Updating trunk VERSION from 2139.0 to 2140.0
[chromium-blink-merge.git] / content / browser / loader / resource_scheduler.h
blob8d0efc5155c4b8aad81770b635a5ae8652e60766
1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_
6 #define CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_
8 #include <map>
9 #include <set>
11 #include "base/basictypes.h"
12 #include "base/compiler_specific.h"
13 #include "base/memory/scoped_ptr.h"
14 #include "base/threading/non_thread_safe.h"
15 #include "base/timer/timer.h"
16 #include "content/common/content_export.h"
17 #include "net/base/priority_queue.h"
18 #include "net/base/request_priority.h"
20 namespace net {
21 class HostPortPair;
22 class URLRequest;
25 namespace content {
26 class ResourceThrottle;
28 // There is one ResourceScheduler. All renderer-initiated HTTP requests are
29 // expected to pass through it.
31 // There are two types of input to the scheduler:
32 // 1. Requests to start, cancel, or finish fetching a resource.
33 // 2. Notifications for renderer events, such as new tabs, navigation and
34 // painting.
36 // These input come from different threads, so they may not be in sync. The UI
37 // thread is considered the authority on renderer lifetime, which means some
38 // IPCs may be meaningless if they arrive after the UI thread signals a renderer
39 // has been deleted.
41 // The ResourceScheduler tracks many Clients, which should correlate with tabs.
42 // A client is uniquely identified by its child_id and route_id.
44 // Each Client may have many Requests in flight. Requests are uniquely
45 // identified within a Client by its ScheduledResourceRequest.
47 // Users should call ScheduleRequest() to notify this ResourceScheduler of a
48 // new request. The returned ResourceThrottle should be destroyed when the load
49 // finishes or is canceled.
51 // The scheduler may defer issuing the request via the ResourceThrottle
52 // interface or it may alter the request's priority by calling set_priority() on
53 // the URLRequest.
54 class CONTENT_EXPORT ResourceScheduler : public base::NonThreadSafe {
55 public:
56 enum ClientThrottleState {
57 // TODO(aiolos): Add logic to ShouldStartRequest for PAUSED Clients to only
58 // issue synchronous requests.
59 // TODO(aiolos): Add max number of THROTTLED Clients, and logic to set
60 // subsquent Clients to PAUSED instead. Also add logic to unpause a Client
61 // when a background Client becomes COALESCED (ie, finishes loading.)
62 // TODO(aiolos): Add tests for the above mentioned logic.
64 // Currently being deleted client.
65 // This state currently follows the same logic for loading requests as
66 // UNTHROTTLED/ACTIVE_AND_LOADING Clients. See above TODO's.
67 PAUSED,
68 // Loaded background client, all observable clients loaded.
69 COALESCED,
70 // Background client, an observable client is loading.
71 THROTTLED,
72 // Observable (active) loaded client or
73 // Loading background client, all observable clients loaded.
74 // Note that clients which would be COALESCED are UNTHROTTLED until
75 // coalescing is turned on.
76 UNTHROTTLED,
77 // Observable (active) loading client.
78 ACTIVE_AND_LOADING,
81 enum RequestClassification {
82 NORMAL_REQUEST,
83 // Low priority in-flight requests
84 IN_FLIGHT_DELAYABLE_REQUEST,
85 // High-priority requests received before the renderer has a <body>
86 LAYOUT_BLOCKING_REQUEST,
89 ResourceScheduler();
90 ~ResourceScheduler();
92 // Use a mock timer when testing.
93 void set_timer_for_testing(scoped_ptr<base::Timer> timer) {
94 coalescing_timer_.reset(timer.release());
97 // TODO(aiolos): Remove when throttling and coalescing have landed
98 void SetThrottleOptionsForTesting(bool should_throttle, bool should_coalesce);
100 bool should_coalesce() const { return should_coalesce_; }
101 bool should_throttle() const { return should_throttle_; }
103 ClientThrottleState GetClientStateForTesting(int child_id, int route_id);
105 // Requests that this ResourceScheduler schedule, and eventually loads, the
106 // specified |url_request|. Caller should delete the returned ResourceThrottle
107 // when the load completes or is canceled.
108 scoped_ptr<ResourceThrottle> ScheduleRequest(
109 int child_id, int route_id, net::URLRequest* url_request);
111 // Signals from the UI thread, posted as tasks on the IO thread:
113 // Called when a renderer is created.
114 void OnClientCreated(int child_id, int route_id, bool is_visible);
116 // Called when a renderer is destroyed.
117 void OnClientDeleted(int child_id, int route_id);
119 // Signals from IPC messages directly from the renderers:
121 // Called when a client navigates to a new main document.
122 void OnNavigate(int child_id, int route_id);
124 // Called when the client has parsed the <body> element. This is a signal that
125 // resource loads won't interfere with first paint.
126 void OnWillInsertBody(int child_id, int route_id);
128 // Signals from the IO thread:
130 // Called when we received a response to a http request that was served
131 // from a proxy using SPDY.
132 void OnReceivedSpdyProxiedHttpResponse(int child_id, int route_id);
134 // Client functions:
136 // Called to check if all user observable tabs have completed loading.
137 bool active_clients_loaded() const { return active_clients_loading_ == 0; }
139 // Called when a Client starts or stops playing audio.
140 void OnAudibilityChanged(int child_id, int route_id, bool is_audible);
142 // Called when a Client is shown or hidden.
143 void OnVisibilityChanged(int child_id, int route_id, bool is_visible);
145 void OnLoadingStateChanged(int child_id, int route_id, bool is_loaded);
147 bool IsClientVisibleForTesting(int child_id, int route_id);
149 private:
150 class RequestQueue;
151 class ScheduledResourceRequest;
152 struct RequestPriorityParams;
153 struct ScheduledResourceSorter {
154 bool operator()(const ScheduledResourceRequest* a,
155 const ScheduledResourceRequest* b) const;
157 class Client;
159 typedef int64 ClientId;
160 typedef std::map<ClientId, Client*> ClientMap;
161 typedef std::set<ScheduledResourceRequest*> RequestSet;
163 // Called when a ScheduledResourceRequest is destroyed.
164 void RemoveRequest(ScheduledResourceRequest* request);
166 // These calls may update the ThrottleState of all clients, and have the
167 // potential to be re-entrant.
168 // Called when a Client newly becomes active loading.
169 void IncrementActiveClientsLoading();
170 // Called when an active and loading Client either completes loading or
171 // becomes inactive.
172 void DecrementActiveClientsLoading();
174 void OnLoadingActiveClientsStateChangedForAllClients();
176 size_t CountActiveClientsLoading() const;
178 // Called when a Client becomes coalesced.
179 void IncrementCoalescedClients();
180 // Called when a client stops being coalesced.
181 void DecrementCoalescedClients();
183 void LoadCoalescedRequests();
185 size_t CountCoalescedClients() const;
187 // Update the queue position for |request|, possibly causing it to start
188 // loading.
190 // Queues are maintained for each priority level. When |request| is
191 // reprioritized, it will move to the end of the queue for that priority
192 // level.
193 void ReprioritizeRequest(ScheduledResourceRequest* request,
194 net::RequestPriority new_priority,
195 int intra_priority_value);
197 // Returns the client ID for the given |child_id| and |route_id| combo.
198 ClientId MakeClientId(int child_id, int route_id);
200 // Returns the client for the given |child_id| and |route_id| combo.
201 Client* GetClient(int child_id, int route_id);
203 bool should_coalesce_;
204 bool should_throttle_;
205 ClientMap client_map_;
206 size_t active_clients_loading_;
207 size_t coalesced_clients_;
208 // This is a repeating timer to initiate requests on COALESCED Clients.
209 scoped_ptr<base::Timer> coalescing_timer_;
210 RequestSet unowned_requests_;
213 } // namespace content
215 #endif // CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_