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 +1,382 @@
+/*
+ * 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
+ * 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/>.
+ */
+
+"use strict";
+
+let {RegExpFilter, WhitelistFilter, ElemHideFilter} = require("filterClasses");
+let {SpecialSubscription} = require("subscriptionClasses");
+let {FilterStorage} = require("filterStorage");
+let {defaultMatcher} = require("matcher");
+let {FilterNotifier} = require("filterNotifier");
+
+const nonRequestTypes = ["DOCUMENT", "ELEMHIDE", "GENERICBLOCK", "GENERICHIDE"];
+
+// 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 getActivePanel(page)
+{
+  let panel = panels[page._id];
+  if(panel && !panel.reload && !panel.reloading)
+    return panel;
+  return null;
+}
+
+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.url       == request.url       &&
+    record.request.docDomain == request.docDomain &&
+
+    // Ignore partial (e.g. ELEMHIDE) whitelisting if there is already
+    // a DOCUMENT exception which disables all means of blocking.
+    (record.request.type == "DOCUMENT" ? nonRequestTypes.indexOf(request.type) != -1
+                                       : record.request.type == request.type) &&
+
+    // 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.
+    (record.filter && record.filter.selector) == (filter && filter.selector)
+  );
+}
+
+function addRecord(panel, request, filter)
+{
+  if (!hasRecord(panel, request, filter))
+  {
+    panel.port.postMessage({
+      type: "add-record",
+      request: request,
+      filter: getFilterInfo(filter)
+    });
+
+    panel.records.push({
+      request: request,
+      filter: filter
+    });
+  }
+}
+
+function matchRequest(request)
+{
+  return defaultMatcher.matchesAny(
+    request.url,
+    RegExpFilter.typeMap[request.type],
+    request.docDomain,
+    request.thirdParty,
+    request.sitekey,
+    request.specificOnly
+  );
+}
+
+/**
+ * Logs a request to 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 {?boolean} specificOnly  Whether generic filters should be ignored
+ * @param {?BlockingFilter} filter The matched filter or null if there is no match
+ */
+exports.logRequest = function(page, url, type, docDomain,
+                              thirdParty, sitekey,
+                              specificOnly, filter)
+{
+  let panel = getActivePanel(page);
+  if (panel)
+  {
+    let request = {
+      url: url,
+      type: type,
+      docDomain: docDomain,
+      thirdParty: thirdParty,
+      sitekey: sitekey,
+      specificOnly: specificOnly
+    };
+
+    addRecord(panel, request, filter);
+  }
+};
+
+/**
+ * Logs active element hiding filters to 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
+ */
+exports.logHiddenElements = function(page, selectors, docDomain)
+{
+  let panel = getActivePanel(page);
+  {
+    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);
+      }
+    }
+  }
+};
+
+/**
+ * Logs a whitelisting filter, that disables (some kind of)
+ * blocking for a particular document, to the devtools panel.
+ *
+ * @param {Page}         page      The page the whitelisting is active on
+ * @param {string}       url       The url of the whitelisted document
+ * @param {number}       typeMask  The bit mask of whitelisting types checked for
+ * @param {string}       docDomain The IDN-decoded hostname of the parent document
+ * @param {WhitelistFilter} filter The matched whitelisting filter
+ */
+exports.logWhitelistedDocument = function(page, url, typeMask, docDomain, filter)
+{
+  let panel = getActivePanel(page);
+  if (panel)
+  {
+    for (let type of nonRequestTypes)
+    {
+      if (typeMask & filter.contentType & RegExpFilter.typeMap[type])
+        addRecord(panel, {url: url, type: type, docDomain: docDomain}, filter);
+    }
+  }
+};
+
+/**
+ * Checks whether a page is inspected by the devtools panel.
+ *
+ * @param {Page} page
+ * @return {boolean}
+ */
+exports.hasPanel = function(page)
+{
+  return page._id in panels;
+};
+
+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.port.postMessage({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)
+{
+  let added, filters;
+  switch (action)
+  {
+    case "filter.added":
+      added = true;
+      filters = [arg];
+      break;
+
+    case "filter.removed":
+      added = false;
+      filters = [arg];
+      break;
+
+    // When there haven't ever been any user filters before, the subscription is
+    // added, triggering a "subscription.added" instead of a "filter.added" event.
+    case "subscription.added":
+      if (arg instanceof SpecialSubscription)
+      {
+        added = true;
+        filters = arg.filters;
+        break;
+      }
+
+    default:
+      return;
+  }
+
+  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 filters that aren't
+      // associated with any sub-resource request. There is no record for these
+      // if they don't already match. In particular, in case of element hiding
+      // filters, we also wouldn't know if any new element matches.
+      if (added)
+      {
+        if (nonRequestTypes.indexOf(record.request.type) != -1)
+          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 that matches now, or none, instead.
+      // For filters that aren't associated with any sub-resource request,
+      // just remove the record. We wouldn't know whether another filter
+      // matches instead until the page is reloaded.
+      else
+      {
+        if (filters.indexOf(record.filter) == -1)
+          continue;
+
+        if (nonRequestTypes.indexOf(record.request.type) != -1)
+        {
+          panel.port.postMessage({
+            type: "remove-record",
+            index: i
+          });
+          panel.records.splice(i--, 1);
+          continue;
+        }
+
+        record.filter = matchRequest(record.request);
+      }
+
+      panel.port.postMessage({
+        type: "update-record",
+        index: i,
+        request: record.request,
+        filter: getFilterInfo(record.filter)
+      });
+    }
+  }
+}
+
+chrome.runtime.onConnect.addListener(port =>
+{
+  let match = port.name.match(/^devtools-(\d+)$/);
+  if (!match)
+    return;
+
+  let inspectedTabId = parseInt(match[1], 10);
+  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);
+  }
+
+  port.onDisconnect.addListener(() =>
+  {
+    delete panels[inspectedTabId];
+    chrome.webRequest.onBeforeRequest.removeListener(localOnBeforeRequest);
+
+    if (!hasPanels())
+    {
+      FilterNotifier.removeListener(onFilterChange);
+      ext.pages.onLoading.removeListener(onLoading);
+    }
+  });
+
+  panels[inspectedTabId] = {port: port, records: []};
+});