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Postgres FD Implementation
Commit baeef0e1 authored by Tom Lane's avatar Tom Lane
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Change rule dumper to produce reasonable output for casts that assign 

a specific length or precision, such as foo::char(8).  Remove erroneous
removal of user-written casts at the top level of a SELECT target item.
parent 7173c485
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Showing with 82 additions and 92 deletions
src/backend/utils/adt/ruleutils.c
View file @ baeef0e1
......@@ -3,7 +3,7 @@
* out of its tuple
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.43 2000/02/21 20:18:10 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.44 2000/02/26 21:13:18 tgl Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
......@@ -49,6 +49,7 @@
#include "optimizer/clauses.h"
#include "optimizer/tlist.h"
#include "parser/keywords.h"
#include "parser/parse_expr.h"
#include "parser/parsetree.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
......@@ -947,7 +948,8 @@ get_select_query_def(Query *query, deparse_context *context)
appendStringInfo(buf, sep);
sep = ", ";
get_tle_expr(tle, context);
/* Do NOT use get_tle_expr here; see its comments! */
get_rule_expr(tle->expr, context);
/* Check if we must say AS ... */
if (! IsA(tle->expr, Var))
......@@ -1486,16 +1488,16 @@ static void
get_func_expr(Expr *expr, deparse_context *context)
{
StringInfo buf = context->buf;
Func *func = (Func *) (expr->oper);
HeapTuple proctup;
Form_pg_proc procStruct;
char *proname;
int32 coercedTypmod;
List *l;
char *sep;
Func *func = (Func *) (expr->oper);
char *proname;
/* ----------
/*
* Get the functions pg_proc tuple
* ----------
*/
proctup = SearchSysCacheTuple(PROCOID,
ObjectIdGetDatum(func->funcid),
......@@ -1527,9 +1529,59 @@ get_func_expr(Expr *expr, deparse_context *context)
}
}
/* ----------
* Build a string of proname(args)
* ----------
/*
* Check to see if function is a length-coercion function for some
* datatype. If so, display the operation as a type cast.
*/
if (exprIsLengthCoercion((Node *) expr, &coercedTypmod))
{
Node *arg = lfirst(expr->args);
/*
* Strip off any RelabelType on the input, so we don't print
* redundancies like x::bpchar::char(8).
* XXX Are there any cases where this is a bad idea?
*/
if (IsA(arg, RelabelType))
arg = ((RelabelType *) arg)->arg;
appendStringInfoChar(buf, '(');
get_rule_expr(arg, context);
appendStringInfo(buf, ")::");
/*
* Show typename with appropriate length decoration.
* Note that since exprIsLengthCoercion succeeded, the function
* name is the same as its output type name.
*/
if (strcmp(proname, "bpchar") == 0)
{
if (coercedTypmod > VARHDRSZ)
appendStringInfo(buf, "char(%d)", coercedTypmod - VARHDRSZ);
else
appendStringInfo(buf, "char");
}
else if (strcmp(proname, "varchar") == 0)
{
if (coercedTypmod > VARHDRSZ)
appendStringInfo(buf, "varchar(%d)", coercedTypmod - VARHDRSZ);
else
appendStringInfo(buf, "varchar");
}
else if (strcmp(proname, "numeric") == 0)
{
if (coercedTypmod >= VARHDRSZ)
appendStringInfo(buf, "numeric(%d,%d)",
((coercedTypmod - VARHDRSZ) >> 16) & 0xffff,
(coercedTypmod - VARHDRSZ) & 0xffff);
else
appendStringInfo(buf, "numeric");
}
else
appendStringInfo(buf, "%s", quote_identifier(proname));
return;
}
/*
* Normal function: display as proname(args)
*/
appendStringInfo(buf, "%s(", quote_identifier(proname));
sep = "";
......@@ -1546,99 +1598,37 @@ get_func_expr(Expr *expr, deparse_context *context)
/* ----------
* get_tle_expr
*
* A target list expression is a bit different from a normal expression.
* If the target column has an atttypmod, the parser usually puts a
* padding-/cut-function call around the expression itself.
* We must get rid of it, otherwise dump/reload/dump... would blow up
* the expressions.
* In an INSERT or UPDATE targetlist item, the parser may have inserted
* a length-coercion function call to coerce the value to the right
* length for the target column. We want to suppress the output of
* that function call, otherwise dump/reload/dump... would blow up the
* expression by adding more and more layers of length-coercion calls.
*
* As of 7.0, this hack is no longer absolutely essential, because the parser
* is now smart enough not to add a redundant length coercion function call.
* But we still suppress the function call just for neatness of displayed
* rules.
*
* Note that this hack must NOT be applied to SELECT targetlist items;
* any length coercion appearing there is something the user actually wrote.
* ----------
*/
static void
get_tle_expr(TargetEntry *tle, deparse_context *context)
{
Expr *expr = (Expr *) (tle->expr);
Func *func;
HeapTuple tup;
Form_pg_proc procStruct;
Form_pg_type typeStruct;
Const *second_arg;
/* ----------
* Check if the result has an atttypmod and if the
* expression in the targetlist entry is a function call
* ----------
*/
if (tle->resdom->restypmod < 0 ||
! IsA(expr, Expr) ||
expr->opType != FUNC_EXPR)
{
get_rule_expr(tle->expr, context);
return;
}
func = (Func *) (expr->oper);
/* ----------
* Get the functions pg_proc tuple
* ----------
*/
tup = SearchSysCacheTuple(PROCOID,
ObjectIdGetDatum(func->funcid), 0, 0, 0);
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup for proc %u failed", func->funcid);
procStruct = (Form_pg_proc) GETSTRUCT(tup);
/* ----------
* It must be a function with two arguments where the first
* is of the same type as the return value and the second is
* an int4.
* ----------
*/
if (procStruct->pronargs != 2 ||
procStruct->prorettype != procStruct->proargtypes[0] ||
procStruct->proargtypes[1] != INT4OID)
{
get_rule_expr(tle->expr, context);
return;
}
int32 coercedTypmod;
/*
* Furthermore, the name of the function must be the same
* as the argument/result type name.
*/
tup = SearchSysCacheTuple(TYPEOID,
ObjectIdGetDatum(procStruct->prorettype),
0, 0, 0);
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup for type %u failed",
procStruct->prorettype);
typeStruct = (Form_pg_type) GETSTRUCT(tup);
if (strncmp(NameStr(procStruct->proname),
NameStr(typeStruct->typname),
NAMEDATALEN) != 0)
{
get_rule_expr(tle->expr, context);
return;
}
/* ----------
* Finally (to be totally safe) the second argument must be a
* const and match the value in the results atttypmod.
* ----------
* If top level is a length coercion to the correct length, suppress it;
* else dump the expression normally.
*/
second_arg = (Const *) lsecond(expr->args);
if (! IsA(second_arg, Const) ||
DatumGetInt32(second_arg->constvalue) != tle->resdom->restypmod)
{
if (tle->resdom->restypmod >= 0 &&
exprIsLengthCoercion((Node *) expr, &coercedTypmod) &&
coercedTypmod == tle->resdom->restypmod)
get_rule_expr((Node *) lfirst(expr->args), context);
else
get_rule_expr(tle->expr, context);
return;
}
/* ----------
* Whow - got it. Now get rid of the padding function
* ----------
*/
get_rule_expr((Node *) lfirst(expr->args), context);
}
......
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