implement our own button class

Button features:

- observe selection changes to enable/disable the button using enableFn()

- pop up confirmation dialog using confirmMsg()

www/manager/Makefile

@@ -4,6 +4,7 @@ JSSRC= 				                 	\
 	Utils.js					\
 	Parser.js					\
 	StateProvider.js				\
+	button/Button.js				\
 	qemu/SendKeyMenu.js				\
 	VNCConsole.js					\
 	data/TimezoneStore.js				\

www/manager/button/Button.js

+/* Button features:
+ * - observe selection changes to enable/disable the button using enableFn()
+ * - pop up confirmation dialog using confirmMsg()
+ */
+Ext.define('PVE.button.Button', {
+    extend: 'Ext.button.Button',
+    alias: 'widget.pveButton',
+
+    // the selection model to observe
+    selModel: undefined,
+
+    // if 'false' handler will not be called (button disabled)
+    enableFn: function(record) { },
+
+    // function(record) or text
+    confirmMsg: false,
+
+    initComponent: function() {
+        var me = this;
+
+	if (me.handler) {
+	    me.realHandler = me.handler;
+
+	    me.handler = function(button, event) {
+		var rec, msg;
+		if (me.selModel) {
+		    rec = me.selModel.getSelection()[0];
+		    if (!rec || (me.enableFn(rec) === false)) {
+			return;
+		    }
+		}
+
+		if (me.confirmMsg) {
+		    var msg = me.confirmMsg;
+		    if (Ext.isFunction(me.confirmMsg)) {
+			msg = me.confirmMsg(rec);
+		    } 
+		    Ext.Msg.confirm('Confirmation', msg, function(btn) {
+			if (btn !== 'yes') {
+			    return;
+			}
+			me.realHandler(button, event, rec);
+		    });
+		} else {
+		    me.realHandler(button, event, rec);
+		}
+	    };
+	}
+
+	me.callParent();
+
+	if (me.selModel) {
+
+	    me.mon(me.selModel, "selectionchange", function() {
+		var rec = me.selModel.getSelection()[0];
+		var enable = me.enableFn(rec);
+		if (Ext.isDefined(enable)) {
+		    me.setDisabled(!enable);
+		}
+	    });
+	}
+    }
+});