error_private.h

  1/* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */
  2/*
  3 * Copyright (c) Meta Platforms, Inc. and affiliates.
  4 * All rights reserved.
  5 *
  6 * This source code is licensed under both the BSD-style license (found in the
  7 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  8 * in the COPYING file in the root directory of this source tree).
  9 * You may select, at your option, one of the above-listed licenses.
 10 */
 11
 12/* Note : this module is expected to remain private, do not expose it */
 13
 14#ifndef ERROR_H_MODULE
 15#define ERROR_H_MODULE
 16
 17/* ****************************************
 18*  Dependencies
 19******************************************/
 20#include <linux/zstd_errors.h>  /* enum list */
 21#include "compiler.h"
 22#include "debug.h"
 23#include "zstd_deps.h"       /* size_t */
 24
 25/* ****************************************
 26*  Compiler-specific
 27******************************************/
 28#define ERR_STATIC static __attribute__((unused))
 29
 30
 31/*-****************************************
 32*  Customization (error_public.h)
 33******************************************/
 34typedef ZSTD_ErrorCode ERR_enum;
 35#define PREFIX(name) ZSTD_error_##name
 36
 37
 38/*-****************************************
 39*  Error codes handling
 40******************************************/
 41#undef ERROR   /* already defined on Visual Studio */
 42#define ERROR(name) ZSTD_ERROR(name)
 43#define ZSTD_ERROR(name) ((size_t)-PREFIX(name))
 44
 45ERR_STATIC unsigned ERR_isError(size_t code) { return (code > ERROR(maxCode)); }
 46
 47ERR_STATIC ERR_enum ERR_getErrorCode(size_t code) { if (!ERR_isError(code)) return (ERR_enum)0; return (ERR_enum) (0-code); }
 48
 49/* check and forward error code */
 50#define CHECK_V_F(e, f)     \
 51    size_t const e = f;     \
 52    do {                    \
 53        if (ERR_isError(e)) \
 54            return e;       \
 55    } while (0)
 56#define CHECK_F(f)   do { CHECK_V_F(_var_err__, f); } while (0)
 57
 58
 59/*-****************************************
 60*  Error Strings
 61******************************************/
 62
 63const char* ERR_getErrorString(ERR_enum code);   /* error_private.c */
 64
 65ERR_STATIC const char* ERR_getErrorName(size_t code)
 66{
 67    return ERR_getErrorString(ERR_getErrorCode(code));
 68}
 69
 70/*
 71 * Ignore: this is an internal helper.
 72 *
 73 * This is a helper function to help force C99-correctness during compilation.
 74 * Under strict compilation modes, variadic macro arguments can't be empty.
 75 * However, variadic function arguments can be. Using a function therefore lets
 76 * us statically check that at least one (string) argument was passed,
 77 * independent of the compilation flags.
 78 */
 79static INLINE_KEYWORD UNUSED_ATTR
 80void _force_has_format_string(const char *format, ...) {
 81  (void)format;
 82}
 83
 84/*
 85 * Ignore: this is an internal helper.
 86 *
 87 * We want to force this function invocation to be syntactically correct, but
 88 * we don't want to force runtime evaluation of its arguments.
 89 */
 90#define _FORCE_HAS_FORMAT_STRING(...)              \
 91    do {                                           \
 92        if (0) {                                   \
 93            _force_has_format_string(__VA_ARGS__); \
 94        }                                          \
 95    } while (0)
 96
 97#define ERR_QUOTE(str) #str
 98
 99/*
100 * Return the specified error if the condition evaluates to true.
101 *
102 * In debug modes, prints additional information.
103 * In order to do that (particularly, printing the conditional that failed),
104 * this can't just wrap RETURN_ERROR().
105 */
106#define RETURN_ERROR_IF(cond, err, ...)                                        \
107    do {                                                                       \
108        if (cond) {                                                            \
109            RAWLOG(3, "%s:%d: ERROR!: check %s failed, returning %s",          \
110                  __FILE__, __LINE__, ERR_QUOTE(cond), ERR_QUOTE(ERROR(err))); \
111            _FORCE_HAS_FORMAT_STRING(__VA_ARGS__);                             \
112            RAWLOG(3, ": " __VA_ARGS__);                                       \
113            RAWLOG(3, "\n");                                                   \
114            return ERROR(err);                                                 \
115        }                                                                      \
116    } while (0)
117
118/*
119 * Unconditionally return the specified error.
120 *
121 * In debug modes, prints additional information.
122 */
123#define RETURN_ERROR(err, ...)                                               \
124    do {                                                                     \
125        RAWLOG(3, "%s:%d: ERROR!: unconditional check failed, returning %s", \
126              __FILE__, __LINE__, ERR_QUOTE(ERROR(err)));                    \
127        _FORCE_HAS_FORMAT_STRING(__VA_ARGS__);                               \
128        RAWLOG(3, ": " __VA_ARGS__);                                         \
129        RAWLOG(3, "\n");                                                     \
130        return ERROR(err);                                                   \
131    } while(0)
132
133/*
134 * If the provided expression evaluates to an error code, returns that error code.
135 *
136 * In debug modes, prints additional information.
137 */
138#define FORWARD_IF_ERROR(err, ...)                                                 \
139    do {                                                                           \
140        size_t const err_code = (err);                                             \
141        if (ERR_isError(err_code)) {                                               \
142            RAWLOG(3, "%s:%d: ERROR!: forwarding error in %s: %s",                 \
143                  __FILE__, __LINE__, ERR_QUOTE(err), ERR_getErrorName(err_code)); \
144            _FORCE_HAS_FORMAT_STRING(__VA_ARGS__);                                 \
145            RAWLOG(3, ": " __VA_ARGS__);                                           \
146            RAWLOG(3, "\n");                                                       \
147            return err_code;                                                       \
148        }                                                                          \
149    } while(0)
150
151#endif /* ERROR_H_MODULE */