/*
* Apply encoding conversion on src and return it. The encoding
* conversion function is chosen from the pg_conversion system catalog
* marked as "default". If it is not found in the schema search path,
* it's taken from pg_catalog schema. If it even is not in the schema,
* warn and returns src. We cannot raise an error, since it will cause
* an infinit loop in error message sending.
*
* In the case of no conversion, src is returned.
*
* XXX We assume that storage for converted result is 4-to-1 growth in
* the worst case. The rate for currently supported encoding pares are within 3
* (SJIS JIS X0201 half width kanna -> UTF-8 is the worst case).
* So "4" should be enough for the moment.
*/
unsigned char *
pg_do_encoding_conversion(unsigned char *src, int len,
int src_encoding, int dest_encoding)
{
unsigned char *result;
Oid proc;
if (!IsTransactionState())
return src;
if (src_encoding == dest_encoding)
return src;
if (src_encoding == PG_SQL_ASCII || dest_encoding == PG_SQL_ASCII)
return src;
if (len <= 0)
return src;
proc = FindDefaultConversionProc(src_encoding, dest_encoding);
if (!OidIsValid(proc))
{
ereport(LOG,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("default conversion function for encoding \"%s\" to \"%s\" does not exist",
pg_encoding_to_char(src_encoding),
pg_encoding_to_char(dest_encoding))));
return src;
}
/*
* XXX we should avoid throwing errors in OidFunctionCall. Otherwise
* we are going into infinite loop! So we have to make sure that the
* function exists before calling OidFunctionCall.
*/
if (!SearchSysCacheExists(PROCOID,
ObjectIdGetDatum(proc),
0, 0, 0))
{
elog(LOG, "cache lookup failed for function %u", proc);
return src;
}
result = palloc(len * 4 + 1);
OidFunctionCall5(proc,
Int32GetDatum(src_encoding),
Int32GetDatum(dest_encoding),
CStringGetDatum(src),
CStringGetDatum(result),
Int32GetDatum(len));
return result;
}
/*
* CREATE CONVERSION
*/
ObjectAddress
CreateConversionCommand(CreateConversionStmt *stmt)
{
Oid namespaceId;
char *conversion_name;
AclResult aclresult;
int from_encoding;
int to_encoding;
Oid funcoid;
const char *from_encoding_name = stmt->for_encoding_name;
const char *to_encoding_name = stmt->to_encoding_name;
List *func_name = stmt->func_name;
static const Oid funcargs[] = {INT4OID, INT4OID, CSTRINGOID, INTERNALOID, INT4OID};
char result[1];
/* Convert list of names to a name and namespace */
namespaceId = QualifiedNameGetCreationNamespace(stmt->conversion_name,
&conversion_name);
/* Check we have creation rights in target namespace */
aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(), ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
get_namespace_name(namespaceId));
/* Check the encoding names */
from_encoding = pg_char_to_encoding(from_encoding_name);
if (from_encoding < 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("source encoding \"%s\" does not exist",
from_encoding_name)));
to_encoding = pg_char_to_encoding(to_encoding_name);
if (to_encoding < 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("destination encoding \"%s\" does not exist",
to_encoding_name)));
/*
* Check the existence of the conversion function. Function name could be
* a qualified name.
*/
funcoid = LookupFuncName(func_name, sizeof(funcargs) / sizeof(Oid),
funcargs, false);
/* Check it returns VOID, else it's probably the wrong function */
if (get_func_rettype(funcoid) != VOIDOID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("encoding conversion function %s must return type %s",
NameListToString(func_name), "void")));
/* Check we have EXECUTE rights for the function */
aclresult = pg_proc_aclcheck(funcoid, GetUserId(), ACL_EXECUTE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_PROC,
NameListToString(func_name));
/*
* Check that the conversion function is suitable for the requested source
* and target encodings. We do that by calling the function with an empty
* string; the conversion function should throw an error if it can't
* perform the requested conversion.
*/
OidFunctionCall5(funcoid,
Int32GetDatum(from_encoding),
Int32GetDatum(to_encoding),
CStringGetDatum(""),
CStringGetDatum(result),
Int32GetDatum(0));
/*
* All seem ok, go ahead (possible failure would be a duplicate conversion
* name)
*/
return ConversionCreate(conversion_name, namespaceId, GetUserId(),
from_encoding, to_encoding, funcoid, stmt->def);
}
/*
* Apply encoding conversion on src and return it. The encoding
* conversion function is chosen from the pg_conversion system catalog
* marked as "default". If it is not found in the schema search path,
* it's taken from pg_catalog schema. If it even is not in the schema,
* warn and return src.
*
* If conversion occurs, a palloc'd null-terminated string is returned.
* In the case of no conversion, src is returned.
*
* CAUTION: although the presence of a length argument means that callers
* can pass non-null-terminated strings, care is required because the same
* string will be passed back if no conversion occurs. Such callers *must*
* check whether result == src and handle that case differently.
*
* Note: we try to avoid raising error, since that could get us into
* infinite recursion when this function is invoked during error message
* sending. It should be OK to raise error for overlength strings though,
* since the recursion will come with a shorter message.
*/
unsigned char *
pg_do_encoding_conversion(unsigned char *src, int len,
int src_encoding, int dest_encoding)
{
unsigned char *result;
Oid proc;
if (!IsTransactionState())
return src;
if (src_encoding == dest_encoding)
return src;
if (src_encoding == PG_SQL_ASCII || dest_encoding == PG_SQL_ASCII)
return src;
if (len <= 0)
return src;
proc = FindDefaultConversionProc(src_encoding, dest_encoding);
if (!OidIsValid(proc))
{
ereport(LOG,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("default conversion function for encoding \"%s\" to \"%s\" does not exist",
pg_encoding_to_char(src_encoding),
pg_encoding_to_char(dest_encoding))));
return src;
}
/*
* XXX we should avoid throwing errors in OidFunctionCall. Otherwise we
* are going into infinite loop! So we have to make sure that the
* function exists before calling OidFunctionCall.
*/
/* XXX: would have been function_exists() */
if (!(caql_getcount(
NULL,
cql("SELECT COUNT(*) FROM pg_proc "
" WHERE oid = :1 ",
ObjectIdGetDatum(proc))) > 0))
{
elog(LOG, "cache lookup failed for function %u", proc);
return src;
}
/*
* Allocate space for conversion result, being wary of integer overflow
*/
if ((Size) len >= (MaxAllocSize / (Size) MAX_CONVERSION_GROWTH))
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("out of memory"),
errdetail("String of %d bytes is too long for encoding conversion.",
len)));
result = palloc(len * MAX_CONVERSION_GROWTH + 1);
OidFunctionCall5(proc,
Int32GetDatum(src_encoding),
Int32GetDatum(dest_encoding),
CStringGetDatum((char *)src),
CStringGetDatum((char *)result),
Int32GetDatum(len));
return result;
}
/*
* Execute SQL99's CONVERT function.
*
* CONVERT <left paren> <character value expression>
* USING <form-of-use conversion name> <right paren>
*
* TEXT convert_using(TEXT string, TEXT conversion_name)
*/
Datum
pg_convert_using(PG_FUNCTION_ARGS)
{
text *string = PG_GETARG_TEXT_P(0);
text *conv_name = PG_GETARG_TEXT_P(1);
text *retval;
List *parsed_name;
Oid convoid;
HeapTuple tuple;
Form_pg_conversion body;
char *str;
char *result;
int len;
/* Convert input string to null-terminated form */
len = VARSIZE(string) - VARHDRSZ;
str = palloc(len + 1);
memcpy(str, VARDATA(string), len);
*(str + len) = '\0';
/* Look up the conversion name */
parsed_name = textToQualifiedNameList(conv_name);
convoid = FindConversionByName(parsed_name);
if (!OidIsValid(convoid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("conversion \"%s\" does not exist",
NameListToString(parsed_name))));
tuple = SearchSysCache(CONOID,
ObjectIdGetDatum(convoid),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for conversion %u", convoid);
body = (Form_pg_conversion) GETSTRUCT(tuple);
/* Temporary result area should be more than big enough */
result = palloc(len * 4 + 1);
OidFunctionCall5(body->conproc,
Int32GetDatum(body->conforencoding),
Int32GetDatum(body->contoencoding),
CStringGetDatum(str),
CStringGetDatum(result),
Int32GetDatum(len));
ReleaseSysCache(tuple);
/*
* build text result structure. we cannot use textin() here, since textin
* assumes that input string encoding is same as database encoding.
*/
len = strlen(result) + VARHDRSZ;
retval = palloc(len);
VARATT_SIZEP(retval) = len;
memcpy(VARDATA(retval), result, len - VARHDRSZ);
pfree(result);
pfree(str);
PG_RETURN_TEXT_P(retval);
}
