Issue 7207 - Implement abort-on-property-write snippet

lib/content/snippets.js

Index: lib/content/snippets.js
===================================================================
--- a/lib/content/snippets.js
+++ b/lib/content/snippets.js
@@ -754,16 +754,48 @@
 }
 
 exports["abort-on-property-read"] = makeInjector(abortOnPropertyRead,
                                                  wrapPropertyAccess,
                                                  overrideOnError,
                                                  randomId);
 
 /**
+ * Patches a property on the window object to abort execution when the
+ * property is written (set).

[Manish Jethani, 2019/01/15 14:13:29]

Nit: I don't think "(set)" is necessary, but it's up to you.

[hub, 2019/01/15 16:40:29]

I ought it clarify, but then I don't for "read" so I'll remove.

+ *
+ * No error is be printed to the console.

[Manish Jethani, 2019/01/15 14:13:30]

Correction: No error is printed to the console.

We should also change this for abort-on-property-read

[hub, 2019/01/15 16:40:29]

Done.

BTW it is a cut&paste error that is found in the previous snippet.

+ *
+ * The idea originates from
+ * {@link https://github.com/uBlockOrigin/uAssets/blob/80b195436f8f8d78ba713237bfc268ecfc9d9d2b/filters/resources.txt#L1671 uBlock Origin}.
+ *
+ * @param {string} property The name of the property.
+ */
+function abortOnPropertyWrite(property)
+{
+  if (!property)
+    return;
+
+  let rid = randomId();
+
+  function abort()
+  {
+    throw new ReferenceError(rid);
+  }
+
+  if (wrapPropertyAccess(window, property, {set: abort}))

[Manish Jethani, 2019/01/15 14:13:29]

Do we need a getter here?

[hub, 2019/01/15 16:40:30]

We don't.

[Manish Jethani, 2019/01/15 17:24:16]

Acknowledged.

+    overrideOnError(rid);
+}
+
+exports["abort-on-property-write"] = makeInjector(abortOnPropertyWrite,
+                                                  wrapPropertyAccess,
+                                                  overrideOnError,
+                                                  randomId);
+
+/**
  * Aborts the execution of an inline script.
  *
  * @param {string} api API function or property name to anchor on.
  * @param {?string} [search] If specified, only scripts containing the given
  *   string are prevented from executing. If the string begins and ends with a
  *   slash (<code>/</code>), the text in between is treated as a regular
  *   expression.
  */