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Side by Side Diff: chrome/browser/ui/webui/chrome_url_data_manager.h

Issue 12049052: Move core url data manager classes to content. (Closed) Base URL: svn://chrome-svn/chrome/trunk/src/
Patch Set: review comments Created 7 years, 11 months ago
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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 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 2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file. 3 // found in the LICENSE file.
4 4
5 #ifndef CHROME_BROWSER_UI_WEBUI_CHROME_URL_DATA_MANAGER_H_ 5 // temporary forwarding header
6 #define CHROME_BROWSER_UI_WEBUI_CHROME_URL_DATA_MANAGER_H_ 6 #include "content/browser/webui/url_data_manager.h"
7
8 #include <string>
9 #include <vector>
10
11 #include "base/callback.h"
12 #include "base/memory/ref_counted.h"
13 #include "base/sequenced_task_runner_helpers.h"
14 #include "base/synchronization/lock.h"
15 #include "chrome/browser/profiles/profile_keyed_service.h"
16
17 class ChromeURLDataManagerBackend;
18 class MessageLoop;
19 class Profile;
20
21 namespace base {
22 class RefCountedMemory;
23 }
24
25 namespace content {
26 class URLDataSource;
27 class WebUIDataSource;
28 }
29
30 class URLDataSourceImpl;
31
32 // To serve dynamic data off of chrome: URLs, implement the
33 // ChromeURLDataManager::DataSource interface and register your handler
34 // with AddDataSource. DataSources must be added on the UI thread (they are also
35 // deleted on the UI thread). Internally the DataSources are maintained by
36 // ChromeURLDataManagerBackend, see it for details.
37 class ChromeURLDataManager : public ProfileKeyedService {
38 public:
39 explicit ChromeURLDataManager(
40 const base::Callback<ChromeURLDataManagerBackend*(void)>& backend);
41 virtual ~ChromeURLDataManager();
42
43 // Adds a DataSource to the collection of data sources. This *must* be invoked
44 // on the UI thread.
45 //
46 // If |AddDataSource| is called more than once for a particular name it will
47 // release the old |DataSource|, most likely resulting in it getting deleted
48 // as there are no other references to it. |DataSource| uses the
49 // |DeleteOnUIThread| trait to insure that the destructor is called on the UI
50 // thread. This is necessary as some |DataSource|s notably |FileIconSource|
51 // and |FaviconSource|, have members that will DCHECK if they are not
52 // destructed in the same thread as they are constructed (the UI thread).
53 void AddDataSource(URLDataSourceImpl* source);
54
55 // Deletes any data sources no longer referenced. This is normally invoked
56 // for you, but can be invoked to force deletion (such as during shutdown).
57 static void DeleteDataSources();
58
59 // Convenience wrapper function to add |source| to |profile|'s
60 // |ChromeURLDataManager|. Creates a URLDataSourceImpl to wrap the given
61 // source.
62 static void AddDataSource(Profile* profile,
63 content::URLDataSource* source);
64
65 // Adds a WebUI data source to |profile|'s |ChromeURLDataManager|.
66 static void AddWebUIDataSource(Profile* profile,
67 content::WebUIDataSource* source);
68
69 private:
70 friend class URLDataSourceImpl;
71 friend struct DeleteURLDataSource;
72 typedef std::vector<const URLDataSourceImpl*> URLDataSources;
73
74 // If invoked on the UI thread the DataSource is deleted immediatlye,
75 // otherwise it is added to |data_sources_| and a task is scheduled to handle
76 // deletion on the UI thread. See note abouve DeleteDataSource for more info.
77 static void DeleteDataSource(const URLDataSourceImpl* data_source);
78
79 // Returns true if |data_source| is scheduled for deletion (|DeleteDataSource|
80 // was invoked).
81 static bool IsScheduledForDeletion(const URLDataSourceImpl* data_source);
82
83 // A callback that returns the ChromeURLDataManagerBackend. Only accessible on
84 // the IO thread. This is necessary because ChromeURLDataManager is created on
85 // the UI thread, but ChromeURLDataManagerBackend lives on the IO thread.
86 const base::Callback<ChromeURLDataManagerBackend*(void)> backend_;
87
88 // |data_sources_| that are no longer referenced and scheduled for deletion.
89 // Protected by g_delete_lock in the .cc file.
90 static URLDataSources* data_sources_;
91
92 DISALLOW_COPY_AND_ASSIGN(ChromeURLDataManager);
93 };
94
95 // Trait used to handle deleting a URLDataSource. Deletion happens on the UI
96 // thread.
97 //
98 // Implementation note: the normal shutdown sequence is for the UI loop to
99 // stop pumping events then the IO loop and thread are stopped. When the
100 // URLDataSources are no longer referenced (which happens when IO thread stops)
101 // they get added to the UI message loop for deletion. But because the UI loop
102 // has stopped by the time this happens the URLDataSources would be leaked.
103 //
104 // To make sure URLDataSources are properly deleted ChromeURLDataManager manages
105 // deletion of the URLDataSources. When a URLDataSource is no longer referenced
106 // it is added to |data_sources_| and a task is posted to the UI thread to
107 // handle the actual deletion. During shutdown |DeleteDataSources| is invoked so
108 // that all pending URLDataSources are properly deleted.
109 struct DeleteURLDataSource {
110 static void Destruct(const URLDataSourceImpl* data_source) {
111 ChromeURLDataManager::DeleteDataSource(data_source);
112 }
113 };
114
115 // A URLDataSource is an object that can answer requests for data
116 // asynchronously. URLDataSources are collectively owned with refcounting smart
117 // pointers and should never be deleted on the IO thread, since their calls
118 // are handled almost always on the UI thread and there's a possibility of a
119 // data race. The |DeleteDataSource| trait above is used to enforce this.
120 class URLDataSourceImpl : public base::RefCountedThreadSafe<
121 URLDataSourceImpl, DeleteURLDataSource> {
122 public:
123 // See source_name_ below for docs on that parameter. Takes ownership of
124 // |source|.
125 URLDataSourceImpl(const std::string& source_name,
126 content::URLDataSource* source);
127
128 // Report that a request has resulted in the data |bytes|.
129 // If the request can't be satisfied, pass NULL for |bytes| to indicate
130 // the request is over.
131 virtual void SendResponse(int request_id, base::RefCountedMemory* bytes);
132
133 const std::string& source_name() const { return source_name_; }
134 content::URLDataSource* source() const { return source_.get(); }
135
136 protected:
137 virtual ~URLDataSourceImpl();
138
139 private:
140 friend class ChromeURLDataManagerBackend;
141 friend class ChromeURLDataManager;
142 friend class base::DeleteHelper<URLDataSourceImpl>;
143
144 // SendResponse invokes this on the IO thread. Notifies the backend to
145 // handle the actual work of sending the data.
146 virtual void SendResponseOnIOThread(
147 int request_id,
148 scoped_refptr<base::RefCountedMemory> bytes);
149
150 // The name of this source.
151 // E.g., for favicons, this could be "favicon", which results in paths for
152 // specific resources like "favicon/34" getting sent to this source.
153 const std::string source_name_;
154
155 // This field is set and maintained by ChromeURLDataManagerBackend. It is
156 // set when the DataSource is added, and unset if the DataSource is removed.
157 // A DataSource can be removed in two ways: the ChromeURLDataManagerBackend
158 // is deleted, or another DataSource is registered with the same
159 // name. backend_ should only be accessed on the IO thread.
160 // This reference can't be via a scoped_refptr else there would be a cycle
161 // between the backend and data source.
162 ChromeURLDataManagerBackend* backend_;
163
164 scoped_ptr<content::URLDataSource> source_;
165 };
166
167 #endif // CHROME_BROWSER_UI_WEBUI_CHROME_URL_DATA_MANAGER_H_
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