From 9b20cdff48158f925eb078ba1b655797b67af604 Mon Sep 17 00:00:00 2001
From: Mike Gerwitz <mike@mikegerwitz.com>
Date: Thu, 12 May 2011 00:05:50 -0400
Subject: [PATCH] Initial concept for protected static property access

---
 lib/class_builder.js              | 43 ++++++++++++++++++++++++++-----
 test/test-class_builder-static.js | 36 ++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 6 deletions(-)

diff --git a/lib/class_builder.js b/lib/class_builder.js
index f8858c0..b65128f 100644
--- a/lib/class_builder.js
+++ b/lib/class_builder.js
@@ -52,6 +52,15 @@ var util           = require( __dirname + '/util' ),
      */
     extending = false,
 
+    /**
+     * A flag to let the system know that we are currently attempting to access
+     * a static property from within a method. This means that the caller should
+     * be given access to additional levels of visibility.
+     *
+     * @type {boolean}
+     */
+    sprop_internal = false,
+
     /**
      * Hash of reserved members
      *
@@ -619,6 +628,19 @@ function initStaticVisibilityObj( ctor, static_members )
     // override __self on the instance's visibility object, giving internal
     // methods access to the restricted static methods
     ctor.___$$svis$$ = sobji;
+
+    // Override the class-level accessor method to allow the system to know we
+    // are within a method. An internal flag is necessary, rather than using an
+    // argument or binding, because those two options are exploitable. An
+    // internal flag cannot be modified by conventional means.
+    sobji.$ = function()
+    {
+        sprop_internal = true;
+        var val = ctor.$.apply( ctor, arguments );
+        sprop_internal = false;
+
+        return val;
+    };
 }
 
 
@@ -666,17 +688,26 @@ function attachStatic( ctor, members, base, inheriting )
             // we use hasOwnProperty to ensure that undefined values will not
             // cause us to continue checking the parent, thereby potentially
             // failing to set perfectly legal values
-            var has = Object.prototype.hasOwnProperty.call(
-                    props[ 'public' ], prop
-                ),
+            var has   = Object.prototype.hasOwnProperty,
+                found = false,
 
                 // Determine if we were invoked in the context of a class. If
                 // so, use that.  Otherwise, use ourself.
                 context = ( this.___$$sprops$$ ) ? this : ctor
             ;
 
+            // Attempt to locate the property. First, we check public. If not
+            // available and we are internal (within a method), we can move on
+            // to check other levels of visibility. `found` will contain the
+            // visibility level the property was found in, or false.
+            found = has.call( props[ 'public' ], prop ) && 'public';
+            if ( !found && sprop_internal )
+            {
+                found = has.call( props[ 'protected' ], prop ) && 'protected';
+            }
+
             // if we don't own the property, let the parent(s) handle it
-            if ( !has )
+            if ( found === false )
             {
                 return base.$.apply( context, arguments );
             }
@@ -686,13 +717,13 @@ function attachStatic( ctor, members, base, inheriting )
             // arguments.length to ensure that setting to undefined works)
             if ( arguments.length > 1 )
             {
-                props[ 'public' ][ prop ] = val;
+                props[ found ][ prop ] = val;
                 return context;
             }
             else
             {
                 // return the value
-                return props[ 'public' ][ prop ];
+                return props[ found ][ prop ];
             }
         } );
     }
diff --git a/test/test-class_builder-static.js b/test/test-class_builder-static.js
index 542f5e0..4bb27bc 100644
--- a/test/test-class_builder-static.js
+++ b/test/test-class_builder-static.js
@@ -464,6 +464,9 @@ var common    = require( './common' ),
     var val = 'foo',
         Foo = builder.build(
         {
+            'protected static prop': val,
+
+
             // the same rules should apply to methods
             'protected static baz': function()
             {
@@ -481,6 +484,16 @@ var common    = require( './common' ),
             {
                 return this.__self.baz();
             },
+
+            'public static staticGetProp': function()
+            {
+                return this.$('prop');
+            },
+
+            'public instGetProp': function()
+            {
+                return this.__self.$('prop');
+            },
         } );
 
     assert.equal( Foo.baz, undefined,
@@ -494,6 +507,14 @@ var common    = require( './common' ),
     assert.equal( Foo().instBaz(), val,
         "Protected methods are accessible to instance methods"
     );
+
+    assert.equal( Foo.staticGetProp(), val,
+        "Protected static properties are accessible to static methods"
+    );
+
+    assert.equal( Foo().instGetProp(), val,
+        "Protected static properties are accessible to instance methods"
+    );
 } )();
 
 
@@ -507,6 +528,8 @@ var common    = require( './common' ),
         val2 = 'bazbaz',
         Foo  = builder.build(
         {
+            'protected static prop': val,
+
             'protected static foo': function()
             {
                 return val;
@@ -529,6 +552,11 @@ var common    = require( './common' ),
             {
                 return this.foo2();
             },
+
+            'public static getProp': function()
+            {
+                return this.$('prop');
+            },
         } ),
 
         SubSubFoo = builder.build( SubFoo, {} )
@@ -546,6 +574,14 @@ var common    = require( './common' ),
     assert.equal( SubSubFoo.bar(), val,
         "Sub-subtypes inherit parents' protected static methods"
     );
+
+    assert.equal( SubFoo.getProp(), val,
+        "Subtypes inherit parents' protected static properties"
+    );
+
+    assert.equal( SubSubFoo.getProp(), val,
+        "Sub-subtypes inherit parents' protected static properties"
+    );
 } )();