Listener {
   public:
    explicit ResourceDispatcher(IPC::Sender* sender);
    virtual ~ResourceDispatcher();
  
    // IPC::Listener implementation.
    virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
  
    // Creates a ResourceLoaderBridge for this type of dispatcher, this is so
    // this can be tested regardless of the ResourceLoaderBridge::Create
    // implementation.  Virtual for tests.
    virtual ResourceLoaderBridge* CreateBridge(const RequestInfo& request_info);
  
    // Adds a request from the |pending_requests_| list, returning the new
    // requests' ID.
    int AddPendingRequest(RequestPeer* callback,
                          ResourceType resource_type,
                          int origin_pid,
                          const GURL& frame_origin,
                          const GURL& request_url,
                          bool download_to_file);
  
    // Removes a request from the |pending_requests_| list, returning true if the
    // request was found and removed.
    bool RemovePendingRequest(int request_id);
  
    // Cancels a request in the |pending_requests_| list.  The request will be
    // removed from the dispatcher as well.
    void CancelPendingRequest(int request_id);
  
    // Toggles the is_deferred attribute for the specified request.
    void SetDefersLoading(int request_id, bool value);
  
    // Indicates the priority of the specified request changed.
    void DidChangePriority(int request_id,
                           net::RequestPriority new_priority,
                           int intra_priority_value);
  
    // The provided data receiver will receive incoming resource data rather
    // than the resource bridge.
    bool AttachThreadedDataReceiver(
        int request_id, blink::WebThreadedDataReceiver* threaded_data_receiver);
  
    IPC::Sender* message_sender() const { return message_sender_; }
  
    // This does not take ownership of the delegate. It is expected that the
    // delegate have a longer lifetime than the ResourceDispatcher.
    void set_delegate(ResourceDispatcherDelegate* delegate) {
      delegate_ = delegate;
    }
  
    // Remembers IO thread timestamp for next resource message.
    void set_io_timestamp(base::TimeTicks io_timestamp) {
      io_timestamp_ = io_timestamp;
    }
  
   private:
    friend class ResourceDispatcherTest;
  
    typedef std::deque<IPC::Message*> MessageQueue;
    struct PendingRequestInfo {
      PendingRequestInfo();
  
      PendingRequestInfo(RequestPeer* peer,
                         ResourceType resource_type,
                         int origin_pid,
                         const GURL& frame_origin,
                         const GURL& request_url,
                         bool download_to_file);
  
      ~PendingRequestInfo();
  
      RequestPeer* peer;
      ThreadedDataProvider* threaded_data_provider;
      ResourceType resource_type;
      // The PID of the original process which issued this request. This gets
      // non-zero only for a request proxied by another renderer, particularly
      // requests from plugins.
      int origin_pid;
      MessageQueue deferred_message_queue;
      bool is_deferred;
      // Original requested url.
      GURL url;
      // The security origin of the frame that initiates this request.
      GURL frame_origin;
      // The url of the latest response even in case of redirection.
      GURL response_url;
      bool download_to_file;
      linked_ptr<IPC::Message> pending_redirect_message;
      base::TimeTicks request_start;
      base::TimeTicks response_start;
      base::TimeTicks completion_time;
      linked_ptr<base::SharedMemory> buffer;
      linked_ptr<SiteIsolationResponseMetaData> site_isolation_metadata;
      bool blocked_response;
      int buffer_size;
    };
    typedef base::hash_map<int, PendingRequestInfo> PendingRequestList;
  
    // Helper to lookup the info based on the request_id.
    // May return NULL if the request as been canceled from the client side.
    PendingRequestInfo* GetPendingRequestInfo(int request_id);
  
    // Follows redirect, if any, for the given request.
    void FollowPendingRedirect(int request_id, PendingRequestInfo& request_info);
  
    // Message response handlers, called by the message handler for this process.
    void OnUploadProgress(int request_id, int64 position, int64 size);
    void OnReceivedResponse(int request_id, const ResourceResponseHead&);
    void OnReceivedCachedMetadata(int request_id, const std::vector<char>& data);
    void OnReceivedRedirect(int request_id,
                            const net::RedirectInfo& redirect_info,
                            const ResourceResponseHead& response_head);
    void OnSetDataBuffer(int request_id,
                         base::SharedMemoryHandle shm_handle,
                         int shm_size,
                         base::ProcessId renderer_pid);
    void OnReceivedData(int request_id,
                        int data_offset,
                        int data_length,
                        int encoded_data_length);
    void OnDownloadedData(int request_id, int data_len, int encoded_data_length);
    void OnRequestComplete(
        int request_id,
        const ResourceMsg_RequestCompleteData& request_complete_data);
  
    // Dispatch the message to one of the message response handlers.
    void DispatchMessage(const IPC::Message& message);
  
    // Dispatch any deferred messages for the given request, provided it is not
    // again in the deferred state.
    void FlushDeferredMessages(int request_id);
  
    void ToResourceResponseInfo(const PendingRequestInfo& request_info,
                                const ResourceResponseHead& browser_info,
                                ResourceResponseInfo* renderer_info) const;
  
    base::TimeTicks ToRendererCompletionTime(
        const PendingRequestInfo& request_info,
        const base::TimeTicks& browser_completion_time) const;
  
    // Returns timestamp provided by IO thread. If no timestamp is supplied,
    // then current time is returned. Saved timestamp is reset, so following
    // invocations will return current time until set_io_timestamp is called.
    base::TimeTicks ConsumeIOTimestamp();
  
    // Returns true if the message passed in is a resource related message.
    static bool IsResourceDispatcherMessage(const IPC::Message& message);
  
    // ViewHostMsg_Resource_DataReceived is not POD, it has a shared memory
    // handle in it that we should cleanup it up nicely. This method accepts any
    // message and determine whether the message is
    // ViewHostMsg_Resource_DataReceived and clean up the shared memory handle.
    static void ReleaseResourcesInDataMessage(const IPC::Message& message);
  
    // Iterate through a message queue and clean up the messages by calling
    // ReleaseResourcesInDataMessage and removing them from the queue. Intended
    // for use on deferred message queues that are no longer needed.
    static void ReleaseResourcesInMessageQueue(MessageQueue* queue);
  
    IPC::Sender* message_sender_;
  
    // All pending requests issued to the host
    PendingRequestList pending_requests_;
  
    base::WeakPtrFactory<ResourceDispatcher> weak_factory_;
  
    ResourceDispatcherDelegate* delegate_;
  
    // IO thread timestamp for ongoing IPC message.
    base::TimeTicks io_timestamp_;
  
    DISALLOW_COPY_AND_ASSIGN(ResourceDispatcher);
  };
  
  }  // namespace content
  
  #endif  // CONTENT_CHILD_RESOURCE_DISPATCHER_H_
  