Issue 3788 - Keep track of Safari tabs without canLoad

safari/ext/content.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 13 matching lines @@
 
 
   /* Intialization */
 
   var beforeLoadEvent = document.createEvent("Event");
   beforeLoadEvent.initEvent("beforeload");
 
   var isTopLevel = window == window.top;
   var isPrerendered = document.visibilityState == "prerender";
 
-  var documentInfo = safari.self.tab.canLoad(
-    beforeLoadEvent,
-    {
-      category: "loading",
-      url: window.location.href,
-      referrer: document.referrer,
-      isTopLevel: isTopLevel,
-      isPrerendered: isPrerendered
-    }
-  );
+  // Notify the background page that this frame is loading, generating ourselves
+  // a random documentId while we're at it. That way the background page can
+  // communicate with us reliably, despite limitations in Safari's extension
+  // API.
+  var documentId = Math.random().toString();

[Sebastian Noack, 2016/03/18 19:32:51]

Nit: It's not important for the logic, but more an ascetic thing;
Math.random().toString() returns a string that always starts with "0." followed
by a couple random digits. So the first two digits are redundant, and could
easily be stripped:

  Math.random().toString().substr(2)

[kzar, 2016/03/18 19:53:38]

Done.

+  safari.self.tab.dispatchMessage("loading",  {
+    url: window.location.href,
+    referrer: document.referrer,
+    isTopLevel: isTopLevel,
+    isPrerendered: isPrerendered,
+    documentId: documentId
+  });
 
   if (isTopLevel && isPrerendered)
   {
     var onVisibilitychange = function()
     {
-      safari.self.tab.dispatchMessage("replaced", {pageId: documentInfo.pageId});
+      safari.self.tab.dispatchMessage("replaced", {documentId: documentId});
       document.removeEventListener("visibilitychange", onVisibilitychange);
     };
     document.addEventListener("visibilitychange", onVisibilitychange);
   }
 
 
   /* Web requests */
 
   document.addEventListener("beforeload", function(event)
   {
@@ skipping 29 matching lines @@
         break;
       case "script":
         type = "SCRIPT";
         break;
       case "link":
         if (/\bstylesheet\b/i.test(event.target.rel))
           type = "STYLESHEET";
         break;
     }
 
-    if (!safari.self.tab.canLoad(
-      event, {
+    if (!safari.self.tab.canLoad(event, {
         category: "webRequest",
         url: event.url,
         type: type,
-        pageId: documentInfo.pageId,
-        frameId: documentInfo.frameId
-      }
-    ))
+        documentId: documentId}))
     {
       event.preventDefault();
 
       // Safari doesn't dispatch the expected events for elements that have been
       // prevented from loading by having their "beforeload" event cancelled.
       // That is a "load" event for blocked frames, and an "error" event for
       // other blocked elements. We need to dispatch those events manually here
       // to avoid breaking element collapsing and pages that rely on those events.
       setTimeout(function()
       {
         var evt = document.createEvent("Event");
         evt.initEvent(eventName);
         event.target.dispatchEvent(evt);
       }, 0);
     }
   }, true);
 
 
   /* Context menus */
 
   document.addEventListener("contextmenu", function(event)
   {
     var element = event.srcElement;
     safari.self.tab.setContextMenuEventUserInfo(event, {
-      pageId: documentInfo.pageId,
+      documentId: documentId,
       tagName: element.localName
     });
   });
 
 
   /* Background page */
 
   var backgroundPageProxy = {
     objects: [],
     callbacks: [],
 
     send: function(message)
     {
       message.category = "proxy";
-      message.pageId = documentInfo.pageId;
+      message.documentId = documentId;
 
       return safari.self.tab.canLoad(beforeLoadEvent, message);
     },
     checkResult: function(result)
     {
       if (!result.succeed)
         throw result.error;
     },
     deserializeResult: function(result)
     {
@@ skipping 11 matching lines @@
         {
           var callbackId;
           if ("__proxyCallbackId" in obj)
             callbackId = obj.__proxyCallbackId;
           else
           {
             callbackId = this.callbacks.push(obj) - 1;
             Object.defineProperty(obj, "__proxyCallbackId", {value: callbackId});
           }
 
-          return {type: "callback", callbackId: callbackId, frameId: documentInfo.frameId};
+          return {type: "callback", callbackId: callbackId,
+                  documentId: documentId};
         }
 
         if (obj.constructor != Date && obj.constructor != RegExp)
         {
           if (!memo)
             memo = {specs: [], objects: []};
 
           var idx = memo.objects.indexOf(obj);
           if (idx != -1)
             return memo.specs[idx];
@@ skipping 185 matching lines @@
         }
       }
 
       return obj;
     }
   };
 
   ext.backgroundPage = {
     sendMessage: function(message, responseCallback)
     {
-      messageProxy.sendMessage(message, responseCallback, documentInfo);
+      messageProxy.sendMessage(message, responseCallback,
+                               {documentId: documentId});
     },
     sendMessageSync: function(message)
     {
       return safari.self.tab.canLoad(
         beforeLoadEvent,
         {
           category: "request",
-          pageId: documentInfo.pageId,
-          frameId: documentInfo.frameId,
+          documentId: documentId,
           payload: message
         }
       );
     },
     getWindow: function()
     {
       return backgroundPageProxy.getObject(0);
     }
   };
 
 
   /* Message processing */
 
   var messageProxy = new ext._MessageProxy(safari.self.tab);
 
   safari.self.addEventListener("message", function(event)
   {
-    if (event.message.pageId == documentInfo.pageId)
+    if (event.name == "requestDocumentId" && isTopLevel)
     {
-      if (event.name == "request")
+      safari.self.tab.dispatchMessage("documentId",  {
+        pageId: event.message.pageId,
+        documentId: documentId
+      });
+    }
+    else if (event.message.targetDocuments.indexOf(documentId) != -1)
+    {
+      switch (event.name)
       {
-        messageProxy.handleRequest(event.message, {});
-        return;
-      }
-
-      if (event.message.frameId == documentInfo.frameId)
-      {
-        switch (event.name)
-        {
-          case "response":
-            messageProxy.handleResponse(event.message);
-            break;
-          case "proxyCallback":
-            backgroundPageProxy.handleCallback(event.message);
-            break;
-        }
+        case "request":
+          messageProxy.handleRequest(event.message, {});
+          break;
+        case "response":
+          messageProxy.handleResponse(event.message);
+          break;
+        case "proxyCallback":
+          backgroundPageProxy.handleCallback(event.message);
+          break;
       }
     }
   });
 
 
   /* Detecting extension reload/disable/uninstall (not supported on Safari) */
 
   ext.onExtensionUnloaded = {
     addListener: function() {},
     removeListener: function() {}
   };
 })();