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      1 /*
      2  * Copyright (c) Meta Platforms, Inc. and affiliates.
      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 *  Dependencies
     18 ******************************************/
     19 #include "../zstd_errors.h"  /* enum list */
     20 #include "compiler.h"
     21 #include "debug.h"
     22 #include "zstd_deps.h"       /* size_t */
     23 
     24 /* ****************************************
     25 *  Compiler-specific
     26 ******************************************/
     27 #if defined(__GNUC__)
     28 #  define ERR_STATIC static __attribute__((unused))
     29 #elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
     30 #  define ERR_STATIC static inline
     31 #elif defined(_MSC_VER)
     32 #  define ERR_STATIC static __inline
     33 #else
     34 #  define ERR_STATIC static  /* this version may generate warnings for unused static functions; disable the relevant warning */
     35 #endif
     36 
     37 
     38 /*-****************************************
     39 *  Customization (error_public.h)
     40 ******************************************/
     41 typedef ZSTD_ErrorCode ERR_enum;
     42 #define PREFIX(name) ZSTD_error_##name
     43 
     44 
     45 /*-****************************************
     46 *  Error codes handling
     47 ******************************************/
     48 #undef ERROR   /* already defined on Visual Studio */
     49 #define ERROR(name) ZSTD_ERROR(name)
     50 #define ZSTD_ERROR(name) ((size_t)-PREFIX(name))
     51 
     52 ERR_STATIC unsigned ERR_isError(size_t code) { return (code > ERROR(maxCode)); }
     53 
     54 ERR_STATIC ERR_enum ERR_getErrorCode(size_t code) { if (!ERR_isError(code)) return (ERR_enum)0; return (ERR_enum) (0-code); }
     55 
     56 /* check and forward error code */
     57 #define CHECK_V_F(e, f)     \
     58     size_t const e = f;     \
     59     do {                    \
     60         if (ERR_isError(e)) \
     61             return e;       \
     62     } while (0)
     63 #define CHECK_F(f)   do { CHECK_V_F(_var_err__, f); } while (0)
     64 
     65 
     66 /*-****************************************
     67 *  Error Strings
     68 ******************************************/
     69 
     70 const char* ERR_getErrorString(ERR_enum code);   /* error_private.c */
     71 
     72 ERR_STATIC const char* ERR_getErrorName(size_t code)
     73 {
     74     return ERR_getErrorString(ERR_getErrorCode(code));
     75 }
     76 
     77 /**
     78  * Ignore: this is an internal helper.
     79  *
     80  * This is a helper function to help force C99-correctness during compilation.
     81  * Under strict compilation modes, variadic macro arguments can't be empty.
     82  * However, variadic function arguments can be. Using a function therefore lets
     83  * us statically check that at least one (string) argument was passed,
     84  * independent of the compilation flags.
     85  */
     86 static INLINE_KEYWORD UNUSED_ATTR
     87 void _force_has_format_string(const char *format, ...) {
     88   (void)format;
     89 }
     90 
     91 /**
     92  * Ignore: this is an internal helper.
     93  *
     94  * We want to force this function invocation to be syntactically correct, but
     95  * we don't want to force runtime evaluation of its arguments.
     96  */
     97 #define _FORCE_HAS_FORMAT_STRING(...)              \
     98     do {                                           \
     99         if (0) {                                   \
    100             _force_has_format_string(__VA_ARGS__); \
    101         }                                          \
    102     } while (0)
    103 
    104 #define ERR_QUOTE(str) #str
    105 
    106 /**
    107  * Return the specified error if the condition evaluates to true.
    108  *
    109  * In debug modes, prints additional information.
    110  * In order to do that (particularly, printing the conditional that failed),
    111  * this can't just wrap RETURN_ERROR().
    112  */
    113 #define RETURN_ERROR_IF(cond, err, ...)                                        \
    114     do {                                                                       \
    115         if (cond) {                                                            \
    116             RAWLOG(3, "%s:%d: ERROR!: check %s failed, returning %s",          \
    117                   __FILE__, __LINE__, ERR_QUOTE(cond), ERR_QUOTE(ERROR(err))); \
    118             _FORCE_HAS_FORMAT_STRING(__VA_ARGS__);                             \
    119             RAWLOG(3, ": " __VA_ARGS__);                                       \
    120             RAWLOG(3, "\n");                                                   \
    121             return ERROR(err);                                                 \
    122         }                                                                      \
    123     } while (0)
    124 
    125 /**
    126  * Unconditionally return the specified error.
    127  *
    128  * In debug modes, prints additional information.
    129  */
    130 #define RETURN_ERROR(err, ...)                                               \
    131     do {                                                                     \
    132         RAWLOG(3, "%s:%d: ERROR!: unconditional check failed, returning %s", \
    133               __FILE__, __LINE__, ERR_QUOTE(ERROR(err)));                    \
    134         _FORCE_HAS_FORMAT_STRING(__VA_ARGS__);                               \
    135         RAWLOG(3, ": " __VA_ARGS__);                                         \
    136         RAWLOG(3, "\n");                                                     \
    137         return ERROR(err);                                                   \
    138     } while(0)
    139 
    140 /**
    141  * If the provided expression evaluates to an error code, returns that error code.
    142  *
    143  * In debug modes, prints additional information.
    144  */
    145 #define FORWARD_IF_ERROR(err, ...)                                                 \
    146     do {                                                                           \
    147         size_t const err_code = (err);                                             \
    148         if (ERR_isError(err_code)) {                                               \
    149             RAWLOG(3, "%s:%d: ERROR!: forwarding error in %s: %s",                 \
    150                   __FILE__, __LINE__, ERR_QUOTE(err), ERR_getErrorName(err_code)); \
    151             _FORCE_HAS_FORMAT_STRING(__VA_ARGS__);                                 \
    152             RAWLOG(3, ": " __VA_ARGS__);                                           \
    153             RAWLOG(3, "\n");                                                       \
    154             return err_code;                                                       \
    155         }                                                                          \
    156     } while(0)
    157 
    158 #endif /* ERROR_H_MODULE */
    159