content/browser/loader/resource_scheduler.h - experimental/chromium/src - Git at Google

 // 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.

 #ifndef CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_
 #define CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_

 #include <stddef.h>
 #include <stdint.h>

 #include <map>
 #include <memory>
 #include <set>

 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/threading/non_thread_safe.h"
 #include "content/common/content_export.h"
 #include "net/base/priority_queue.h"
 #include "net/base/request_priority.h"

 namespace net {
 class HostPortPair;
 class URLRequest;
 }

 namespace content {
 class ResourceThrottle;

 // There is one ResourceScheduler. All renderer-initiated HTTP requests are
 // expected to pass through it.
 //
 // There are two types of input to the scheduler:
 // 1. Requests to start, cancel, or finish fetching a resource.
 // 2. Notifications for renderer events, such as new tabs, navigation and
 //    painting.
 //
 // These input come from different threads, so they may not be in sync. The UI
 // thread is considered the authority on renderer lifetime, which means some
 // IPCs may be meaningless if they arrive after the UI thread signals a renderer
 // has been deleted.
 //
 // The ResourceScheduler tracks many Clients, which should correlate with tabs.
 // A client is uniquely identified by its child_id and route_id.
 //
 // Each Client may have many Requests in flight. Requests are uniquely
 // identified within a Client by its ScheduledResourceRequest.
 //
 // Users should call ScheduleRequest() to notify this ResourceScheduler of a new
 // request. The returned ResourceThrottle should be destroyed when the load
 // finishes or is canceled, before the net::URLRequest.
 //
 // The scheduler may defer issuing the request via the ResourceThrottle
 // interface or it may alter the request's priority by calling set_priority() on
 // the URLRequest.
 class CONTENT_EXPORT ResourceScheduler : public base::NonThreadSafe {
  public:
   ResourceScheduler();
   ~ResourceScheduler();

   // Requests that this ResourceScheduler schedule, and eventually loads, the
   // specified |url_request|. Caller should delete the returned ResourceThrottle
   // when the load completes or is canceled, before |url_request| is deleted.
   std::unique_ptr<ResourceThrottle> ScheduleRequest(
       int child_id,
       int route_id,
       bool is_async,
       net::URLRequest* url_request);

   // Signals from the UI thread, posted as tasks on the IO thread:

   // Called when a renderer is created.
   void OnClientCreated(int child_id, int route_id);

   // Called when a renderer is destroyed.
   void OnClientDeleted(int child_id, int route_id);

   // Called when a renderer stops or restarts loading.
   void OnLoadingStateChanged(int child_id, int route_id, bool is_loaded);

   // Signals from IPC messages directly from the renderers:

   // Called when a client navigates to a new main document.
   void OnNavigate(int child_id, int route_id);

   // Called when the client has parsed the <body> element. This is a signal that
   // resource loads won't interfere with first paint.
   void OnWillInsertBody(int child_id, int route_id);

   // Signals from the IO thread:

   // Called when we received a response to a http request that was served
   // from a proxy using SPDY.
   void OnReceivedSpdyProxiedHttpResponse(int child_id, int route_id);

   // Client functions:

   // Returns true if at least one client is currently loading.
   bool HasLoadingClients() const;

   // Update the priority for |request|. Modifies request->priority(), and may
   // start the request loading if it wasn't already started.
   void ReprioritizeRequest(net::URLRequest* request,
                            net::RequestPriority new_priority,
                            int intra_priority_value);

  private:
   // Returns true if limiting of outstanding requests is enabled.
   bool limit_outstanding_requests() const {
     return limit_outstanding_requests_;
   }

   // Returns the outstanding request limit.  Only valid if
   // |IsLimitingOutstandingRequests()|.
   size_t outstanding_request_limit() const {
     return outstanding_request_limit_;
   }

   // Returns the maximum number of delayable requests to all be in-flight at
   // any point in time (across all hosts).
   size_t max_num_delayable_requests() const {
     return max_num_delayable_requests_;
   }

   class RequestQueue;
   class ScheduledResourceRequest;
   struct RequestPriorityParams;
   struct ScheduledResourceSorter {
     bool operator()(const ScheduledResourceRequest* a,
                     const ScheduledResourceRequest* b) const;
   };
   class Client;

   typedef int64_t ClientId;
   typedef std::map<ClientId, Client*> ClientMap;
   typedef std::set<ScheduledResourceRequest*> RequestSet;

   // Called when a ScheduledResourceRequest is destroyed.
   void RemoveRequest(ScheduledResourceRequest* request);

   // Returns the client ID for the given |child_id| and |route_id| combo.
   ClientId MakeClientId(int child_id, int route_id);

   // Returns the client for the given |child_id| and |route_id| combo.
   Client* GetClient(int child_id, int route_id);

   ClientMap client_map_;
   bool limit_outstanding_requests_;
   size_t outstanding_request_limit_;
   size_t max_num_delayable_requests_;
   RequestSet unowned_requests_;

   DISALLOW_COPY_AND_ASSIGN(ResourceScheduler);
 };

 }  // namespace content

 #endif  // CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_
	// 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.

	#ifndef CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_
	#define CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_

	#include <stddef.h>
	#include <stdint.h>

	#include <map>
	#include <memory>
	#include <set>

	#include "base/compiler_specific.h"
	#include "base/macros.h"
	#include "base/threading/non_thread_safe.h"
	#include "content/common/content_export.h"
	#include "net/base/priority_queue.h"
	#include "net/base/request_priority.h"

	namespace net {
	class HostPortPair;
	class URLRequest;
	}

	namespace content {
	class ResourceThrottle;

	// There is one ResourceScheduler. All renderer-initiated HTTP requests are
	// expected to pass through it.
	//
	// There are two types of input to the scheduler:
	// 1. Requests to start, cancel, or finish fetching a resource.
	// 2. Notifications for renderer events, such as new tabs, navigation and
	// painting.
	//
	// These input come from different threads, so they may not be in sync. The UI
	// thread is considered the authority on renderer lifetime, which means some
	// IPCs may be meaningless if they arrive after the UI thread signals a renderer
	// has been deleted.
	//
	// The ResourceScheduler tracks many Clients, which should correlate with tabs.
	// A client is uniquely identified by its child_id and route_id.
	//
	// Each Client may have many Requests in flight. Requests are uniquely
	// identified within a Client by its ScheduledResourceRequest.
	//
	// Users should call ScheduleRequest() to notify this ResourceScheduler of a new
	// request. The returned ResourceThrottle should be destroyed when the load
	// finishes or is canceled, before the net::URLRequest.
	//
	// The scheduler may defer issuing the request via the ResourceThrottle
	// interface or it may alter the request's priority by calling set_priority() on
	// the URLRequest.
	class CONTENT_EXPORT ResourceScheduler : public base::NonThreadSafe {
	public:
	ResourceScheduler();
	~ResourceScheduler();

	// Requests that this ResourceScheduler schedule, and eventually loads, the
	// specified \|url_request\|. Caller should delete the returned ResourceThrottle
	// when the load completes or is canceled, before \|url_request\| is deleted.
	std::unique_ptr<ResourceThrottle> ScheduleRequest(
	int child_id,
	int route_id,
	bool is_async,
	net::URLRequest* url_request);

	// Signals from the UI thread, posted as tasks on the IO thread:

	// Called when a renderer is created.
	void OnClientCreated(int child_id, int route_id);

	// Called when a renderer is destroyed.
	void OnClientDeleted(int child_id, int route_id);

	// Called when a renderer stops or restarts loading.
	void OnLoadingStateChanged(int child_id, int route_id, bool is_loaded);

	// Signals from IPC messages directly from the renderers:

	// Called when a client navigates to a new main document.
	void OnNavigate(int child_id, int route_id);

	// Called when the client has parsed the <body> element. This is a signal that
	// resource loads won't interfere with first paint.
	void OnWillInsertBody(int child_id, int route_id);

	// Signals from the IO thread:

	// Called when we received a response to a http request that was served
	// from a proxy using SPDY.
	void OnReceivedSpdyProxiedHttpResponse(int child_id, int route_id);

	// Client functions:

	// Returns true if at least one client is currently loading.
	bool HasLoadingClients() const;

	// Update the priority for \|request\|. Modifies request->priority(), and may
	// start the request loading if it wasn't already started.
	void ReprioritizeRequest(net::URLRequest* request,
	net::RequestPriority new_priority,
	int intra_priority_value);

	private:
	// Returns true if limiting of outstanding requests is enabled.
	bool limit_outstanding_requests() const {
	return limit_outstanding_requests_;
	}

	// Returns the outstanding request limit. Only valid if
	// \|IsLimitingOutstandingRequests()\|.
	size_t outstanding_request_limit() const {
	return outstanding_request_limit_;
	}

	// Returns the maximum number of delayable requests to all be in-flight at
	// any point in time (across all hosts).
	size_t max_num_delayable_requests() const {
	return max_num_delayable_requests_;
	}

	class RequestQueue;
	class ScheduledResourceRequest;
	struct RequestPriorityParams;
	struct ScheduledResourceSorter {
	bool operator()(const ScheduledResourceRequest* a,
	const ScheduledResourceRequest* b) const;
	};
	class Client;

	typedef int64_t ClientId;
	typedef std::map<ClientId, Client*> ClientMap;
	typedef std::set<ScheduledResourceRequest*> RequestSet;

	// Called when a ScheduledResourceRequest is destroyed.
	void RemoveRequest(ScheduledResourceRequest* request);

	// Returns the client ID for the given \|child_id\| and \|route_id\| combo.
	ClientId MakeClientId(int child_id, int route_id);

	// Returns the client for the given \|child_id\| and \|route_id\| combo.
	Client* GetClient(int child_id, int route_id);

	ClientMap client_map_;
	bool limit_outstanding_requests_;
	size_t outstanding_request_limit_;
	size_t max_num_delayable_requests_;
	RequestSet unowned_requests_;

	DISALLOW_COPY_AND_ASSIGN(ResourceScheduler);
	};

	} // namespace content

	#endif // CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_