Issue 154 - Added devtools panel showing blocked and blockable items

lib/devtools.js

Index: lib/devtools.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/lib/devtools.js
@@ -0,0 +1,349 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-2015 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
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+let info = require("info");
+if (info.platform == "chromium")
+{
+  let {WhitelistFilter, ElemHideFilter} = require("filterClasses");
+  let {SpecialSubscription} = require("subscriptionClasses");
+  let {FilterStorage} = require("filterStorage");
+  let {defaultMatcher} = require("matcher");
+  let {FilterNotifier} = require("filterNotifier");
+
+  // Mapping of inspected tabs to their devpanel page
+  // and recorded items. We can't use a PageMap here,
+  // because data must persist after navigation/reload.
+  let panels = Object.create(null);
+
+  function hasPanels()
+  {
+    return Object.keys(panels).length > 0;
+  }
+
+  function getRequestInfo(request)
+  {
+    return {
+      url: request.url,
+      type: request.type,
+      docDomain: request.docDomain
+    };
+  }
+
+  function getFilterInfo(filter)
+  {
+    if (!filter)
+      return null;
+
+    let userDefined = false;
+    let subscriptionTitle = null;
+
+    for (let subscription of filter.subscriptions)
+    {
+      if (!subscription.disabled)
+      {
+        if (subscription instanceof SpecialSubscription)
+          userDefined = true;
+        else
+          subscriptionTitle = subscription.title;
+      }
+    }
+
+    return {
+      text: filter.text,
+      whitelisted: filter instanceof WhitelistFilter,
+      userDefined: userDefined,
+      subscription: subscriptionTitle
+    };
+  }
+
+  function hasRecord(panel, request, filter)
+  {
+    return panel.records.some(record =>
+      record.request.type      == request.type      &&
+      record.request.url       == request.url       &&
+      record.request.docDomain == request.docDomain &&
+
+      // Matched element hiding filters don't relate to a particular request,
+      // so we also have to match the CSS selector in order to distinguish them.
+      (request.type != "ELEMHIDE" || record.filter.selector == filter.selector)
+    );
+  }
+
+  function addRecord(panel, request, filter)
+  {
+    if (!hasRecord(panel, request, filter))
+    {
+      panel.panel.sendMessage({
+        type: "add-record",
+        request: getRequestInfo(request),
+        filter: getFilterInfo(filter)
+      });
+
+      panel.records.push({
+        request: request,
+        filter: filter
+      });
+    }
+  }
+
+  function matchRequest(request)
+  {
+    return defaultMatcher.matchesAny(
+      request.url,
+      request.type,
+      request.docDomain,
+      request.thirdParty,
+      request.sitekey
+    );
+  }
+
+  /**
+   * Logs a request in the devtools panel.
+   *
+   * @param {Page}    page        The page the request occured on
+   * @param {string]  url         The URL of the request
+   * @param {string}  type        The request type
+   * @param {string}  docDomain   The IDN-decoded hostname of the document
+   * @param {Boolean} thirdParty  Whether the origin of the request and document differs
+   * @param {string}  [sitekey]   The active sitekey if there is any
+   * @param {filter}  [filter]    The matched filter or null if there is no match
+   */
+  function logRequest(page, url, type, docDomain, thirdParty, sitekey, filter)
+  {
+    let panel = panels[page._id];
+    if (panel && !panel.reload && !panel.reloading)
+    {
+      let request = {
+        url: url,
+        type: type,
+        docDomain: docDomain,
+        thirdParty: thirdParty,
+        sitekey: sitekey
+      };
+
+      addRecord(panel, request, filter);
+    }
+  }
+  exports.logRequest = logRequest;
+
+  /**
+   * Logs active element hiding filters in the devtools panel.
+   *
+   * @param {Page}     page       The page the elements were hidden on
+   * @param {string[]} selectors  The CSS selectors of active elemhide filters
+   * @param {string}   docDomain  The IDN-decoded hostname of the document
+   */
+  function logHiddenElements(page, selectors, docDomain)
+  {
+    let panel = panels[page._id];
+    if (panel && !panel.reload && !panel.reloading)
+    {
+      for (let subscription of FilterStorage.subscriptions)
+      {
+        if (subscription.disabled)
+          continue;
+
+        for (let filter of subscription.filters)
+        {
+          if (!(filter instanceof ElemHideFilter))
+            continue;
+          if (selectors.indexOf(filter.selector) == -1)
+            continue;
+          if (!filter.isActiveOnDomain(docDomain))
+            continue;
+
+          addRecord(panel, {type: "ELEMHIDE", docDomain: docDomain}, filter);
+        }
+      }
+    }
+  };
+  exports.logHiddenElements = logHiddenElements;
+
+  /**
+   * Checks whether a page is inspected by the devtools panel.
+   *
+   * @param {Page} page
+   * @return {Boolean}
+   */
+  function hasDevToolsPanel(page)
+  {
+    return page._id in panels;
+  }
+  exports.hasDevToolsPanel = hasDevToolsPanel;
+
+  function onBeforeRequest(details)
+  {
+    let panel = panels[details.tabId];
+
+    // Clear the devtools panel and reload the inspected tab without caching
+    // when a new request is issued. However, make sure that we don't end up
+    // in an infinite recursion if we already triggered a reload.
+    if (panel.reloading)
+    {
+      panel.reloading = false;
+    }
+    else
+    {
+      panel.records = [];
+      panel.panel.sendMessage({type: "reset"});
+
+      // We can't repeat the request if it isn't a GET request. Chrome would
+      // prompt the user to confirm reloading the page, and POST requests are
+      // known to cause issues on many websites if repeated.
+      if (details.method == "GET")
+        panel.reload = true;
+    }
+  }
+
+  function onLoading(page)
+  {
+    let tabId = page._id;
+    let panel = panels[tabId];
+
+    // Reloading the tab is the only way that allows bypassing all caches, in
+    // order to see all requests in the devtools panel. Reloading must not be
+    // performed before the tab changes to "loading", otherwise it will load the
+    // previous URL.
+    if (panel && panel.reload)
+    {
+      chrome.tabs.reload(tabId, {bypassCache: true});
+
+      panel.reload = false;
+      panel.reloading = true;
+    }
+  }
+
+  function onFilterChange(action, arg)
+  {
+    // When there haven't ever been any user filters before, the
+    // subscription is added, but no "filter.added" event is triggered.
+    let added, filters;
+    if (action == "subscription.added")
+    {
+      if (!(arg instanceof SpecialSubscription))
+        return;
+
+      added = true;
+      filters = arg.filters;
+    }
+    else
+    {
+      added = (action == "filter.added");
+
+      if (!added && action != "filter.removed")
+        return;
+
+      filters = [arg];
+    }
+
+    for (let tabId in panels)
+    {
+      let panel = panels[tabId];
+
+      for (let i = 0; i < panel.records.length; i++)
+      {
+        let record = panel.records[i];
+
+        // If an added filter matches a request shown in the devtools panel,
+        // update that record to show the new filter. Ignore element hiding
+        // filters since there are only records for element hiding filters that
+        // already match, and also we don't know if any new element matches.
+        if (added)
+        {
+          if (record.request.type == "ELEMHIDE")
+            continue;
+
+          let filter = matchRequest(record.request);
+          if (filters.indexOf(filter) == -1)
+            continue;
+
+          record.filter = filter;
+        }
+
+        // If a filter shown in the devtools panel got removed, update that
+        // record to show the filter (if any) that matches now instead.
+        // However, for element hiding, just remove the record, since we don't
+        // know whether another filter would match until the page is reloaded.
+        else
+        {
+          if (filters.indexOf(record.filter) == -1)
+            continue;
+
+          if (record.request.type == "ELEMHIDE")
+          {
+            panel.panel.sendMessage({
+              type: "remove-record",
+              index: i
+            });
+            panel.records.splice(i--, 1);
+            continue;
+          }
+
+          record.filter = matchRequest(record.request);
+        }
+
+        panel.panel.sendMessage({
+          type: "update-record",
+          index: i,
+          request: getRequestInfo(record.request),
+          filter: getFilterInfo(record.filter)
+        });
+      }
+    }
+  }
+
+  ext.devtools.onCreated.addListener(function(panel)
+  {
+    let inspectedTabId = panel.inspectedTabId;
+    let localOnBeforeRequest = onBeforeRequest.bind();
+
+    chrome.webRequest.onBeforeRequest.addListener(
+      localOnBeforeRequest,
+      {
+        urls:  ["<all_urls>"],
+        types: ["main_frame"],
+        tabId: inspectedTabId
+      }
+    );
+
+    if (!hasPanels())
+    {
+      ext.pages.onLoading.addListener(onLoading);
+      FilterNotifier.addListener(onFilterChange);
+    }
+
+    panel.onRemoved.addListener(function()
+    {
+      delete panels[inspectedTabId];
+      chrome.webRequest.onBeforeRequest.removeListener(localOnBeforeRequest);
+
+      if (!hasPanels())
+      {
+        FilterNotifier.removeListener(onFilterChange);
+        ext.pages.onLoading.removeListener(onLoading);
+      }
+    });
+
+    panels[inspectedTabId] = {panel: panel, records: []};
+  });
+}
+else
+{
+  exports.logRequest        = () => {};
+  exports.logHiddenElements = () => {};
+  exports.hasDevToolsPanel  = () => false;
+}