michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["WindowsRegistry"];
michael@0: 
michael@0: const WindowsRegistry = {
michael@0:   /**
michael@0:    * Safely reads a value from the registry.
michael@0:    *
michael@0:    * @param aRoot
michael@0:    *        The root registry to use.
michael@0:    * @param aPath
michael@0:    *        The registry path to the key.
michael@0:    * @param aKey
michael@0:    *        The key name.
michael@0:    * @return The key value or undefined if it doesn't exist.  If the key is
michael@0:    *         a REG_MULTI_SZ, an array is returned.
michael@0:    */
michael@0:   readRegKey: function(aRoot, aPath, aKey) {
michael@0:     const kRegMultiSz = 7;
michael@0:     let registry = Cc["@mozilla.org/windows-registry-key;1"].
michael@0:                    createInstance(Ci.nsIWindowsRegKey);
michael@0:     try {
michael@0:       registry.open(aRoot, aPath, Ci.nsIWindowsRegKey.ACCESS_READ);
michael@0:       if (registry.hasValue(aKey)) {
michael@0:         let type = registry.getValueType(aKey);
michael@0:         switch (type) {
michael@0:           case kRegMultiSz:
michael@0:             // nsIWindowsRegKey doesn't support REG_MULTI_SZ type out of the box.
michael@0:             let str = registry.readStringValue(aKey);
michael@0:             return [v for each (v in str.split("\0")) if (v)];
michael@0:           case Ci.nsIWindowsRegKey.TYPE_STRING:
michael@0:             return registry.readStringValue(aKey);
michael@0:           case Ci.nsIWindowsRegKey.TYPE_INT:
michael@0:             return registry.readIntValue(aKey);
michael@0:           default:
michael@0:             throw new Error("Unsupported registry value.");
michael@0:         }
michael@0:       }
michael@0:     } catch (ex) {
michael@0:     } finally {
michael@0:       registry.close();
michael@0:     }
michael@0:     return undefined;
michael@0:   },
michael@0: };