Bug 1056170 - Expose pref service 'dirty' flag and test it. r=bsmedberg

modules/libpref/Preferences.cpp

@@ -788,6 +788,11 @@ Preferences::GetDefaultBranch(const char *aPrefRoot, nsIPrefBranch **_retval)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+Preferences::GetDirty(bool *_retval) {
+  *_retval = gDirty;
+  return NS_OK;
+}
 
 nsresult
 Preferences::NotifyServiceObservers(const char *aTopic)

modules/libpref/nsIPrefService.idl

@@ -27,7 +27,7 @@ interface nsIFile;
  * @see nsIPrefBranch
  */
 
-[scriptable, uuid(decb9cc7-c08f-4ea5-be91-a8fc637ce2d2)]
+[scriptable, uuid(1f84fd56-3956-40df-b86a-1ea01402ee96)]
 interface nsIPrefService : nsISupports
 {
   /**
@@ -120,6 +120,11 @@ interface nsIPrefService : nsISupports
    */
   nsIPrefBranch getDefaultBranch(in string aPrefRoot);
 
+  /**
+   * The preference service is 'dirty' if there are changes to user preferences
+   * that have not been written to disk
+   */
+  readonly attribute boolean dirty;
 };
 
 %{C++

modules/libpref/prefapi.cpp

@@ -312,7 +312,7 @@ pref_SetPref(const dom::PrefSetting& aPref)
     if (userValue.type() == dom::MaybePrefValue::TPrefValue) {
         rv = SetPrefValue(prefName, userValue.get_PrefValue(), USER_VALUE);
     } else {
-        rv = PREF_ClearUserPref(prefName);      
+        rv = PREF_ClearUserPref(prefName);
     }
 
     // NB: we should never try to clear a default value, that doesn't
@@ -725,7 +725,6 @@ static void pref_SetValue(PrefValue* existingValue, uint16_t *existingFlags,
     else {
         *existingValue = newValue;
     }
-    gDirty = true;
 }
 
 PrefHashEntry* pref_HashTableLookup(const void *key)
@@ -785,6 +784,8 @@ nsresult pref_HashPref(const char *key, PrefValue value, PrefType type, uint32_t
                 if (!PREF_HAS_USER_VALUE(pref))
                     valueChanged = true;
             }
+            // What if we change the default to be the same as the user value?
+            // Should we clear the user value?
         }
     }
     else
@@ -799,8 +800,10 @@ nsresult pref_HashPref(const char *key, PrefValue value, PrefType type, uint32_t
             {
                 /* XXX should we free a user-set string value if there is one? */
                 pref->flags &= ~PREF_USERSET;
-                if (!PREF_IS_LOCKED(pref))
+                if (!PREF_IS_LOCKED(pref)) {
+                    gDirty = true;
                     valueChanged = true;
+                }
             }
         }
         else if (!PREF_HAS_USER_VALUE(pref) ||
@@ -809,20 +812,17 @@ nsresult pref_HashPref(const char *key, PrefValue value, PrefType type, uint32_t
         {
             pref_SetValue(&pref->userPref, &pref->flags, value, type);
             pref->flags |= PREF_USERSET;
-            if (!PREF_IS_LOCKED(pref))
+            if (!PREF_IS_LOCKED(pref)) {
+                gDirty = true;
                 valueChanged = true;
+            }
         }
     }
 
-    nsresult rv = NS_OK;
     if (valueChanged) {
-        gDirty = true;
-
-        nsresult rv2 = pref_DoCallback(key);
-        if (NS_FAILED(rv2))
-            rv = rv2;
+        return pref_DoCallback(key);
     }
-    return rv;
+    return NS_OK;
 }
 
 size_t

modules/libpref/test/unit/head_libPrefs.js

@@ -32,7 +32,7 @@ var provider = {
     persistent.value = true;
     if (prop == NS_APP_USER_PROFILE_50_DIR)
       return dirSvc.get("CurProcD", Ci.nsIFile);
-    throw Cr.NS_ERROR_FAILURE;
+    throw Components.Exception("Tried to get test directory '" + prop + "'", Cr.NS_ERROR_FAILURE);
   },
   QueryInterface: function(iid) {
     if (iid.equals(Ci.nsIDirectoryServiceProvider) ||

modules/libpref/test/unit/test_dirtyPrefs.js

@@ -0,0 +1,75 @@
+/* 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/. */
+
+/* Tests for handling of the preferences 'dirty' flag (bug 985998) */
+
+const PREF_INVALID = 0;
+const PREF_BOOL    = 128;
+const PREF_INT     = 64;
+const PREF_STRING  = 32;
+
+function run_test() {
+
+  var ps = Cc["@mozilla.org/preferences-service;1"].
+            getService(Ci.nsIPrefService);
+
+  let defaultBranch = ps.getDefaultBranch("");
+  let userBranch = ps.getBranch("");
+
+  let prefFile = do_get_profile();
+  prefFile.append("prefs.js");
+
+  //**************************************************************************//
+  // prefs are not dirty after a write
+  ps.savePrefFile(prefFile);
+  do_check_false(ps.dirty);
+
+  // set a new a user value, we should become dirty
+  userBranch.setBoolPref("DirtyTest.new.bool", true);
+  do_check_true(ps.dirty);
+  ps.savePrefFile(prefFile);
+  // Overwrite a pref with the same value => not dirty
+  userBranch.setBoolPref("DirtyTest.new.bool", true);
+  do_check_false(ps.dirty);
+
+  // Repeat for the other two types
+  userBranch.setIntPref("DirtyTest.new.int", 1);
+  do_check_true(ps.dirty);
+  ps.savePrefFile(prefFile);
+  // Overwrite a pref with the same value => not dirty
+  userBranch.setIntPref("DirtyTest.new.int", 1);
+  do_check_false(ps.dirty);
+
+  userBranch.setCharPref("DirtyTest.new.char", "oop");
+  do_check_true(ps.dirty);
+  ps.savePrefFile(prefFile);
+  // Overwrite a pref with the same value => not dirty
+  userBranch.setCharPref("DirtyTest.new.char", "oop");
+  do_check_false(ps.dirty);
+
+  // change *type* of a user value -> dirty
+  userBranch.setBoolPref("DirtyTest.new.char", false);
+  do_check_true(ps.dirty);
+  ps.savePrefFile(prefFile);
+
+  // Set a default pref => not dirty (defaults don't go into prefs.js)
+  defaultBranch.setBoolPref("DirtyTest.existing.bool", true);
+  do_check_false(ps.dirty);
+  // Fail to change type of a pref with default value -> not dirty
+  do_check_throws(function() {
+    userBranch.setCharPref("DirtyTest.existing.bool", "boo"); }, Cr.NS_ERROR_UNEXPECTED);
+  do_check_false(ps.dirty);
+
+  // Set user value same as default, not dirty
+  userBranch.setBoolPref("DirtyTest.existing.bool", true);
+  do_check_false(ps.dirty);
+  // User value different from default, dirty
+  userBranch.setBoolPref("DirtyTest.existing.bool", false);
+  do_check_true(ps.dirty);
+  ps.savePrefFile(prefFile);
+  // Back to default value, dirty again
+  userBranch.setBoolPref("DirtyTest.existing.bool", true);
+  do_check_true(ps.dirty);
+  ps.savePrefFile(prefFile);
+}

modules/libpref/test/unit/xpcshell.ini

@@ -11,5 +11,6 @@ support-files =
 [test_bug577950.js]
 [test_bug790374.js]
 [test_changeType.js]
+[test_dirtyPrefs.js]
 [test_extprefs.js]
 [test_libPrefs.js]