diff options
Diffstat (limited to 'src/backend/optimizer/util/var.c')
| -rw-r--r-- | src/backend/optimizer/util/var.c | 57 |
1 files changed, 36 insertions, 21 deletions
diff --git a/src/backend/optimizer/util/var.c b/src/backend/optimizer/util/var.c index 30f02de5c72..9b620c80f5a 100644 --- a/src/backend/optimizer/util/var.c +++ b/src/backend/optimizer/util/var.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/util/var.c,v 1.31 2001/04/18 20:42:55 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/util/var.c,v 1.32 2001/05/09 23:13:35 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -28,8 +28,9 @@ typedef struct typedef struct { int varno; + int varattno; int sublevels_up; -} contain_whole_tuple_var_context; +} contain_var_reference_context; typedef struct { @@ -39,8 +40,8 @@ typedef struct static bool pull_varnos_walker(Node *node, pull_varnos_context *context); -static bool contain_whole_tuple_var_walker(Node *node, - contain_whole_tuple_var_context *context); +static bool contain_var_reference_walker(Node *node, + contain_var_reference_context *context); static bool contain_var_clause_walker(Node *node, void *context); static bool pull_var_clause_walker(Node *node, pull_var_clause_context *context); @@ -129,10 +130,10 @@ pull_varnos_walker(Node *node, pull_varnos_context *context) /* - * contain_whole_tuple_var + * contain_var_reference * - * Detect whether a parsetree contains any references to the whole - * tuple of a given rtable entry (ie, a Var with varattno = 0). + * Detect whether a parsetree contains any references to a specified + * attribute of a specified rtable entry. * * NOTE: this is used on not-yet-planned expressions. It may therefore find * bare SubLinks, and if so it needs to recurse into them to look for uplevel @@ -140,11 +141,12 @@ pull_varnos_walker(Node *node, pull_varnos_context *context) * SubPlan, we only need to look at the parameters passed to the subplan. */ bool -contain_whole_tuple_var(Node *node, int varno, int levelsup) +contain_var_reference(Node *node, int varno, int varattno, int levelsup) { - contain_whole_tuple_var_context context; + contain_var_reference_context context; context.varno = varno; + context.varattno = varattno; context.sublevels_up = levelsup; /* @@ -154,15 +156,15 @@ contain_whole_tuple_var(Node *node, int varno, int levelsup) */ if (node && IsA(node, Query)) return query_tree_walker((Query *) node, - contain_whole_tuple_var_walker, + contain_var_reference_walker, (void *) &context, true); else - return contain_whole_tuple_var_walker(node, &context); + return contain_var_reference_walker(node, &context); } static bool -contain_whole_tuple_var_walker(Node *node, - contain_whole_tuple_var_context *context) +contain_var_reference_walker(Node *node, + contain_var_reference_context *context) { if (node == NULL) return false; @@ -171,8 +173,8 @@ contain_whole_tuple_var_walker(Node *node, Var *var = (Var *) node; if (var->varno == context->varno && - var->varlevelsup == context->sublevels_up && - var->varattno == InvalidAttrNumber) + var->varattno == context->varattno && + var->varlevelsup == context->sublevels_up) return true; return false; } @@ -187,11 +189,11 @@ contain_whole_tuple_var_walker(Node *node, */ Expr *expr = (Expr *) node; - if (contain_whole_tuple_var_walker((Node *) ((SubPlan *) expr->oper)->sublink->oper, - context)) + if (contain_var_reference_walker((Node *) ((SubPlan *) expr->oper)->sublink->oper, + context)) return true; - if (contain_whole_tuple_var_walker((Node *) expr->args, - context)) + if (contain_var_reference_walker((Node *) expr->args, + context)) return true; return false; } @@ -202,17 +204,30 @@ contain_whole_tuple_var_walker(Node *node, context->sublevels_up++; result = query_tree_walker((Query *) node, - contain_whole_tuple_var_walker, + contain_var_reference_walker, (void *) context, true); context->sublevels_up--; return result; } - return expression_tree_walker(node, contain_whole_tuple_var_walker, + return expression_tree_walker(node, contain_var_reference_walker, (void *) context); } /* + * contain_whole_tuple_var + * + * Detect whether a parsetree contains any references to the whole + * tuple of a given rtable entry (ie, a Var with varattno = 0). + */ +bool +contain_whole_tuple_var(Node *node, int varno, int levelsup) +{ + return contain_var_reference(node, varno, InvalidAttrNumber, levelsup); +} + + +/* * contain_var_clause * Recursively scan a clause to discover whether it contains any Var nodes * (of the current query level). |