Detect and handle the case of our own typo correction extension being installed in parallel

lib/typoBootstrap.js

Index: lib/typoBootstrap.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/lib/typoBootstrap.js
@@ -0,0 +1,87 @@
+/*
+ * This Source Code is subject to the terms of the Mozilla Public License
+ * version 2.0 (the "License"). You can obtain a copy of the License at
+ * http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * @fileOverview Adds typo correction feature
+ */
+
+Cu.import("resource://gre/modules/AddonManager.jsm");
+
+let {Prefs} = require("prefs");
+let urlfixerID = "{0fa2149e-bb2c-4ac2-a8d3-479599819475}";
+let addonListener = null;
+
+function init()
+{
+  if (!Prefs.correctTyposAsked || (Prefs.correctTyposAsked && Prefs.correctTypos))
+  {
+    AddonManager.getAddonByID(urlfixerID, function(addon)
+    {
+      startTypoCorrection(addon && addon.isActive);
+    });
+  }
+  else
+  {
+    let onPrefChange = function(name)
+    {
+      if (name == "correctTypos" && Prefs[name])
+      {
+        init();
+        Prefs.removeListener(onPrefChange);
+      }
+    }
+    
+    Prefs.addListener(onPrefChange);
+  }
+}
+
+function cleanup()
+{
+  if (addonListener)
+  {
+    AddonManager.removeAddonListener(addonListener);
+    addonListener = null;
+  }
+}
+onShutdown.add(cleanup);

[Wladimir Palant, 2012/11/20 11:13:30]

Seriously, please look around at how this is done everywhere else (search for
onShutdown.add). If we have to remember to keep cleanup handlers in sync with
the code this will become an unmanageable mess. The only way to keep things
manageable is to add a cleanup handler immediately after doing something that
requires reverting. Meaning that after calling AddonManager.addAddonListener()
the next line should be:

    onShutdown.add(function() AddonManager.removeAddonListener(...));

No need for any checks or variable cleanup.

+
+function startTypoCorrection(isInstalledAndEnabled)
+{
+  if (isInstalledAndEnabled)
+    require("typoFixer").detachWindowObserver();
+  else
+    require("typoFixer").attachWindowObserver();
+  
+  if (!addonListener)
+  {
+    addonListener = {
+      onEnabling: function(addon, needsRestart)
+      {
+        if (addon.id == urlfixerID)
+          startTypoCorrection(true);
+      },
+      onDisabled: function(addon)
+      {
+        if (addon.id == urlfixerID)
+          startTypoCorrection(false);
+      },
+      onInstalling: function(addon, needsRestart)
+      {
+        if (addon.id == urlfixerID)
+          startTypoCorrection(true);
+      },
+      onUninstalled: function(addon)
+      {
+        if (addon.id == urlfixerID)
+          startTypoCorrection(false);
+      }
+    }
+    
+    AddonManager.addAddonListener(addonListener);
+  }
+}
+
+init();