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Code cleanup inspired by recent resname bug report (doesn't fix the bug

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yet, though).  Avoid using nth() to fetch tlist entries; provide a
common routine get_tle_by_resno() to search a tlist for a particular
resno.  This replaces a couple uses of nth() and a dozen hand-coded
search loops.  Also, replace a few uses of nth(length-1, list) with
llast().
This commit is contained in:
Tom Lane
2003-08-11 20:46:47 +00:00
parent cae912d05b
commit 88381ade63
12 changed files with 161 additions and 316 deletions
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170
src/backend/rewrite/rewriteManip.c
View File

@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteManip.c,v 1.77 2003/08/08 21:41:58 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteManip.c,v 1.78 2003/08/11 20:46:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -838,44 +838,6 @@ AddInvertedQual(Query *parsetree, Node *qual)
}
/* Find a targetlist entry by resno */
static Node *
FindMatchingNew(List *tlist, int attno)
{
List *i;
foreach(i, tlist)
{
TargetEntry *tle = lfirst(i);
if (tle->resdom->resno == attno)
return (Node *) tle->expr;
}
return NULL;
}
#ifdef NOT_USED
/* Find a targetlist entry by resname */
static Node *
FindMatchingTLEntry(List *tlist, char *e_attname)
{
List *i;
foreach(i, tlist)
{
TargetEntry *tle = lfirst(i);
char *resname;
resname = tle->resdom->resname;
if (strcmp(e_attname, resname) == 0)
return tle->expr;
}
return NULL;
}
#endif
/*
* ResolveNew - replace Vars with corresponding items from a targetlist
*
@@ -908,7 +870,7 @@ ResolveNew_mutator(Node *node, ResolveNew_context *context)
if (this_varno == context->target_varno &&
this_varlevelsup == context->sublevels_up)
{
Node *n;
TargetEntry *tle;
/* band-aid: don't do the wrong thing with a whole-tuple Var */
if (var->varattno == InvalidAttrNumber)
@@ -916,9 +878,9 @@ ResolveNew_mutator(Node *node, ResolveNew_context *context)
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot handle whole-tuple reference")));
n = FindMatchingNew(context->targetlist, var->varattno);
tle = get_tle_by_resno(context->targetlist, var->varattno);
if (n == NULL)
if (tle == NULL)
{
if (context->event == CMD_UPDATE)
{
@@ -937,7 +899,8 @@ ResolveNew_mutator(Node *node, ResolveNew_context *context)
else
{
/* Make a copy of the tlist item to return */
n = copyObject(n);
Node *n = copyObject(tle->expr);
/* Adjust varlevelsup if tlist item is from higher query */
if (this_varlevelsup > 0)
IncrementVarSublevelsUp(n, this_varlevelsup, 0);
@@ -985,124 +948,3 @@ ResolveNew(Node *node, int target_varno, int sublevels_up,
(void *) &context,
0);
}
#ifdef NOT_USED
/*
* HandleRIRAttributeRule
* Replace Vars matching a given RT index with copies of TL expressions.
*
* Handles 'on retrieve to relation.attribute
* do instead retrieve (attribute = expression) w/qual'
*/
typedef struct
{
List *rtable;
List *targetlist;
int rt_index;
int attr_num;
int *modified;
int *badsql;
int sublevels_up;
} HandleRIRAttributeRule_context;
static Node *
HandleRIRAttributeRule_mutator(Node *node,
HandleRIRAttributeRule_context * context)
{
if (node == NULL)
return NULL;
if (IsA(node, Var))
{
Var *var = (Var *) node;
int this_varno = var->varno;
int this_varattno = var->varattno;
int this_varlevelsup = var->varlevelsup;
if (this_varno == context->rt_index &&
this_varattno == context->attr_num &&
this_varlevelsup == context->sublevels_up)
{
if (var->vartype == 32)
{ /* HACK: disallow SET variables */
*context->modified = TRUE;
*context->badsql = TRUE;
return (Node *) makeNullConst(var->vartype);
}
else
{
char *name_to_look_for;
name_to_look_for = get_attname(getrelid(this_varno,
context->rtable),
this_varattno);
if (name_to_look_for)
{
Node *n;
*context->modified = TRUE;
n = FindMatchingTLEntry(context->targetlist,
name_to_look_for);
if (n == NULL)
return (Node *) makeNullConst(var->vartype);
/* Make a copy of the tlist item to return */
n = copyObject(n);
/*
* Adjust varlevelsup if tlist item is from higher
* query
*/
if (this_varlevelsup > 0)
IncrementVarSublevelsUp(n, this_varlevelsup, 0);
return n;
}
}
}
/* otherwise fall through to copy the var normally */
}
if (IsA(node, Query))
{
/* Recurse into RTE subquery or not-yet-planned sublink subquery */
Query *newnode;
context->sublevels_up++;
newnode = query_tree_mutator((Query *) node,
HandleRIRAttributeRule_mutator,
(void *) context,
0);
context->sublevels_up--;
return (Node *) newnode;
}
return expression_tree_mutator(node, HandleRIRAttributeRule_mutator,
(void *) context);
}
void
HandleRIRAttributeRule(Query *parsetree,
List *rtable,
List *targetlist,
int rt_index,
int attr_num,
int *modified,
int *badsql)
{
HandleRIRAttributeRule_context context;
context.rtable = rtable;
context.targetlist = targetlist;
context.rt_index = rt_index;
context.attr_num = attr_num;
context.modified = modified;
context.badsql = badsql;
context.sublevels_up = 0;
query_tree_mutator(parsetree,
HandleRIRAttributeRule_mutator,
(void *) &context,
QTW_DONT_COPY_QUERY);
}
#endif /* NOT_USED */