/*------------------------------------------------------------------------- * * rewriteDefine.c-- * routines for defining a rewrite rule * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $Header: /usr/local/cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.6 1997/09/08 21:46:35 momjian Exp $ * *------------------------------------------------------------------------- */ #include #include #include "postgres.h" #include "utils/rel.h" /* for Relation stuff */ #include "access/heapam.h" /* access methods like amopenr */ #include "utils/builtins.h" #include "utils/elog.h" /* for elog */ #include "utils/palloc.h" #include "utils/lsyscache.h" /* for get_typlen */ #include "nodes/pg_list.h" /* for Lisp support */ #include "nodes/parsenodes.h" #include "parser/catalog_utils.h" #include "rewrite/locks.h" #include "rewrite/rewriteDefine.h" #include "rewrite/rewriteRemove.h" #include "rewrite/rewriteSupport.h" #include "tcop/tcopprot.h" Oid LastOidProcessed = InvalidOid; /* * This is too small for many rule plans, but it'll have to do for now. * Rule plans, etc will eventually have to be large objects. * * should this be smaller? */ #define RULE_PLAN_SIZE 8192 static void strcpyq(char *dest, char *source) { char *current = source, *destp = dest; for (current = source; *current; current++) { if (*current == '\"') { *destp = '\\'; destp++; } *destp = *current; destp++; } *destp = '\0'; } /* * InsertRule - * takes the arguments and inserts them as attributes into the system * relation "pg_rewrite" * * MODS : changes the value of LastOidProcessed as a side * effect of inserting the rule tuple * * ARGS : rulname - name of the rule * evtype - one of RETRIEVE,REPLACE,DELETE,APPEND * evobj - name of relation * evslot - comma delimited list of slots * if null => multi-attr rule * evinstead - is an instead rule * actiontree - parsetree(s) of rule action */ static Oid InsertRule(char *rulname, int evtype, char *evobj, char *evslot, char *evqual, bool evinstead, char *actiontree) { static char rulebuf[RULE_PLAN_SIZE]; static char actionbuf[RULE_PLAN_SIZE]; static char qualbuf[RULE_PLAN_SIZE]; Oid eventrel_oid = InvalidOid; AttrNumber evslot_index = InvalidAttrNumber; Relation eventrel = NULL; char *is_instead = "f"; extern void eval_as_new_xact(); char *template; eventrel = heap_openr(evobj); if (eventrel == NULL) { elog(WARN, "rules cannot be defined on relations not in schema"); } eventrel_oid = RelationGetRelationId(eventrel); /* * if the slotname is null, we know that this is a multi-attr rule */ if (evslot == NULL) evslot_index = -1; else evslot_index = varattno(eventrel, (char *) evslot); heap_close(eventrel); if (evinstead) is_instead = "t"; if (evqual == NULL) evqual = "nil"; if (IsDefinedRewriteRule(rulname)) elog(WARN, "Attempt to insert rule '%s' failed: already exists", rulname); strcpyq(actionbuf, actiontree); strcpyq(qualbuf, evqual); template = "INSERT INTO pg_rewrite \ (rulename, ev_type, ev_class, ev_attr, action, ev_qual, is_instead) VALUES \ ('%s', %d::char, %d::oid, %d::int2, '%s'::text, '%s'::text, \ '%s'::bool);"; if (strlen(template) + strlen(rulname) + strlen(actionbuf) + strlen(qualbuf) + 20 /* fudge fac */ > RULE_PLAN_SIZE) { elog(WARN, "DefineQueryRewrite: rule plan string too big."); } sprintf(rulebuf, template, rulname, evtype, eventrel_oid, evslot_index, actionbuf, qualbuf, is_instead); pg_eval(rulebuf, (char **) NULL, (Oid *) NULL, 0); return (LastOidProcessed); } /* * for now, event_object must be a single attribute */ static void ValidateRule(int event_type, char *eobj_string, char *eslot_string, Node *event_qual, List **action, int is_instead, Oid event_attype) { if (((event_type == CMD_INSERT) || (event_type == CMD_DELETE)) && eslot_string) { elog(WARN, "rules not allowed for insert or delete events to an attribute"); } if (event_qual && !*action && is_instead) elog(WARN, "event_quals on 'instead nothing' rules not currently supported"); #if 0 /* * on retrieve to class.attribute do instead nothing is converted to * 'on retrieve to class.attribute do instead retrieve (attribute = * NULL)' --- this is also a terrible hack that works well -- glass */ if (is_instead && !*action && eslot_string && event_type == CMD_SELECT) { char *temp_buffer = (char *) palloc(strlen(template) + 80); sprintf(temp_buffer, template, event_attype, get_typlen(event_attype), eslot_string, event_attype); *action = (List *) stringToNode(temp_buffer); pfree(temp_buffer); } #endif } void DefineQueryRewrite(RuleStmt *stmt) { CmdType event_type = stmt->event; Attr *event_obj = stmt->object; Node *event_qual = stmt->whereClause; bool is_instead = stmt->instead; List *action = stmt->actions; Relation event_relation = NULL; Oid ruleId; Oid ev_relid = 0; char *eslot_string = NULL; int event_attno = 0; Oid event_attype = 0; char *actionP, *event_qualP; if (event_obj->attrs) eslot_string = strVal(lfirst(event_obj->attrs)); else eslot_string = NULL; event_relation = heap_openr(event_obj->relname); if (event_relation == NULL) { elog(WARN, "virtual relations not supported yet"); } ev_relid = RelationGetRelationId(event_relation); if (eslot_string == NULL) { event_attno = -1; event_attype = -1; /* XXX - don't care */ } else { event_attno = varattno(event_relation, eslot_string); event_attype = att_typeid(event_relation, event_attno); } heap_close(event_relation); /* fix bug about instead nothing */ ValidateRule(event_type, event_obj->relname, eslot_string, event_qual, &action, is_instead, event_attype); if (action == NULL) { if (!is_instead) return; /* doesn't do anything */ event_qualP = nodeToString(event_qual); ruleId = InsertRule(stmt->rulename, event_type, event_obj->relname, eslot_string, event_qualP, true, "nil"); prs2_addToRelation(ev_relid, ruleId, event_type, event_attno, TRUE, event_qual, NIL); } else { event_qualP = nodeToString(event_qual); actionP = nodeToString(action); ruleId = InsertRule(stmt->rulename, event_type, event_obj->relname, eslot_string, event_qualP, is_instead, actionP); /* what is the max size of type text? XXX -- glass */ if (length(action) > 15) elog(WARN, "max # of actions exceeded"); prs2_addToRelation(ev_relid, ruleId, event_type, event_attno, is_instead, event_qual, action); } }