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1 // Copyright 2015 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. | |
4 | |
5 #ifndef EXTENSIONS_BROWSER_EXTENSION_API_FRAME_ID_MAP_H_ | |
6 #define EXTENSIONS_BROWSER_EXTENSION_API_FRAME_ID_MAP_H_ | |
7 | |
8 #include <list> | |
9 #include <map> | |
10 | |
11 #include "base/callback.h" | |
12 #include "base/lazy_instance.h" | |
13 #include "base/macros.h" | |
14 #include "base/synchronization/lock.h" | |
15 | |
16 namespace content { | |
17 class RenderFrameHost; | |
18 class WebContents; | |
19 } // namespace content | |
20 | |
21 namespace extensions { | |
22 | |
23 // Extension frame IDs are exposed through the chrome.* APIs and have the | |
24 // following characteristics: | |
25 // - The top-level frame has ID 0. | |
26 // - Any child frame has a positive ID. | |
27 // - A non-existant frame has ID -1. | |
28 // - They are only guaranteed to be unique within a tab. | |
29 // - The ID does not change during the frame's lifetime and is not re-used after | |
30 // the frame is removed. The frame may change its current RenderFrameHost over | |
31 // time, so multiple RenderFrameHosts may map to the same extension frame ID. | |
32 | |
33 // This class provides a mapping from a (render_process_id, frame_routing_id) | |
34 // pair that maps a RenderFrameHost to an extension frame ID. | |
35 // Unless stated otherwise, the methods can only be called on the UI thread. | |
36 // | |
37 // The non-static methods of this class use an internal cache. This cache is | |
38 // used to minimize IO->UI->IO round-trips of GetFrameIdOnIO. If the cost of | |
39 // attaching FrameTreeNode IDs to requests is negligible (crbug.com/524228), | |
40 // then we can remove all key caching and remove the cache from this class. | |
41 // TODO(robwu): Keep an eye on crbug.com/524228 and act upon the outcome. | |
42 class ExtensionApiFrameIdMap { | |
43 public: | |
44 using FrameIdCallback = | |
45 base::Callback<void(int extension_api_frame_id, | |
46 int extension_api_parent_frame_id)>; | |
47 | |
48 // An invalid extension API frame ID. | |
49 static const int kInvalidFrameId; | |
50 | |
51 static ExtensionApiFrameIdMap* Get(); | |
52 | |
53 // Get the extension API frame ID for |rfh|. | |
54 static int GetFrameId(content::RenderFrameHost* rfh); | |
55 // Get the extension API frame ID for the parent of |rfh|. | |
nasko
2016/01/05 00:39:58
nit: Empty line above the comment.
robwu
2016/01/05 10:59:03
Done.
| |
56 static int GetParentFrameId(content::RenderFrameHost* rfh); | |
57 | |
58 // Find the current RenderFrameHost for a given WebContents and extension | |
59 // frame ID. | |
60 // Returns nullptr if not found. | |
61 static content::RenderFrameHost* GetRenderFrameHostById( | |
62 content::WebContents* web_contents, | |
63 int frame_id); | |
64 | |
65 // Runs |callback| with the result that is equivalent to calling GetFrameId() | |
66 // on the UI thread. Thread hopping is minimized if possible. Callbacks for | |
67 // the same |render_process_id| and |frame_routing_id| are guaranteed to be | |
68 // run in order. The order of other callbacks is undefined. | |
69 void GetFrameIdOnIO(int render_process_id, | |
70 int frame_routing_id, | |
71 const FrameIdCallback& callback); | |
72 | |
73 // Look up the frame ID and store it in the map. This method should be called | |
nasko
2016/01/05 00:39:58
nit: "Looks up", "stores it".
robwu
2016/01/05 10:59:03
Done.
| |
74 // as early as possible, e.g. in a WebContentsObserver::RenderFrameCreated | |
75 // notification. | |
76 void CacheFrameId(content::RenderFrameHost* rfh); | |
77 | |
78 // Remove the frame ID mapping for a given frame. This method can be called at | |
nasko
2016/01/05 00:39:58
nit: "Removes the"
robwu
2016/01/05 10:59:03
Done.
| |
79 // any time, but it is typical to call this method when a frame is destroyed. | |
80 // If this method is not called, the cached mapping for the frame is retained | |
81 // forever. | |
82 void RemoveFrameId(content::RenderFrameHost* rfh); | |
83 | |
84 protected: | |
nasko
2016/01/05 00:39:58
Why are all the members protected instead of priva
robwu
2016/01/05 10:59:03
For unit tests, so that the internal state of the
| |
85 friend struct base::DefaultLazyInstanceTraits<ExtensionApiFrameIdMap>; | |
86 | |
87 // A set of identifiers that uniquely identifies a RenderFrame. | |
88 struct RenderFrameIdKey { | |
89 RenderFrameIdKey(); | |
90 RenderFrameIdKey(int render_process_id, int frame_routing_id); | |
91 | |
92 // The process ID of the renderer that contains the RenderFrame. | |
93 int render_process_id; | |
94 // The routing ID of the RenderFrame. | |
nasko
2016/01/05 00:39:58
nit: Empty line before comment.
robwu
2016/01/05 10:59:03
Done.
| |
95 int frame_routing_id; | |
96 | |
97 bool operator<(const RenderFrameIdKey& other) const; | |
98 bool operator==(const RenderFrameIdKey& other) const; | |
99 }; | |
100 | |
101 // The cached pair of frame IDs of the frame. Every RenderFrameIdKey | |
102 // maps to a CachedFrameIdPair. | |
103 struct CachedFrameIdPair { | |
104 CachedFrameIdPair(); | |
105 CachedFrameIdPair(int frame_id, int parent_frame_id); | |
106 | |
107 // The extension API frame ID of the frame. | |
108 int frame_id; | |
109 // The extension API frame ID of the parent of the frame. | |
nasko
2016/01/05 00:39:58
nit: Empty line before comment.
robwu
2016/01/05 10:59:03
Done.
| |
110 int parent_frame_id; | |
111 }; | |
112 | |
113 struct FrameIdCallbacks { | |
114 FrameIdCallbacks(); | |
115 ~FrameIdCallbacks(); | |
116 | |
117 // This is a std::list so that iterators are not invalidated when the list | |
118 // is modified during an iteration. | |
119 std::list<FrameIdCallback> callbacks; | |
120 | |
121 // To avoid re-entrant processing of callbacks. | |
122 bool is_iterating; | |
123 }; | |
124 | |
125 using FrameIdMap = std::map<RenderFrameIdKey, CachedFrameIdPair>; | |
126 using FrameIdCallbacksMap = std::map<RenderFrameIdKey, FrameIdCallbacks>; | |
127 | |
128 ExtensionApiFrameIdMap(); | |
129 ~ExtensionApiFrameIdMap(); | |
130 | |
131 // Determines the value to be stored in |frame_id_map_| for a given key. This | |
132 // method is only called when |key| is not in |frame_id_map_|. | |
133 // virtual for testing. | |
134 virtual CachedFrameIdPair KeyToValue(const RenderFrameIdKey& key) const; | |
135 | |
136 CachedFrameIdPair LookupFrameIdOnUI(const RenderFrameIdKey& key); | |
137 | |
138 // Called as soon as the frame ID is found for the given |key|, and runs all | |
139 // queued callbacks with |cached_frame_id_pair|. | |
140 void GotFrameIdOnIO(const RenderFrameIdKey& key, | |
141 const CachedFrameIdPair& cached_frame_id_pair); | |
142 | |
143 // Implementation of CacheFrameId(RenderFrameHost), separated for testing. | |
144 void CacheFrameId(const RenderFrameIdKey& key); | |
145 // Implementation of RemoveFrameId(RenderFrameHost), separated for testing. | |
nasko
2016/01/05 00:39:58
nit: Empty line before comment.
robwu
2016/01/05 10:59:03
Done.
| |
146 void RemoveFrameId(const RenderFrameIdKey& key); | |
147 | |
148 // Queued callbacks for use on the IO thread. | |
149 FrameIdCallbacksMap callbacks_map_; | |
150 | |
151 // This frameId map is only modified on the UI thread and used to minimize the | |
nasko
2016/01/05 00:39:58
"frameId" is not used before and it doesn't match
robwu
2016/01/05 10:59:03
Done.
| |
152 // number of thread hops on the IO thread. | |
153 FrameIdMap frame_id_map_; | |
154 | |
155 // This lock protects |frame_id_map| from being concurrently written on the UI | |
nasko
2016/01/05 00:39:58
frame_id_map_
robwu
2016/01/05 10:59:03
Done.
| |
156 // thread and read on the IO thread. | |
157 base::Lock frame_id_map_lock_; | |
158 | |
159 DISALLOW_COPY_AND_ASSIGN(ExtensionApiFrameIdMap); | |
160 }; | |
161 | |
162 } // namespace extensions | |
163 | |
164 #endif // EXTENSIONS_BROWSER_EXTENSION_API_FRAME_ID_MAP_H_ | |
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