xpcom/base/nsError.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 nsError_h__
   8 #define nsError_h__
   9
  10 #ifndef __cplusplus
  11 #  error nsError.h no longer supports C sources
  12 #endif
  13
  14 #include "mozilla/Attributes.h"
  15 #include "mozilla/Likely.h"
  16
  17 #include <stdint.h>
  18
  19 #define NS_ERROR_SEVERITY_SUCCESS 0
  20 #define NS_ERROR_SEVERITY_ERROR 1
  21
  22 #include "ErrorList.h"  // IWYU pragma: export
  23
  24 /**
  25  * @name Standard Error Handling Macros
  26  * @return 0 or 1 (false/true with bool type for C++)
  27  */
  28
  29 inline uint32_t NS_FAILED_impl(nsresult aErr) {
  30   return static_cast<uint32_t>(aErr) & 0x80000000;
  31 }
  32 #define NS_FAILED(_nsresult) ((bool)MOZ_UNLIKELY(NS_FAILED_impl(_nsresult)))
  33 #define NS_SUCCEEDED(_nsresult) ((bool)MOZ_LIKELY(!NS_FAILED_impl(_nsresult)))
  34
  35 /* Check that our enum type is actually uint32_t as expected */
  36 static_assert(((nsresult)0) < ((nsresult)-1),
  37               "nsresult must be an unsigned type");
  38 static_assert(sizeof(nsresult) == sizeof(uint32_t), "nsresult must be 32 bits");
  39
  40 #define MOZ_ALWAYS_SUCCEEDS(expr) MOZ_ALWAYS_TRUE(NS_SUCCEEDED(expr))
  41
  42 /**
  43  * @name Standard Error Generating Macros
  44  */
  45
  46 #define NS_ERROR_GENERATE(sev, module, code)                            \
  47   (nsresult)(((uint32_t)(sev) << 31) |                                  \
  48              ((uint32_t)(module + NS_ERROR_MODULE_BASE_OFFSET) << 16) | \
  49              ((uint32_t)(code)))
  50
  51 #define NS_ERROR_GENERATE_SUCCESS(module, code) \
  52   NS_ERROR_GENERATE(NS_ERROR_SEVERITY_SUCCESS, module, code)
  53
  54 #define NS_ERROR_GENERATE_FAILURE(module, code) \
  55   NS_ERROR_GENERATE(NS_ERROR_SEVERITY_ERROR, module, code)
  56
  57 /*
  58  * This will return the nsresult corresponding to the most recent NSPR failure
  59  * returned by PR_GetError.
  60  *
  61  ***********************************************************************
  62  *      Do not depend on this function. It will be going away!
  63  ***********************************************************************
  64  */
  65 extern nsresult NS_ErrorAccordingToNSPR();
  66
  67 /**
  68  * @name Standard Macros for retrieving error bits
  69  */
  70
  71 inline constexpr uint16_t NS_ERROR_GET_CODE(nsresult aErr) {
  72   return uint32_t(aErr) & 0xffff;
  73 }
  74 inline constexpr uint16_t NS_ERROR_GET_MODULE(nsresult aErr) {
  75   return ((uint32_t(aErr) >> 16) - NS_ERROR_MODULE_BASE_OFFSET) & 0x1fff;
  76 }
  77 inline bool NS_ERROR_GET_SEVERITY(nsresult aErr) {
  78   return uint32_t(aErr) >> 31;
  79 }
  80
  81 #ifdef _MSC_VER
  82 #  pragma warning(disable : 4251) /* 'nsCOMPtr<class nsIInputStream>' needs to \
  83                                      have dll-interface to be used by clients  \
  84                                      of class 'nsInputStream' */
  85 #  pragma warning(                                                          \
  86       disable : 4275) /* non dll-interface class 'nsISupports' used as base \
  87                          for dll-interface class 'nsIRDFNode' */
  88 #endif
  89
  90 #endif