Issue 5436 - Allow relative selectors in :-abp-has()

chrome/content/elemHideEmulation.js

Index: chrome/content/elemHideEmulation.js
===================================================================
--- a/chrome/content/elemHideEmulation.js
+++ b/chrome/content/elemHideEmulation.js
@@ -186,16 +186,17 @@
    */
   *getSelectors(prefix, subtree, styles)
   {
     yield [prefix + this._selector, subtree];
   }
 };
 
 const incompletePrefixRegexp = /[\s>+~]$/;
+const relativeSelectorRegexp = /^[\s>+~]/;

[Wladimir Palant, 2017/08/10 13:42:17]

\s doesn't belong in here.

[hub, 2017/08/14 14:25:32]

Done.

 
 function HasSelector(selectors)
 {
   this._innerSelectors = selectors;
 }
 
 HasSelector.prototype = {
   requiresHiding: true,
@@ -221,18 +222,22 @@
   {
     let actualPrefix = (!prefix || incompletePrefixRegexp.test(prefix)) ?
         prefix + "*" : prefix;
     let elements = subtree.querySelectorAll(actualPrefix);
     for (let element of elements)
     {
       let iter = evaluate(this._innerSelectors, 0, "", element, styles);
       for (let selector of iter)
+      {
+        if (relativeSelectorRegexp.test(selector))
+          selector = ":scope" + selector;

[Wladimir Palant, 2017/08/10 13:36:08]

Nice one, I didn't know about :scope yet. Browser support is problematic
however. Scoped stylesheets are being cited as the primary usage example, yet
this feature appears to be dead. Chrome deprecated it
(https://www.chromestatus.com/features/5374137958662144) and Edge isn't planning
to implement it
(https://developer.microsoft.com/en-us/microsoft-edge/platform/status/scopedst...).

Now using :scoped with element.querySelector() is different and part of the DOM4
spec, so I hope that this feature won't be removed from Firefox and Chrome.
Still questionable whether/when Microsoft chooses to implement it in Edge.

I just checked with Sebastian and Dave on IRC about what they think about
missing Edge support here. It seems that not having this work on Edge is
acceptable. However, it shouldn't break things either, so you need to catch the
error element.querySelector() will throw there.

[hub, 2017/08/14 14:25:32]

Good point. Will catch the exception. I'll see if there is a better way to do
it.

         if (element.querySelector(selector))
           yield element;
+      }
     }
   }
 };
 
 function PropsSelector(propertyExpression)
 {
   let regexpString;
   if (propertyExpression.length >= 2 && propertyExpression[0] == "/" &&