greenplumn string_utils 源码
greenplumn string_utils 代码
文件路径：/src/fe_utils/string_utils.c
/*-------------------------------------------------------------------------
*
* String-processing utility routines for frontend code
*
* Assorted utility functions that are useful in constructing SQL queries
* and interpreting backend output.
*
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/fe_utils/string_utils.c
*
*-------------------------------------------------------------------------
*/
#include "postgres_fe.h"
#include <ctype.h>
#include "fe_utils/string_utils.h"
#include "common/keywords.h"
static PQExpBuffer defaultGetLocalPQExpBuffer(void);
/* Globals exported by this file */
int quote_all_identifiers = 0;
PQExpBuffer (*getLocalPQExpBuffer) (void) = defaultGetLocalPQExpBuffer;
/*
* Returns a temporary PQExpBuffer, valid until the next call to the function.
* This is used by fmtId and fmtQualifiedId.
*
* Non-reentrant and non-thread-safe but reduces memory leakage. You can
* replace this with a custom version by setting the getLocalPQExpBuffer
* function pointer.
*/
static PQExpBuffer
defaultGetLocalPQExpBuffer(void)
{
static PQExpBuffer id_return = NULL;
if (id_return) /* first time through? */
{
/* same buffer, just wipe contents */
resetPQExpBuffer(id_return);
}
else
{
/* new buffer */
id_return = createPQExpBuffer();
}
return id_return;
}
/*
* Quotes input string if it's not a legitimate SQL identifier as-is.
*
* Note that the returned string must be used before calling fmtId again,
* since we re-use the same return buffer each time.
*/
const char *
fmtId(const char *rawid)
{
PQExpBuffer id_return = getLocalPQExpBuffer();
const char *cp;
bool need_quotes = false;
/*
* These checks need to match the identifier production in scan.l. Don't
* use islower() etc.
*/
if (quote_all_identifiers)
need_quotes = true;
/* slightly different rules for first character */
else if (!((rawid[0] >= 'a' && rawid[0] <= 'z') || rawid[0] == '_'))
need_quotes = true;
else
{
/* otherwise check the entire string */
for (cp = rawid; *cp; cp++)
{
if (!((*cp >= 'a' && *cp <= 'z')
|| (*cp >= '0' && *cp <= '9')
|| (*cp == '_')))
{
need_quotes = true;
break;
}
}
}
if (!need_quotes)
{
/*
* Check for keyword. We quote keywords except for unreserved ones.
* (In some cases we could avoid quoting a col_name or type_func_name
* keyword, but it seems much harder than it's worth to tell that.)
*
* Note: ScanKeywordLookup() does case-insensitive comparison, but
* that's fine, since we already know we have all-lower-case.
*/
int kwnum = ScanKeywordLookup(rawid, &ScanKeywords);
if (kwnum >= 0 && ScanKeywordCategories[kwnum] != UNRESERVED_KEYWORD)
need_quotes = true;
}
if (!need_quotes)
{
/* no quoting needed */
appendPQExpBufferStr(id_return, rawid);
}
else
{
appendPQExpBufferChar(id_return, '"');
for (cp = rawid; *cp; cp++)
{
/*
* Did we find a double-quote in the string? Then make this a
* double double-quote per SQL99. Before, we put in a
* backslash/double-quote pair. - thomas 2000-08-05
*/
if (*cp == '"')
appendPQExpBufferChar(id_return, '"');
appendPQExpBufferChar(id_return, *cp);
}
appendPQExpBufferChar(id_return, '"');
}
return id_return->data;
}
/*
* fmtQualifiedId - construct a schema-qualified name, with quoting as needed.
*
* Like fmtId, use the result before calling again.
*
* Since we call fmtId and it also uses getLocalPQExpBuffer() we cannot
* use that buffer until we're finished with calling fmtId().
*/
const char *
fmtQualifiedId(const char *schema, const char *id)
{
PQExpBuffer id_return;
PQExpBuffer lcl_pqexp = createPQExpBuffer();
/* Some callers might fail to provide a schema name */
if (schema && *schema)
{
appendPQExpBuffer(lcl_pqexp, "%s.", fmtId(schema));
}
appendPQExpBufferStr(lcl_pqexp, fmtId(id));
id_return = getLocalPQExpBuffer();
appendPQExpBufferStr(id_return, lcl_pqexp->data);
destroyPQExpBuffer(lcl_pqexp);
return id_return->data;
}
/*
* Format a Postgres version number (in the PG_VERSION_NUM integer format
* returned by PQserverVersion()) as a string. This exists mainly to
* encapsulate knowledge about two-part vs. three-part version numbers.
*
* For reentrancy, caller must supply the buffer the string is put in.
* Recommended size of the buffer is 32 bytes.
*
* Returns address of 'buf', as a notational convenience.
*/
char *
formatPGVersionNumber(int version_number, bool include_minor,
char *buf, size_t buflen)
{
if (version_number >= 100000)
{
/* New two-part style */
if (include_minor)
snprintf(buf, buflen, "%d.%d", version_number / 10000,
version_number % 10000);
else
snprintf(buf, buflen, "%d", version_number / 10000);
}
else
{
/* Old three-part style */
if (include_minor)
snprintf(buf, buflen, "%d.%d.%d", version_number / 10000,
(version_number / 100) % 100,
version_number % 100);
else
snprintf(buf, buflen, "%d.%d", version_number / 10000,
(version_number / 100) % 100);
}
return buf;
}
/*
* Convert a string value to an SQL string literal and append it to
* the given buffer. We assume the specified client_encoding and
* standard_conforming_strings settings.
*
* This is essentially equivalent to libpq's PQescapeStringInternal,
* except for the output buffer structure. We need it in situations
* where we do not have a PGconn available. Where we do,
* appendStringLiteralConn is a better choice.
*/
void
appendStringLiteral(PQExpBuffer buf, const char *str,
int encoding, bool std_strings)
{
size_t length = strlen(str);
const char *source = str;
char *target;
if (!enlargePQExpBuffer(buf, 2 * length + 2))
return;
target = buf->data + buf->len;
*target++ = '\'';
while (*source != '\0')
{
char c = *source;
int len;
int i;
/* Fast path for plain ASCII */
if (!IS_HIGHBIT_SET(c))
{
/* Apply quoting if needed */
if (SQL_STR_DOUBLE(c, !std_strings))
*target++ = c;
/* Copy the character */
*target++ = c;
source++;
continue;
}
/* Slow path for possible multibyte characters */
len = PQmblen(source, encoding);
/* Copy the character */
for (i = 0; i < len; i++)
{
if (*source == '\0')
break;
*target++ = *source++;
}
/*
* If we hit premature end of string (ie, incomplete multibyte
* character), try to pad out to the correct length with spaces. We
* may not be able to pad completely, but we will always be able to
* insert at least one pad space (since we'd not have quoted a
* multibyte character). This should be enough to make a string that
* the server will error out on.
*/
if (i < len)
{
char *stop = buf->data + buf->maxlen - 2;
for (; i < len; i++)
{
if (target >= stop)
break;
*target++ = ' ';
}
break;
}
}
/* Write the terminating quote and NUL character. */
*target++ = '\'';
*target = '\0';
buf->len = target - buf->data;
}
/*
* Convert a string value to an SQL string literal and append it to
* the given buffer. Encoding and string syntax rules are as indicated
* by current settings of the PGconn.
*/
void
appendStringLiteralConn(PQExpBuffer buf, const char *str, PGconn *conn)
{
size_t length = strlen(str);
/*
* XXX This is a kluge to silence escape_string_warning in our utility
* programs. It should go away someday.
*/
if (strchr(str, '\\') != NULL && PQserverVersion(conn) >= 80100)
{
/* ensure we are not adjacent to an identifier */
if (buf->len > 0 && buf->data[buf->len - 1] != ' ')
appendPQExpBufferChar(buf, ' ');
appendPQExpBufferChar(buf, ESCAPE_STRING_SYNTAX);
appendStringLiteral(buf, str, PQclientEncoding(conn), false);
return;
}
/* XXX end kluge */
if (!enlargePQExpBuffer(buf, 2 * length + 2))
return;
appendPQExpBufferChar(buf, '\'');
buf->len += PQescapeStringConn(conn, buf->data + buf->len,
str, length, NULL);
appendPQExpBufferChar(buf, '\'');
}
/*
* Convert a string value to a dollar quoted literal and append it to
* the given buffer. If the dqprefix parameter is not NULL then the
* dollar quote delimiter will begin with that (after the opening $).
*
* No escaping is done at all on str, in compliance with the rules
* for parsing dollar quoted strings. Also, we need not worry about
* encoding issues.
*/
void
appendStringLiteralDQ(PQExpBuffer buf, const char *str, const char *dqprefix)
{
static const char suffixes[] = "_XXXXXXX";
int nextchar = 0;
PQExpBuffer delimBuf = createPQExpBuffer();
/* start with $ + dqprefix if not NULL */
appendPQExpBufferChar(delimBuf, '$');
if (dqprefix)
appendPQExpBufferStr(delimBuf, dqprefix);
/*
* Make sure we choose a delimiter which (without the trailing $) is not
* present in the string being quoted. We don't check with the trailing $
* because a string ending in $foo must not be quoted with $foo$.
*/
while (strstr(str, delimBuf->data) != NULL)
{
appendPQExpBufferChar(delimBuf, suffixes[nextchar++]);
nextchar %= sizeof(suffixes) - 1;
}
/* add trailing $ */
appendPQExpBufferChar(delimBuf, '$');
/* quote it and we are all done */
appendPQExpBufferStr(buf, delimBuf->data);
appendPQExpBufferStr(buf, str);
appendPQExpBufferStr(buf, delimBuf->data);
destroyPQExpBuffer(delimBuf);
}
/*
* Convert a bytea value (presented as raw bytes) to an SQL string literal
* and append it to the given buffer. We assume the specified
* standard_conforming_strings setting.
*
* This is needed in situations where we do not have a PGconn available.
* Where we do, PQescapeByteaConn is a better choice.
*/
void
appendByteaLiteral(PQExpBuffer buf, const unsigned char *str, size_t length,
bool std_strings)
{
const unsigned char *source = str;
char *target;
static const char hextbl[] = "0123456789abcdef";
/*
* This implementation is hard-wired to produce hex-format output. We do
* not know the server version the output will be loaded into, so making
* an intelligent format choice is impossible. It might be better to
* always use the old escaped format.
*/
if (!enlargePQExpBuffer(buf, 2 * length + 5))
return;
target = buf->data + buf->len;
*target++ = '\'';
if (!std_strings)
*target++ = '\\';
*target++ = '\\';
*target++ = 'x';
while (length-- > 0)
{
unsigned char c = *source++;
*target++ = hextbl[(c >> 4) & 0xF];
*target++ = hextbl[c & 0xF];
}
/* Write the terminating quote and NUL character. */
*target++ = '\'';
*target = '\0';
buf->len = target - buf->data;
}
/*
* Append the given string to the shell command being built in the buffer,
* with shell-style quoting as needed to create exactly one argument.
*
* Forbid LF or CR characters, which have scant practical use beyond designing
* security breaches. The Windows command shell is unusable as a conduit for
* arguments containing LF or CR characters. A future major release should
* reject those characters in CREATE ROLE and CREATE DATABASE, because use
* there eventually leads to errors here.
*
* appendShellString() simply prints an error and dies if LF or CR appears.
* appendShellStringNoError() omits those characters from the result, and
* returns false if there were any.
*/
void
appendShellString(PQExpBuffer buf, const char *str)
{
if (!appendShellStringNoError(buf, str))
{
fprintf(stderr,
_("shell command argument contains a newline or carriage return: \"%s\"\n"),
str);
exit(EXIT_FAILURE);
}
}
bool
appendShellStringNoError(PQExpBuffer buf, const char *str)
{
#ifdef WIN32
int backslash_run_length = 0;
#endif
bool ok = true;
const char *p;
/*
* Don't bother with adding quotes if the string is nonempty and clearly
* contains only safe characters.
*/
if (*str != '\0' &&
strspn(str, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_./:") == strlen(str))
{
appendPQExpBufferStr(buf, str);
return ok;
}
#ifndef WIN32
appendPQExpBufferChar(buf, '\'');
for (p = str; *p; p++)
{
if (*p == '\n' || *p == '\r')
{
ok = false;
continue;
}
if (*p == '\'')
appendPQExpBufferStr(buf, "'\"'\"'");
else
appendPQExpBufferChar(buf, *p);
}
appendPQExpBufferChar(buf, '\'');
#else /* WIN32 */
/*
* A Windows system() argument experiences two layers of interpretation.
* First, cmd.exe interprets the string. Its behavior is undocumented,
* but a caret escapes any byte except LF or CR that would otherwise have
* special meaning. Handling of a caret before LF or CR differs between
* "cmd.exe /c" and other modes, and it is unusable here.
*
* Second, the new process parses its command line to construct argv (see
* https://msdn.microsoft.com/en-us/library/17w5ykft.aspx). This treats
* backslash-double quote sequences specially.
*/
appendPQExpBufferStr(buf, "^\"");
for (p = str; *p; p++)
{
if (*p == '\n' || *p == '\r')
{
ok = false;
continue;
}
/* Change N backslashes before a double quote to 2N+1 backslashes. */
if (*p == '"')
{
while (backslash_run_length)
{
appendPQExpBufferStr(buf, "^\\");
backslash_run_length--;
}
appendPQExpBufferStr(buf, "^\\");
}
else if (*p == '\\')
backslash_run_length++;
else
backslash_run_length = 0;
/*
* Decline to caret-escape the most mundane characters, to ease
* debugging and lest we approach the command length limit.
*/
if (!((*p >= 'a' && *p <= 'z') ||
(*p >= 'A' && *p <= 'Z') ||
(*p >= '0' && *p <= '9')))
appendPQExpBufferChar(buf, '^');
appendPQExpBufferChar(buf, *p);
}
/*
* Change N backslashes at end of argument to 2N backslashes, because they
* precede the double quote that terminates the argument.
*/
while (backslash_run_length)
{
appendPQExpBufferStr(buf, "^\\");
backslash_run_length--;
}
appendPQExpBufferStr(buf, "^\"");
#endif /* WIN32 */
return ok;
}
/*
* Append the given string to the buffer, with suitable quoting for passing
* the string as a value in a keyword/value pair in a libpq connection string.
*/
void
appendConnStrVal(PQExpBuffer buf, const char *str)
{
const char *s;
bool needquotes;
/*
* If the string is one or more plain ASCII characters, no need to quote
* it. This is quite conservative, but better safe than sorry.
*/
needquotes = true;
for (s = str; *s; s++)
{
if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
(*s >= '0' && *s <= '9') || *s == '_' || *s == '.'))
{
needquotes = true;
break;
}
needquotes = false;
}
if (needquotes)
{
appendPQExpBufferChar(buf, '\'');
while (*str)
{
/* ' and \ must be escaped by to \' and \\ */
if (*str == '\'' || *str == '\\')
appendPQExpBufferChar(buf, '\\');
appendPQExpBufferChar(buf, *str);
str++;
}
appendPQExpBufferChar(buf, '\'');
}
else
appendPQExpBufferStr(buf, str);
}
/*
* Append a psql meta-command that connects to the given database with the
* then-current connection's user, host and port.
*/
void
appendPsqlMetaConnect(PQExpBuffer buf, const char *dbname)
{
const char *s;
bool complex;
/*
* If the name is plain ASCII characters, emit a trivial "\connect "foo"".
* For other names, even many not technically requiring it, skip to the
* general case. No database has a zero-length name.
*/
complex = false;
for (s = dbname; *s; s++)
{
if (*s == '\n' || *s == '\r')
{
fprintf(stderr,
_("database name contains a newline or carriage return: \"%s\"\n"),
dbname);
exit(EXIT_FAILURE);
}
if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
(*s >= '0' && *s <= '9') || *s == '_' || *s == '.'))
{
complex = true;
}
}
appendPQExpBufferStr(buf, "\\connect ");
if (complex)
{
PQExpBufferData connstr;
initPQExpBuffer(&connstr);
appendPQExpBuffer(&connstr, "dbname=");
appendConnStrVal(&connstr, dbname);
appendPQExpBuffer(buf, "-reuse-previous=on ");
/*
* As long as the name does not contain a newline, SQL identifier
* quoting satisfies the psql meta-command parser. Prefer not to
* involve psql-interpreted single quotes, which behaved differently
* before PostgreSQL 9.2.
*/
appendPQExpBufferStr(buf, fmtId(connstr.data));
termPQExpBuffer(&connstr);
}
else
appendPQExpBufferStr(buf, fmtId(dbname));
appendPQExpBufferChar(buf, '\n');
}
/*
* Deconstruct the text representation of a 1-dimensional Postgres array
* into individual items.
*
* On success, returns true and sets *itemarray and *nitems to describe
* an array of individual strings. On parse failure, returns false;
* *itemarray may exist or be NULL.
*
* NOTE: free'ing itemarray is sufficient to deallocate the working storage.
*/
bool
parsePGArray(const char *atext, char ***itemarray, int *nitems)
{
int inputlen;
char **items;
char *strings;
int curitem;
/*
* We expect input in the form of "{item,item,item}" where any item is
* either raw data, or surrounded by double quotes (in which case embedded
* characters including backslashes and quotes are backslashed).
*
* We build the result as an array of pointers followed by the actual
* string data, all in one malloc block for convenience of deallocation.
* The worst-case storage need is not more than one pointer and one
* character for each input character (consider "{,,,,,,,,,,}").
*/
*itemarray = NULL;
*nitems = 0;
inputlen = strlen(atext);
if (inputlen < 2 || atext[0] != '{' || atext[inputlen - 1] != '}')
return false; /* bad input */
items = (char **) malloc(inputlen * (sizeof(char *) + sizeof(char)));
if (items == NULL)
return false; /* out of memory */
*itemarray = items;
strings = (char *) (items + inputlen);
atext++; /* advance over initial '{' */
curitem = 0;
while (*atext != '}')
{
if (*atext == '\0')
return false; /* premature end of string */
items[curitem] = strings;
while (*atext != '}' && *atext != ',')
{
if (*atext == '\0')
return false; /* premature end of string */
if (*atext != '"')
*strings++ = *atext++; /* copy unquoted data */
else
{
/* process quoted substring */
atext++;
while (*atext != '"')
{
if (*atext == '\0')
return false; /* premature end of string */
if (*atext == '\\')
{
atext++;
if (*atext == '\0')
return false; /* premature end of string */
}
*strings++ = *atext++; /* copy quoted data */
}
atext++;
}
}
*strings++ = '\0';
if (*atext == ',')
atext++;
curitem++;
}
if (atext[1] != '\0')
return false; /* bogus syntax (embedded '}') */
*nitems = curitem;
return true;
}
/*
* Append one element to the text representation of a 1-dimensional Postgres
* array.
*
* The caller must provide the initial '{' and closing '}' of the array.
* This function handles all else, including insertion of commas and
* quoting of values.
*
* We assume that typdelim is ','.
*/
void
appendPGArray(PQExpBuffer buffer, const char *value)
{
bool needquote;
const char *tmp;
if (buffer->data[buffer->len - 1] != '{')
appendPQExpBufferChar(buffer, ',');
/* Decide if we need quotes; this should match array_out()'s choices. */
if (value[0] == '\0')
needquote = true; /* force quotes for empty string */
else if (pg_strcasecmp(value, "NULL") == 0)
needquote = true; /* force quotes for literal NULL */
else
needquote = false;
if (!needquote)
{
for (tmp = value; *tmp; tmp++)
{
char ch = *tmp;
if (ch == '"' || ch == '\\' ||
ch == '{' || ch == '}' || ch == ',' ||
/* these match array_isspace(): */
ch == ' ' || ch == '\t' || ch == '\n' ||
ch == '\r' || ch == '\v' || ch == '\f')
{
needquote = true;
break;
}
}
}
if (needquote)
{
appendPQExpBufferChar(buffer, '"');
for (tmp = value; *tmp; tmp++)
{
char ch = *tmp;
if (ch == '"' || ch == '\\')
appendPQExpBufferChar(buffer, '\\');
appendPQExpBufferChar(buffer, ch);
}
appendPQExpBufferChar(buffer, '"');
}
else
appendPQExpBufferStr(buffer, value);
}
/*
* Format a reloptions array and append it to the given buffer.
*
* "prefix" is prepended to the option names; typically it's "" or "toast.".
*
* Returns false if the reloptions array could not be parsed (in which case
* nothing will have been appended to the buffer), or true on success.
*
* Note: this logic should generally match the backend's flatten_reloptions()
* (in adt/ruleutils.c).
*/
bool
appendReloptionsArray(PQExpBuffer buffer, const char *reloptions,
const char *prefix, int encoding, bool std_strings)
{
char **options;
int noptions;
int i;
if (!parsePGArray(reloptions, &options, &noptions))
{
if (options)
free(options);
return false;
}
for (i = 0; i < noptions; i++)
{
char *option = options[i];
char *name;
char *separator;
char *value;
/*
* Each array element should have the form name=value. If the "=" is
* missing for some reason, treat it like an empty value.
*/
name = option;
separator = strchr(option, '=');
if (separator)
{
*separator = '\0';
value = separator + 1;
}
else
value = "";
if (i > 0)
appendPQExpBufferStr(buffer, ", ");
appendPQExpBuffer(buffer, "%s%s=", prefix, fmtId(name));
/*
* In general we need to quote the value; but to avoid unnecessary
* clutter, do not quote if it is an identifier that would not need
* quoting. (We could also allow numbers, but that is a bit trickier
* than it looks --- for example, are leading zeroes significant? We
* don't want to assume very much here about what custom reloptions
* might mean.)
*/
if (strcmp(fmtId(value), value) == 0)
appendPQExpBufferStr(buffer, value);
else
appendStringLiteral(buffer, value, encoding, std_strings);
}
if (options)
free(options);
return true;
}
/*
* processSQLNamePattern
*
* Scan a wildcard-pattern string and generate appropriate WHERE clauses
* to limit the set of objects returned. The WHERE clauses are appended
* to the already-partially-constructed query in buf. Returns whether
* any clause was added.
*
* conn: connection query will be sent to (consulted for escaping rules).
* buf: output parameter.
* pattern: user-specified pattern option, or NULL if none ("*" is implied).
* have_where: true if caller already emitted "WHERE" (clauses will be ANDed
* onto the existing WHERE clause).
* force_escape: always quote regexp special characters, even outside
* double quotes (else they are quoted only between double quotes).
* schemavar: name of query variable to match against a schema-name pattern.
* Can be NULL if no schema.
* namevar: name of query variable to match against an object-name pattern.
* altnamevar: NULL, or name of an alternative variable to match against name.
* visibilityrule: clause to use if we want to restrict to visible objects
* (for example, "pg_catalog.pg_table_is_visible(p.oid)"). Can be NULL.
*
* Formatting note: the text already present in buf should end with a newline.
* The appended text, if any, will end with one too.
*/
bool
processSQLNamePattern(PGconn *conn, PQExpBuffer buf, const char *pattern,
bool have_where, bool force_escape,
const char *schemavar, const char *namevar,
const char *altnamevar, const char *visibilityrule)
{
PQExpBufferData schemabuf;
PQExpBufferData namebuf;
int encoding = PQclientEncoding(conn);
bool inquotes;
const char *cp;
int i;
bool added_clause = false;
#define WHEREAND() \
(appendPQExpBufferStr(buf, have_where ? " AND " : "WHERE "), \
have_where = true, added_clause = true)
if (pattern == NULL)
{
/* Default: select all visible objects */
if (visibilityrule)
{
WHEREAND();
appendPQExpBuffer(buf, "%s\n", visibilityrule);
}
return added_clause;
}
initPQExpBuffer(&schemabuf);
initPQExpBuffer(&namebuf);
/*
* Parse the pattern, converting quotes and lower-casing unquoted letters.
* Also, adjust shell-style wildcard characters into regexp notation.
*
* We surround the pattern with "^(...)$" to force it to match the whole
* string, as per SQL practice. We have to have parens in case the string
* contains "|", else the "^" and "$" will be bound into the first and
* last alternatives which is not what we want.
*
* Note: the result of this pass is the actual regexp pattern(s) we want
* to execute. Quoting/escaping into SQL literal format will be done
* below using appendStringLiteralConn().
*/
appendPQExpBufferStr(&namebuf, "^(");
inquotes = false;
cp = pattern;
while (*cp)
{
char ch = *cp;
if (ch == '"')
{
if (inquotes && cp[1] == '"')
{
/* emit one quote, stay in inquotes mode */
appendPQExpBufferChar(&namebuf, '"');
cp++;
}
else
inquotes = !inquotes;
cp++;
}
else if (!inquotes && isupper((unsigned char) ch))
{
appendPQExpBufferChar(&namebuf,
pg_tolower((unsigned char) ch));
cp++;
}
else if (!inquotes && ch == '*')
{
appendPQExpBufferStr(&namebuf, ".*");
cp++;
}
else if (!inquotes && ch == '?')
{
appendPQExpBufferChar(&namebuf, '.');
cp++;
}
else if (!inquotes && ch == '.')
{
/* Found schema/name separator, move current pattern to schema */
resetPQExpBuffer(&schemabuf);
appendPQExpBufferStr(&schemabuf, namebuf.data);
resetPQExpBuffer(&namebuf);
appendPQExpBufferStr(&namebuf, "^(");
cp++;
}
else if (ch == '$')
{
/*
* Dollar is always quoted, whether inside quotes or not. The
* reason is that it's allowed in SQL identifiers, so there's a
* significant use-case for treating it literally, while because
* we anchor the pattern automatically there is no use-case for
* having it possess its regexp meaning.
*/
appendPQExpBufferStr(&namebuf, "\\$");
cp++;
}
else
{
/*
* Ordinary data character, transfer to pattern
*
* Inside double quotes, or at all times if force_escape is true,
* quote regexp special characters with a backslash to avoid
* regexp errors. Outside quotes, however, let them pass through
* as-is; this lets knowledgeable users build regexp expressions
* that are more powerful than shell-style patterns.
*/
if ((inquotes || force_escape) &&
strchr("|*+?()[]{}.^$\\", ch))
appendPQExpBufferChar(&namebuf, '\\');
i = PQmblen(cp, encoding);
while (i-- && *cp)
{
appendPQExpBufferChar(&namebuf, *cp);
cp++;
}
}
}
/*
* Now decide what we need to emit. We may run under a hostile
* search_path, so qualify EVERY name. Note there will be a leading "^("
* in the patterns in any case.
*
* We want the regex matches to use the database's default collation where
* collation-sensitive behavior is required (for example, which characters
* match '\w'). That happened by default before PG v12, but if the server
* is >= v12 then we need to force it through explicit COLLATE clauses,
* otherwise the "C" collation attached to "name" catalog columns wins.
*/
if (namebuf.len > 2)
{
/* We have a name pattern, so constrain the namevar(s) */
appendPQExpBufferStr(&namebuf, ")$");
/* Optimize away a "*" pattern */
if (strcmp(namebuf.data, "^(.*)$") != 0)
{
WHEREAND();
if (altnamevar)
{
appendPQExpBuffer(buf,
"(%s OPERATOR(pg_catalog.~) ", namevar);
appendStringLiteralConn(buf, namebuf.data, conn);
if (PQserverVersion(conn) >= 120000)
appendPQExpBufferStr(buf, " COLLATE pg_catalog.default");
appendPQExpBuffer(buf,
"\n OR %s OPERATOR(pg_catalog.~) ",
altnamevar);
appendStringLiteralConn(buf, namebuf.data, conn);
if (PQserverVersion(conn) >= 120000)
appendPQExpBufferStr(buf, " COLLATE pg_catalog.default");
appendPQExpBufferStr(buf, ")\n");
}
else
{
appendPQExpBuffer(buf, "%s OPERATOR(pg_catalog.~) ", namevar);
appendStringLiteralConn(buf, namebuf.data, conn);
if (PQserverVersion(conn) >= 120000)
appendPQExpBufferStr(buf, " COLLATE pg_catalog.default");
appendPQExpBufferChar(buf, '\n');
}
}
}
if (schemabuf.len > 2)
{
/* We have a schema pattern, so constrain the schemavar */
appendPQExpBufferStr(&schemabuf, ")$");
/* Optimize away a "*" pattern */
if (strcmp(schemabuf.data, "^(.*)$") != 0 && schemavar)
{
WHEREAND();
appendPQExpBuffer(buf, "%s OPERATOR(pg_catalog.~) ", schemavar);
appendStringLiteralConn(buf, schemabuf.data, conn);
if (PQserverVersion(conn) >= 120000)
appendPQExpBufferStr(buf, " COLLATE pg_catalog.default");
appendPQExpBufferChar(buf, '\n');
}
}
else
{
/* No schema pattern given, so select only visible objects */
if (visibilityrule)
{
WHEREAND();
appendPQExpBuffer(buf, "%s\n", visibilityrule);
}
}
termPQExpBuffer(&schemabuf);
termPQExpBuffer(&namebuf);
return added_clause;
#undef WHEREAND
}
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