Crawler frontend

lib/crawler.js

Index: lib/crawler.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/lib/crawler.js
@@ -0,0 +1,115 @@
+Cu.import("resource://gre/modules/Services.jsm");
+
+function abprequire(module)
+{
+  let result = {};
+  result.wrappedJSObject = result;
+  Services.obs.notifyObservers(result, "adblockplus-require", module);
+  return result.exports;
+}
+
+let {Storage} = require("storage");
+let {Client} = require("client");
+
+let {Policy} = abprequire("contentPolicy");
+let {Filter} = abprequire("filterClasses");
+let {Utils} = abprequire("utils");
+
+let origProcessNode = Policy.processNode;
+
+let siteTabs;
+let currentTabs;
+
+function processNode(wnd, node, contentType, location, collapse)
+{
+  let result = origProcessNode.apply(this, arguments);
+  let url = (contentType === Policy.type.ELEMHIDE) ? location.text :
+      location.spec;
+  let topWindow = wnd.top;
+  let tabbrowser = Utils.getChromeWindow(topWindow).gBrowser;
+  let browser = tabbrowser.getBrowserForDocument(topWindow.document);
+  let site = siteTabs.get(browser);

[Wladimir Palant, 2012/09/25 16:51:30]

I would probably add a few more checks here. The three lines above failing if
ABP and Crawler are the only extensions installed is unexpected - but it isn't
impossible. Meaning: the chrome window doesn't necessarily have a gBrowser
property (e.g. a non-browser window making a request), the tabbrowser doesn't
necessarily know the document (e.g. a request in a browser sidebar) and we don't
necessarily know the browser (e.g. a browser belonging to a pop-up window that
was somehow opened despite the pop-up blocker).

+  let filtered = !result;
+  Storage.write([url, site, filtered]);
+  return result;
+}
+
+function loadSite(site, window, callback)
+{
+  if (!site)
+    return;
+
+  let tabbrowser = window.gBrowser;
+  let tab = tabbrowser.addTab(site);
+  let browser = tabbrowser.getBrowserForTab(tab);
+
+  let progressListener = {
+    onStateChange: function(aBrowser, aWebProgress, aRequest, aStateFlags, aStatus)
+    {
+      if (browser !== aBrowser)
+        return;
+
+      if (!(aStateFlags & Ci.nsIWebProgressListener.STATE_STOP))
+        return;
+
+      tabbrowser.removeTabsProgressListener(progressListener);
+      tabbrowser.removeTab(tab);
+      callback();
+    },
+    onLocationChange: function(aBrowser, aWebProgress, aRequest, aLocation, aFlags)
+    {
+      if (browser === aBrowser)
+        siteTabs.set(browser, site);

[Wladimir Palant, 2012/09/25 16:51:30]

Why are we doing this in the progress listener and not at the top of loadSite?
We already know the browser there, onLocationChange() shouldn't be necessary.

+    }
+  };
+  tabbrowser.addTabsProgressListener(progressListener);
+}
+
+function loadSites(backendUrl, parallelTabs, window, sites, callback)
+{
+  while (currentTabs < parallelTabs && sites.length)
+  {
+    currentTabs++;
+    let site = sites.shift();
+    loadSite(site, window, function()
+    {
+      currentTabs--;
+      if (!sites.length && !currentTabs)
+      {
+        Storage.finish();
+        let dataFilePath = Storage.dataFile.path;
+        Client.sendCrawlerDataFile(backendUrl, dataFilePath, function()
+        {
+          Storage.destroy();
+          callback();
+        });
+      }
+      else
+        loadSites(backendUrl, parallelTabs, window, sites, callback);
+    });
+  }
+}
+
+let Crawler = exports.Crawler = {};
+
+Crawler.crawl = function(backendUrl, parallelTabs, window, callback)
+{
+  if (Policy.processNode != origProcessNode)
+    return;
+
+  Policy.processNode = processNode;
+
+  siteTabs = new WeakMap();

[Wladimir Palant, 2012/09/25 16:51:30]

You should null out this variable when you are done, to make sure the map can be
garbage collected (the usual trouble with global variables).

+  currentTabs = 0;
+
+  Storage.init();
+
+  Client.fetchCrawlableSites(backendUrl, function(sites)
+  {
+    loadSites(backendUrl, parallelTabs, window, sites, function()
+    {
+      Policy.processNode = origProcessNode;
+      callback();
+    });
+  });
+};