1// Copyright 2014 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_RENDERER_CONTENT_WATCHER_H_
6#define EXTENSIONS_RENDERER_CONTENT_WATCHER_H_
7
8#include <map>
9#include <set>
10#include <string>
11#include <vector>
12
13#include "third_party/WebKit/public/platform/WebVector.h"
14
15namespace blink {
16class WebFrame;
17class WebString;
18}
19
20namespace extensions {
21class Dispatcher;
22class Extension;
23class NativeHandler;
24
25// Watches the content of WebFrames to notify extensions when they match various
26// patterns.  This class tracks the set of relevant patterns (set by
27// ExtensionMsg_WatchPages) and the set that match on each WebFrame, and sends a
28// ExtensionHostMsg_OnWatchedPageChange whenever a RenderView's set changes.
29//
30// There's one ContentWatcher per Dispatcher rather than per RenderView because
31// WebFrames can move between RenderViews through adoptNode.
32class ContentWatcher {
33 public:
34  ContentWatcher();
35  ~ContentWatcher();
36
37  // Handler for ExtensionMsg_WatchPages.
38  void OnWatchPages(const std::vector<std::string>& css_selectors);
39
40  // Uses WebDocument::watchCSSSelectors to watch the selectors in
41  // css_selectors_ and get a callback into DidMatchCSS() whenever the set of
42  // matching selectors in |frame| changes.
43  void DidCreateDocumentElement(blink::WebFrame* frame);
44
45  // Records that |newly_matching_selectors| have started matching on |*frame|,
46  // and |stopped_matching_selectors| have stopped matching.
47  void DidMatchCSS(
48      blink::WebFrame* frame,
49      const blink::WebVector<blink::WebString>& newly_matching_selectors,
50      const blink::WebVector<blink::WebString>& stopped_matching_selectors);
51
52 private:
53  // Given that we saw a change in the CSS selectors that |changed_frame|
54  // matched, tell the browser about the new set of matching selectors in its
55  // top-level page.  We filter this so that if an extension were to be granted
56  // activeTab permission on that top-level page, we only send CSS selectors for
57  // frames that it could run on.
58  void NotifyBrowserOfChange(blink::WebFrame* changed_frame) const;
59
60  // If any of these selectors match on a page, we need to send an
61  // ExtensionHostMsg_OnWatchedPageChange back to the browser.
62  blink::WebVector<blink::WebString> css_selectors_;
63
64  // Maps live WebFrames to the set of CSS selectors they match. Blink sends
65  // back diffs, which we apply to these sets.
66  std::map<blink::WebFrame*, std::set<std::string> > matching_selectors_;
67};
68
69}  // namespace extensions
70
71#endif  // EXTENSIONS_RENDERER_CONTENT_WATCHER_H_
72