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_
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"
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
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
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
54 class CONTENT_EXPORT ResourceScheduler : public base::NonThreadSafe {
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.
68 // Loaded background client, all observable clients loaded.
70 // Background client, an observable client is loading.
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.
77 // Observable (active) loading client.
84 // Use a mock timer when testing.
85 void set_timer_for_testing(scoped_ptr<base::Timer> timer) {
86 coalescing_timer_.reset(timer.release());
89 // TODO(aiolos): Remove when throttling and coalescing have landed
90 void SetThrottleOptionsForTesting(bool should_throttle, bool should_coalesce);
92 bool should_coalesce() const { return should_coalesce_; }
93 bool should_throttle() const { return should_throttle_; }
95 ClientThrottleState GetClientStateForTesting(int child_id, int route_id);
97 // Requests that this ResourceScheduler schedule, and eventually loads, the
98 // specified |url_request|. Caller should delete the returned ResourceThrottle
99 // when the load completes or is canceled.
100 scoped_ptr<ResourceThrottle> ScheduleRequest(
101 int child_id, int route_id, net::URLRequest* url_request);
103 // Signals from the UI thread, posted as tasks on the IO thread:
105 // Called when a renderer is created.
106 void OnClientCreated(int child_id, int route_id);
108 // Called when a renderer is destroyed.
109 void OnClientDeleted(int child_id, int route_id);
111 // Signals from IPC messages directly from the renderers:
113 // Called when a client navigates to a new main document.
114 void OnNavigate(int child_id, int route_id);
116 // Called when the client has parsed the <body> element. This is a signal that
117 // resource loads won't interfere with first paint.
118 void OnWillInsertBody(int child_id, int route_id);
120 // Signals from the IO thread:
122 // Called when we received a response to a http request that was served
123 // from a proxy using SPDY.
124 void OnReceivedSpdyProxiedHttpResponse(int child_id, int route_id);
128 // Called to check if all user observable tabs have completed loading.
129 bool active_clients_loaded() const { return active_clients_loading_ == 0; }
131 // Called when a Client starts or stops playing audio.
132 void OnAudibilityChanged(int child_id, int route_id, bool is_audible);
134 // Called when a Client is shown or hidden.
135 void OnVisibilityChanged(int child_id, int route_id, bool is_visible);
137 void OnLoadingStateChanged(int child_id, int route_id, bool is_loaded);
141 class ScheduledResourceRequest;
142 struct RequestPriorityParams;
143 struct ScheduledResourceSorter {
144 bool operator()(const ScheduledResourceRequest* a,
145 const ScheduledResourceRequest* b) const;
149 typedef int64 ClientId;
150 typedef std::map<ClientId, Client*> ClientMap;
151 typedef std::set<ScheduledResourceRequest*> RequestSet;
153 // Called when a ScheduledResourceRequest is destroyed.
154 void RemoveRequest(ScheduledResourceRequest* request);
156 // These calls may update the ThrottleState of all clients, and have the
157 // potential to be re-entrant.
158 // Called when a Client newly becomes active loading.
159 void IncrementActiveClientsLoading();
160 // Called when an active and loading Client either completes loading or
162 void DecrementActiveClientsLoading();
164 void OnLoadingActiveClientsStateChangedForAllClients();
166 size_t CountActiveClientsLoading() const;
168 // Called when a Client becomes coalesced.
169 void IncrementCoalescedClients();
170 // Called when a client stops being coalesced.
171 void DecrementCoalescedClients();
173 void LoadCoalescedRequests();
175 size_t CountCoalescedClients() const;
177 // Update the queue position for |request|, possibly causing it to start
180 // Queues are maintained for each priority level. When |request| is
181 // reprioritized, it will move to the end of the queue for that priority
183 void ReprioritizeRequest(ScheduledResourceRequest* request,
184 net::RequestPriority new_priority,
185 int intra_priority_value);
187 // Returns the client ID for the given |child_id| and |route_id| combo.
188 ClientId MakeClientId(int child_id, int route_id);
190 // Returns the client for the given |child_id| and |route_id| combo.
191 Client* GetClient(int child_id, int route_id);
193 bool should_coalesce_;
194 bool should_throttle_;
195 ClientMap client_map_;
196 size_t active_clients_loading_;
197 size_t coalesced_clients_;
198 // This is a repeating timer to initiate requests on COALESCED Clients.
199 scoped_ptr<base::Timer> coalescing_timer_;
200 RequestSet unowned_requests_;
203 } // namespace content
205 #endif // CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_