extensions/renderer/content_watcher.h

   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
  15 namespace blink {
  16 class WebFrame;
  17 class WebString;
  18 }
  19
  20 namespace extensions {
  21 class Dispatcher;
  22 class Extension;
  23 class 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.
  32 class 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_