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|
/*-------------------------------------------------------------------------
*
* percentrepl.c
* Common routines to replace percent placeholders in strings
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/common/percentrepl.c
*
*-------------------------------------------------------------------------
*/
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#include "common/logging.h"
#endif
#include "common/percentrepl.h"
#include "lib/stringinfo.h"
/*
* replace_percent_placeholders
*
* Replace percent-letter placeholders in input string with the supplied
* values. For example, to replace %f with foo and %b with bar, call
*
* replace_percent_placeholders(instr, "param_name", "bf", bar, foo);
*
* The return value is palloc'd.
*
* "%%" is replaced by a single "%".
*
* This throws an error for an unsupported placeholder or a "%" at the end of
* the input string.
*
* A value may be NULL. If the corresponding placeholder is found in the
* input string, it will be treated as if an unsupported placeholder was used.
* This allows callers to share a "letters" specification but vary the
* actually supported placeholders at run time.
*
* This functions is meant for cases where all the values are readily
* available or cheap to compute and most invocations will use most values
* (for example for archive_command). Also, it requires that all values are
* strings. It won't be a good match for things like log prefixes or prompts
* that use a mix of data types and any invocation will only use a few of the
* possible values.
*
* param_name is the name of the underlying GUC parameter, for error
* reporting. At the moment, this function is only used for GUC parameters.
* If other kinds of uses were added, the error reporting would need to be
* revised.
*/
char *
replace_percent_placeholders(const char *instr, const char *param_name, const char *letters,...)
{
StringInfoData result;
initStringInfo(&result);
for (const char *sp = instr; *sp; sp++)
{
if (*sp == '%')
{
if (sp[1] == '%')
{
/* Convert %% to a single % */
sp++;
appendStringInfoChar(&result, *sp);
}
else if (sp[1] == '\0')
{
/* Incomplete escape sequence, expected a character afterward */
#ifdef FRONTEND
pg_log_error("invalid value for parameter \"%s\": \"%s\"", param_name, instr);
pg_log_error_detail("String ends unexpectedly after escape character \"%%\".");
exit(1);
#else
ereport(ERROR,
errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid value for parameter \"%s\": \"%s\"", param_name, instr),
errdetail("String ends unexpectedly after escape character \"%%\"."));
#endif
}
else
{
/* Look up placeholder character */
bool found = false;
va_list ap;
sp++;
va_start(ap, letters);
for (const char *lp = letters; *lp; lp++)
{
char *val = va_arg(ap, char *);
if (*sp == *lp)
{
if (val)
{
appendStringInfoString(&result, val);
found = true;
}
/* If val is NULL, we will report an error. */
break;
}
}
va_end(ap);
if (!found)
{
/* Unknown placeholder */
#ifdef FRONTEND
pg_log_error("invalid value for parameter \"%s\": \"%s\"", param_name, instr);
pg_log_error_detail("String contains unexpected placeholder \"%%%c\".", *sp);
exit(1);
#else
ereport(ERROR,
errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid value for parameter \"%s\": \"%s\"", param_name, instr),
errdetail("String contains unexpected placeholder \"%%%c\".", *sp));
#endif
}
}
}
else
{
appendStringInfoChar(&result, *sp);
}
}
return result.data;
}
|
