Better "return this" rewrite (#243)

server-side rewrite: js obj proxy:
- rewrite 'return this' more generally, but not 'return this.', update tests

pywb/rewrite/regex_rewriters.py

@@ -186,13 +186,13 @@ if (!self.__WB_pmw) {{ self.__WB_pmw = function(obj) {{ return obj; }} }}\n\
         return lambda x: x.replace('this', replacer)
 
     def __init__(self, rewriter, rules=[]):
-        func_rw = 'Function("return {0}")'.format(self.THIS_RW)
+        #func_rw = 'Function("return {0}")'.format(self.THIS_RW)
-
         prop_str = '|'.join(self.local_objs)
 
         rules = rules + [
            (r'(?<=\.)postMessage\b\(', self.add_prefix('__WB_pmw(self).'), 0),
-           (r'Function\(["\']return this["\']\)', self.fixed(func_rw), 0),
+           #(r'Function\(["\']return this["\']\)', self.fixed(func_rw), 0),
+           (r'\breturn\s+this\b\s*(?![.$])', self.replace_str(self.THIS_RW), 0),
            (r'(?<=[\n])\s*this\b(?=(?:\.(?:{0})\b))'.format(prop_str), self.replace_str(';' + self.THIS_RW), 0),
            (r'(?<![$.])\s*this\b(?=(?:\.(?:{0})\b))'.format(prop_str), self.replace_str(self.THIS_RW), 0),
            (r'(?<=[=])\s*this\b\s*(?![.$])', self.replace_str(self.THIS_RW), 0),

pywb/rewrite/test/test_regex_rewriters.py

@@ -148,6 +148,9 @@ r"""
 >>> _test_js_obj_proxy('func(Function("return this"));')
 'func(Function("return (this && this._WB_wombat_obj_proxy || this)"));'
 
+>>> _test_js_obj_proxy('A.call(function() { return   this });')
+'A.call(function() { return   (this && this._WB_wombat_obj_proxy || this) });'
+
 >>> _test_js_obj_proxy('this.document.location = foo')
 '(this && this._WB_wombat_obj_proxy || this).document.location = foo'
 
@@ -167,6 +170,9 @@ r"""
 >>> _test_js_obj_proxy('|||this|||')
 '|||this|||'
 
+>>> _test_js_obj_proxy('return this.foo')
+'return this.foo'
+
 
 #=================================================================
 # XML Rewriting