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Prepare pg_dump internals for additional compression methods

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Commit bf9aa490db introduced a compression API in compress_io.{c,h} to
make reuse easier, and allow adding more compression algorithms.
However, pg_backup_archiver.c was not switched to this API and continued
to call the compression directly.

This commit teaches pg_backup_archiver.c about the compression API, so
that it can benefit from bf9aa490db (simpler code, easier addition of
new compression methods).

Author: Georgios Kokolatos
Reviewed-by: Michael Paquier, Rachel Heaton, Justin Pryzby, Tomas Vondra
Discussion: https://postgr.es/m/faUNEOpts9vunEaLnmxmG-DldLSg_ql137OC3JYDmgrOMHm1RvvWY2IdBkv_CRxm5spCCb_OmKNk2T03TMm0fBEWveFF9wA1WizPuAgB7Ss%3D%40protonmail.com
This commit is contained in:
Tomas Vondra
2023-02-23 15:38:14 +01:00
parent 009eeee746
commit 03d02f54a6
4 changed files with 139 additions and 129 deletions
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97
src/bin/pg_dump/compress_io.c
View File

@@ -56,6 +56,41 @@
#include "compress_io.h"
#include "pg_backup_utils.h"
#ifdef HAVE_LIBZ
#include <zlib.h>
#endif
/*----------------------
* Generic functions
*----------------------
*/
/*
* Checks whether a compression algorithm is supported.
*
* On success returns NULL, otherwise returns a malloc'ed string which can be
* used by the caller in an error message.
*/
char *
supports_compression(const pg_compress_specification compression_spec)
{
const pg_compress_algorithm algorithm = compression_spec.algorithm;
bool supported = false;
if (algorithm == PG_COMPRESSION_NONE)
supported = true;
#ifdef HAVE_LIBZ
if (algorithm == PG_COMPRESSION_GZIP)
supported = true;
#endif
if (!supported)
return psprintf("this build does not support compression with %s",
get_compress_algorithm_name(algorithm));
return NULL;
}
/*----------------------
* Compressor API
*----------------------
@@ -490,16 +525,19 @@ cfopen_write(const char *path, const char *mode,
}
/*
* Opens file 'path' in 'mode'. If compression is GZIP, the file
* is opened with libz gzopen(), otherwise with plain fopen().
* This is the workhorse for cfopen() or cfdopen(). It opens file 'path' or
* associates a stream 'fd', if 'fd' is a valid descriptor, in 'mode'. The
* descriptor is not dup'ed and it is the caller's responsibility to do so.
* The caller must verify that the 'compress_algorithm' is supported by the
* current build.
*
* On failure, return NULL with an error code in errno.
*/
cfp *
cfopen(const char *path, const char *mode,
const pg_compress_specification compression_spec)
static cfp *
cfopen_internal(const char *path, int fd, const char *mode,
pg_compress_specification compression_spec)
{
cfp *fp = pg_malloc(sizeof(cfp));
cfp *fp = pg_malloc0(sizeof(cfp));
if (compression_spec.algorithm == PG_COMPRESSION_GZIP)
{
@@ -511,15 +549,20 @@ cfopen(const char *path, const char *mode,
snprintf(mode_compression, sizeof(mode_compression), "%s%d",
mode, compression_spec.level);
fp->compressedfp = gzopen(path, mode_compression);
if (fd >= 0)
fp->compressedfp = gzdopen(fd, mode_compression);
else
fp->compressedfp = gzopen(path, mode_compression);
}
else
{
/* don't specify a level, just use the zlib default */
fp->compressedfp = gzopen(path, mode);
if (fd >= 0)
fp->compressedfp = gzdopen(fd, mode);
else
fp->compressedfp = gzopen(path, mode);
}
fp->uncompressedfp = NULL;
if (fp->compressedfp == NULL)
{
free_keep_errno(fp);
@@ -531,10 +574,11 @@ cfopen(const char *path, const char *mode,
}
else
{
#ifdef HAVE_LIBZ
fp->compressedfp = NULL;
#endif
fp->uncompressedfp = fopen(path, mode);
if (fd >= 0)
fp->uncompressedfp = fdopen(fd, mode);
else
fp->uncompressedfp = fopen(path, mode);
if (fp->uncompressedfp == NULL)
{
free_keep_errno(fp);
@@ -545,6 +589,33 @@ cfopen(const char *path, const char *mode,
return fp;
}
/*
* Opens file 'path' in 'mode' and compression as defined in
* compression_spec. The caller must verify that the compression
* is supported by the current build.
*
* On failure, return NULL with an error code in errno.
*/
cfp *
cfopen(const char *path, const char *mode,
const pg_compress_specification compression_spec)
{
return cfopen_internal(path, -1, mode, compression_spec);
}
/*
* Associates a stream 'fd', if 'fd' is a valid descriptor, in 'mode'
* and compression as defined in compression_spec. The caller must
* verify that the compression is supported by the current build.
*
* On failure, return NULL with an error code in errno.
*/
cfp *
cfdopen(int fd, const char *mode,
const pg_compress_specification compression_spec)
{
return cfopen_internal(NULL, fd, mode, compression_spec);
}
int
cfread(void *ptr, int size, cfp *fp)