From d72258e637e954674a5695f85326a05e3a9e9ada Mon Sep 17 00:00:00 2001
From: Geoff Lankow <geoff@darktrojan.net>
Date: Wed, 18 Jul 2012 01:24:51 +1200
Subject: [PATCH] Bug 767320 - Cache results of Addon.hasResource() to try
 avoid unnecessary IO; r=Unfocused

---
 toolkit/mozapps/extensions/XPIProvider.jsm    | 20 ++++++++++++++++---
 .../test/xpcshell/test_getresource.js         | 13 ++++++++----
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/toolkit/mozapps/extensions/XPIProvider.jsm b/toolkit/mozapps/extensions/XPIProvider.jsm
index 7215981676b..e1140cd0416 100644
--- a/toolkit/mozapps/extensions/XPIProvider.jsm
+++ b/toolkit/mozapps/extensions/XPIProvider.jsm
@@ -3842,6 +3842,9 @@ var XPIProvider = {
     if (aAddon._installLocation.locked)
       throw new Error("Cannot uninstall addons from locked install locations");
 
+    if ("_hasResourceCache" in aAddon)
+      aAddon._hasResourceCache = new Map();
+
     // Inactive add-ons don't require a restart to uninstall
     let requiresRestart = this.uninstallRequiresRestart(aAddon);
 
@@ -5710,8 +5713,10 @@ XPIProvider.DBAddonInternal = DBAddonInternal;
 function createWrapper(aAddon) {
   if (!aAddon)
     return null;
-  if (!aAddon._wrapper)
+  if (!aAddon._wrapper) {
+    aAddon._hasResourceCache = new Map();
     aAddon._wrapper = new AddonWrapper(aAddon);
+  }
   return aAddon._wrapper;
 }
 
@@ -6106,6 +6111,9 @@ function AddonWrapper(aAddon) {
   };
 
   this.hasResource = function(aPath) {
+    if (aAddon._hasResourceCache.has(aPath))
+      return aAddon._hasResourceCache.get(aPath);
+
     let bundle = aAddon._sourceBundle.clone();
 
     // Bundle may not exist any more if the addon has just been uninstalled,
@@ -6113,6 +6121,7 @@ function AddonWrapper(aAddon) {
     try {
       var isDir = bundle.isDirectory();
     } catch (e) {
+      aAddon._hasResourceCache.set(aPath, false);
       return false;
     }
 
@@ -6122,16 +6131,21 @@ function AddonWrapper(aAddon) {
           bundle.append(aPart);
         });
       }
-      return bundle.exists();
+      let result = bundle.exists();
+      aAddon._hasResourceCache.set(aPath, result);
+      return result;
     }
 
     let zipReader = Cc["@mozilla.org/libjar/zip-reader;1"].
                     createInstance(Ci.nsIZipReader);
     try {
       zipReader.open(bundle);
-      return zipReader.hasEntry(aPath);
+      let result = zipReader.hasEntry(aPath);
+      aAddon._hasResourceCache.set(aPath, result);
+      return result;
     }
     catch (e) {
+      aAddon._hasResourceCache.set(aPath, false);
       return false;
     }
     finally {
diff --git a/toolkit/mozapps/extensions/test/xpcshell/test_getresource.js b/toolkit/mozapps/extensions/test/xpcshell/test_getresource.js
index 67a093dc896..33c72182dbd 100644
--- a/toolkit/mozapps/extensions/test/xpcshell/test_getresource.js
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_getresource.js
@@ -75,12 +75,17 @@ function run_test() {
           do_check_true(false);
         }
 
-        restartManager();
+        AddonManager.getInstallForFile(do_get_addon("test_getresource"), function(aInstall) {
+          do_check_false(a1.hasResource("icon.png"));
+          do_check_true(aInstall.addon.hasResource("icon.png"));
 
-        AddonManager.getAddonByID("addon1@tests.mozilla.org", function(newa1) {
-          do_check_eq(newa1, null);
+          restartManager();
 
-          do_test_finished();
+          AddonManager.getAddonByID("addon1@tests.mozilla.org", function(newa1) {
+            do_check_eq(newa1, null);
+
+            do_test_finished();
+          });
         });
       });
     });