lib/zstd/common/error_private.h

   1 /*
   2  * Copyright (c) Yann Collet, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under both the BSD-style license (found in the
   6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
   7  * in the COPYING file in the root directory of this source tree).
   8  * You may select, at your option, one of the above-listed licenses.
   9  */
  10
  11 /* Note : this module is expected to remain private, do not expose it */
  12
  13 #ifndef ERROR_H_MODULE
  14 #define ERROR_H_MODULE
  15
  16
  17
  18 /* ****************************************
  19 *  Dependencies
  20 ******************************************/
  21 #include <linux/zstd_errors.h>  /* enum list */
  22 #include "compiler.h"
  23 #include "debug.h"
  24 #include "zstd_deps.h"       /* size_t */
  25
  26
  27 /* ****************************************
  28 *  Compiler-specific
  29 ******************************************/
  30 #define ERR_STATIC static __attribute__((unused))
  31
  32
  33 /*-****************************************
  34 *  Customization (error_public.h)
  35 ******************************************/
  36 typedef ZSTD_ErrorCode ERR_enum;
  37 #define PREFIX(name) ZSTD_error_##name
  38
  39
  40 /*-****************************************
  41 *  Error codes handling
  42 ******************************************/
  43 #undef ERROR   /* already defined on Visual Studio */
  44 #define ERROR(name) ZSTD_ERROR(name)
  45 #define ZSTD_ERROR(name) ((size_t)-PREFIX(name))
  46
  47 ERR_STATIC unsigned ERR_isError(size_t code) { return (code > ERROR(maxCode)); }
  48
  49 ERR_STATIC ERR_enum ERR_getErrorCode(size_t code) { if (!ERR_isError(code)) return (ERR_enum)0; return (ERR_enum) (0-code); }
  50
  51 /* check and forward error code */
  52 #define CHECK_V_F(e, f) size_t const e = f; if (ERR_isError(e)) return e
  53 #define CHECK_F(f)   { CHECK_V_F(_var_err__, f); }
  54
  55
  56 /*-****************************************
  57 *  Error Strings
  58 ******************************************/
  59
  60 const char* ERR_getErrorString(ERR_enum code);   /* error_private.c */
  61
  62 ERR_STATIC const char* ERR_getErrorName(size_t code)
  63 {
  64     return ERR_getErrorString(ERR_getErrorCode(code));
  65 }
  66
  67 /*
  68  * Ignore: this is an internal helper.
  69  *
  70  * This is a helper function to help force C99-correctness during compilation.
  71  * Under strict compilation modes, variadic macro arguments can't be empty.
  72  * However, variadic function arguments can be. Using a function therefore lets
  73  * us statically check that at least one (string) argument was passed,
  74  * independent of the compilation flags.
  75  */
  76 static INLINE_KEYWORD UNUSED_ATTR
  77 void _force_has_format_string(const char *format, ...) {
  78   (void)format;
  79 }
  80
  81 /*
  82  * Ignore: this is an internal helper.
  83  *
  84  * We want to force this function invocation to be syntactically correct, but
  85  * we don't want to force runtime evaluation of its arguments.
  86  */
  87 #define _FORCE_HAS_FORMAT_STRING(...) \
  88   if (0) { \
  89     _force_has_format_string(__VA_ARGS__); \
  90   }
  91
  92 #define ERR_QUOTE(str) #str
  93
  94 /*
  95  * Return the specified error if the condition evaluates to true.
  96  *
  97  * In debug modes, prints additional information.
  98  * In order to do that (particularly, printing the conditional that failed),
  99  * this can't just wrap RETURN_ERROR().
 100  */
 101 #define RETURN_ERROR_IF(cond, err, ...) \
 102   if (cond) { \
 103     RAWLOG(3, "%s:%d: ERROR!: check %s failed, returning %s", \
 104            __FILE__, __LINE__, ERR_QUOTE(cond), ERR_QUOTE(ERROR(err))); \
 105     _FORCE_HAS_FORMAT_STRING(__VA_ARGS__); \
 106     RAWLOG(3, ": " __VA_ARGS__); \
 107     RAWLOG(3, "\n"); \
 108     return ERROR(err); \
 109   }
 110
 111 /*
 112  * Unconditionally return the specified error.
 113  *
 114  * In debug modes, prints additional information.
 115  */
 116 #define RETURN_ERROR(err, ...) \
 117   do { \
 118     RAWLOG(3, "%s:%d: ERROR!: unconditional check failed, returning %s", \
 119            __FILE__, __LINE__, ERR_QUOTE(ERROR(err))); \
 120     _FORCE_HAS_FORMAT_STRING(__VA_ARGS__); \
 121     RAWLOG(3, ": " __VA_ARGS__); \
 122     RAWLOG(3, "\n"); \
 123     return ERROR(err); \
 124   } while(0);
 125
 126 /*
 127  * If the provided expression evaluates to an error code, returns that error code.
 128  *
 129  * In debug modes, prints additional information.
 130  */
 131 #define FORWARD_IF_ERROR(err, ...) \
 132   do { \
 133     size_t const err_code = (err); \
 134     if (ERR_isError(err_code)) { \
 135       RAWLOG(3, "%s:%d: ERROR!: forwarding error in %s: %s", \
 136              __FILE__, __LINE__, ERR_QUOTE(err), ERR_getErrorName(err_code)); \
 137       _FORCE_HAS_FORMAT_STRING(__VA_ARGS__); \
 138       RAWLOG(3, ": " __VA_ARGS__); \
 139       RAWLOG(3, "\n"); \
 140       return err_code; \
 141     } \
 142   } while(0);
 143
 144
 145 #endif /* ERROR_H_MODULE */