Issue 6791 - Implement abort-current-inline-script snippet

lib/content/snippets.js

Index: lib/content/snippets.js
===================================================================
--- a/lib/content/snippets.js
+++ b/lib/content/snippets.js
@@ -62,8 +62,85 @@
 exports.log = log;
 
 function uabinjectDefuser()
 {
   window.trckd = window.uabpdl = window.uabInject = window.uabDetect = true;
 }
 
 exports["uabinject-defuser"] = makeInjector(uabinjectDefuser);
+
+function abortCurrentInlineScript(target, needle)
+{
+  "use strict";
+
+  if (!target)
+    return;
+
+  let reText = ".?";
+
+  if (needle)
+  {
+    reText = /^\/.+\/$/.test(needle) ?
+               needle.slice(1, -1) :
+               needle.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+  }
+
+  let re = new RegExp(reText);
+  let chain = target.split(".");
+
+  let owner = window;
+  let property = null;
+
+  while (true)
+  {
+    property = chain.shift();
+    if (chain.length == 0)
+      break;
+
+    owner = owner[property];
+    if (!(owner instanceof Object))
+      return;
+  }
+
+  let descriptor = Object.getOwnPropertyDescriptor(owner, property);
+  if (descriptor && descriptor.get)
+    return;
+
+  let magic = String.fromCharCode(Date.now() % 26 + 97) +
+              Math.floor(Math.random() * 982451653 + 982451653).toString(36);
+  let value = owner[property];
+
+  let validate = () =>
+  {
+    let element = document.currentScript;
+    if (element instanceof HTMLScriptElement &&
+        element.src == "" && re.test(element.textContent))
+    {
+      throw new ReferenceError(magic);
+    }
+  };
+
+  Object.defineProperty(owner, property, {
+    get()
+    {
+      validate();
+      return value;
+    },
+    set(newValue)
+    {
+      validate();
+      value = newValue;
+    }
+  });
+
+  let {onerror} = window;
+  window.onerror = function(message, ...rest)
+  {
+    if (typeof message == "string" && message.indexOf(magic) != -1)
+      return true;
+
+    if (onerror instanceof Function)
+      return onerror.call(this, message, ...rest);
+  };
+}
+
+exports["abort-current-inline-script"] = makeInjector(abortCurrentInlineScript);