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128 lines
3.5 KiB
C
128 lines
3.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* scansup.c
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* scanner support routines used by the core lexer
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*
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* Portions Copyright (c) 1996-2023, 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/backend/parser/scansup.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <ctype.h>
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#include "mb/pg_wchar.h"
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#include "parser/scansup.h"
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/*
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* downcase_truncate_identifier() --- do appropriate downcasing and
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* truncation of an unquoted identifier. Optionally warn of truncation.
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*
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* Returns a palloc'd string containing the adjusted identifier.
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*
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* Note: in some usages the passed string is not null-terminated.
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*
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* Note: the API of this function is designed to allow for downcasing
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* transformations that increase the string length, but we don't yet
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* support that. If you want to implement it, you'll need to fix
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* SplitIdentifierString() in utils/adt/varlena.c.
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*/
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char *
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downcase_truncate_identifier(const char *ident, int len, bool warn)
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{
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return downcase_identifier(ident, len, warn, true);
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}
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/*
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* a workhorse for downcase_truncate_identifier
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*/
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char *
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downcase_identifier(const char *ident, int len, bool warn, bool truncate)
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{
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char *result;
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int i;
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bool enc_is_single_byte;
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result = palloc(len + 1);
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enc_is_single_byte = pg_database_encoding_max_length() == 1;
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/*
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* SQL99 specifies Unicode-aware case normalization, which we don't yet
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* have the infrastructure for. Instead we use tolower() to provide a
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* locale-aware translation. However, there are some locales where this
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* is not right either (eg, Turkish may do strange things with 'i' and
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* 'I'). Our current compromise is to use tolower() for characters with
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* the high bit set, as long as they aren't part of a multi-byte
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* character, and use an ASCII-only downcasing for 7-bit characters.
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*/
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for (i = 0; i < len; i++)
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{
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unsigned char ch = (unsigned char) ident[i];
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if (ch >= 'A' && ch <= 'Z')
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ch += 'a' - 'A';
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else if (enc_is_single_byte && IS_HIGHBIT_SET(ch) && isupper(ch))
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ch = tolower(ch);
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result[i] = (char) ch;
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}
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result[i] = '\0';
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if (i >= NAMEDATALEN && truncate)
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truncate_identifier(result, i, warn);
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return result;
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}
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/*
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* truncate_identifier() --- truncate an identifier to NAMEDATALEN-1 bytes.
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*
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* The given string is modified in-place, if necessary. A warning is
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* issued if requested.
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*
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* We require the caller to pass in the string length since this saves a
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* strlen() call in some common usages.
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*/
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void
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truncate_identifier(char *ident, int len, bool warn)
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{
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if (len >= NAMEDATALEN)
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{
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len = pg_mbcliplen(ident, len, NAMEDATALEN - 1);
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if (warn)
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ereport(NOTICE,
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(errcode(ERRCODE_NAME_TOO_LONG),
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errmsg("identifier \"%s\" will be truncated to \"%.*s\"",
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ident, len, ident)));
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ident[len] = '\0';
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}
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}
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/*
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* scanner_isspace() --- return true if flex scanner considers char whitespace
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*
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* This should be used instead of the potentially locale-dependent isspace()
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* function when it's important to match the lexer's behavior.
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*
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* In principle we might need similar functions for isalnum etc, but for the
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* moment only isspace seems needed.
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*/
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bool
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scanner_isspace(char ch)
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{
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/* This must match scan.l's list of {space} characters */
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if (ch == ' ' ||
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ch == '\t' ||
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ch == '\n' ||
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ch == '\r' ||
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ch == '\f')
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return true;
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return false;
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}
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