Bug 539907 - Have getPref use asynchronous statements when called with an optional callback. r=myk, sr=robstrong

dom/interfaces/base/nsIContentPrefService.idl

@@ -65,7 +65,13 @@ interface nsIContentPrefObserver : nsISupports
   void onContentPrefRemoved(in AString aGroup, in AString aName);
 };
 
-[scriptable, uuid(b3976fa1-189f-4fcb-9c3b-49d1f6d8073d)]
+[scriptable, function, uuid(c1b3d6df-5373-4606-8494-8bcf14a7fc62)]
+interface nsIContentPrefCallback : nsISupports
+{
+  void onResult(in nsIVariant aResult);
+};
+
+[scriptable, uuid(36715960-de39-457b-9d02-b800d5d3079b)]
 interface nsIContentPrefService : nsISupports
 {
   /**
@@ -81,13 +87,17 @@ interface nsIContentPrefService : nsISupports
    *                       (typically in the format of a hostname), or null 
    *                       to get the global pref (applies to all sites)
    * @param    aName       the name of the pref to get
+   * @param    aCallback   an optional nsIContentPrefCallback to receive the
+   *                       result. If desired, JavaScript callers can instead
+   *                       provide a function to call upon completion
    *
    * @returns  the value of the pref
    * @throws   NS_ERROR_ILLEGAL_VALUE if aGroup is not a string, nsIURI, or null
    * @throws   NS_ERROR_ILLEGAL_VALUE if aName is null or an empty string
    */
-  nsIVariant getPref(in nsIVariant aGroup, in AString aName);
-  
+  nsIVariant getPref(in nsIVariant aGroup, in AString aName,
+                     [optional] in nsIContentPrefCallback aCallback);
+
   /**
    * Set a pref.
    *

layout/forms/nsFileControlFrame.cpp

@@ -447,7 +447,7 @@ nsFileControlFrame::FetchLastUsedDirectory(nsIURI* aURI, nsILocalFile* aFile)
   PRBool hasPref;
   if (NS_SUCCEEDED(contentPrefService->HasPref(uri, prefName, &hasPref)) && hasPref) {
     nsCOMPtr<nsIVariant> pref;
-    contentPrefService->GetPref(uri, prefName, getter_AddRefs(pref));
+    contentPrefService->GetPref(uri, prefName, nsnull, getter_AddRefs(pref));
     nsString prefStr;
     pref->GetAsAString(prefStr);
     return aFile->InitWithPath(prefStr);

toolkit/components/contentprefs/src/nsContentPrefService.js

@@ -128,19 +128,17 @@ ContentPrefService.prototype = {
   //**************************************************************************//
   // nsIContentPrefService
 
-  getPref: function ContentPrefService_getPref(aGroup, aName) {
+  getPref: function ContentPrefService_getPref(aGroup, aName, aCallback) {
     if (!aName)
       throw Components.Exception("aName cannot be null or an empty string",
                                  Cr.NS_ERROR_ILLEGAL_VALUE);
 
     if (aGroup == null)
-      return this._selectGlobalPref(aName);
+      return this._selectGlobalPref(aName, aCallback);
     if (aGroup.constructor.name == "String")
-      return this._selectPref(aGroup.toString(), aName);
-    if (aGroup instanceof Ci.nsIURI) {
-      var group = this.grouper.group(aGroup);
-      return this._selectPref(group, aName);
-    }
+      return this._selectPref(aGroup.toString(), aName, aCallback);
+    if (aGroup instanceof Ci.nsIURI)
+      return this._selectPref(this.grouper.group(aGroup), aName, aCallback);
 
     throw Components.Exception("aGroup is not a string, nsIURI or null",
                                Cr.NS_ERROR_ILLEGAL_VALUE);
@@ -425,14 +423,16 @@ ContentPrefService.prototype = {
     return this.__stmtSelectPref;
   },
 
-  _selectPref: function ContentPrefService__selectPref(aGroup, aSetting) {
+  _selectPref: function ContentPrefService__selectPref(aGroup, aSetting, aCallback) {
     var value;
 
     try {
       this._stmtSelectPref.params.group = aGroup;
       this._stmtSelectPref.params.setting = aSetting;
 
-      if (this._stmtSelectPref.executeStep())
+      if (aCallback)
+        new AsyncStatement(this._stmtSelectPref).execute(aCallback);
+      else if (this._stmtSelectPref.executeStep())
         value = this._stmtSelectPref.row["value"];
     }
     finally {
@@ -456,13 +456,15 @@ ContentPrefService.prototype = {
     return this.__stmtSelectGlobalPref;
   },
 
-  _selectGlobalPref: function ContentPrefService__selectGlobalPref(aName) {
+  _selectGlobalPref: function ContentPrefService__selectGlobalPref(aName, aCallback) {
     var value;
 
     try {
       this._stmtSelectGlobalPref.params.name = aName;
 
-      if (this._stmtSelectGlobalPref.executeStep())
+      if (aCallback)
+        new AsyncStatement(this._stmtSelectGlobalPref).execute(aCallback);
+      else if (this._stmtSelectGlobalPref.executeStep())
         value = this._stmtSelectGlobalPref.row["value"];
     }
     finally {
@@ -1064,6 +1066,32 @@ HostnameGrouper.prototype = {
   }
 };
 
+function AsyncStatement(aStatement) {
+  this.stmt = aStatement;
+}
+
+AsyncStatement.prototype = {
+  execute: function AsyncStmt_execute(aCallback) {
+    let stmt = this.stmt;
+    stmt.executeAsync({
+      _callback: aCallback,
+      _hadResult: false,
+      handleResult: function(aResult) {
+        this._hadResult = true;
+        if (this._callback) {
+          let row = aResult.getNextRow();
+          this._callback.onResult(row.getResultByName("value"));
+        }
+      },
+      handleCompletion: function(aReason) {
+        if (!this._hadResult && this._callback &&
+            aReason == Ci.mozIStorageStatementCallback.REASON_FINISHED)
+          this._callback.onResult(undefined);
+      },
+      handleError: function(aError) {}
+    });
+  }
+};
 
 //****************************************************************************//
 // XPCOM Plumbing

toolkit/components/contentprefs/tests/unit/test_getPrefAsync.js

@@ -0,0 +1,67 @@
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2010
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Ryan Flint <rflint@mozilla.com> (Original Author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+var cps = Cc["@mozilla.org/content-pref/service;1"].
+          getService(Ci.nsIContentPrefService);
+var uri = ContentPrefTest.getURI("http://www.example.com/");
+
+function run_test() {
+  do_test_pending();
+
+  cps.setPref(uri, "asynctest", "pie");
+  do_check_eq(cps.getPref(uri, "asynctest"), "pie");
+
+  cps.getPref(uri, "asynctest", function(aValue) {
+    do_check_eq(aValue, "pie");
+    testCallbackObj();
+  });
+}
+
+function testCallbackObj() {
+  cps.getPref(uri, "asynctest", {
+    onResult: function(aValue) {
+      do_check_eq(aValue, "pie");
+      cps.removePref(uri, "asynctest");
+      testNoResult();
+    }
+  });
+}
+
+function testNoResult() {
+  cps.getPref(uri, "asynctest", function(aValue) {
+    do_check_eq(aValue, undefined);
+    do_test_finished();
+  });
+}