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Support pg_read_[binary_]file (filename, missing_ok).

Browse Source 
There wasn't an especially nice way to read all of a file while
passing missing_ok = true.  Add an additional overloaded variant
to support that use-case.

While here, refactor the C code to avoid a rats-nest of PG_NARGS
checks, instead handling the argument collection in the outer
wrapper functions.  It's a bit longer this way, but far more
straightforward.

(Upon looking at the code coverage report for genfile.c, I was
impelled to also add a test case for pg_stat_file() -- tgl)

Kyotaro Horiguchi

Discussion: https://postgr.es/m/20220607.160520.1984541900138970018.horikyota.ntt@gmail.com
This commit is contained in:
Tom Lane
2022-07-29 15:38:49 -04:00
parent fd96d14d95
commit 283129e325
7 changed files with 254 additions and 72 deletions
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200
src/backend/utils/adt/genfile.c
View File

@ -278,81 +278,50 @@ pg_read_file(PG_FUNCTION_ARGS)
*
* No superuser check done here- instead privileges are handled by the
* GRANT system.
*
* If read_to_eof is true, bytes_to_read must be -1, otherwise negative values
* are not allowed for bytes_to_read.
*/
Datum
pg_read_file_v2(PG_FUNCTION_ARGS)
static text *
pg_read_file_common(text *filename_t, int64 seek_offset, int64 bytes_to_read,
bool read_to_eof, bool missing_ok)
{
text *filename_t = PG_GETARG_TEXT_PP(0);
int64 seek_offset = 0;
int64 bytes_to_read = -1;
bool missing_ok = false;
char *filename;
text *result;
if (read_to_eof)
Assert(bytes_to_read == -1);
else if (bytes_to_read < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("requested length cannot be negative")));
/* handle optional arguments */
if (PG_NARGS() >= 3)
{
seek_offset = PG_GETARG_INT64(1);
bytes_to_read = PG_GETARG_INT64(2);
if (bytes_to_read < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("requested length cannot be negative")));
}
if (PG_NARGS() >= 4)
missing_ok = PG_GETARG_BOOL(3);
filename = convert_and_check_filename(filename_t);
result = read_text_file(filename, seek_offset, bytes_to_read, missing_ok);
if (result)
PG_RETURN_TEXT_P(result);
else
PG_RETURN_NULL();
return read_text_file(convert_and_check_filename(filename_t),
seek_offset, bytes_to_read, missing_ok);
}
/*
* Read a section of a file, returning it as bytea
*
* Parameters are interpreted the same as pg_read_file_common().
*/
Datum
pg_read_binary_file(PG_FUNCTION_ARGS)
static bytea *
pg_read_binary_file_common(text *filename_t,
int64 seek_offset, int64 bytes_to_read,
bool read_to_eof, bool missing_ok)
{
text *filename_t = PG_GETARG_TEXT_PP(0);
int64 seek_offset = 0;
int64 bytes_to_read = -1;
bool missing_ok = false;
char *filename;
bytea *result;
if (read_to_eof)
Assert(bytes_to_read == -1);
else if (bytes_to_read < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("requested length cannot be negative")));
/* handle optional arguments */
if (PG_NARGS() >= 3)
{
seek_offset = PG_GETARG_INT64(1);
bytes_to_read = PG_GETARG_INT64(2);
if (bytes_to_read < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("requested length cannot be negative")));
}
if (PG_NARGS() >= 4)
missing_ok = PG_GETARG_BOOL(3);
filename = convert_and_check_filename(filename_t);
result = read_binary_file(filename, seek_offset,
bytes_to_read, missing_ok);
if (result)
PG_RETURN_BYTEA_P(result);
else
PG_RETURN_NULL();
return read_binary_file(convert_and_check_filename(filename_t),
seek_offset, bytes_to_read, missing_ok);
}
/*
* Wrapper functions for the 1 and 3 argument variants of pg_read_file_v2()
* and pg_read_binary_file().
* Wrapper functions for the variants of SQL functions pg_read_file() and
* pg_read_binary_file().
*
* These are necessary to pass the sanity check in opr_sanity, which checks
* that all built-in functions that share the implementing C function take
@ -361,25 +330,126 @@ pg_read_binary_file(PG_FUNCTION_ARGS)
Datum
pg_read_file_off_len(PG_FUNCTION_ARGS)
{
return pg_read_file_v2(fcinfo);
text *filename_t = PG_GETARG_TEXT_PP(0);
int64 seek_offset = PG_GETARG_INT64(1);
int64 bytes_to_read = PG_GETARG_INT64(2);
text *ret;
ret = pg_read_file_common(filename_t, seek_offset, bytes_to_read,
false, false);
if (!ret)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(ret);
}
Datum
pg_read_file_off_len_missing(PG_FUNCTION_ARGS)
{
text *filename_t = PG_GETARG_TEXT_PP(0);
int64 seek_offset = PG_GETARG_INT64(1);
int64 bytes_to_read = PG_GETARG_INT64(2);
bool missing_ok = PG_GETARG_BOOL(3);
text *ret;
ret = pg_read_file_common(filename_t, seek_offset, bytes_to_read,
false, missing_ok);
if (!ret)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(ret);
}
Datum
pg_read_file_all(PG_FUNCTION_ARGS)
{
return pg_read_file_v2(fcinfo);
text *filename_t = PG_GETARG_TEXT_PP(0);
text *ret;
ret = pg_read_file_common(filename_t, 0, -1, true, false);
if (!ret)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(ret);
}
Datum
pg_read_file_all_missing(PG_FUNCTION_ARGS)
{
text *filename_t = PG_GETARG_TEXT_PP(0);
bool missing_ok = PG_GETARG_BOOL(1);
text *ret;
ret = pg_read_file_common(filename_t, 0, -1, true, missing_ok);
if (!ret)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(ret);
}
Datum
pg_read_binary_file_off_len(PG_FUNCTION_ARGS)
{
return pg_read_binary_file(fcinfo);
text *filename_t = PG_GETARG_TEXT_PP(0);
int64 seek_offset = PG_GETARG_INT64(1);
int64 bytes_to_read = PG_GETARG_INT64(2);
text *ret;
ret = pg_read_binary_file_common(filename_t, seek_offset, bytes_to_read,
false, false);
if (!ret)
PG_RETURN_NULL();
PG_RETURN_BYTEA_P(ret);
}
Datum
pg_read_binary_file_off_len_missing(PG_FUNCTION_ARGS)
{
text *filename_t = PG_GETARG_TEXT_PP(0);
int64 seek_offset = PG_GETARG_INT64(1);
int64 bytes_to_read = PG_GETARG_INT64(2);
bool missing_ok = PG_GETARG_BOOL(3);
text *ret;
ret = pg_read_binary_file_common(filename_t, seek_offset, bytes_to_read,
false, missing_ok);
if (!ret)
PG_RETURN_NULL();
PG_RETURN_BYTEA_P(ret);
}
Datum
pg_read_binary_file_all(PG_FUNCTION_ARGS)
{
return pg_read_binary_file(fcinfo);
text *filename_t = PG_GETARG_TEXT_PP(0);
text *ret;
ret = pg_read_binary_file_common(filename_t, 0, -1, true, false);
if (!ret)
PG_RETURN_NULL();
PG_RETURN_BYTEA_P(ret);
}
Datum
pg_read_binary_file_all_missing(PG_FUNCTION_ARGS)
{
text *filename_t = PG_GETARG_TEXT_PP(0);
bool missing_ok = PG_GETARG_BOOL(1);
text *ret;
ret = pg_read_binary_file_common(filename_t, 0, -1, true, missing_ok);
if (!ret)
PG_RETURN_NULL();
PG_RETURN_BYTEA_P(ret);
}
/*