// 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.
// This is the browser side of the resource dispatcher, it receives requests
// from the RenderProcessHosts, and dispatches them to URLRequests. It then
// fowards the messages from the URLRequests back to the correct process for
// handling.
//
// See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
#ifndef CONTENT_BROWSER_LOADER_RESOURCE_HANDLER_H_
#define CONTENT_BROWSER_LOADER_RESOURCE_HANDLER_H_
#include <string>
#include "base/memory/ref_counted.h"
#include "base/sequenced_task_runner_helpers.h"
#include "base/threading/non_thread_safe.h"
#include "content/common/content_export.h"
class GURL;
namespace net {
class IOBuffer;
class URLRequest;
class URLRequestStatus;
} // namespace net
namespace content {
class ResourceController;
class ResourceMessageFilter;
class ResourceRequestInfoImpl;
struct ResourceResponse;
// The resource dispatcher host uses this interface to process network events
// for an URLRequest instance. A ResourceHandler's lifetime is bound to its
// associated URLRequest.
class CONTENT_EXPORT ResourceHandler
: public NON_EXPORTED_BASE(base::NonThreadSafe) {
public:
virtual ~ResourceHandler() {}
// Sets the controller for this handler.
virtual void SetController(ResourceController* controller);
// Called as upload progress is made. The return value is ignored.
virtual bool OnUploadProgress(int request_id,
uint64 position,
uint64 size) = 0;
// The request was redirected to a new URL. |*defer| has an initial value of
// false. Set |*defer| to true to defer the redirect. The redirect may be
// followed later on via ResourceDispatcherHost::FollowDeferredRedirect. If
// the handler returns false, then the request is cancelled.
virtual bool OnRequestRedirected(int request_id, const GURL& url,
ResourceResponse* response,
bool* defer) = 0;
// Response headers and meta data are available. If the handler returns
// false, then the request is cancelled. Set |*defer| to true to defer
// processing of the response. Call ResourceDispatcherHostImpl::
// ResumeDeferredRequest to continue processing the response.
virtual bool OnResponseStarted(int request_id,
ResourceResponse* response,
bool* defer) = 0;
// Called before the net::URLRequest for |request_id| (whose url is |url|) is
// to be started. If the handler returns false, then the request is
// cancelled. Otherwise if the return value is true, the ResourceHandler can
// delay the request from starting by setting |*defer = true|. A deferred
// request will not have called net::URLRequest::Start(), and will not resume
// until someone calls ResourceDispatcherHost::StartDeferredRequest().
virtual bool OnWillStart(int request_id, const GURL& url, bool* defer) = 0;
// Called before the net::URLRequest for |request_id| (whose url is |url|}
// uses the network for the first time to load the resource. If the handler
// returns false, then the request is cancelled. Otherwise if the return value
// is true, the ResourceHandler can delay the request from starting by setting
// |*defer = true|. Call controller()->Resume() to continue if deferred.
virtual bool OnBeforeNetworkStart(int request_id,
const GURL& url,
bool* defer) = 0;
// Data will be read for the response. Upon success, this method places the
// size and address of the buffer where the data is to be written in its
// out-params. This call will be followed by either OnReadCompleted or
// OnResponseCompleted, at which point the buffer may be recycled.
//
// If the handler returns false, then the request is cancelled. Otherwise,
// once data is available, OnReadCompleted will be called.
virtual bool OnWillRead(int request_id,
scoped_refptr<net::IOBuffer>* buf,
int* buf_size,
int min_size) = 0;
// Data (*bytes_read bytes) was written into the buffer provided by
// OnWillRead. A return value of false cancels the request, true continues
// reading data. Set |*defer| to true to defer reading more response data.
// Call controller()->Resume() to continue reading response data.
virtual bool OnReadCompleted(int request_id, int bytes_read,
bool* defer) = 0;
// The response is complete. The final response status is given. Set
// |*defer| to true to defer destruction to a later time. Otherwise, the
// request will be destroyed upon return.
virtual void OnResponseCompleted(int request_id,
const net::URLRequestStatus& status,
const std::string& security_info,
bool* defer) = 0;
// This notification is synthesized by the RedirectToFileResourceHandler
// to indicate progress of 'download_to_file' requests. OnReadCompleted
// calls are consumed by the RedirectToFileResourceHandler and replaced
// with OnDataDownloaded calls.
virtual void OnDataDownloaded(int request_id, int bytes_downloaded) = 0;
protected:
ResourceHandler(net::URLRequest* request);
ResourceController* controller() const { return controller_; }
net::URLRequest* request() const { return request_; }
// Convenience functions.
ResourceRequestInfoImpl* GetRequestInfo() const;
int GetRequestID() const;
ResourceMessageFilter* GetFilter() const;
private:
ResourceController* controller_;
net::URLRequest* request_;
};
} // namespace content
#endif // CONTENT_BROWSER_LOADER_RESOURCE_HANDLER_H_