diff options
Diffstat (limited to 'src/backend/rewrite/rewriteManip.c')
| -rw-r--r-- | src/backend/rewrite/rewriteManip.c | 1025 |
1 files changed, 0 insertions, 1025 deletions
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c deleted file mode 100644 index 87fe1c95264..00000000000 --- a/src/backend/rewrite/rewriteManip.c +++ /dev/null @@ -1,1025 +0,0 @@ -/*------------------------------------------------------------------------- - * - * rewriteManip.c - * - * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group - * Portions Copyright (c) 1994, Regents of the University of California - * - * - * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteManip.c,v 1.64 2002/06/20 20:29:34 momjian Exp $ - * - *------------------------------------------------------------------------- - */ -#include "postgres.h" - -#include "nodes/makefuncs.h" -#include "optimizer/clauses.h" -#include "optimizer/tlist.h" -#include "parser/parsetree.h" -#include "parser/parse_clause.h" -#include "rewrite/rewriteManip.h" -#include "utils/lsyscache.h" - - -/* macros borrowed from expression_tree_mutator */ - -#define FLATCOPY(newnode, node, nodetype) \ - ( (newnode) = makeNode(nodetype), \ - memcpy((newnode), (node), sizeof(nodetype)) ) - -#define MUTATE(newfield, oldfield, fieldtype, mutator, context) \ - ( (newfield) = (fieldtype) mutator((Node *) (oldfield), (context)) ) - -static bool checkExprHasAggs_walker(Node *node, void *context); -static bool checkExprHasSubLink_walker(Node *node, void *context); - - -/* - * checkExprHasAggs - - * Queries marked hasAggs might not have them any longer after - * rewriting. Check it. - */ -bool -checkExprHasAggs(Node *node) -{ - /* - * If a Query is passed, examine it --- but we will not recurse into - * sub-Queries. - */ - if (node && IsA(node, Query)) - return query_tree_walker((Query *) node, checkExprHasAggs_walker, - NULL, false); - else - return checkExprHasAggs_walker(node, NULL); -} - -static bool -checkExprHasAggs_walker(Node *node, void *context) -{ - if (node == NULL) - return false; - if (IsA(node, Aggref)) - return true; /* abort the tree traversal and return - * true */ - return expression_tree_walker(node, checkExprHasAggs_walker, context); -} - -/* - * checkExprHasSubLink - - * Queries marked hasSubLinks might not have them any longer after - * rewriting. Check it. - */ -bool -checkExprHasSubLink(Node *node) -{ - /* - * If a Query is passed, examine it --- but we will not recurse into - * sub-Queries. - */ - if (node && IsA(node, Query)) - return query_tree_walker((Query *) node, checkExprHasSubLink_walker, - NULL, false); - else - return checkExprHasSubLink_walker(node, NULL); -} - -static bool -checkExprHasSubLink_walker(Node *node, void *context) -{ - if (node == NULL) - return false; - if (IsA(node, SubLink)) - return true; /* abort the tree traversal and return - * true */ - return expression_tree_walker(node, checkExprHasSubLink_walker, context); -} - - -/* - * OffsetVarNodes - adjust Vars when appending one query's RT to another - * - * Find all Var nodes in the given tree with varlevelsup == sublevels_up, - * and increment their varno fields (rangetable indexes) by 'offset'. - * The varnoold fields are adjusted similarly. Also, RangeTblRef and - * JoinExpr nodes in join trees and setOp trees are adjusted. - * - * NOTE: although this has the form of a walker, we cheat and modify the - * nodes in-place. The given expression tree should have been copied - * earlier to ensure that no unwanted side-effects occur! - */ - -typedef struct -{ - int offset; - int sublevels_up; -} OffsetVarNodes_context; - -static bool -OffsetVarNodes_walker(Node *node, OffsetVarNodes_context *context) -{ - if (node == NULL) - return false; - if (IsA(node, Var)) - { - Var *var = (Var *) node; - - if (var->varlevelsup == context->sublevels_up) - { - var->varno += context->offset; - var->varnoold += context->offset; - } - return false; - } - if (IsA(node, RangeTblRef)) - { - RangeTblRef *rtr = (RangeTblRef *) node; - - if (context->sublevels_up == 0) - rtr->rtindex += context->offset; - /* the subquery itself is visited separately */ - return false; - } - if (IsA(node, JoinExpr)) - { - JoinExpr *j = (JoinExpr *) node; - - if (context->sublevels_up == 0) - j->rtindex += context->offset; - /* fall through to examine children */ - } - if (IsA(node, Query)) - { - /* Recurse into subselects */ - bool result; - - context->sublevels_up++; - result = query_tree_walker((Query *) node, OffsetVarNodes_walker, - (void *) context, true); - context->sublevels_up--; - return result; - } - return expression_tree_walker(node, OffsetVarNodes_walker, - (void *) context); -} - -void -OffsetVarNodes(Node *node, int offset, int sublevels_up) -{ - OffsetVarNodes_context context; - - context.offset = offset; - context.sublevels_up = sublevels_up; - - /* - * Must be prepared to start with a Query or a bare expression tree; - * if it's a Query, go straight to query_tree_walker to make sure that - * sublevels_up doesn't get incremented prematurely. - */ - if (node && IsA(node, Query)) - { - Query *qry = (Query *) node; - List *l; - - /* - * If we are starting at a Query, and sublevels_up is zero, then - * we must also fix rangetable indexes in the Query itself --- - * namely resultRelation and rowMarks entries. sublevels_up - * cannot be zero when recursing into a subquery, so there's no - * need to have the same logic inside OffsetVarNodes_walker. - */ - if (sublevels_up == 0) - { - if (qry->resultRelation) - qry->resultRelation += offset; - foreach(l, qry->rowMarks) - lfirsti(l) += offset; - } - query_tree_walker(qry, OffsetVarNodes_walker, - (void *) &context, true); - } - else - OffsetVarNodes_walker(node, &context); -} - -/* - * ChangeVarNodes - adjust Var nodes for a specific change of RT index - * - * Find all Var nodes in the given tree belonging to a specific relation - * (identified by sublevels_up and rt_index), and change their varno fields - * to 'new_index'. The varnoold fields are changed too. Also, RangeTblRef - * and JoinExpr nodes in join trees and setOp trees are adjusted. - * - * NOTE: although this has the form of a walker, we cheat and modify the - * nodes in-place. The given expression tree should have been copied - * earlier to ensure that no unwanted side-effects occur! - */ - -typedef struct -{ - int rt_index; - int new_index; - int sublevels_up; -} ChangeVarNodes_context; - -static bool -ChangeVarNodes_walker(Node *node, ChangeVarNodes_context *context) -{ - if (node == NULL) - return false; - if (IsA(node, Var)) - { - Var *var = (Var *) node; - - if (var->varlevelsup == context->sublevels_up && - var->varno == context->rt_index) - { - var->varno = context->new_index; - var->varnoold = context->new_index; - } - return false; - } - if (IsA(node, RangeTblRef)) - { - RangeTblRef *rtr = (RangeTblRef *) node; - - if (context->sublevels_up == 0 && - rtr->rtindex == context->rt_index) - rtr->rtindex = context->new_index; - /* the subquery itself is visited separately */ - return false; - } - if (IsA(node, JoinExpr)) - { - JoinExpr *j = (JoinExpr *) node; - - if (context->sublevels_up == 0 && - j->rtindex == context->rt_index) - j->rtindex = context->new_index; - /* fall through to examine children */ - } - if (IsA(node, Query)) - { - /* Recurse into subselects */ - bool result; - - context->sublevels_up++; - result = query_tree_walker((Query *) node, ChangeVarNodes_walker, - (void *) context, true); - context->sublevels_up--; - return result; - } - return expression_tree_walker(node, ChangeVarNodes_walker, - (void *) context); -} - -void -ChangeVarNodes(Node *node, int rt_index, int new_index, int sublevels_up) -{ - ChangeVarNodes_context context; - - context.rt_index = rt_index; - context.new_index = new_index; - context.sublevels_up = sublevels_up; - - /* - * Must be prepared to start with a Query or a bare expression tree; - * if it's a Query, go straight to query_tree_walker to make sure that - * sublevels_up doesn't get incremented prematurely. - */ - if (node && IsA(node, Query)) - { - Query *qry = (Query *) node; - List *l; - - /* - * If we are starting at a Query, and sublevels_up is zero, then - * we must also fix rangetable indexes in the Query itself --- - * namely resultRelation and rowMarks entries. sublevels_up - * cannot be zero when recursing into a subquery, so there's no - * need to have the same logic inside ChangeVarNodes_walker. - */ - if (sublevels_up == 0) - { - if (qry->resultRelation == rt_index) - qry->resultRelation = new_index; - foreach(l, qry->rowMarks) - { - if (lfirsti(l) == rt_index) - lfirsti(l) = new_index; - } - } - query_tree_walker(qry, ChangeVarNodes_walker, - (void *) &context, true); - } - else - ChangeVarNodes_walker(node, &context); -} - -/* - * IncrementVarSublevelsUp - adjust Var nodes when pushing them down in tree - * - * Find all Var nodes in the given tree having varlevelsup >= min_sublevels_up, - * and add delta_sublevels_up to their varlevelsup value. This is needed when - * an expression that's correct for some nesting level is inserted into a - * subquery. Ordinarily the initial call has min_sublevels_up == 0 so that - * all Vars are affected. The point of min_sublevels_up is that we can - * increment it when we recurse into a sublink, so that local variables in - * that sublink are not affected, only outer references to vars that belong - * to the expression's original query level or parents thereof. - * - * NOTE: although this has the form of a walker, we cheat and modify the - * Var nodes in-place. The given expression tree should have been copied - * earlier to ensure that no unwanted side-effects occur! - */ - -typedef struct -{ - int delta_sublevels_up; - int min_sublevels_up; -} IncrementVarSublevelsUp_context; - -static bool -IncrementVarSublevelsUp_walker(Node *node, - IncrementVarSublevelsUp_context *context) -{ - if (node == NULL) - return false; - if (IsA(node, Var)) - { - Var *var = (Var *) node; - - if (var->varlevelsup >= context->min_sublevels_up) - var->varlevelsup += context->delta_sublevels_up; - return false; - } - if (IsA(node, Query)) - { - /* Recurse into subselects */ - bool result; - - context->min_sublevels_up++; - result = query_tree_walker((Query *) node, - IncrementVarSublevelsUp_walker, - (void *) context, true); - context->min_sublevels_up--; - return result; - } - return expression_tree_walker(node, IncrementVarSublevelsUp_walker, - (void *) context); -} - -void -IncrementVarSublevelsUp(Node *node, int delta_sublevels_up, - int min_sublevels_up) -{ - IncrementVarSublevelsUp_context context; - - context.delta_sublevels_up = delta_sublevels_up; - context.min_sublevels_up = min_sublevels_up; - - /* - * Must be prepared to start with a Query or a bare expression tree; - * if it's a Query, go straight to query_tree_walker to make sure that - * sublevels_up doesn't get incremented prematurely. - */ - if (node && IsA(node, Query)) - query_tree_walker((Query *) node, IncrementVarSublevelsUp_walker, - (void *) &context, true); - else - IncrementVarSublevelsUp_walker(node, &context); -} - - -/* - * rangeTableEntry_used - detect whether an RTE is referenced somewhere - * in var nodes or join or setOp trees of a query or expression. - */ - -typedef struct -{ - int rt_index; - int sublevels_up; -} rangeTableEntry_used_context; - -static bool -rangeTableEntry_used_walker(Node *node, - rangeTableEntry_used_context *context) -{ - if (node == NULL) - return false; - if (IsA(node, Var)) - { - Var *var = (Var *) node; - - if (var->varlevelsup == context->sublevels_up && - var->varno == context->rt_index) - return true; - return false; - } - if (IsA(node, RangeTblRef)) - { - RangeTblRef *rtr = (RangeTblRef *) node; - - if (rtr->rtindex == context->rt_index && - context->sublevels_up == 0) - return true; - /* the subquery itself is visited separately */ - return false; - } - if (IsA(node, JoinExpr)) - { - JoinExpr *j = (JoinExpr *) node; - - if (j->rtindex == context->rt_index && - context->sublevels_up == 0) - return true; - /* fall through to examine children */ - } - if (IsA(node, Query)) - { - /* Recurse into subselects */ - bool result; - - context->sublevels_up++; - result = query_tree_walker((Query *) node, rangeTableEntry_used_walker, - (void *) context, true); - context->sublevels_up--; - return result; - } - return expression_tree_walker(node, rangeTableEntry_used_walker, - (void *) context); -} - -bool -rangeTableEntry_used(Node *node, int rt_index, int sublevels_up) -{ - rangeTableEntry_used_context context; - - context.rt_index = rt_index; - context.sublevels_up = sublevels_up; - - /* - * Must be prepared to start with a Query or a bare expression tree; - * if it's a Query, go straight to query_tree_walker to make sure that - * sublevels_up doesn't get incremented prematurely. - */ - if (node && IsA(node, Query)) - return query_tree_walker((Query *) node, rangeTableEntry_used_walker, - (void *) &context, true); - else - return rangeTableEntry_used_walker(node, &context); -} - - -/* - * attribute_used - - * Check if a specific attribute number of a RTE is used - * somewhere in the query or expression. - */ - -typedef struct -{ - int rt_index; - int attno; - int sublevels_up; -} attribute_used_context; - -static bool -attribute_used_walker(Node *node, - attribute_used_context *context) -{ - if (node == NULL) - return false; - if (IsA(node, Var)) - { - Var *var = (Var *) node; - - if (var->varlevelsup == context->sublevels_up && - var->varno == context->rt_index && - var->varattno == context->attno) - return true; - return false; - } - if (IsA(node, Query)) - { - /* Recurse into subselects */ - bool result; - - context->sublevels_up++; - result = query_tree_walker((Query *) node, attribute_used_walker, - (void *) context, true); - context->sublevels_up--; - return result; - } - return expression_tree_walker(node, attribute_used_walker, - (void *) context); -} - -bool -attribute_used(Node *node, int rt_index, int attno, int sublevels_up) -{ - attribute_used_context context; - - context.rt_index = rt_index; - context.attno = attno; - context.sublevels_up = sublevels_up; - - /* - * Must be prepared to start with a Query or a bare expression tree; - * if it's a Query, go straight to query_tree_walker to make sure that - * sublevels_up doesn't get incremented prematurely. - */ - if (node && IsA(node, Query)) - return query_tree_walker((Query *) node, attribute_used_walker, - (void *) &context, true); - else - return attribute_used_walker(node, &context); -} - - -/* - * If the given Query is an INSERT ... SELECT construct, extract and - * return the sub-Query node that represents the SELECT part. Otherwise - * return the given Query. - * - * If subquery_ptr is not NULL, then *subquery_ptr is set to the location - * of the link to the SELECT subquery inside parsetree, or NULL if not an - * INSERT ... SELECT. - * - * This is a hack needed because transformations on INSERT ... SELECTs that - * appear in rule actions should be applied to the source SELECT, not to the - * INSERT part. Perhaps this can be cleaned up with redesigned querytrees. - */ -Query * -getInsertSelectQuery(Query *parsetree, Query ***subquery_ptr) -{ - Query *selectquery; - RangeTblEntry *selectrte; - RangeTblRef *rtr; - - if (subquery_ptr) - *subquery_ptr = NULL; - - if (parsetree == NULL) - return parsetree; - if (parsetree->commandType != CMD_INSERT) - return parsetree; - - /* - * Currently, this is ONLY applied to rule-action queries, and so we - * expect to find the *OLD* and *NEW* placeholder entries in the given - * query. If they're not there, it must be an INSERT/SELECT in which - * they've been pushed down to the SELECT. - */ - if (length(parsetree->rtable) >= 2 && - strcmp(rt_fetch(PRS2_OLD_VARNO, parsetree->rtable)->eref->aliasname, - "*OLD*") == 0 && - strcmp(rt_fetch(PRS2_NEW_VARNO, parsetree->rtable)->eref->aliasname, - "*NEW*") == 0) - return parsetree; - Assert(parsetree->jointree && IsA(parsetree->jointree, FromExpr)); - if (length(parsetree->jointree->fromlist) != 1) - elog(ERROR, "getInsertSelectQuery: expected to find SELECT subquery"); - rtr = (RangeTblRef *) lfirst(parsetree->jointree->fromlist); - Assert(IsA(rtr, RangeTblRef)); - selectrte = rt_fetch(rtr->rtindex, parsetree->rtable); - selectquery = selectrte->subquery; - if (!(selectquery && IsA(selectquery, Query) && - selectquery->commandType == CMD_SELECT)) - elog(ERROR, "getInsertSelectQuery: expected to find SELECT subquery"); - if (length(selectquery->rtable) >= 2 && - strcmp(rt_fetch(PRS2_OLD_VARNO, selectquery->rtable)->eref->aliasname, - "*OLD*") == 0 && - strcmp(rt_fetch(PRS2_NEW_VARNO, selectquery->rtable)->eref->aliasname, - "*NEW*") == 0) - { - if (subquery_ptr) - *subquery_ptr = &(selectrte->subquery); - return selectquery; - } - elog(ERROR, "getInsertSelectQuery: can't find rule placeholders"); - return NULL; /* not reached */ -} - - -/* - * Add the given qualifier condition to the query's WHERE clause - */ -void -AddQual(Query *parsetree, Node *qual) -{ - Node *copy; - - if (qual == NULL) - return; - - if (parsetree->commandType == CMD_UTILITY) - { - /* - * There's noplace to put the qual on a utility statement. - * - * If it's a NOTIFY, silently ignore the qual; this means that the - * NOTIFY will execute, whether or not there are any qualifying - * rows. While clearly wrong, this is much more useful than - * refusing to execute the rule at all, and extra NOTIFY events - * are harmless for typical uses of NOTIFY. - * - * If it isn't a NOTIFY, error out, since unconditional execution of - * other utility stmts is unlikely to be wanted. (This case is - * not currently allowed anyway, but keep the test for safety.) - */ - if (parsetree->utilityStmt && IsA(parsetree->utilityStmt, NotifyStmt)) - return; - else - elog(ERROR, "Conditional utility statements are not implemented"); - } - - /* INTERSECT want's the original, but we need to copy - Jan */ - copy = copyObject(qual); - - parsetree->jointree->quals = make_and_qual(parsetree->jointree->quals, - copy); - - /* - * Make sure query is marked correctly if added qual has sublinks or - * aggregates (not sure it can ever have aggs, but sublinks - * definitely). - */ - parsetree->hasAggs |= checkExprHasAggs(copy); - parsetree->hasSubLinks |= checkExprHasSubLink(copy); -} - -/* - * Add the given havingQual to the one already contained in the parsetree - * just as AddQual does for the normal 'where' qual - */ -void -AddHavingQual(Query *parsetree, Node *havingQual) -{ - Node *copy; - - if (havingQual == NULL) - return; - - if (parsetree->commandType == CMD_UTILITY) - { - /* - * There's noplace to put the qual on a utility statement. - * - * See comments in AddQual for motivation. - */ - if (parsetree->utilityStmt && IsA(parsetree->utilityStmt, NotifyStmt)) - return; - else - elog(ERROR, "Conditional utility statements are not implemented"); - } - - /* INTERSECT want's the original, but we need to copy - Jan */ - copy = copyObject(havingQual); - - parsetree->havingQual = make_and_qual(parsetree->havingQual, - copy); - - /* - * Make sure query is marked correctly if added qual has sublinks or - * aggregates (not sure it can ever have aggs, but sublinks - * definitely). - */ - parsetree->hasAggs |= checkExprHasAggs(copy); - parsetree->hasSubLinks |= checkExprHasSubLink(copy); -} - -#ifdef NOT_USED -void -AddNotHavingQual(Query *parsetree, Node *havingQual) -{ - Node *notqual; - - if (havingQual == NULL) - return; - - /* Need not copy input qual, because AddHavingQual will... */ - notqual = (Node *) make_notclause((Expr *) havingQual); - - AddHavingQual(parsetree, notqual); -} -#endif - -void -AddNotQual(Query *parsetree, Node *qual) -{ - Node *notqual; - - if (qual == NULL) - return; - - /* Need not copy input qual, because AddQual will... */ - notqual = (Node *) make_notclause((Expr *) qual); - - AddQual(parsetree, notqual); -} - - -/* 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 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 - * - * Vars matching target_varno and sublevels_up are replaced by the - * entry with matching resno from targetlist, if there is one. - * If not, we either change the unmatched Var's varno to update_varno - * (when event == CMD_UPDATE) or replace it with a constant NULL. - */ - -typedef struct -{ - int target_varno; - int sublevels_up; - List *targetlist; - int event; - int update_varno; -} ResolveNew_context; - -static Node * -ResolveNew_mutator(Node *node, ResolveNew_context *context) -{ - if (node == NULL) - return NULL; - if (IsA(node, Var)) - { - Var *var = (Var *) node; - int this_varno = (int) var->varno; - int this_varlevelsup = (int) var->varlevelsup; - - if (this_varno == context->target_varno && - this_varlevelsup == context->sublevels_up) - { - Node *n; - - /* band-aid: don't do the wrong thing with a whole-tuple Var */ - if (var->varattno == InvalidAttrNumber) - elog(ERROR, "ResolveNew: can't handle whole-tuple reference"); - - n = FindMatchingNew(context->targetlist, var->varattno); - - if (n == NULL) - { - if (context->event == CMD_UPDATE) - { - /* For update, just change unmatched var's varno */ - var = (Var *) copyObject(node); - var->varno = context->update_varno; - var->varnoold = context->update_varno; - return (Node *) var; - } - else - { - /* Otherwise replace unmatched var with a null */ - return (Node *) makeNullConst(var->vartype); - } - } - else - { - /* 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 */ - } - - /* - * Since expression_tree_mutator won't touch subselects, we have to - * handle them specially. - */ - if (IsA(node, SubLink)) - { - SubLink *sublink = (SubLink *) node; - SubLink *newnode; - - FLATCOPY(newnode, sublink, SubLink); - MUTATE(newnode->lefthand, sublink->lefthand, List *, - ResolveNew_mutator, context); - MUTATE(newnode->subselect, sublink->subselect, Node *, - ResolveNew_mutator, context); - return (Node *) newnode; - } - if (IsA(node, Query)) - { - Query *query = (Query *) node; - Query *newnode; - - FLATCOPY(newnode, query, Query); - context->sublevels_up++; - query_tree_mutator(newnode, ResolveNew_mutator, context, true); - context->sublevels_up--; - return (Node *) newnode; - } - return expression_tree_mutator(node, ResolveNew_mutator, - (void *) context); -} - -Node * -ResolveNew(Node *node, int target_varno, int sublevels_up, - List *targetlist, int event, int update_varno) -{ - ResolveNew_context context; - - context.target_varno = target_varno; - context.sublevels_up = sublevels_up; - context.targetlist = targetlist; - context.event = event; - context.update_varno = update_varno; - - /* - * Must be prepared to start with a Query or a bare expression tree; - * if it's a Query, go straight to query_tree_mutator to make sure - * that sublevels_up doesn't get incremented prematurely. - */ - if (node && IsA(node, Query)) - { - Query *query = (Query *) node; - Query *newnode; - - FLATCOPY(newnode, query, Query); - query_tree_mutator(newnode, ResolveNew_mutator, - (void *) &context, true); - return (Node *) newnode; - } - else - return ResolveNew_mutator(node, &context); -} - - -#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 */ - } - - /* - * Since expression_tree_mutator won't touch subselects, we have to - * handle them specially. - */ - if (IsA(node, SubLink)) - { - SubLink *sublink = (SubLink *) node; - SubLink *newnode; - - FLATCOPY(newnode, sublink, SubLink); - MUTATE(newnode->lefthand, sublink->lefthand, List *, - HandleRIRAttributeRule_mutator, context); - MUTATE(newnode->subselect, sublink->subselect, Node *, - HandleRIRAttributeRule_mutator, context); - return (Node *) newnode; - } - if (IsA(node, Query)) - { - Query *query = (Query *) node; - Query *newnode; - - FLATCOPY(newnode, query, Query); - context->sublevels_up++; - query_tree_mutator(newnode, HandleRIRAttributeRule_mutator, - context, true); - 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, true); -} - -#endif /* NOT_USED */ |