reftable: add error related functionality

The reftable/ directory is structured as a library, so it cannot
crash on misuse. Instead, it returns an error code.

In addition to signaling errors, the error code can be used to signal
conditions from lower levels of the library to be handled by higher
levels of the library. For example, in a transaction we might
legitimately write an empty reftable file, but in that case, we want to
shortcut the transaction.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Han-Wen Nienhuys 2021-10-07 20:24:59 +00:00 коммит произвёл Junio C Hamano
Родитель 27f7ed2a07
Коммит 890044708d
2 изменённых файлов: 103 добавлений и 0 удалений

41
reftable/error.c Normal file
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/*
Copyright 2020 Google LLC
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file or at
https://developers.google.com/open-source/licenses/bsd
*/
#include "reftable-error.h"
#include <stdio.h>
const char *reftable_error_str(int err)
{
static char buf[250];
switch (err) {
case REFTABLE_IO_ERROR:
return "I/O error";
case REFTABLE_FORMAT_ERROR:
return "corrupt reftable file";
case REFTABLE_NOT_EXIST_ERROR:
return "file does not exist";
case REFTABLE_LOCK_ERROR:
return "data is outdated";
case REFTABLE_API_ERROR:
return "misuse of the reftable API";
case REFTABLE_ZLIB_ERROR:
return "zlib failure";
case REFTABLE_NAME_CONFLICT:
return "file/directory conflict";
case REFTABLE_EMPTY_TABLE_ERROR:
return "wrote empty table";
case REFTABLE_REFNAME_ERROR:
return "invalid refname";
case -1:
return "general error";
default:
snprintf(buf, sizeof(buf), "unknown error code %d", err);
return buf;
}
}

62
reftable/reftable-error.h Normal file
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/*
Copyright 2020 Google LLC
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file or at
https://developers.google.com/open-source/licenses/bsd
*/
#ifndef REFTABLE_ERROR_H
#define REFTABLE_ERROR_H
/*
* Errors in reftable calls are signaled with negative integer return values. 0
* means success.
*/
enum reftable_error {
/* Unexpected file system behavior */
REFTABLE_IO_ERROR = -2,
/* Format inconsistency on reading data */
REFTABLE_FORMAT_ERROR = -3,
/* File does not exist. Returned from block_source_from_file(), because
* it needs special handling in stack.
*/
REFTABLE_NOT_EXIST_ERROR = -4,
/* Trying to write out-of-date data. */
REFTABLE_LOCK_ERROR = -5,
/* Misuse of the API:
* - on writing a record with NULL refname.
* - on writing a reftable_ref_record outside the table limits
* - on writing a ref or log record before the stack's
* next_update_inde*x
* - on writing a log record with multiline message with
* exact_log_message unset
* - on reading a reftable_ref_record from log iterator, or vice versa.
*
* When a call misuses the API, the internal state of the library is
* kept unchanged.
*/
REFTABLE_API_ERROR = -6,
/* Decompression error */
REFTABLE_ZLIB_ERROR = -7,
/* Wrote a table without blocks. */
REFTABLE_EMPTY_TABLE_ERROR = -8,
/* Dir/file conflict. */
REFTABLE_NAME_CONFLICT = -9,
/* Invalid ref name. */
REFTABLE_REFNAME_ERROR = -10,
};
/* convert the numeric error code to a string. The string should not be
* deallocated. */
const char *reftable_error_str(int err);
#endif