xpcom/base/nsQueryObject.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef nsQueryObject_h
   8 #define nsQueryObject_h
   9
  10 #include "mozilla/Attributes.h"
  11
  12 #include "nsCOMPtr.h"
  13 #include "mozilla/RefPtr.h"
  14
  15 /*****************************************************************************/
  16
  17 template <class T>
  18 class MOZ_STACK_CLASS nsQueryObject final : public nsCOMPtr_helper {
  19  public:
  20   explicit nsQueryObject(T* aRawPtr) : mRawPtr(aRawPtr) {}
  21
  22   virtual nsresult NS_FASTCALL operator()(const nsIID& aIID,
  23                                           void** aResult) const override {
  24     nsresult status = mRawPtr ? mRawPtr->QueryInterface(aIID, aResult)
  25                               : NS_ERROR_NULL_POINTER;
  26     return status;
  27   }
  28
  29  private:
  30   T* MOZ_NON_OWNING_REF mRawPtr;
  31 };
  32
  33 template <class T>
  34 class MOZ_STACK_CLASS nsQueryObjectWithError final : public nsCOMPtr_helper {
  35  public:
  36   nsQueryObjectWithError(T* aRawPtr, nsresult* aErrorPtr)
  37       : mRawPtr(aRawPtr), mErrorPtr(aErrorPtr) {}
  38
  39   virtual nsresult NS_FASTCALL operator()(const nsIID& aIID,
  40                                           void** aResult) const override {
  41     nsresult status = mRawPtr ? mRawPtr->QueryInterface(aIID, aResult)
  42                               : NS_ERROR_NULL_POINTER;
  43     if (mErrorPtr) {
  44       *mErrorPtr = status;
  45     }
  46     return status;
  47   }
  48
  49  private:
  50   T* MOZ_NON_OWNING_REF mRawPtr;
  51   nsresult* mErrorPtr;
  52 };
  53
  54 /*****************************************************************************/
  55
  56 /*****************************************************************************/
  57
  58 template <class T>
  59 inline nsQueryObject<T> do_QueryObject(T* aRawPtr) {
  60   return nsQueryObject<T>(aRawPtr);
  61 }
  62
  63 template <class T>
  64 inline nsQueryObject<T> do_QueryObject(const nsCOMPtr<T>& aRawPtr) {
  65   return nsQueryObject<T>(aRawPtr);
  66 }
  67
  68 template <class T>
  69 inline nsQueryObject<T> do_QueryObject(const RefPtr<T>& aRawPtr) {
  70   return nsQueryObject<T>(aRawPtr);
  71 }
  72
  73 template <class T>
  74 inline nsQueryObjectWithError<T> do_QueryObject(T* aRawPtr,
  75                                                 nsresult* aErrorPtr) {
  76   return nsQueryObjectWithError<T>(aRawPtr, aErrorPtr);
  77 }
  78
  79 template <class T>
  80 inline nsQueryObjectWithError<T> do_QueryObject(const nsCOMPtr<T>& aRawPtr,
  81                                                 nsresult* aErrorPtr) {
  82   return nsQueryObjectWithError<T>(aRawPtr, aErrorPtr);
  83 }
  84
  85 template <class T>
  86 inline nsQueryObjectWithError<T> do_QueryObject(const RefPtr<T>& aRawPtr,
  87                                                 nsresult* aErrorPtr) {
  88   return nsQueryObjectWithError<T>(aRawPtr, aErrorPtr);
  89 }
  90
  91 /*****************************************************************************/
  92
  93 #endif  // !defined(nsQueryObject_h)