Bug 1132203 - Load JSON viewer dynamically on demand; r=jryans

devtools/client/jsonview/converter-child.js

@@ -6,26 +6,23 @@
 
 "use strict";
 
-const Cu = Components.utils;
-const Ci = Components.interfaces;
-const Cc = Components.classes;
-
-const {devtools} = Cu.import("resource://gre/modules/devtools/shared/Loader.jsm", {});
-const {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
-
-let require = devtools.require;
-
+const {Cu, Cc, Ci, components} = require("chrome");
 const {Class} = require("sdk/core/heritage");
 const {Unknown} = require("sdk/platform/xpcom");
 const xpcom = require("sdk/platform/xpcom");
 const Events = require("sdk/dom/events");
 const Clipboard = require("sdk/clipboard");
 
-const NetworkHelper = require("devtools/shared/webconsole/network-helper");
-const JsonViewUtils = require("devtools/client/jsonview/utils");
+loader.lazyRequireGetter(this, "NetworkHelper",
+                               "devtools/shared/webconsole/network-helper");
+loader.lazyRequireGetter(this, "JsonViewUtils",
+                               "devtools/client/jsonview/utils");
 
-let childProcessMessageManager = Cc["@mozilla.org/childprocessmessagemanager;1"].
-  getService(Ci.nsISyncMessageSender);
+const {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
+
+const childProcessMessageManager =
+  Cc["@mozilla.org/childprocessmessagemanager;1"].
+    getService(Ci.nsISyncMessageSender);
 
 // Amount of space that will be allocated for the stream's backing-store.
 // Must be power of 2. Used to copy the data stream in onStopRequest.
@@ -117,10 +114,6 @@ var Converter = Class({
       request: []
     }
 
-    if (!(aRequest instanceof Ci.nsIHttpChannel)) {
-      return;
-    }
-
     let win = NetworkHelper.getWindowForRequest(aRequest);
 
     let Locale = {
@@ -141,17 +134,21 @@ var Converter = Class({
       });
     })
 
-    aRequest.visitResponseHeaders({
-      visitHeader: function(name, value) {
-        headers.response.push({name: name, value: value});
-      }
-    });
+    // The request doesn't have to be always nsIHttpChannel
+    // (e.g. in case of data: URLs)
+    if (aRequest instanceof Ci.nsIHttpChannel) {
+      aRequest.visitResponseHeaders({
+        visitHeader: function(name, value) {
+          headers.response.push({name: name, value: value});
+        }
+      });
 
-    aRequest.visitRequestHeaders({
-      visitHeader: function(name, value) {
-        headers.request.push({name: name, value: value});
-      }
-    });
+      aRequest.visitRequestHeaders({
+        visitHeader: function(name, value) {
+          headers.request.push({name: name, value: value});
+        }
+      });
+    }
 
     let outputDoc = "";
 
@@ -276,28 +273,37 @@ var Converter = Class({
   }
 });
 
-// Stream converter component registration
-const JSON_TYPE = "application/json";
-const CONTRACT_ID = "@mozilla.org/streamconv;1?from=" + JSON_TYPE + "&to=*/*";
+// Stream converter component definition
+const CONTRACT_ID = "@mozilla.org/streamconv;1?from=application/json&to=*/*";
 const CLASS_ID = "{d8c9acee-dec5-11e4-8c75-1681e6b88ec1}";
-const GECKO_VIEWER = "Gecko-Content-Viewers";
 
 var service = xpcom.Service({
-  id: Components.ID(CLASS_ID),
+  id: components.ID(CLASS_ID),
   contract: CONTRACT_ID,
   Component: Converter,
   register: false,
   unregister: false
 });
 
-if (!xpcom.isRegistered(service)) {
-  xpcom.register(service);
+function register() {
+  if (!xpcom.isRegistered(service)) {
+    xpcom.register(service);
+    return true;
+  }
+
+  return false;
 }
 
-// Remove native Gecko viewer
-var categoryManager = Cc["@mozilla.org/categorymanager;1"].
-  getService(Ci.nsICategoryManager);
-categoryManager.deleteCategoryEntry(GECKO_VIEWER, JSON_TYPE, false);
+function unregister() {
+  if (xpcom.isRegistered(service)) {
+    xpcom.unregister(service);
+    return true;
+  }
 
-categoryManager.addCategoryEntry("ext-to-type-mapping", "json",
-  JSON_TYPE, false, true);
+  return false;
+}
+
+exports.JsonViewService = {
+  register: register,
+  unregister: unregister
+}

devtools/client/jsonview/converter-observer.js

@@ -0,0 +1,111 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const Cu = Components.utils;
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+
+const {XPCOMUtils} = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
+const {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
+
+const categoryManager = Cc["@mozilla.org/categorymanager;1"].getService(Ci.nsICategoryManager);
+
+// Load JsonView service module (converter-child.js) as soon as required.
+XPCOMUtils.defineLazyGetter(this, "JsonViewService", function() {
+  const {devtools} = Cu.import("resource://gre/modules/devtools/shared/Loader.jsm", {});
+  const {JsonViewService} = devtools.require("devtools/client/jsonview/converter-child");
+  return JsonViewService;
+});
+
+const JSON_TYPE = "application/json";
+const GECKO_VIEWER = "Gecko-Content-Viewers";
+const JSON_VIEW_PREF = "devtools.jsonview.enabled";
+const GECKO_TYPE_MAPPING = "ext-to-type-mapping";
+
+/**
+ * Listen for 'devtools.jsonview.enabled' preference changes and
+ * register/unregister the JSON View XPCOM service as appropriate.
+ */
+function ConverterObserver() {
+}
+
+ConverterObserver.prototype = {
+  initialize: function() {
+    this.geckoViewer = categoryManager.getCategoryEntry(GECKO_VIEWER, JSON_TYPE);
+
+    // Only the DevEdition has this feature available by default.
+    // Users need to manually flip 'devtools.jsonview.enabled' preference
+    // to have it available in other distributions.
+    if (this.isEnabled()) {
+      this.register();
+    }
+
+    Services.prefs.addObserver(JSON_VIEW_PREF, this, false);
+    Services.obs.addObserver(this, "xpcom-shutdown", false);
+  },
+
+  observe: function(subject, topic, data) {
+    switch (topic) {
+      case "xpcom-shutdown":
+        this.onShutdown();
+        break;
+      case "nsPref:changed":
+        this.onPrefChanged();
+        break;
+    };
+  },
+
+  onShutdown: function() {
+    Services.prefs.removeObserver(JSON_VIEW_PREF, observer);
+    Services.obs.removeObserver(observer, "xpcom-shutdown");
+  },
+
+  onPrefChanged: function() {
+    if (this.isEnabled()) {
+      this.register();
+    } else {
+      this.unregister();
+    }
+  },
+
+  register: function() {
+    if (JsonViewService.register()) {
+      // Delete default JSON viewer (text)
+      categoryManager.deleteCategoryEntry(GECKO_VIEWER, JSON_TYPE, false);
+
+      // Append new *.json -> application/json type mapping
+      this.geckoMapping = categoryManager.addCategoryEntry(GECKO_TYPE_MAPPING,
+        "json", JSON_TYPE, false, true);
+    }
+  },
+
+  unregister: function() {
+    if (JsonViewService.unregister()) {
+      categoryManager.addCategoryEntry(GECKO_VIEWER, JSON_TYPE,
+        this.geckoViewer, false, false);
+
+      if (this.geckoMapping) {
+        categoryManager.addCategoryEntry(GECKO_TYPE_MAPPING, "json",
+          this.geckoMapping, false, true);
+      } else {
+        categoryManager.deleteCategoryEntry(GECKO_TYPE_MAPPING,
+          JSON_TYPE, false)
+      }
+    }
+  },
+
+  isEnabled: function() {
+    return Services.prefs.getBoolPref(JSON_VIEW_PREF);
+  },
+};
+
+// Listen to JSON View 'enable' pref and perform dynamic
+// registration or unregistration of the main application
+// component.
+var observer = new ConverterObserver();
+observer.initialize();

devtools/client/jsonview/main.js

@@ -6,20 +6,12 @@
 
 "use strict";
 
-const { Cu, Ci, Cc } = require("chrome");
+const {Cu, Ci, Cc} = require("chrome");
 const JsonViewUtils = require("devtools/client/jsonview/utils");
 
-Cu.import("resource://gre/modules/Services.jsm");
-
-const { makeInfallible } = require("devtools/shared/DevToolsUtils");
-
-const globalMessageManager = Cc["@mozilla.org/globalmessagemanager;1"].
-  getService(Ci.nsIMessageListenerManager);
-const parentProcessMessageManager = Cc["@mozilla.org/parentprocessmessagemanager;1"].
-  getService(Ci.nsIMessageBroadcaster);
-
 // Constants
-const JSON_VIEW_PREF = "devtools.jsonview.enabled";
+const {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
+const {makeInfallible} = require("devtools/shared/DevToolsUtils");
 
 /**
  * Singleton object that represents the JSON View in-content tool.
@@ -28,31 +20,24 @@ const JSON_VIEW_PREF = "devtools.jsonview.enabled";
  */
 var JsonView = {
   initialize: makeInfallible(function() {
-    // Only the DevEdition has this feature available by default.
-    // Users need to manually flip 'devtools.jsonview.enabled' preference
-    // to have it available in other distributions.
-    if (Services.prefs.getBoolPref(JSON_VIEW_PREF)) {
-      // Load JSON converter module. This converter is responsible
-      // for handling 'application/json' documents and converting
-      // them into a simple web-app that allows easy inspection
-      // of the JSON data.
-      globalMessageManager.loadFrameScript(
-        "resource:///modules/devtools/client/jsonview/converter-child.js",
-        true);
+    // Load JSON converter module. This converter is responsible
+    // for handling 'application/json' documents and converting
+    // them into a simple web-app that allows easy inspection
+    // of the JSON data.
+    Services.ppmm.loadProcessScript(
+      "resource:///modules/devtools/client/jsonview/converter-observer.js",
+      true);
 
-      this.onSaveListener = this.onSave.bind(this);
+    this.onSaveListener = this.onSave.bind(this);
 
-      // Register for messages coming from the child process.
-      parentProcessMessageManager.addMessageListener(
-        "devtools:jsonview:save", this.onSaveListener);
-    }
+    // Register for messages coming from the child process.
+    Services.ppmm.addMessageListener(
+      "devtools:jsonview:save", this.onSaveListener);
   }),
 
   destroy: makeInfallible(function() {
-    if (this.onSaveListener) {
-      parentProcessMessageManager.removeMessageListener(
-        "devtools:jsonview:save", this.onSaveListener);
-    }
+    Services.ppmm.removeMessageListener(
+      "devtools:jsonview:save", this.onSaveListener);
   }),
 
   // Message handlers for events from child processes

devtools/client/jsonview/moz.build

@@ -12,6 +12,7 @@ DIRS += [
 
 DevToolsModules(
     'converter-child.js',
+    'converter-observer.js',
     'json-viewer.js',
     'main.js',
     'utils.js',

devtools/client/jsonview/test/head.js

@@ -8,6 +8,15 @@
 Services.scriptloader.loadSubScript(
   "chrome://mochitests/content/browser/devtools/client/framework/test/head.js", this);
 
+const JSON_VIEW_PREF = "devtools.jsonview.enabled";
+
+// Enable JSON View for the test
+Services.prefs.setBoolPref(JSON_VIEW_PREF, true);
+
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref(JSON_VIEW_PREF);
+});
+
 // XXX move some API into devtools/framework/test/shared-head.js
 
 /**

testing/profiles/prefs_general.js

@@ -28,7 +28,6 @@ user_pref("javascript.options.showInConsole", true);
 user_pref("devtools.browsertoolbox.panel", "jsdebugger");
 user_pref("devtools.errorconsole.enabled", true);
 user_pref("devtools.debugger.remote-port", 6023);
-user_pref("devtools.jsonview.enabled", true);
 user_pref("browser.EULA.override", true);
 user_pref("gfx.color_management.force_srgb", true);
 user_pref("network.manage-offline-status", false);