[gnome-shell] extensionUtils: Use signals rather than callbacks for finding extensions

[Jasper St. Pierre <jstpierre src gnome org>]

commit 498b023989000f277529ad5f4e3193844be87dd6
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Mon Jun 4 17:14:18 2012 -0400

    extensionUtils: Use signals rather than callbacks for finding extensions
    
    This allows us to move to a file-monitor based approach in the future.
    
    Since we need signals, we convert the current set of functions to an
    object we attach signals too, leading to the new ExtensionFinder object.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=677586

 js/extensionPrefs/main.js |   37 +++++++++++++----------
 js/misc/extensionUtils.js |   70 +++++++++++++++++++++++++--------------------
 js/ui/extensionSystem.js  |    4 ++-
 3 files changed, 63 insertions(+), 48 deletions(-)
---
diff --git a/js/extensionPrefs/main.js b/js/extensionPrefs/main.js
index a403cdb..90fd9ab 100644
--- a/js/extensionPrefs/main.js
+++ b/js/extensionPrefs/main.js
@@ -202,24 +202,29 @@ const Application = new Lang.Class({
     },
 
     _scanExtensions: function() {
-        ExtensionUtils.scanExtensions(Lang.bind(this, function(uuid, dir, type) {
-            if (ExtensionUtils.extensions[uuid] !== undefined)
-                return;
-
-            let extension;
-            try {
-                extension = ExtensionUtils.createExtensionObject(uuid, dir, type);
-            } catch(e) {
-                logError(e, 'Could not create extensions object');
-                return;
-            }
-
-            let iter = this._model.append();
-            this._model.set(iter, [0, 1], [uuid, extension.metadata.name]);
-            this._extensionIters[uuid] = iter;
-        }));
+        let finder = new ExtensionUtils.ExtensionFinder();
+        finder.connect('extension-found', Lang.bind(this, this._extensionFound));
+        finder.scanExtensions();
     },
 
+    _extensionFound: function(signals, uuid, dir, type) {
+        if (ExtensionUtils.extensions[uuid] !== undefined)
+            return;
+
+        let extension;
+        try {
+            extension = ExtensionUtils.createExtensionObject(uuid, dir, type);
+        } catch(e) {
+            logError(e, 'Could not create extensions object');
+            return;
+        }
+
+        let iter = this._model.append();
+        this._model.set(iter, [0, 1], [uuid, extension.metadata.name]);
+        this._extensionIters[uuid] = iter;
+    },
+
+
     _onActivate: function() {
         this._window.present();
     },
diff --git a/js/misc/extensionUtils.js b/js/misc/extensionUtils.js
index d086484..3eaa1b9 100644
--- a/js/misc/extensionUtils.js
+++ b/js/misc/extensionUtils.js
@@ -3,6 +3,9 @@
 // Common utils for the extension system and the extension
 // preferences tool
 
+const Lang = imports.lang;
+const Signals = imports.signals;
+
 const GLib = imports.gi.GLib;
 const Gio = imports.gi.Gio;
 const ShellJS = imports.gi.ShellJS;
@@ -149,36 +152,41 @@ function installImporter(extension) {
     _extension = null;
 }
 
-function scanExtensionsInDirectory(callback, dir, type) {
-    let fileEnum;
-    let file, info;
-    try {
-        fileEnum = dir.enumerate_children('standard::*', Gio.FileQueryInfoFlags.NONE, null);
-    } catch(e) {
-        logError(e, 'Could not enumerate extensions directory');
-        return;
-    }
-
-    while ((info = fileEnum.next_file(null)) != null) {
-        let fileType = info.get_file_type();
-        if (fileType != Gio.FileType.DIRECTORY)
-            continue;
-        let uuid = info.get_name();
-        let extensionDir = dir.get_child(uuid);
-        callback(uuid, extensionDir, type);
-    }
-    fileEnum.close(null);
-}
-
-function scanExtensions(callback) {
-    let userExtensionsDir = Gio.File.new_for_path(GLib.build_filenamev([global.userdatadir, 'extensions']));
-    scanExtensionsInDirectory(callback, userExtensionsDir, ExtensionType.PER_USER);
+const ExtensionFinder = new Lang.Class({
+    Name: 'ExtensionFinder',
+
+    _scanExtensionsInDirectory: function(dir, type) {
+        let fileEnum;
+        let file, info;
+        try {
+            fileEnum = dir.enumerate_children('standard::*', Gio.FileQueryInfoFlags.NONE, null);
+        } catch(e) {
+            logError(e, 'Could not enumerate extensions directory');
+            return;
+        }
 
-    let systemDataDirs = GLib.get_system_data_dirs();
-    for (let i = 0; i < systemDataDirs.length; i++) {
-        let dirPath = GLib.build_filenamev([systemDataDirs[i], 'gnome-shell', 'extensions']);
-        let dir = Gio.file_new_for_path(dirPath);
-        if (dir.query_exists(null))
-            scanExtensionsInDirectory(callback, dir, ExtensionType.SYSTEM);
+        while ((info = fileEnum.next_file(null)) != null) {
+            let fileType = info.get_file_type();
+            if (fileType != Gio.FileType.DIRECTORY)
+                continue;
+            let uuid = info.get_name();
+            let extensionDir = dir.get_child(uuid);
+            this.emit('extension-found', uuid, extensionDir, type);
+        }
+        fileEnum.close(null);
+    },
+
+    scanExtensions: function() {
+        let userExtensionsDir = Gio.File.new_for_path(GLib.build_filenamev([global.userdatadir, 'extensions']));
+        this._scanExtensionsInDirectory(userExtensionsDir, ExtensionType.PER_USER);
+
+        let systemDataDirs = GLib.get_system_data_dirs();
+        for (let i = 0; i < systemDataDirs.length; i++) {
+            let dirPath = GLib.build_filenamev([systemDataDirs[i], 'gnome-shell', 'extensions']);
+            let dir = Gio.file_new_for_path(dirPath);
+            if (dir.query_exists(null))
+                this._scanExtensionsInDirectory(dir, ExtensionType.SYSTEM);
+        }
     }
-}
+});
+Signals.addSignalMethods(ExtensionFinder.prototype);
diff --git a/js/ui/extensionSystem.js b/js/ui/extensionSystem.js
index efb9144..902ecb6 100644
--- a/js/ui/extensionSystem.js
+++ b/js/ui/extensionSystem.js
@@ -262,8 +262,10 @@ function init() {
 }
 
 function loadExtensions() {
-    ExtensionUtils.scanExtensions(function(uuid, dir, type) {
+    let finder = new ExtensionUtils.ExtensionFinder();
+    finder.connect('extension-found', function(signals, uuid, dir, type) {
         let enabled = enabledExtensions.indexOf(uuid) != -1;
         loadExtension(dir, type, enabled);
     });
+    finder.scanExtensions();
 }