From f0ff70db324f14ebf01f93be03b20af7a951efcd Mon Sep 17 00:00:00 2001
From: Daniel Freedman <dfreedm@google.com>
Date: Wed, 29 Nov 2017 11:05:43 -0800
Subject: [PATCH] Make `:dir` more robust

Fixes #4952
---
 src/lib/style-transformer.html | 45 ++++++++++++++++++-------------
 test/smoke/dir.html            | 49 ++++++++++++++++++++++++++++++++++
 test/unit/dir.html             | 34 +++++++++++++++++++++++
 3 files changed, 109 insertions(+), 19 deletions(-)
 create mode 100644 test/smoke/dir.html

diff --git a/src/lib/style-transformer.html b/src/lib/style-transformer.html
index ee27292c40..d33ef27afe 100644
--- a/src/lib/style-transformer.html
+++ b/src/lib/style-transformer.html
@@ -37,7 +37,7 @@
 
      * :host-context(...): scopeName..., ... scopeName
 
-     * ...:dir(ltr|rtl) -> [dir="ltr|rtl"] ..., ...[dir="ltr|rtl"]
+     * ...:dir(ltr|rtl) -> :host-context([dir]) -> [dir="ltr|rtl"] scopeName ..., scopeName[dir="ltr|rtl"] ...
 
      * :host(:dir[rtl]) -> scopeName:dir(rtl) -> [dir="rtl"] scopeName, scopeName[dir="rtl"]
 
@@ -189,6 +189,17 @@
         return p$.join(COMPLEX_SELECTOR_SEP);
       },
 
+      // make sure `:dir() {` acts as `*:dir() {`
+      // otherwise, it would transform to `:host-context([dir="rtl"])` and apply incorrectly to the host
+      // so make it `:host-context([dir="rtl"]) *`
+      _ensureScopedDir: function(s) {
+        var m = s.match(DIR_PAREN);
+        if (m && m[1] === '' && m[0].length === s.length) {
+          s = '*' + s;
+        }
+        return s;
+      },
+
       _transformComplexSelector: function(selector, scope, hostScope) {
         var stop = false;
         var hostContext = false;
@@ -197,6 +208,7 @@
         selector = this._slottedToContent(selector);
         selector = selector.replace(ROOT, ':host > *');
         selector = selector.replace(CONTENT_START, HOST + ' $1');
+        selector = this._ensureScopedDir(selector);
         selector = selector.replace(SIMPLE_SELECTOR_SEP, function(m, c, s) {
           if (!stop) {
             var info = self._transformCompoundSelector(s, c, scope, hostScope);
@@ -219,10 +231,19 @@
         return selector;
       },
 
+      _transformDir: function (s) {
+        // replaces :host(:dir(rtl)) with :host-context([dir="rtl"])
+        s = s.replace(HOST_DIR, HOST_DIR_REPLACE);
+        // replaces `.foo :dir(rtl)` with `:host-context([dir="rtl") .foo`
+        s = s.replace(DIR_PAREN, DIR_REPLACE);
+        return s;
+      },
+
       _transformCompoundSelector: function(selector, combinator, scope, hostScope) {
         // replace :host with host scoping class
         var jumpIndex = selector.search(SCOPE_JUMP);
         var hostContext = false;
+        selector = this._transformDir(selector);
         if (selector.indexOf(HOST_CONTEXT) >=0) {
           hostContext = true;
         } else if (selector.indexOf(HOST) >=0) {
@@ -243,7 +264,6 @@
           selector = selector.replace(SCOPE_JUMP, ' ');
           stop = true;
         }
-        selector = selector.replace(DIR_PAREN, DIR_REPLACE);
         return {value: selector, combinator: combinator, stop: stop,
           hostContext: hostContext};
       },
@@ -318,21 +338,9 @@
 
       _dirShadowTransform: function(selector) {
         return selector.split(',').map(function(s) {
-          // replaces :host(:dir(rtl)) with :host-context([dir="rtl"])
-          s = s.replace(HOST_DIR, HOST_DIR_REPLACE);
-          var m;
-          if ((m = s.match(DIR_PAREN))) {
-            // replaces `.foo :dir(rtl)` with `:host-context([dir="rtl") .foo`
-            s = s.replace(DIR_PAREN, SHADOW_DIR_REPLACE);
-            // make sure `:dir() {` acts as `*:dir() {`
-            // otherwise, it would transform to `:host-context([dir="rtl"])` and apply incorrectly to the host
-            // so make it `:host-context([dir="rtl"]) *`
-            if (!m[1] || m[1].match(/^\s*$/)) {
-              s = s + '*';
-            }
-          }
-          return s;
-        }).join(',');
+          s = this._ensureScopedDir(s);
+          return this._transformDir(s);
+        }, this).join(',');
       },
 
       SCOPE_NAME: 'style-scope'
@@ -364,8 +372,7 @@
     var SLOTTED_PAREN = /(?:::slotted)(?:\(((?:\([^)(]*\)|[^)(]*)+?)\))/g;
     var HOST_OR_HOST_GT_STAR = /:host(?:\s*>\s*\*)?/;
     var DIR_PAREN = /(.*):dir\((ltr|rtl)\)/;
-    var DIR_REPLACE = '[dir="$2"] $1, $1[dir="$2"]';
-    var SHADOW_DIR_REPLACE = ':host-context([dir="$2"]) $1';
+    var DIR_REPLACE = ':host-context([dir="$2"]) $1';
     var HOST_DIR = /:host\(:dir\((rtl|ltr)\)\)/g;
     var HOST_DIR_REPLACE = ':host-context([dir="$1"])';
 
diff --git a/test/smoke/dir.html b/test/smoke/dir.html
new file mode 100644
index 0000000000..3e3b151ed3
--- /dev/null
+++ b/test/smoke/dir.html
@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<!--
+@license
+Copyright (c) 2017 The Polymer Project Authors. All rights reserved.
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+Code distributed by Google as part of the polymer project is also
+subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+-->
+<html dir="rtl">
+<head>
+  <meta charset="utf-8">
+  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
+  <meta name="viewport" content="width=device-width, minimum-scale=1.0, initial-scale=1, user-scalable=yes">
+
+  <title>Polymer</title>
+
+  <script src="../../../webcomponentsjs/webcomponents-lite.js"></script>
+  <link rel="import" href="../../polymer.html">
+</head>
+<body>
+
+  <x-el></x-el>
+
+  <dom-module id="x-el">
+    <template>
+      <style>
+        #target {
+          padding: 20px;
+          color: white;
+          background: blue;
+        }
+        :dir(rtl) #target {
+          background: red;
+        }
+      </style>
+      <div>hello</div>
+      <div id="target">am i red?</div>
+    </template>
+    <script>
+      addEventListener('WebComponentsReady', function() {
+        Polymer({is: 'x-el'});
+      });
+    </script>
+  </dom-module>
+
+</body>
+</html>
\ No newline at end of file
diff --git a/test/unit/dir.html b/test/unit/dir.html
index 110a37195c..7840593c6b 100644
--- a/test/unit/dir.html
+++ b/test/unit/dir.html
@@ -109,6 +109,28 @@
     </script>
   </dom-module>
 
+  <dom-module id="x-complicated">
+    <template>
+      <style>
+        #target {
+          padding: 20px;
+          color: white;
+          background: rgb(0, 0, 255);
+        }
+        :dir(rtl) #target {
+          background: rgb(255, 0, 0);
+        }
+      </style>
+      <div id="normal">hello</div>
+      <div id="target">am i red?</div>
+    </template>
+    <script>
+      addEventListener('WebComponentsReady', function() {
+        Polymer({is: 'x-complicated'});
+      });
+    </script>
+  </dom-module>
+
   <test-fixture id="dir">
     <template>
       <x-dir></x-dir>
@@ -133,6 +155,12 @@
     </template>
   </test-fixture>
 
+  <test-fixture id="complicated">
+    <template>
+      <x-complicated></x-complicated>
+    </template>
+  </test-fixture>
+
   <script>
     function assertComputed(node, expected, property) {
       property = property || 'border-top-width';
@@ -208,6 +236,12 @@
         var el = fixture('var')[1];
         assertComputed(el, '10px');
         assertComputed(el.$.inner, '2px');
+      });
+
+      test('complicated styles work as expected', function() {
+        var el = fixture('complicated');
+        assertComputed(el.$.normal, '0px', 'padding-left');
+        assertComputed(el.$.target, 'rgb(255, 0, 0)', 'background-color');
       })
     });
   </script>