dom/base/nsDOMJSUtils.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #ifndef nsDOMJSUtils_h__
   6 #define nsDOMJSUtils_h__
   7
   8 #include "nsIScriptContext.h"
   9 #include "jsapi.h"
  10
  11 class nsIJSArgArray;
  12
  13 // seems like overkill for just this 1 function - but let's see what else
  14 // falls out first.
  15 inline nsIScriptContext *
  16 GetScriptContextFromJSContext(JSContext *cx)
  17 {
  18   if (!(JS::ContextOptionsRef(cx).privateIsNSISupports())) {
  19     return nullptr;
  20   }
  21
  22   nsCOMPtr<nsIScriptContext> scx =
  23     do_QueryInterface(static_cast<nsISupports *>
  24                                  (::JS_GetContextPrivate(cx)));
  25
  26   // This will return a pointer to something that's about to be
  27   // released, but that's ok here.
  28   return scx;
  29 }
  30
  31 JSObject* GetDefaultScopeFromJSContext(JSContext *cx);
  32
  33 // A factory function for turning a JS::Value argv into an nsIArray
  34 // but also supports an effecient way of extracting the original argv.
  35 // Bug 312003 describes why this must be "void *", but argv will be cast to
  36 // JS::Value* and the args are found at:
  37 //    ((JS::Value*)aArgv)[0], ..., ((JS::Value*)aArgv)[aArgc - 1]
  38 // The resulting object will take a copy of the array, and ensure each
  39 // element is rooted.
  40 // Optionally, aArgv may be nullptr, in which case the array is allocated and
  41 // rooted, but all items remain nullptr.  This presumably means the caller
  42 // will then QI us for nsIJSArgArray, and set our array elements.
  43 nsresult NS_CreateJSArgv(JSContext *aContext, uint32_t aArgc, void *aArgv,
  44                          nsIJSArgArray **aArray);
  45
  46 #endif // nsDOMJSUtils_h__