extensions/renderer/content_watcher.cc

   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 #include "extensions/renderer/content_watcher.h"
   6
   7 #include "content/public/renderer/render_view.h"
   8 #include "content/public/renderer/render_view_visitor.h"
   9 #include "extensions/common/extension_messages.h"
  10 #include "third_party/WebKit/public/web/WebDocument.h"
  11 #include "third_party/WebKit/public/web/WebElement.h"
  12 #include "third_party/WebKit/public/web/WebFrame.h"
  13 #include "third_party/WebKit/public/web/WebScriptBindings.h"
  14 #include "third_party/WebKit/public/web/WebView.h"
  15
  16 namespace extensions {
  17
  18 using blink::WebString;
  19 using blink::WebVector;
  20 using blink::WebView;
  21
  22 ContentWatcher::ContentWatcher() {}
  23 ContentWatcher::~ContentWatcher() {}
  24
  25 void ContentWatcher::OnWatchPages(
  26     const std::vector<std::string>& new_css_selectors_utf8) {
  27   blink::WebVector<blink::WebString> new_css_selectors(
  28       new_css_selectors_utf8.size());
  29   bool changed = new_css_selectors.size() != css_selectors_.size();
  30   for (size_t i = 0; i < new_css_selectors.size(); ++i) {
  31     new_css_selectors[i] =
  32         blink::WebString::fromUTF8(new_css_selectors_utf8[i]);
  33     if (!changed && new_css_selectors[i] != css_selectors_[i])
  34       changed = true;
  35   }
  36
  37   if (!changed)
  38     return;
  39
  40   css_selectors_.swap(new_css_selectors);
  41
  42   // Tell each frame's document about the new set of watched selectors. These
  43   // will trigger calls to DidMatchCSS after Blink has a chance to apply the new
  44   // style, which will in turn notify the browser about the changes.
  45   struct WatchSelectors : public content::RenderViewVisitor {
  46     explicit WatchSelectors(const WebVector<WebString>& css_selectors)
  47         : css_selectors_(css_selectors) {}
  48
  49     bool Visit(content::RenderView* view) override {
  50       for (blink::WebFrame* frame = view->GetWebView()->mainFrame(); frame;
  51            frame = frame->traverseNext(/*wrap=*/false))
  52         frame->document().watchCSSSelectors(css_selectors_);
  53
  54       return true;  // Continue visiting.
  55     }
  56
  57     const WebVector<WebString>& css_selectors_;
  58   };
  59   WatchSelectors visitor(css_selectors_);
  60   content::RenderView::ForEach(&visitor);
  61 }
  62
  63 void ContentWatcher::DidCreateDocumentElement(blink::WebFrame* frame) {
  64   frame->document().watchCSSSelectors(css_selectors_);
  65 }
  66
  67 void ContentWatcher::DidMatchCSS(
  68     blink::WebFrame* frame,
  69     const WebVector<WebString>& newly_matching_selectors,
  70     const WebVector<WebString>& stopped_matching_selectors) {
  71   std::set<std::string>& frame_selectors = matching_selectors_[frame];
  72   for (size_t i = 0; i < stopped_matching_selectors.size(); ++i)
  73     frame_selectors.erase(stopped_matching_selectors[i].utf8());
  74   for (size_t i = 0; i < newly_matching_selectors.size(); ++i)
  75     frame_selectors.insert(newly_matching_selectors[i].utf8());
  76
  77   if (frame_selectors.empty())
  78     matching_selectors_.erase(frame);
  79
  80   NotifyBrowserOfChange(frame);
  81 }
  82
  83 void ContentWatcher::NotifyBrowserOfChange(
  84     blink::WebFrame* changed_frame) const {
  85   blink::WebFrame* const top_frame = changed_frame->top();
  86   const blink::WebSecurityOrigin top_origin = top_frame->securityOrigin();
  87   // Want to aggregate matched selectors from all frames where an
  88   // extension with access to top_origin could run on the frame.
  89   if (!top_origin.canAccess(changed_frame->document().securityOrigin())) {
  90     // If the changed frame can't be accessed by the top frame, then
  91     // no change in it could affect the set of selectors we'd send back.
  92     return;
  93   }
  94
  95   std::set<base::StringPiece> transitive_selectors;
  96   for (blink::WebFrame* frame = top_frame; frame;
  97        frame = frame->traverseNext(/*wrap=*/false)) {
  98     if (top_origin.canAccess(frame->document().securityOrigin())) {
  99       std::map<blink::WebFrame*, std::set<std::string> >::const_iterator
 100           frame_selectors = matching_selectors_.find(frame);
 101       if (frame_selectors != matching_selectors_.end()) {
 102         transitive_selectors.insert(frame_selectors->second.begin(),
 103                                     frame_selectors->second.end());
 104       }
 105     }
 106   }
 107   std::vector<std::string> selector_strings;
 108   for (std::set<base::StringPiece>::const_iterator it =
 109            transitive_selectors.begin();
 110        it != transitive_selectors.end();
 111        ++it)
 112     selector_strings.push_back(it->as_string());
 113   content::RenderView* view =
 114       content::RenderView::FromWebView(top_frame->view());
 115   view->Send(new ExtensionHostMsg_OnWatchedPageChange(view->GetRoutingID(),
 116                                                       selector_strings));
 117 }
 118
 119 }  // namespace extensions