Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * conversioncmds.c
       4             :  *    conversion creation command support code
       5             :  *
       6             :  * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994, Regents of the University of California
       8             :  *
       9             :  *
      10             :  * IDENTIFICATION
      11             :  *    src/backend/commands/conversioncmds.c
      12             :  *
      13             :  *-------------------------------------------------------------------------
      14             :  */
      15             : #include "postgres.h"
      16             : 
      17             : #include "access/htup_details.h"
      18             : #include "catalog/dependency.h"
      19             : #include "catalog/indexing.h"
      20             : #include "catalog/pg_conversion.h"
      21             : #include "catalog/pg_conversion_fn.h"
      22             : #include "catalog/pg_type.h"
      23             : #include "commands/alter.h"
      24             : #include "commands/conversioncmds.h"
      25             : #include "mb/pg_wchar.h"
      26             : #include "miscadmin.h"
      27             : #include "parser/parse_func.h"
      28             : #include "utils/builtins.h"
      29             : #include "utils/lsyscache.h"
      30             : #include "utils/rel.h"
      31             : #include "utils/syscache.h"
      32             : 
      33             : /*
      34             :  * CREATE CONVERSION
      35             :  */
      36             : ObjectAddress
      37         142 : CreateConversionCommand(CreateConversionStmt *stmt)
      38             : {
      39             :     Oid         namespaceId;
      40             :     char       *conversion_name;
      41             :     AclResult   aclresult;
      42             :     int         from_encoding;
      43             :     int         to_encoding;
      44             :     Oid         funcoid;
      45         142 :     const char *from_encoding_name = stmt->for_encoding_name;
      46         142 :     const char *to_encoding_name = stmt->to_encoding_name;
      47         142 :     List       *func_name = stmt->func_name;
      48             :     static const Oid funcargs[] = {INT4OID, INT4OID, CSTRINGOID, INTERNALOID, INT4OID};
      49             :     char        result[1];
      50             : 
      51             :     /* Convert list of names to a name and namespace */
      52         142 :     namespaceId = QualifiedNameGetCreationNamespace(stmt->conversion_name,
      53             :                                                     &conversion_name);
      54             : 
      55             :     /* Check we have creation rights in target namespace */
      56         142 :     aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(), ACL_CREATE);
      57         142 :     if (aclresult != ACLCHECK_OK)
      58           0 :         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
      59           0 :                        get_namespace_name(namespaceId));
      60             : 
      61             :     /* Check the encoding names */
      62         142 :     from_encoding = pg_char_to_encoding(from_encoding_name);
      63         142 :     if (from_encoding < 0)
      64           0 :         ereport(ERROR,
      65             :                 (errcode(ERRCODE_UNDEFINED_OBJECT),
      66             :                  errmsg("source encoding \"%s\" does not exist",
      67             :                         from_encoding_name)));
      68             : 
      69         142 :     to_encoding = pg_char_to_encoding(to_encoding_name);
      70         142 :     if (to_encoding < 0)
      71           0 :         ereport(ERROR,
      72             :                 (errcode(ERRCODE_UNDEFINED_OBJECT),
      73             :                  errmsg("destination encoding \"%s\" does not exist",
      74             :                         to_encoding_name)));
      75             : 
      76             :     /*
      77             :      * Check the existence of the conversion function. Function name could be
      78             :      * a qualified name.
      79             :      */
      80         142 :     funcoid = LookupFuncName(func_name, sizeof(funcargs) / sizeof(Oid),
      81             :                              funcargs, false);
      82             : 
      83             :     /* Check it returns VOID, else it's probably the wrong function */
      84         142 :     if (get_func_rettype(funcoid) != VOIDOID)
      85           0 :         ereport(ERROR,
      86             :                 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
      87             :                  errmsg("encoding conversion function %s must return type %s",
      88             :                         NameListToString(func_name), "void")));
      89             : 
      90             :     /* Check we have EXECUTE rights for the function */
      91         142 :     aclresult = pg_proc_aclcheck(funcoid, GetUserId(), ACL_EXECUTE);
      92         142 :     if (aclresult != ACLCHECK_OK)
      93           0 :         aclcheck_error(aclresult, ACL_KIND_PROC,
      94           0 :                        NameListToString(func_name));
      95             : 
      96             :     /*
      97             :      * Check that the conversion function is suitable for the requested source
      98             :      * and target encodings. We do that by calling the function with an empty
      99             :      * string; the conversion function should throw an error if it can't
     100             :      * perform the requested conversion.
     101             :      */
     102         142 :     OidFunctionCall5(funcoid,
     103             :                      Int32GetDatum(from_encoding),
     104             :                      Int32GetDatum(to_encoding),
     105             :                      CStringGetDatum(""),
     106             :                      CStringGetDatum(result),
     107             :                      Int32GetDatum(0));
     108             : 
     109             :     /*
     110             :      * All seem ok, go ahead (possible failure would be a duplicate conversion
     111             :      * name)
     112             :      */
     113         142 :     return ConversionCreate(conversion_name, namespaceId, GetUserId(),
     114         142 :                             from_encoding, to_encoding, funcoid, stmt->def);
     115             : }