138 lines
3.8 KiB
C
138 lines
3.8 KiB
C
/*-------------------------------------------------------------------------
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*
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* percentrepl.c
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* Common routines to replace percent placeholders in strings
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*
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* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* src/common/percentrepl.c
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef FRONTEND
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#include "postgres.h"
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#else
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#include "postgres_fe.h"
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#include "common/logging.h"
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#endif
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#include "common/percentrepl.h"
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#include "lib/stringinfo.h"
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/*
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* replace_percent_placeholders
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*
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* Replace percent-letter placeholders in input string with the supplied
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* values. For example, to replace %f with foo and %b with bar, call
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*
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* replace_percent_placeholders(instr, "param_name", "bf", bar, foo);
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*
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* The return value is palloc'd.
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*
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* "%%" is replaced by a single "%".
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*
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* This throws an error for an unsupported placeholder or a "%" at the end of
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* the input string.
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*
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* A value may be NULL. If the corresponding placeholder is found in the
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* input string, it will be treated as if an unsupported placeholder was used.
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* This allows callers to share a "letters" specification but vary the
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* actually supported placeholders at run time.
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*
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* This functions is meant for cases where all the values are readily
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* available or cheap to compute and most invocations will use most values
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* (for example for archive_command). Also, it requires that all values are
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* strings. It won't be a good match for things like log prefixes or prompts
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* that use a mix of data types and any invocation will only use a few of the
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* possible values.
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*
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* param_name is the name of the underlying GUC parameter, for error
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* reporting. At the moment, this function is only used for GUC parameters.
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* If other kinds of uses were added, the error reporting would need to be
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* revised.
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*/
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char *
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replace_percent_placeholders(const char *instr, const char *param_name, const char *letters,...)
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{
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StringInfoData result;
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initStringInfo(&result);
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for (const char *sp = instr; *sp; sp++)
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{
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if (*sp == '%')
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{
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if (sp[1] == '%')
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{
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/* Convert %% to a single % */
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sp++;
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appendStringInfoChar(&result, *sp);
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}
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else if (sp[1] == '\0')
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{
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/* Incomplete escape sequence, expected a character afterward */
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#ifdef FRONTEND
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pg_log_error("invalid value for parameter \"%s\": \"%s\"", param_name, instr);
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pg_log_error_detail("String ends unexpectedly after escape character \"%%\".");
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exit(1);
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#else
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ereport(ERROR,
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errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("invalid value for parameter \"%s\": \"%s\"", param_name, instr),
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errdetail("String ends unexpectedly after escape character \"%%\"."));
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#endif
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}
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else
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{
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/* Look up placeholder character */
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bool found = false;
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va_list ap;
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sp++;
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va_start(ap, letters);
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for (const char *lp = letters; *lp; lp++)
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{
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char *val = va_arg(ap, char *);
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if (*sp == *lp)
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{
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if (val)
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{
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appendStringInfoString(&result, val);
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found = true;
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}
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/* If val is NULL, we will report an error. */
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break;
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}
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}
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va_end(ap);
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if (!found)
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{
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/* Unknown placeholder */
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#ifdef FRONTEND
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pg_log_error("invalid value for parameter \"%s\": \"%s\"", param_name, instr);
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pg_log_error_detail("String contains unexpected placeholder \"%%%c\".", *sp);
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exit(1);
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#else
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ereport(ERROR,
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errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("invalid value for parameter \"%s\": \"%s\"", param_name, instr),
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errdetail("String contains unexpected placeholder \"%%%c\".", *sp));
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#endif
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}
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}
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}
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else
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{
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appendStringInfoChar(&result, *sp);
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}
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}
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return result.data;
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}
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