mirror of https://github.com/postgres/postgres
Teach ruleutils to drill down into RECORD-type Vars in the same way
that the parser now can, so that it can reverse-list cases involving FieldSelect from a RECORD Var.
This commit is contained in:
Tom Lane
parent
83b72ee286
commit
6dfe64ee57
|
|
@ -3,7 +3,7 @@
|
|||
* back to source text
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.197 2005/05/30 01:57:27 tgl Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.198 2005/05/31 03:03:59 tgl Exp $
|
||||
*
|
||||
* This software is copyrighted by Jan Wieck - Hamburg.
|
||||
*
|
||||
|
|
@ -55,6 +55,7 @@
|
|||
#include "catalog/pg_shadow.h"
|
||||
#include "catalog/pg_trigger.h"
|
||||
#include "executor/spi.h"
|
||||
#include "funcapi.h"
|
||||
#include "lib/stringinfo.h"
|
||||
#include "miscadmin.h"
|
||||
#include "nodes/makefuncs.h"
|
||||
|
|
@ -2420,6 +2421,43 @@ get_utility_query_def(Query *query, deparse_context *context)
|
|||
}
|
||||
|
||||
|
||||
/*
|
||||
* Get the RTE referenced by a (possibly nonlocal) Var.
|
||||
*
|
||||
* In some cases (currently only when recursing into an unnamed join)
|
||||
* the Var's varlevelsup has to be interpreted with respect to a context
|
||||
* above the current one; levelsup indicates the offset.
|
||||
*/
|
||||
static RangeTblEntry *
|
||||
get_rte_for_var(Var *var, int levelsup, deparse_context *context)
|
||||
{
|
||||
RangeTblEntry *rte;
|
||||
int netlevelsup;
|
||||
deparse_namespace *dpns;
|
||||
|
||||
/* Find appropriate nesting depth */
|
||||
netlevelsup = var->varlevelsup + levelsup;
|
||||
if (netlevelsup >= list_length(context->namespaces))
|
||||
elog(ERROR, "bogus varlevelsup: %d offset %d",
|
||||
var->varlevelsup, levelsup);
|
||||
dpns = (deparse_namespace *) list_nth(context->namespaces,
|
||||
netlevelsup);
|
||||
|
||||
/* Find the relevant RTE */
|
||||
if (var->varno >= 1 && var->varno <= list_length(dpns->rtable))
|
||||
rte = rt_fetch(var->varno, dpns->rtable);
|
||||
else if (var->varno == dpns->outer_varno)
|
||||
rte = dpns->outer_rte;
|
||||
else if (var->varno == dpns->inner_varno)
|
||||
rte = dpns->inner_rte;
|
||||
else
|
||||
rte = NULL;
|
||||
if (rte == NULL)
|
||||
elog(ERROR, "bogus varno: %d", var->varno);
|
||||
return rte;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Get the schemaname, refname and attname for a (possibly nonlocal) Var.
|
||||
*
|
||||
|
|
@ -2442,29 +2480,10 @@ static void
|
|||
get_names_for_var(Var *var, int levelsup, deparse_context *context,
|
||||
char **schemaname, char **refname, char **attname)
|
||||
{
|
||||
int netlevelsup;
|
||||
deparse_namespace *dpns;
|
||||
RangeTblEntry *rte;
|
||||
|
||||
/* Find appropriate nesting depth */
|
||||
netlevelsup = var->varlevelsup + levelsup;
|
||||
if (netlevelsup >= list_length(context->namespaces))
|
||||
elog(ERROR, "bogus varlevelsup: %d offset %d",
|
||||
var->varlevelsup, levelsup);
|
||||
dpns = (deparse_namespace *) list_nth(context->namespaces,
|
||||
netlevelsup);
|
||||
|
||||
/* Find the relevant RTE */
|
||||
if (var->varno >= 1 && var->varno <= list_length(dpns->rtable))
|
||||
rte = rt_fetch(var->varno, dpns->rtable);
|
||||
else if (var->varno == dpns->outer_varno)
|
||||
rte = dpns->outer_rte;
|
||||
else if (var->varno == dpns->inner_varno)
|
||||
rte = dpns->inner_rte;
|
||||
else
|
||||
rte = NULL;
|
||||
if (rte == NULL)
|
||||
elog(ERROR, "bogus varno: %d", var->varno);
|
||||
/* Find appropriate RTE */
|
||||
rte = get_rte_for_var(var, levelsup, context);
|
||||
|
||||
/* Emit results */
|
||||
*schemaname = NULL; /* default assumptions */
|
||||
|
|
@ -2505,7 +2524,8 @@ get_names_for_var(Var *var, int levelsup, deparse_context *context,
|
|||
var->varattno-1);
|
||||
if (IsA(aliasvar, Var))
|
||||
{
|
||||
get_names_for_var(aliasvar, netlevelsup, context,
|
||||
get_names_for_var(aliasvar,
|
||||
var->varlevelsup + levelsup, context,
|
||||
schemaname, refname, attname);
|
||||
return;
|
||||
}
|
||||
|
|
@ -2521,6 +2541,127 @@ get_names_for_var(Var *var, int levelsup, deparse_context *context,
|
|||
*attname = get_rte_attribute_name(rte, var->varattno);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Get the name of a field of a Var of type RECORD.
|
||||
*
|
||||
* Since no actual table or view column is allowed to have type RECORD, such
|
||||
* a Var must refer to a JOIN or FUNCTION RTE or to a subquery output. We
|
||||
* drill down to find the ultimate defining expression and attempt to infer
|
||||
* the field name from it. We ereport if we can't determine the name.
|
||||
*
|
||||
* levelsup is an extra offset to interpret the Var's varlevelsup correctly.
|
||||
*
|
||||
* Note: this has essentially the same logic as the parser's
|
||||
* expandRecordVariable() function, but we are dealing with a different
|
||||
* representation of the input context, and we only need one field name not
|
||||
* a TupleDesc.
|
||||
*/
|
||||
static const char *
|
||||
get_name_for_var_field(Var *var, int fieldno,
|
||||
int levelsup, deparse_context *context)
|
||||
{
|
||||
RangeTblEntry *rte;
|
||||
AttrNumber attnum;
|
||||
TupleDesc tupleDesc;
|
||||
Node *expr;
|
||||
|
||||
/* Check my caller didn't mess up */
|
||||
Assert(IsA(var, Var));
|
||||
Assert(var->vartype == RECORDOID);
|
||||
|
||||
/* Find appropriate RTE */
|
||||
rte = get_rte_for_var(var, levelsup, context);
|
||||
|
||||
attnum = var->varattno;
|
||||
|
||||
if (attnum == InvalidAttrNumber)
|
||||
{
|
||||
/* Var is whole-row reference to RTE, so select the right field */
|
||||
return get_rte_attribute_name(rte, fieldno);
|
||||
}
|
||||
|
||||
expr = (Node *) var; /* default if we can't drill down */
|
||||
|
||||
switch (rte->rtekind)
|
||||
{
|
||||
case RTE_RELATION:
|
||||
case RTE_SPECIAL:
|
||||
/*
|
||||
* This case should not occur: a column of a table shouldn't have
|
||||
* type RECORD. Fall through and fail (most likely) at the
|
||||
* bottom.
|
||||
*/
|
||||
break;
|
||||
case RTE_SUBQUERY:
|
||||
{
|
||||
/* Subselect-in-FROM: examine sub-select's output expr */
|
||||
TargetEntry *ste = get_tle_by_resno(rte->subquery->targetList,
|
||||
attnum);
|
||||
|
||||
if (ste == NULL || ste->resjunk)
|
||||
elog(ERROR, "subquery %s does not have attribute %d",
|
||||
rte->eref->aliasname, attnum);
|
||||
expr = (Node *) ste->expr;
|
||||
if (IsA(expr, Var))
|
||||
{
|
||||
/*
|
||||
* Recurse into the sub-select to see what its Var refers
|
||||
* to. We have to build an additional level of namespace
|
||||
* to keep in step with varlevelsup in the subselect.
|
||||
*/
|
||||
deparse_namespace mydpns;
|
||||
const char *result;
|
||||
|
||||
mydpns.rtable = rte->subquery->rtable;
|
||||
mydpns.outer_varno = mydpns.inner_varno = 0;
|
||||
mydpns.outer_rte = mydpns.inner_rte = NULL;
|
||||
|
||||
context->namespaces = lcons(&mydpns, context->namespaces);
|
||||
|
||||
result = get_name_for_var_field((Var *) expr, fieldno,
|
||||
0, context);
|
||||
|
||||
context->namespaces = list_delete_first(context->namespaces);
|
||||
|
||||
return result;
|
||||
}
|
||||
/* else fall through to inspect the expression */
|
||||
}
|
||||
break;
|
||||
case RTE_JOIN:
|
||||
/* Join RTE --- recursively inspect the alias variable */
|
||||
Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
|
||||
expr = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
|
||||
if (IsA(expr, Var))
|
||||
return get_name_for_var_field((Var *) expr, fieldno,
|
||||
var->varlevelsup + levelsup,
|
||||
context);
|
||||
/* else fall through to inspect the expression */
|
||||
break;
|
||||
case RTE_FUNCTION:
|
||||
/*
|
||||
* We couldn't get here unless a function is declared with one
|
||||
* of its result columns as RECORD, which is not allowed.
|
||||
*/
|
||||
break;
|
||||
}
|
||||
|
||||
/*
|
||||
* We now have an expression we can't expand any more, so see if
|
||||
* get_expr_result_type() can do anything with it. If not, pass
|
||||
* to lookup_rowtype_tupdesc() which will probably fail, but will
|
||||
* give an appropriate error message while failing.
|
||||
*/
|
||||
if (get_expr_result_type(expr, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
|
||||
tupleDesc = lookup_rowtype_tupdesc(exprType(expr), exprTypmod(expr));
|
||||
|
||||
/* Got the tupdesc, so we can extract the field name */
|
||||
Assert(fieldno >= 1 && fieldno <= tupleDesc->natts);
|
||||
return NameStr(tupleDesc->attrs[fieldno - 1]->attname);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* find_rte_by_refname - look up an RTE by refname in a deparse context
|
||||
*
|
||||
|
|
@ -3109,19 +3250,11 @@ get_rule_expr(Node *node, deparse_context *context,
|
|||
case T_FieldSelect:
|
||||
{
|
||||
FieldSelect *fselect = (FieldSelect *) node;
|
||||
Oid argType = exprType((Node *) fselect->arg);
|
||||
Oid typrelid;
|
||||
char *fieldname;
|
||||
Node *arg = (Node *) fselect->arg;
|
||||
int fno = fselect->fieldnum;
|
||||
const char *fieldname;
|
||||
bool need_parens;
|
||||
|
||||
/* lookup arg type and get the field name */
|
||||
typrelid = get_typ_typrelid(argType);
|
||||
if (!OidIsValid(typrelid))
|
||||
elog(ERROR, "argument type %s of FieldSelect is not a tuple type",
|
||||
format_type_be(argType));
|
||||
fieldname = get_relid_attribute_name(typrelid,
|
||||
fselect->fieldnum);
|
||||
|
||||
/*
|
||||
* Parenthesize the argument unless it's an ArrayRef or
|
||||
* another FieldSelect. Note in particular that it would
|
||||
|
|
@ -3129,13 +3262,36 @@ get_rule_expr(Node *node, deparse_context *context,
|
|||
* is not the issue here, having the right number of names
|
||||
* is.
|
||||
*/
|
||||
need_parens = !IsA(fselect->arg, ArrayRef) &&
|
||||
!IsA(fselect->arg, FieldSelect);
|
||||
need_parens = !IsA(arg, ArrayRef) && !IsA(arg, FieldSelect);
|
||||
if (need_parens)
|
||||
appendStringInfoChar(buf, '(');
|
||||
get_rule_expr((Node *) fselect->arg, context, true);
|
||||
get_rule_expr(arg, context, true);
|
||||
if (need_parens)
|
||||
appendStringInfoChar(buf, ')');
|
||||
|
||||
/*
|
||||
* If it's a Var of type RECORD, we have to find what the Var
|
||||
* refers to; otherwise we can use get_expr_result_type.
|
||||
* If that fails, we try lookup_rowtype_tupdesc, which will
|
||||
* probably fail too, but will ereport an acceptable message.
|
||||
*/
|
||||
if (IsA(arg, Var) &&
|
||||
((Var *) arg)->vartype == RECORDOID)
|
||||
fieldname = get_name_for_var_field((Var *) arg, fno,
|
||||
0, context);
|
||||
else
|
||||
{
|
||||
TupleDesc tupdesc;
|
||||
|
||||
if (get_expr_result_type(arg, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
|
||||
tupdesc = lookup_rowtype_tupdesc(exprType(arg),
|
||||
exprTypmod(arg));
|
||||
Assert(tupdesc);
|
||||
/* Got the tupdesc, so we can extract the field name */
|
||||
Assert(fno >= 1 && fno <= tupdesc->natts);
|
||||
fieldname = NameStr(tupdesc->attrs[fno - 1]->attname);
|
||||
}
|
||||
|
||||
appendStringInfo(buf, ".%s", quote_identifier(fieldname));
|
||||
}
|
||||
break;
|
||||
|
|
|
|||
Loading…
Reference in New Issue