[gjs] Rework Lang module to be ES5 compliant

[Giovanni Campagna <gcampagna src gnome org>]

commit c39baaac33eddbfc7a1e7ddff0d05eecaf62714e
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Sun Jun 17 20:44:22 2012 +0200

    Rework Lang module to be ES5 compliant
    
    Use ES5 features to provide the same functionality without a native
    module, and stop relying on SpiderMonkey details for accessor
    properties.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=692025

 Makefile-modules.am |   14 +----------
 modules/lang.c      |   65 ---------------------------------------------------
 modules/lang.h      |   38 -----------------------------
 modules/lang.js     |   27 ++++++++++++++++++---
 4 files changed, 24 insertions(+), 120 deletions(-)
---
diff --git a/Makefile-modules.am b/Makefile-modules.am
index 7a14264..89f5f14 100644
--- a/Makefile-modules.am
+++ b/Makefile-modules.am
@@ -17,7 +17,7 @@ dist_gjsjs_DATA +=		\
 	modules/promise.js	\
 	modules/format.js
 
-gjsnative_LTLIBRARIES += console.la langNative.la system.la
+gjsnative_LTLIBRARIES += console.la system.la
 
 if ENABLE_CAIRO
 dist_gjsjs_DATA +=		\
@@ -37,18 +37,6 @@ JS_NATIVE_MODULE_LDFLAGS =	\
 	$(EXTRA_LINK_FLAGS)	\
         -module -avoid-version -no-undefined -rdynamic
 
-langNative_la_CFLAGS = 				\
-	$(JS_NATIVE_MODULE_CFLAGS)
-langNative_la_LIBADD = \
-	libgjs.la				\
-	$(JS_NATIVE_MODULE_LIBADD)
-langNative_la_LDFLAGS = 			\
-	$(JS_NATIVE_MODULE_LDFLAGS)
-
-langNative_la_SOURCES =				\
-	modules/lang.h				\
-	modules/lang.c
-
 cairoNative_la_CFLAGS =                         \
         $(JS_NATIVE_MODULE_CFLAGS)              \
         $(GJS_CAIRO_CFLAGS)                     \
diff --git a/modules/lang.js b/modules/lang.js
index 9703add..9c8d45e 100644
--- a/modules/lang.js
+++ b/modules/lang.js
@@ -92,7 +92,9 @@ function bind(obj, callback) {
                 typeof(callback));
     }
 
-    if (callback.bind && arguments.length == 2) // ECMAScript 5 (but only if not passing any bindArguments)
+    // Use ES5 Function.prototype.bind, but only if not passing any bindArguments,
+    // because ES5 has them at the beginning, not at the end
+    if (arguments.length == 2)
 	return callback.bind(obj);
 
     let me = obj;
@@ -112,6 +114,26 @@ function defineAccessorProperty(object, name, getter, setter) {
 					  enumerable: true });
 }
 
+function _deepFreeze(o) {
+    Object.freeze(o);
+
+    for (prop in o) {
+        if (!o.hasOwnProperty(prop) || !(typeof o === "object") || Object.isFrozen(o))
+            continue;
+
+        _deepFreeze(o[prop]);
+    }
+}
+
+// The name of this function is unfortunate, as it wraps
+// Object.freeze, not Object.seal
+function seal(object, deep) {
+    if (deep)
+        _deepFreeze(object);
+    else
+        Object.freeze(object);
+}
+
 // Class magic
 // Adapted from MooTools, MIT license
 // https://github.com/mootools/moootools-core
@@ -274,6 +296,3 @@ Class.prototype._init = function(params) {
                     enumerable: false,
                     value: _parent }});
 };
-
-// Merge stuff defined in native code
-copyProperties(imports.langNative, this);