/********************************************************************** * ruleutils.c - Functions to convert stored expressions/querytrees * back to source text * * IDENTIFICATION * $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.86 2001/10/25 05:49:45 momjian Exp $ * * This software is copyrighted by Jan Wieck - Hamburg. * * The author hereby grants permission to use, copy, modify, * distribute, and license this software and its documentation * for any purpose, provided that existing copyright notices are * retained in all copies and that this notice is included * verbatim in any distributions. No written agreement, license, * or royalty fee is required for any of the authorized uses. * Modifications to this software may be copyrighted by their * author and need not follow the licensing terms described * here, provided that the new terms are clearly indicated on * the first page of each file where they apply. * * IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR * CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF THIS * SOFTWARE, ITS DOCUMENTATION, OR ANY DERIVATIVES THEREOF, EVEN * IF THE AUTHOR HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH * DAMAGE. * * THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR * PURPOSE, AND NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON * AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAVE NO * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, * ENHANCEMENTS, OR MODIFICATIONS. * **********************************************************************/ #include "postgres.h" #include #include #include "catalog/heap.h" #include "catalog/index.h" #include "catalog/pg_index.h" #include "catalog/pg_opclass.h" #include "catalog/pg_operator.h" #include "catalog/pg_shadow.h" #include "executor/spi.h" #include "lib/stringinfo.h" #include "optimizer/clauses.h" #include "optimizer/tlist.h" #include "parser/keywords.h" #include "parser/parse_expr.h" #include "parser/parsetree.h" #include "rewrite/rewriteManip.h" #include "rewrite/rewriteSupport.h" #include "utils/lsyscache.h" /* ---------- * Local data types * ---------- */ /* Context info needed for invoking a recursive querytree display routine */ typedef struct { StringInfo buf; /* output buffer to append to */ List *namespaces; /* List of deparse_namespace nodes */ bool varprefix; /* TRUE to print prefixes on Vars */ } deparse_context; /* * Each level of query context around a subtree needs a level of Var namespace. * The rangetable is the list of actual RTEs, and the namespace indicates * which parts of the rangetable are accessible (and under what aliases) * in the expression currently being looked at. A Var having varlevelsup=N * refers to the N'th item (counting from 0) in the current context's * namespaces list. */ typedef struct { List *rtable; /* List of RangeTblEntry nodes */ List *namespace; /* List of joinlist items (RangeTblRef and * JoinExpr nodes) */ } deparse_namespace; /* ---------- * Global data * ---------- */ static char *rulename = NULL; static void *plan_getrule = NULL; static char *query_getrule = "SELECT * FROM pg_rewrite WHERE rulename = $1"; static void *plan_getview = NULL; static char *query_getview = "SELECT * FROM pg_rewrite WHERE rulename = $1"; /* ---------- * Local functions * * Most of these functions used to use fixed-size buffers to build their * results. Now, they take an (already initialized) StringInfo object * as a parameter, and append their text output to its contents. * ---------- */ static void make_ruledef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc); static void make_viewdef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc); static void get_query_def(Query *query, StringInfo buf, List *parentnamespace); static void get_select_query_def(Query *query, deparse_context *context); static void get_insert_query_def(Query *query, deparse_context *context); static void get_update_query_def(Query *query, deparse_context *context); static void get_delete_query_def(Query *query, deparse_context *context); static void get_utility_query_def(Query *query, deparse_context *context); static void get_basic_select_query(Query *query, deparse_context *context); static void get_setop_query(Node *setOp, Query *query, deparse_context *context, bool toplevel); static void get_rule_sortgroupclause(SortClause *srt, List *tlist, bool force_colno, deparse_context *context); static void get_names_for_var(Var *var, deparse_context *context, char **refname, char **attname); static bool get_alias_for_case(CaseExpr *caseexpr, deparse_context *context, char **refname, char **attname); static bool find_alias_in_namespace(Node *nsnode, Node *expr, List *rangetable, int levelsup, char **refname, char **attname); static bool phony_equal(Node *expr1, Node *expr2, int levelsup); static void get_rule_expr(Node *node, deparse_context *context); static void get_func_expr(Expr *expr, deparse_context *context); static Node *strip_type_coercion(Node *expr, Oid resultType); static void get_tle_expr(TargetEntry *tle, deparse_context *context); static void get_const_expr(Const *constval, deparse_context *context); static void get_sublink_expr(Node *node, deparse_context *context); static void get_from_clause(Query *query, deparse_context *context); static void get_from_clause_item(Node *jtnode, Query *query, deparse_context *context); static void get_opclass_name(Oid opclass, Oid actual_datatype, StringInfo buf); static bool tleIsArrayAssign(TargetEntry *tle); static char *quote_identifier(char *ident); static char *get_relation_name(Oid relid); static char *get_relid_attribute_name(Oid relid, AttrNumber attnum); #define only_marker(rte) ((rte)->inh ? "" : "ONLY ") /* ---------- * get_ruledef - Do it all and return a text * that could be used as a statement * to recreate the rule * ---------- */ Datum pg_get_ruledef(PG_FUNCTION_ARGS) { Name rname = PG_GETARG_NAME(0); text *ruledef; Datum args[1]; char nulls[2]; int spirc; HeapTuple ruletup; TupleDesc rulettc; StringInfoData buf; int len; /* * We need the rules name somewhere deep down: rulename is global */ rulename = pstrdup(NameStr(*rname)); /* * Connect to SPI manager */ if (SPI_connect() != SPI_OK_CONNECT) elog(ERROR, "get_ruledef: cannot connect to SPI manager"); /* * On the first call prepare the plan to lookup pg_proc. We read * pg_proc over the SPI manager instead of using the syscache to be * checked for read access on pg_proc. */ if (plan_getrule == NULL) { Oid argtypes[1]; void *plan; argtypes[0] = NAMEOID; plan = SPI_prepare(query_getrule, 1, argtypes); if (plan == NULL) elog(ERROR, "SPI_prepare() failed for \"%s\"", query_getrule); plan_getrule = SPI_saveplan(plan); } /* * Get the pg_rewrite tuple for this rule */ args[0] = PointerGetDatum(rulename); nulls[0] = (rulename == NULL) ? 'n' : ' '; nulls[1] = '\0'; spirc = SPI_execp(plan_getrule, args, nulls, 1); if (spirc != SPI_OK_SELECT) elog(ERROR, "failed to get pg_rewrite tuple for %s", rulename); if (SPI_processed != 1) { if (SPI_finish() != SPI_OK_FINISH) elog(ERROR, "get_ruledef: SPI_finish() failed"); ruledef = palloc(VARHDRSZ + 1); VARATT_SIZEP(ruledef) = VARHDRSZ + 1; VARDATA(ruledef)[0] = '-'; PG_RETURN_TEXT_P(ruledef); } ruletup = SPI_tuptable->vals[0]; rulettc = SPI_tuptable->tupdesc; /* * Get the rules definition and put it into executors memory */ initStringInfo(&buf); make_ruledef(&buf, ruletup, rulettc); len = buf.len + VARHDRSZ; ruledef = SPI_palloc(len); VARATT_SIZEP(ruledef) = len; memcpy(VARDATA(ruledef), buf.data, buf.len); pfree(buf.data); /* * Disconnect from SPI manager */ if (SPI_finish() != SPI_OK_FINISH) elog(ERROR, "get_ruledef: SPI_finish() failed"); /* * Easy - isn't it? */ PG_RETURN_TEXT_P(ruledef); } /* ---------- * get_viewdef - Mainly the same thing, but we * only return the SELECT part of a view * ---------- */ Datum pg_get_viewdef(PG_FUNCTION_ARGS) { Name vname = PG_GETARG_NAME(0); text *ruledef; Datum args[1]; char nulls[1]; int spirc; HeapTuple ruletup; TupleDesc rulettc; StringInfoData buf; int len; char *name; /* * We need the view name somewhere deep down */ rulename = pstrdup(NameStr(*vname)); /* * Connect to SPI manager */ if (SPI_connect() != SPI_OK_CONNECT) elog(ERROR, "get_viewdef: cannot connect to SPI manager"); /* * On the first call prepare the plan to lookup pg_proc. We read * pg_proc over the SPI manager instead of using the syscache to be * checked for read access on pg_proc. */ if (plan_getview == NULL) { Oid argtypes[1]; void *plan; argtypes[0] = NAMEOID; plan = SPI_prepare(query_getview, 1, argtypes); if (plan == NULL) elog(ERROR, "SPI_prepare() failed for \"%s\"", query_getview); plan_getview = SPI_saveplan(plan); } /* * Get the pg_rewrite tuple for this rule: rulename is actually * viewname here */ name = MakeRetrieveViewRuleName(rulename); args[0] = PointerGetDatum(name); nulls[0] = ' '; spirc = SPI_execp(plan_getview, args, nulls, 1); if (spirc != SPI_OK_SELECT) elog(ERROR, "failed to get pg_rewrite tuple for view %s", rulename); initStringInfo(&buf); if (SPI_processed != 1) appendStringInfo(&buf, "Not a view"); else { /* * Get the rules definition and put it into executors memory */ ruletup = SPI_tuptable->vals[0]; rulettc = SPI_tuptable->tupdesc; make_viewdef(&buf, ruletup, rulettc); } len = buf.len + VARHDRSZ; ruledef = SPI_palloc(len); VARATT_SIZEP(ruledef) = len; memcpy(VARDATA(ruledef), buf.data, buf.len); pfree(buf.data); pfree(name); /* * Disconnect from SPI manager */ if (SPI_finish() != SPI_OK_FINISH) elog(ERROR, "get_viewdef: SPI_finish() failed"); /* * Easy - isn't it? */ PG_RETURN_TEXT_P(ruledef); } /* ---------- * get_indexdef - Get the definition of an index * ---------- */ Datum pg_get_indexdef(PG_FUNCTION_ARGS) { Oid indexrelid = PG_GETARG_OID(0); text *indexdef; HeapTuple ht_idx; HeapTuple ht_idxrel; HeapTuple ht_indrel; Form_pg_index idxrec; Form_pg_class idxrelrec; Form_pg_class indrelrec; Form_pg_am amrec; int len; int keyno; StringInfoData buf; StringInfoData keybuf; char *sep; /* * Fetch the pg_index tuple by the Oid of the index */ ht_idx = SearchSysCache(INDEXRELID, ObjectIdGetDatum(indexrelid), 0, 0, 0); if (!HeapTupleIsValid(ht_idx)) elog(ERROR, "syscache lookup for index %u failed", indexrelid); idxrec = (Form_pg_index) GETSTRUCT(ht_idx); /* * Fetch the pg_class tuple of the index relation */ ht_idxrel = SearchSysCache(RELOID, ObjectIdGetDatum(idxrec->indexrelid), 0, 0, 0); if (!HeapTupleIsValid(ht_idxrel)) elog(ERROR, "syscache lookup for relid %u failed", idxrec->indexrelid); idxrelrec = (Form_pg_class) GETSTRUCT(ht_idxrel); /* * Fetch the pg_class tuple of the indexed relation */ ht_indrel = SearchSysCache(RELOID, ObjectIdGetDatum(idxrec->indrelid), 0, 0, 0); if (!HeapTupleIsValid(ht_indrel)) elog(ERROR, "syscache lookup for relid %u failed", idxrec->indrelid); indrelrec = (Form_pg_class) GETSTRUCT(ht_indrel); /* * Fetch the pg_am tuple of the index' access method * * There is no syscache for this, so use index.c subroutine. */ amrec = AccessMethodObjectIdGetForm(idxrelrec->relam, CurrentMemoryContext); if (!amrec) elog(ERROR, "lookup for AM %u failed", idxrelrec->relam); /* * Start the index definition */ initStringInfo(&buf); appendStringInfo(&buf, "CREATE %sINDEX %s ON %s USING %s (", idxrec->indisunique ? "UNIQUE " : "", quote_identifier(NameStr(idxrelrec->relname)), quote_identifier(NameStr(indrelrec->relname)), quote_identifier(NameStr(amrec->amname))); /* * Collect the indexed attributes in keybuf */ initStringInfo(&keybuf); sep = ""; for (keyno = 0; keyno < INDEX_MAX_KEYS; keyno++) { AttrNumber attnum = idxrec->indkey[keyno]; if (attnum == InvalidAttrNumber) break; appendStringInfo(&keybuf, sep); sep = ", "; /* * Add the indexed field name */ appendStringInfo(&keybuf, "%s", quote_identifier(get_relid_attribute_name(idxrec->indrelid, attnum))); /* * If not a functional index, add the operator class name */ if (idxrec->indproc == InvalidOid) get_opclass_name(idxrec->indclass[keyno], get_atttype(idxrec->indrelid, attnum), &keybuf); } if (idxrec->indproc != InvalidOid) { /* * For functional index say 'func (attrs) opclass' */ HeapTuple proctup; Form_pg_proc procStruct; proctup = SearchSysCache(PROCOID, ObjectIdGetDatum(idxrec->indproc), 0, 0, 0); if (!HeapTupleIsValid(proctup)) elog(ERROR, "cache lookup for proc %u failed", idxrec->indproc); procStruct = (Form_pg_proc) GETSTRUCT(proctup); appendStringInfo(&buf, "%s(%s)", quote_identifier(NameStr(procStruct->proname)), keybuf.data); get_opclass_name(idxrec->indclass[0], procStruct->prorettype, &buf); ReleaseSysCache(proctup); } else { /* * Otherwise say 'attr opclass [, ...]' */ appendStringInfo(&buf, "%s", keybuf.data); } appendStringInfo(&buf, ")"); /* * If it's a partial index, decompile and append the predicate */ if (VARSIZE(&idxrec->indpred) > VARHDRSZ) { Node *node; List *context; char *exprstr; char *str; /* Convert TEXT object to C string */ exprstr = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(&idxrec->indpred))); /* Convert expression to node tree */ node = (Node *) stringToNode(exprstr); /* * If top level is a List, assume it is an implicit-AND structure, * and convert to explicit AND. This is needed for partial index * predicates. */ if (node && IsA(node, List)) node = (Node *) make_ands_explicit((List *) node); /* Deparse */ context = deparse_context_for(NameStr(indrelrec->relname), idxrec->indrelid); str = deparse_expression(node, context, false); appendStringInfo(&buf, " WHERE %s", str); } /* * Create the result as a TEXT datum, and free working data */ len = buf.len + VARHDRSZ; indexdef = (text *) palloc(len); VARATT_SIZEP(indexdef) = len; memcpy(VARDATA(indexdef), buf.data, buf.len); pfree(buf.data); pfree(keybuf.data); pfree(amrec); ReleaseSysCache(ht_idx); ReleaseSysCache(ht_idxrel); ReleaseSysCache(ht_indrel); PG_RETURN_TEXT_P(indexdef); } /* ---------- * get_expr - Decompile an expression tree * * Input: an expression tree in nodeToString form, and a relation OID * * Output: reverse-listed expression * * Currently, the expression can only refer to a single relation, namely * the one specified by the second parameter. This is sufficient for * partial indexes, column default expressions, etc. * ---------- */ Datum pg_get_expr(PG_FUNCTION_ARGS) { text *expr = PG_GETARG_TEXT_P(0); Oid relid = PG_GETARG_OID(1); text *result; Node *node; List *context; char *exprstr; char *relname; char *str; /* Get the name for the relation */ relname = get_rel_name(relid); if (relname == NULL) PG_RETURN_NULL(); /* should we raise an error? */ /* Convert input TEXT object to C string */ exprstr = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(expr))); /* Convert expression to node tree */ node = (Node *) stringToNode(exprstr); /* * If top level is a List, assume it is an implicit-AND structure, and * convert to explicit AND. This is needed for partial index * predicates. */ if (node && IsA(node, List)) node = (Node *) make_ands_explicit((List *) node); /* Deparse */ context = deparse_context_for(relname, relid); str = deparse_expression(node, context, false); /* Pass the result back as TEXT */ result = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(str))); PG_RETURN_TEXT_P(result); } /* ---------- * get_userbyid - Get a user name by usesysid and * fallback to 'unknown (UID=n)' * ---------- */ Datum pg_get_userbyid(PG_FUNCTION_ARGS) { int32 uid = PG_GETARG_INT32(0); Name result; HeapTuple usertup; Form_pg_shadow user_rec; /* * Allocate space for the result */ result = (Name) palloc(NAMEDATALEN); memset(NameStr(*result), 0, NAMEDATALEN); /* * Get the pg_shadow entry and print the result */ usertup = SearchSysCache(SHADOWSYSID, ObjectIdGetDatum(uid), 0, 0, 0); if (HeapTupleIsValid(usertup)) { user_rec = (Form_pg_shadow) GETSTRUCT(usertup); StrNCpy(NameStr(*result), NameStr(user_rec->usename), NAMEDATALEN); ReleaseSysCache(usertup); } else sprintf(NameStr(*result), "unknown (UID=%d)", uid); PG_RETURN_NAME(result); } /* ---------- * deparse_expression - General utility for deparsing expressions * * expr is the node tree to be deparsed. It must be a transformed expression * tree (ie, not the raw output of gram.y). * * dpcontext is a list of deparse_namespace nodes representing the context * for interpreting Vars in the node tree. * * forceprefix is TRUE to force all Vars to be prefixed with their table names. * * The result is a palloc'd string. * ---------- */ char * deparse_expression(Node *expr, List *dpcontext, bool forceprefix) { StringInfoData buf; deparse_context context; initStringInfo(&buf); context.buf = &buf; context.namespaces = dpcontext; context.varprefix = forceprefix; rulename = ""; /* in case of errors */ get_rule_expr(expr, &context); return buf.data; } /* ---------- * deparse_context_for - Build deparse context for a single relation * * Given the name and OID of a relation, build deparsing context for an * expression referencing only that relation (as varno 1, varlevelsup 0). * This is presently sufficient for the external uses of deparse_expression. * ---------- */ List * deparse_context_for(char *relname, Oid relid) { deparse_namespace *dpns; RangeTblEntry *rte; RangeTblRef *rtr; dpns = (deparse_namespace *) palloc(sizeof(deparse_namespace)); /* Build a minimal RTE for the rel */ rte = makeNode(RangeTblEntry); rte->relname = relname; rte->relid = relid; rte->eref = makeNode(Attr); rte->eref->relname = relname; rte->inh = false; rte->inFromCl = true; /* Build one-element rtable */ dpns->rtable = makeList1(rte); /* Build a namespace list referencing this RTE only */ rtr = makeNode(RangeTblRef); rtr->rtindex = 1; dpns->namespace = makeList1(rtr); /* Return a one-deep namespace stack */ return makeList1(dpns); } /* ---------- * make_ruledef - reconstruct the CREATE RULE command * for a given pg_rewrite tuple * ---------- */ static void make_ruledef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc) { char ev_type; Oid ev_class; int2 ev_attr; bool is_instead; char *ev_qual; char *ev_action; List *actions = NIL; int fno; bool isnull; /* * Get the attribute values from the rules tuple */ fno = SPI_fnumber(rulettc, "ev_type"); ev_type = (char) SPI_getbinval(ruletup, rulettc, fno, &isnull); fno = SPI_fnumber(rulettc, "ev_class"); ev_class = (Oid) SPI_getbinval(ruletup, rulettc, fno, &isnull); fno = SPI_fnumber(rulettc, "ev_attr"); ev_attr = (int2) SPI_getbinval(ruletup, rulettc, fno, &isnull); fno = SPI_fnumber(rulettc, "is_instead"); is_instead = (bool) SPI_getbinval(ruletup, rulettc, fno, &isnull); fno = SPI_fnumber(rulettc, "ev_qual"); ev_qual = SPI_getvalue(ruletup, rulettc, fno); fno = SPI_fnumber(rulettc, "ev_action"); ev_action = SPI_getvalue(ruletup, rulettc, fno); if (ev_action != NULL) actions = (List *) stringToNode(ev_action); /* * Build the rules definition text */ appendStringInfo(buf, "CREATE RULE %s AS ON ", quote_identifier(rulename)); /* The event the rule is fired for */ switch (ev_type) { case '1': appendStringInfo(buf, "SELECT"); break; case '2': appendStringInfo(buf, "UPDATE"); break; case '3': appendStringInfo(buf, "INSERT"); break; case '4': appendStringInfo(buf, "DELETE"); break; default: elog(ERROR, "get_ruledef: rule %s has unsupported event type %d", rulename, ev_type); break; } /* The relation the rule is fired on */ appendStringInfo(buf, " TO %s", quote_identifier(get_relation_name(ev_class))); if (ev_attr > 0) appendStringInfo(buf, ".%s", quote_identifier(get_relid_attribute_name(ev_class, ev_attr))); /* If the rule has an event qualification, add it */ if (ev_qual == NULL) ev_qual = ""; if (strlen(ev_qual) > 0 && strcmp(ev_qual, "<>") != 0) { Node *qual; Query *query; deparse_context context; deparse_namespace dpns; appendStringInfo(buf, " WHERE "); qual = stringToNode(ev_qual); query = (Query *) lfirst(actions); context.buf = buf; context.namespaces = makeList1(&dpns); context.varprefix = (length(query->rtable) != 1); dpns.rtable = query->rtable; dpns.namespace = query->jointree ? query->jointree->fromlist : NIL; get_rule_expr(qual, &context); } appendStringInfo(buf, " DO "); /* The INSTEAD keyword (if so) */ if (is_instead) appendStringInfo(buf, "INSTEAD "); /* Finally the rules actions */ if (length(actions) > 1) { List *action; Query *query; appendStringInfo(buf, "("); foreach(action, actions) { query = (Query *) lfirst(action); get_query_def(query, buf, NIL); appendStringInfo(buf, "; "); } appendStringInfo(buf, ");"); } else { if (length(actions) == 0) { appendStringInfo(buf, "NOTHING;"); } else { Query *query; query = (Query *) lfirst(actions); get_query_def(query, buf, NIL); appendStringInfo(buf, ";"); } } } /* ---------- * make_viewdef - reconstruct the SELECT part of a * view rewrite rule * ---------- */ static void make_viewdef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc) { Query *query; char ev_type; Oid ev_class; int2 ev_attr; bool is_instead; char *ev_qual; char *ev_action; List *actions = NIL; int fno; bool isnull; /* * Get the attribute values from the rules tuple */ fno = SPI_fnumber(rulettc, "ev_type"); ev_type = (char) SPI_getbinval(ruletup, rulettc, fno, &isnull); fno = SPI_fnumber(rulettc, "ev_class"); ev_class = (Oid) SPI_getbinval(ruletup, rulettc, fno, &isnull); fno = SPI_fnumber(rulettc, "ev_attr"); ev_attr = (int2) SPI_getbinval(ruletup, rulettc, fno, &isnull); fno = SPI_fnumber(rulettc, "is_instead"); is_instead = (bool) SPI_getbinval(ruletup, rulettc, fno, &isnull); fno = SPI_fnumber(rulettc, "ev_qual"); ev_qual = SPI_getvalue(ruletup, rulettc, fno); fno = SPI_fnumber(rulettc, "ev_action"); ev_action = SPI_getvalue(ruletup, rulettc, fno); if (ev_action != NULL) actions = (List *) stringToNode(ev_action); if (length(actions) != 1) { appendStringInfo(buf, "Not a view"); return; } query = (Query *) lfirst(actions); if (ev_type != '1' || ev_attr >= 0 || !is_instead || strcmp(ev_qual, "<>") != 0) { appendStringInfo(buf, "Not a view"); return; } get_query_def(query, buf, NIL); appendStringInfo(buf, ";"); } /* ---------- * get_query_def - Parse back one action from * the parsetree in the actions * list * ---------- */ static void get_query_def(Query *query, StringInfo buf, List *parentnamespace) { deparse_context context; deparse_namespace dpns; context.buf = buf; context.namespaces = lcons(&dpns, parentnamespace); context.varprefix = (parentnamespace != NIL || length(query->rtable) != 1); dpns.rtable = query->rtable; dpns.namespace = query->jointree ? query->jointree->fromlist : NIL; switch (query->commandType) { case CMD_SELECT: get_select_query_def(query, &context); break; case CMD_UPDATE: get_update_query_def(query, &context); break; case CMD_INSERT: get_insert_query_def(query, &context); break; case CMD_DELETE: get_delete_query_def(query, &context); break; case CMD_NOTHING: appendStringInfo(buf, "NOTHING"); break; case CMD_UTILITY: get_utility_query_def(query, &context); break; default: elog(ERROR, "get_ruledef of %s: query command type %d not implemented yet", rulename, query->commandType); break; } } /* ---------- * get_select_query_def - Parse back a SELECT parsetree * ---------- */ static void get_select_query_def(Query *query, deparse_context *context) { StringInfo buf = context->buf; bool force_colno; char *sep; List *l; /* * If the Query node has a setOperations tree, then it's the top level * of a UNION/INTERSECT/EXCEPT query; only the ORDER BY and LIMIT * fields are interesting in the top query itself. */ if (query->setOperations) { get_setop_query(query->setOperations, query, context, true); /* ORDER BY clauses must be simple in this case */ force_colno = true; } else { get_basic_select_query(query, context); force_colno = false; } /* Add the ORDER BY clause if given */ if (query->sortClause != NIL) { appendStringInfo(buf, " ORDER BY "); sep = ""; foreach(l, query->sortClause) { SortClause *srt = (SortClause *) lfirst(l); char *opname; appendStringInfo(buf, sep); get_rule_sortgroupclause(srt, query->targetList, force_colno, context); opname = get_opname(srt->sortop); if (strcmp(opname, "<") != 0) { if (strcmp(opname, ">") == 0) appendStringInfo(buf, " DESC"); else appendStringInfo(buf, " USING %s", opname); } sep = ", "; } } /* Add the LIMIT clause if given */ if (query->limitOffset != NULL) { appendStringInfo(buf, " OFFSET "); get_rule_expr(query->limitOffset, context); } if (query->limitCount != NULL) { appendStringInfo(buf, " LIMIT "); if (IsA(query->limitCount, Const) && ((Const *) query->limitCount)->constisnull) appendStringInfo(buf, "ALL"); else get_rule_expr(query->limitCount, context); } } static void get_basic_select_query(Query *query, deparse_context *context) { StringInfo buf = context->buf; char *sep; List *l; /* * Build up the query string - first we say SELECT */ appendStringInfo(buf, "SELECT"); /* Add the DISTINCT clause if given */ if (query->distinctClause != NIL) { if (has_distinct_on_clause(query)) { appendStringInfo(buf, " DISTINCT ON ("); sep = ""; foreach(l, query->distinctClause) { SortClause *srt = (SortClause *) lfirst(l); appendStringInfo(buf, sep); get_rule_sortgroupclause(srt, query->targetList, false, context); sep = ", "; } appendStringInfo(buf, ")"); } else appendStringInfo(buf, " DISTINCT"); } /* Then we tell what to select (the targetlist) */ sep = " "; foreach(l, query->targetList) { TargetEntry *tle = (TargetEntry *) lfirst(l); bool tell_as = false; if (tle->resdom->resjunk) continue; /* ignore junk entries */ appendStringInfo(buf, sep); sep = ", "; /* Do NOT use get_tle_expr here; see its comments! */ get_rule_expr(tle->expr, context); /* Check if we must say AS ... */ if (!IsA(tle->expr, Var)) tell_as = (strcmp(tle->resdom->resname, "?column?") != 0); else { Var *var = (Var *) (tle->expr); char *refname; char *attname; get_names_for_var(var, context, &refname, &attname); tell_as = (attname == NULL || strcmp(attname, tle->resdom->resname) != 0); } /* and do if so */ if (tell_as) appendStringInfo(buf, " AS %s", quote_identifier(tle->resdom->resname)); } /* Add the FROM clause if needed */ get_from_clause(query, context); /* Add the WHERE clause if given */ if (query->jointree->quals != NULL) { appendStringInfo(buf, " WHERE "); get_rule_expr(query->jointree->quals, context); } /* Add the GROUP BY clause if given */ if (query->groupClause != NULL) { appendStringInfo(buf, " GROUP BY "); sep = ""; foreach(l, query->groupClause) { GroupClause *grp = (GroupClause *) lfirst(l); appendStringInfo(buf, sep); get_rule_sortgroupclause(grp, query->targetList, false, context); sep = ", "; } } /* Add the HAVING clause if given */ if (query->havingQual != NULL) { appendStringInfo(buf, " HAVING "); get_rule_expr(query->havingQual, context); } } static void get_setop_query(Node *setOp, Query *query, deparse_context *context, bool toplevel) { StringInfo buf = context->buf; if (IsA(setOp, RangeTblRef)) { RangeTblRef *rtr = (RangeTblRef *) setOp; RangeTblEntry *rte = rt_fetch(rtr->rtindex, query->rtable); Query *subquery = rte->subquery; Assert(subquery != NULL); get_query_def(subquery, buf, context->namespaces); } else if (IsA(setOp, SetOperationStmt)) { SetOperationStmt *op = (SetOperationStmt *) setOp; /* * Must suppress parens at top level of a setop tree because of * grammar limitations... */ if (!toplevel) appendStringInfo(buf, "("); get_setop_query(op->larg, query, context, false); switch (op->op) { case SETOP_UNION: appendStringInfo(buf, " UNION "); break; case SETOP_INTERSECT: appendStringInfo(buf, " INTERSECT "); break; case SETOP_EXCEPT: appendStringInfo(buf, " EXCEPT "); break; default: elog(ERROR, "get_setop_query: unexpected set op %d", (int) op->op); } if (op->all) appendStringInfo(buf, "ALL "); get_setop_query(op->rarg, query, context, false); if (!toplevel) appendStringInfo(buf, ")"); } else { elog(ERROR, "get_setop_query: unexpected node %d", (int) nodeTag(setOp)); } } /* * Display a sort/group clause. */ static void get_rule_sortgroupclause(SortClause *srt, List *tlist, bool force_colno, deparse_context *context) { StringInfo buf = context->buf; TargetEntry *tle; Node *expr; tle = get_sortgroupclause_tle(srt, tlist); expr = tle->expr; /* * Use column-number form if requested by caller or if expression is a * constant --- a constant is ambiguous (and will be misinterpreted by * findTargetlistEntry()) if we dump it explicitly. */ if (force_colno || (expr && IsA(expr, Const))) { Assert(!tle->resdom->resjunk); appendStringInfo(buf, "%d", tle->resdom->resno); } else get_rule_expr(expr, context); } /* ---------- * get_insert_query_def - Parse back an INSERT parsetree * ---------- */ static void get_insert_query_def(Query *query, deparse_context *context) { StringInfo buf = context->buf; RangeTblEntry *select_rte = NULL; RangeTblEntry *rte; char *sep; List *l; /* * If it's an INSERT ... SELECT there will be a single subquery RTE * for the SELECT. */ foreach(l, query->rtable) { rte = (RangeTblEntry *) lfirst(l); if (rte->subquery == NULL) continue; if (select_rte) elog(ERROR, "get_insert_query_def: too many RTEs in INSERT!"); select_rte = rte; } /* * Start the query with INSERT INTO relname */ rte = rt_fetch(query->resultRelation, query->rtable); appendStringInfo(buf, "INSERT INTO %s", quote_identifier(rte->relname)); /* Add the insert-column-names list */ sep = " ("; foreach(l, query->targetList) { TargetEntry *tle = (TargetEntry *) lfirst(l); if (tle->resdom->resjunk) continue; /* ignore junk entries */ appendStringInfo(buf, sep); sep = ", "; appendStringInfo(buf, "%s", quote_identifier(tle->resdom->resname)); } appendStringInfo(buf, ") "); /* Add the VALUES or the SELECT */ if (select_rte == NULL) { appendStringInfo(buf, "VALUES ("); sep = ""; foreach(l, query->targetList) { TargetEntry *tle = (TargetEntry *) lfirst(l); if (tle->resdom->resjunk) continue; /* ignore junk entries */ appendStringInfo(buf, sep); sep = ", "; get_tle_expr(tle, context); } appendStringInfoChar(buf, ')'); } else get_query_def(select_rte->subquery, buf, NIL); } /* ---------- * get_update_query_def - Parse back an UPDATE parsetree * ---------- */ static void get_update_query_def(Query *query, deparse_context *context) { StringInfo buf = context->buf; char *sep; RangeTblEntry *rte; List *l; /* * Start the query with UPDATE relname SET */ rte = rt_fetch(query->resultRelation, query->rtable); appendStringInfo(buf, "UPDATE %s%s SET ", only_marker(rte), quote_identifier(rte->relname)); /* Add the comma separated list of 'attname = value' */ sep = ""; foreach(l, query->targetList) { TargetEntry *tle = (TargetEntry *) lfirst(l); if (tle->resdom->resjunk) continue; /* ignore junk entries */ appendStringInfo(buf, sep); sep = ", "; /* * If the update expression is an array assignment, we mustn't put * out "attname =" here; it will come out of the display of the * ArrayRef node instead. */ if (!tleIsArrayAssign(tle)) appendStringInfo(buf, "%s = ", quote_identifier(tle->resdom->resname)); get_tle_expr(tle, context); } /* Add the FROM clause if needed */ get_from_clause(query, context); /* Finally add a WHERE clause if given */ if (query->jointree->quals != NULL) { appendStringInfo(buf, " WHERE "); get_rule_expr(query->jointree->quals, context); } } /* ---------- * get_delete_query_def - Parse back a DELETE parsetree * ---------- */ static void get_delete_query_def(Query *query, deparse_context *context) { StringInfo buf = context->buf; RangeTblEntry *rte; /* * Start the query with DELETE FROM relname */ rte = rt_fetch(query->resultRelation, query->rtable); appendStringInfo(buf, "DELETE FROM %s%s", only_marker(rte), quote_identifier(rte->relname)); /* Add a WHERE clause if given */ if (query->jointree->quals != NULL) { appendStringInfo(buf, " WHERE "); get_rule_expr(query->jointree->quals, context); } } /* ---------- * get_utility_query_def - Parse back a UTILITY parsetree * ---------- */ static void get_utility_query_def(Query *query, deparse_context *context) { StringInfo buf = context->buf; if (query->utilityStmt && IsA(query->utilityStmt, NotifyStmt)) { NotifyStmt *stmt = (NotifyStmt *) query->utilityStmt; appendStringInfo(buf, "NOTIFY %s", quote_identifier(stmt->relname)); } else elog(ERROR, "get_utility_query_def: unexpected statement type"); } /* * Get the relation refname and attname for a (possibly nonlocal) Var. * * attname will be returned as NULL if the Var represents a whole tuple * of the relation. * * This is trickier than it ought to be because of the possibility of aliases * and limited scope of refnames. We have to try to return the correct alias * with respect to the current namespace given by the context. */ static void get_names_for_var(Var *var, deparse_context *context, char **refname, char **attname) { List *nslist = context->namespaces; int sup = var->varlevelsup; deparse_namespace *dpns; RangeTblEntry *rte; /* Find appropriate nesting depth */ while (sup-- > 0 && nslist != NIL) nslist = lnext(nslist); if (nslist == NIL) elog(ERROR, "get_names_for_var: bogus varlevelsup %d", var->varlevelsup); dpns = (deparse_namespace *) lfirst(nslist); /* Scan namespace to see if we can find an alias for the var */ if (find_alias_in_namespace((Node *) dpns->namespace, (Node *) var, dpns->rtable, var->varlevelsup, refname, attname)) return; /* * Otherwise, fall back on the rangetable entry. This should happen * only for uses of special RTEs like *NEW* and *OLD*, which won't get * placed in our namespace. */ rte = rt_fetch(var->varno, dpns->rtable); *refname = rte->eref->relname; if (var->varattno == InvalidAttrNumber) *attname = NULL; else *attname = get_rte_attribute_name(rte, var->varattno); } /* * Check to see if a CASE expression matches a FULL JOIN's output expression. * If so, return the refname and alias it should be expressed as. */ static bool get_alias_for_case(CaseExpr *caseexpr, deparse_context *context, char **refname, char **attname) { List *nslist; int sup; /* * This could be done more efficiently if we first groveled through * the CASE to find varlevelsup values, but it's probably not worth * the trouble. All this code will go away someday anyway ... */ sup = 0; foreach(nslist, context->namespaces) { deparse_namespace *dpns = (deparse_namespace *) lfirst(nslist); if (find_alias_in_namespace((Node *) dpns->namespace, (Node *) caseexpr, dpns->rtable, sup, refname, attname)) return true; sup++; } return false; } /* * Recursively scan a namespace (same representation as a jointree) to see * if we can find an alias for the given expression. If so, return the * correct alias refname and attname. The expression may be either a plain * Var or a CASE expression (which may be a FULL JOIN reference). */ static bool find_alias_in_namespace(Node *nsnode, Node *expr, List *rangetable, int levelsup, char **refname, char **attname) { if (nsnode == NULL) return false; if (IsA(nsnode, RangeTblRef)) { if (IsA(expr, Var)) { Var *var = (Var *) expr; int rtindex = ((RangeTblRef *) nsnode)->rtindex; if (var->varno == rtindex && var->varlevelsup == levelsup) { RangeTblEntry *rte = rt_fetch(rtindex, rangetable); *refname = rte->eref->relname; if (var->varattno == InvalidAttrNumber) *attname = NULL; else *attname = get_rte_attribute_name(rte, var->varattno); return true; } } } else if (IsA(nsnode, JoinExpr)) { JoinExpr *j = (JoinExpr *) nsnode; if (j->alias) { List *vlist; List *nlist; /* * Does the expr match any of the output columns of the join? * * We can't just use equal() here, because the given expr may * have nonzero levelsup, whereas the saved expression in the * JoinExpr should have zero levelsup. */ nlist = j->colnames; foreach(vlist, j->colvars) { if (phony_equal(lfirst(vlist), expr, levelsup)) { *refname = j->alias->relname; *attname = strVal(lfirst(nlist)); return true; } nlist = lnext(nlist); } /* * Tables within an aliased join are invisible from outside * the join, according to the scope rules of SQL92 (the join * is considered a subquery). So, stop here. */ return false; } if (find_alias_in_namespace(j->larg, expr, rangetable, levelsup, refname, attname)) return true; if (find_alias_in_namespace(j->rarg, expr, rangetable, levelsup, refname, attname)) return true; } else if (IsA(nsnode, List)) { List *l; foreach(l, (List *) nsnode) { if (find_alias_in_namespace(lfirst(l), expr, rangetable, levelsup, refname, attname)) return true; } } else elog(ERROR, "find_alias_in_namespace: unexpected node type %d", nodeTag(nsnode)); return false; } /* * Check for equality of two expressions, with the proviso that all Vars in * expr1 should have varlevelsup = 0, while all Vars in expr2 should have * varlevelsup = levelsup. * * In reality we only need to support equality checks on Vars and the type * of CASE expression that is used for FULL JOIN outputs, so not all node * types need be handled here. * * Otherwise, this code is a straight ripoff from equalfuncs.c. */ static bool phony_equal(Node *expr1, Node *expr2, int levelsup) { if (expr1 == NULL || expr2 == NULL) return (expr1 == expr2); if (nodeTag(expr1) != nodeTag(expr2)) return false; if (IsA(expr1, Var)) { Var *a = (Var *) expr1; Var *b = (Var *) expr2; if (a->varno != b->varno) return false; if (a->varattno != b->varattno) return false; if (a->vartype != b->vartype) return false; if (a->vartypmod != b->vartypmod) return false; if (a->varlevelsup != 0 || b->varlevelsup != levelsup) return false; if (a->varnoold != b->varnoold) return false; if (a->varoattno != b->varoattno) return false; return true; } if (IsA(expr1, CaseExpr)) { CaseExpr *a = (CaseExpr *) expr1; CaseExpr *b = (CaseExpr *) expr2; if (a->casetype != b->casetype) return false; if (!phony_equal(a->arg, b->arg, levelsup)) return false; if (!phony_equal((Node *) a->args, (Node *) b->args, levelsup)) return false; if (!phony_equal(a->defresult, b->defresult, levelsup)) return false; return true; } if (IsA(expr1, CaseWhen)) { CaseWhen *a = (CaseWhen *) expr1; CaseWhen *b = (CaseWhen *) expr2; if (!phony_equal(a->expr, b->expr, levelsup)) return false; if (!phony_equal(a->result, b->result, levelsup)) return false; return true; } if (IsA(expr1, Expr)) { Expr *a = (Expr *) expr1; Expr *b = (Expr *) expr2; if (a->opType != b->opType) return false; if (!phony_equal(a->oper, b->oper, levelsup)) return false; if (!phony_equal((Node *) a->args, (Node *) b->args, levelsup)) return false; return true; } if (IsA(expr1, Func)) { Func *a = (Func *) expr1; Func *b = (Func *) expr2; if (a->funcid != b->funcid) return false; if (a->functype != b->functype) return false; return true; } if (IsA(expr1, List)) { List *la = (List *) expr1; List *lb = (List *) expr2; List *l; if (length(la) != length(lb)) return false; foreach(l, la) { if (!phony_equal(lfirst(l), lfirst(lb), levelsup)) return false; lb = lnext(lb); } return true; } /* If we get here, there was something weird in a JOIN's colvars list */ elog(ERROR, "phony_equal: unexpected node type %d", nodeTag(expr1)); return false; } /* ---------- * get_rule_expr - Parse back an expression * ---------- */ static void get_rule_expr(Node *node, deparse_context *context) { StringInfo buf = context->buf; if (node == NULL) return; /* * Each level of get_rule_expr must emit an indivisible term * (parenthesized if necessary) to ensure result is reparsed into the * same expression tree. * * There might be some work left here to support additional node types. * Can we ever see Param nodes here? */ switch (nodeTag(node)) { case T_Const: get_const_expr((Const *) node, context); break; case T_Var: { Var *var = (Var *) node; char *refname; char *attname; get_names_for_var(var, context, &refname, &attname); if (context->varprefix || attname == NULL) { if (strcmp(refname, "*NEW*") == 0) appendStringInfo(buf, "new"); else if (strcmp(refname, "*OLD*") == 0) appendStringInfo(buf, "old"); else appendStringInfo(buf, "%s", quote_identifier(refname)); if (attname) appendStringInfoChar(buf, '.'); } if (attname) appendStringInfo(buf, "%s", quote_identifier(attname)); } break; case T_Expr: { Expr *expr = (Expr *) node; List *args = expr->args; /* * Expr nodes have to be handled a bit detailed */ switch (expr->opType) { case OP_EXPR: appendStringInfoChar(buf, '('); if (length(args) == 2) { /* binary operator */ get_rule_expr((Node *) lfirst(args), context); appendStringInfo(buf, " %s ", get_opname(((Oper *) expr->oper)->opno)); get_rule_expr((Node *) lsecond(args), context); } else { /* unary operator --- but which side? */ Oid opno = ((Oper *) expr->oper)->opno; HeapTuple tp; Form_pg_operator optup; tp = SearchSysCache(OPEROID, ObjectIdGetDatum(opno), 0, 0, 0); if (!HeapTupleIsValid(tp)) elog(ERROR, "cache lookup for operator %u failed", opno); optup = (Form_pg_operator) GETSTRUCT(tp); switch (optup->oprkind) { case 'l': appendStringInfo(buf, "%s ", get_opname(opno)); get_rule_expr((Node *) lfirst(args), context); break; case 'r': get_rule_expr((Node *) lfirst(args), context); appendStringInfo(buf, " %s", get_opname(opno)); break; default: elog(ERROR, "get_rule_expr: bogus oprkind"); } ReleaseSysCache(tp); } appendStringInfoChar(buf, ')'); break; case OR_EXPR: appendStringInfoChar(buf, '('); get_rule_expr((Node *) lfirst(args), context); while ((args = lnext(args)) != NIL) { appendStringInfo(buf, " OR "); get_rule_expr((Node *) lfirst(args), context); } appendStringInfoChar(buf, ')'); break; case AND_EXPR: appendStringInfoChar(buf, '('); get_rule_expr((Node *) lfirst(args), context); while ((args = lnext(args)) != NIL) { appendStringInfo(buf, " AND "); get_rule_expr((Node *) lfirst(args), context); } appendStringInfoChar(buf, ')'); break; case NOT_EXPR: appendStringInfo(buf, "(NOT "); get_rule_expr((Node *) lfirst(args), context); appendStringInfoChar(buf, ')'); break; case FUNC_EXPR: get_func_expr((Expr *) node, context); break; default: elog(ERROR, "get_rule_expr: expr opType %d not supported", expr->opType); } } break; case T_Aggref: { Aggref *aggref = (Aggref *) node; appendStringInfo(buf, "%s(%s", quote_identifier(aggref->aggname), aggref->aggdistinct ? "DISTINCT " : ""); if (aggref->aggstar) appendStringInfo(buf, "*"); else get_rule_expr(aggref->target, context); appendStringInfoChar(buf, ')'); } break; case T_Iter: get_rule_expr(((Iter *) node)->iterexpr, context); break; case T_ArrayRef: { ArrayRef *aref = (ArrayRef *) node; bool savevarprefix = context->varprefix; List *lowlist; List *uplist; /* * If we are doing UPDATE array[n] = expr, we need to * suppress any prefix on the array name. Currently, that * is the only context in which we will see a non-null * refassgnexpr --- but someday a smarter test may be * needed. */ if (aref->refassgnexpr) context->varprefix = false; get_rule_expr(aref->refexpr, context); context->varprefix = savevarprefix; lowlist = aref->reflowerindexpr; foreach(uplist, aref->refupperindexpr) { appendStringInfo(buf, "["); if (lowlist) { get_rule_expr((Node *) lfirst(lowlist), context); appendStringInfo(buf, ":"); lowlist = lnext(lowlist); } get_rule_expr((Node *) lfirst(uplist), context); appendStringInfo(buf, "]"); } if (aref->refassgnexpr) { appendStringInfo(buf, " = "); get_rule_expr(aref->refassgnexpr, context); } } break; case T_FieldSelect: { FieldSelect *fselect = (FieldSelect *) node; HeapTuple typetup; Form_pg_type typeStruct; Oid typrelid; char *fieldname; /* we do NOT parenthesize the arg expression, for now */ get_rule_expr(fselect->arg, context); typetup = SearchSysCache(TYPEOID, ObjectIdGetDatum(exprType(fselect->arg)), 0, 0, 0); if (!HeapTupleIsValid(typetup)) elog(ERROR, "cache lookup of type %u failed", exprType(fselect->arg)); typeStruct = (Form_pg_type) GETSTRUCT(typetup); typrelid = typeStruct->typrelid; if (!OidIsValid(typrelid)) elog(ERROR, "Argument type %s of FieldSelect is not a tuple type", NameStr(typeStruct->typname)); fieldname = get_relid_attribute_name(typrelid, fselect->fieldnum); appendStringInfo(buf, ".%s", quote_identifier(fieldname)); ReleaseSysCache(typetup); } break; case T_RelabelType: { RelabelType *relabel = (RelabelType *) node; HeapTuple typetup; Form_pg_type typeStruct; char *extval; appendStringInfoChar(buf, '('); get_rule_expr(relabel->arg, context); typetup = SearchSysCache(TYPEOID, ObjectIdGetDatum(relabel->resulttype), 0, 0, 0); if (!HeapTupleIsValid(typetup)) elog(ERROR, "cache lookup of type %u failed", relabel->resulttype); typeStruct = (Form_pg_type) GETSTRUCT(typetup); extval = pstrdup(NameStr(typeStruct->typname)); appendStringInfo(buf, ")::%s", quote_identifier(extval)); pfree(extval); ReleaseSysCache(typetup); } break; case T_CaseExpr: { CaseExpr *caseexpr = (CaseExpr *) node; List *temp; char *refname; char *attname; /* Hack for providing aliases for FULL JOIN outputs */ if (get_alias_for_case(caseexpr, context, &refname, &attname)) { if (context->varprefix) appendStringInfo(buf, "%s.", quote_identifier(refname)); appendStringInfo(buf, "%s", quote_identifier(attname)); break; } appendStringInfo(buf, "CASE"); foreach(temp, caseexpr->args) { CaseWhen *when = (CaseWhen *) lfirst(temp); appendStringInfo(buf, " WHEN "); get_rule_expr(when->expr, context); appendStringInfo(buf, " THEN "); get_rule_expr(when->result, context); } appendStringInfo(buf, " ELSE "); get_rule_expr(caseexpr->defresult, context); appendStringInfo(buf, " END"); } break; case T_NullTest: { NullTest *ntest = (NullTest *) node; appendStringInfo(buf, "("); get_rule_expr(ntest->arg, context); switch (ntest->nulltesttype) { case IS_NULL: appendStringInfo(buf, " IS NULL)"); break; case IS_NOT_NULL: appendStringInfo(buf, " IS NOT NULL)"); break; default: elog(ERROR, "get_rule_expr: unexpected nulltesttype %d", (int) ntest->nulltesttype); } } break; case T_BooleanTest: { BooleanTest *btest = (BooleanTest *) node; appendStringInfo(buf, "("); get_rule_expr(btest->arg, context); switch (btest->booltesttype) { case IS_TRUE: appendStringInfo(buf, " IS TRUE)"); break; case IS_NOT_TRUE: appendStringInfo(buf, " IS NOT TRUE)"); break; case IS_FALSE: appendStringInfo(buf, " IS FALSE)"); break; case IS_NOT_FALSE: appendStringInfo(buf, " IS NOT FALSE)"); break; case IS_UNKNOWN: appendStringInfo(buf, " IS UNKNOWN)"); break; case IS_NOT_UNKNOWN: appendStringInfo(buf, " IS NOT UNKNOWN)"); break; default: elog(ERROR, "get_rule_expr: unexpected booltesttype %d", (int) btest->booltesttype); } } break; case T_SubLink: get_sublink_expr(node, context); break; default: printf("\n%s\n", nodeToString(node)); elog(ERROR, "get_ruledef of %s: unknown node type %d in get_rule_expr()", rulename, nodeTag(node)); break; } } /* ---------- * get_func_expr - Parse back a Func node * ---------- */ static void get_func_expr(Expr *expr, deparse_context *context) { StringInfo buf = context->buf; Func *func = (Func *) (expr->oper); Oid funcoid = func->funcid; HeapTuple proctup; Form_pg_proc procStruct; char *proname; int32 coercedTypmod; List *l; char *sep; /* * Get the functions pg_proc tuple */ proctup = SearchSysCache(PROCOID, ObjectIdGetDatum(funcoid), 0, 0, 0); if (!HeapTupleIsValid(proctup)) elog(ERROR, "cache lookup for proc %u failed", funcoid); procStruct = (Form_pg_proc) GETSTRUCT(proctup); proname = NameStr(procStruct->proname); /* * Check to see if function is a length-coercion function for some * datatype. If so, display the operation as a type cast. */ if (exprIsLengthCoercion((Node *) expr, &coercedTypmod)) { Node *arg = lfirst(expr->args); char *typdesc; /* * Strip off any type coercions on the input, so we don't print * redundancies like x::bpchar::character(8). * * XXX Are there any cases where this is a bad idea? */ arg = strip_type_coercion(arg, procStruct->prorettype); appendStringInfoChar(buf, '('); get_rule_expr(arg, context); /* * Show typename with appropriate length decoration. Note that * since exprIsLengthCoercion succeeded, the function's output * type is the right thing to use. * * XXX In general it is incorrect to quote the result of * format_type_with_typemod, but are there any special cases where * we should do so? */ typdesc = format_type_with_typemod(procStruct->prorettype, coercedTypmod); appendStringInfo(buf, ")::%s", typdesc); pfree(typdesc); ReleaseSysCache(proctup); return; } /* * Normal function: display as proname(args) */ appendStringInfo(buf, "%s(", quote_identifier(proname)); sep = ""; foreach(l, expr->args) { appendStringInfo(buf, sep); sep = ", "; get_rule_expr((Node *) lfirst(l), context); } appendStringInfoChar(buf, ')'); ReleaseSysCache(proctup); } /* * strip_type_coercion * Strip any type coercions at the top of the given expression tree, * as long as they are coercions to the given datatype. * * A RelabelType node is always a type coercion. A function call is also * considered a type coercion if it has one argument and the function name * is the same as the (internal) name of its result type. * * XXX It'd be better if the parsetree retained some explicit indication * of the coercion, so we didn't need these heuristics. */ static Node * strip_type_coercion(Node *expr, Oid resultType) { if (expr == NULL || exprType(expr) != resultType) return expr; if (IsA(expr, RelabelType)) return strip_type_coercion(((RelabelType *) expr)->arg, resultType); if (IsA(expr, Expr) &&((Expr *) expr)->opType == FUNC_EXPR) { Func *func; HeapTuple procTuple; HeapTuple typeTuple; Form_pg_proc procStruct; Form_pg_type typeStruct; func = (Func *) (((Expr *) expr)->oper); Assert(IsA(func, Func)); if (length(((Expr *) expr)->args) != 1) return expr; /* Lookup the function in pg_proc */ procTuple = SearchSysCache(PROCOID, ObjectIdGetDatum(func->funcid), 0, 0, 0); if (!HeapTupleIsValid(procTuple)) elog(ERROR, "cache lookup for proc %u failed", func->funcid); procStruct = (Form_pg_proc) GETSTRUCT(procTuple); /* Double-check func has one arg and correct result type */ if (procStruct->pronargs != 1 || procStruct->prorettype != resultType) { ReleaseSysCache(procTuple); return expr; } /* See if function has same name as its result type */ typeTuple = SearchSysCache(TYPEOID, ObjectIdGetDatum(procStruct->prorettype), 0, 0, 0); if (!HeapTupleIsValid(typeTuple)) elog(ERROR, "cache lookup for type %u failed", procStruct->prorettype); typeStruct = (Form_pg_type) GETSTRUCT(typeTuple); if (strncmp(NameStr(procStruct->proname), NameStr(typeStruct->typname), NAMEDATALEN) != 0) { ReleaseSysCache(procTuple); ReleaseSysCache(typeTuple); return expr; } /* Okay, it is indeed a type-coercion function */ ReleaseSysCache(procTuple); ReleaseSysCache(typeTuple); return strip_type_coercion(lfirst(((Expr *) expr)->args), resultType); } return expr; } /* ---------- * get_tle_expr * * In an INSERT or UPDATE targetlist item, the parser may have inserted * a length-coercion function call to coerce the value to the right * length for the target column. We want to suppress the output of * that function call, otherwise dump/reload/dump... would blow up the * expression by adding more and more layers of length-coercion calls. * * As of 7.0, this hack is no longer absolutely essential, because the parser * is now smart enough not to add a redundant length coercion function call. * But we still suppress the function call just for neatness of displayed * rules. * * Note that this hack must NOT be applied to SELECT targetlist items; * any length coercion appearing there is something the user actually wrote. * ---------- */ static void get_tle_expr(TargetEntry *tle, deparse_context *context) { Expr *expr = (Expr *) (tle->expr); int32 coercedTypmod; /* * If top level is a length coercion to the correct length, suppress * it; else dump the expression normally. */ if (tle->resdom->restypmod >= 0 && exprIsLengthCoercion((Node *) expr, &coercedTypmod) && coercedTypmod == tle->resdom->restypmod) get_rule_expr((Node *) lfirst(expr->args), context); else get_rule_expr(tle->expr, context); } /* ---------- * get_const_expr * * Make a string representation of a Const * ---------- */ static void get_const_expr(Const *constval, deparse_context *context) { StringInfo buf = context->buf; HeapTuple typetup; Form_pg_type typeStruct; char *extval; char *valptr; typetup = SearchSysCache(TYPEOID, ObjectIdGetDatum(constval->consttype), 0, 0, 0); if (!HeapTupleIsValid(typetup)) elog(ERROR, "cache lookup of type %u failed", constval->consttype); typeStruct = (Form_pg_type) GETSTRUCT(typetup); if (constval->constisnull) { /* * Always label the type of a NULL constant. This not only * prevents misdecisions about the type, but it ensures that our * output is a valid b_expr. */ extval = pstrdup(NameStr(typeStruct->typname)); appendStringInfo(buf, "NULL::%s", quote_identifier(extval)); pfree(extval); ReleaseSysCache(typetup); return; } extval = DatumGetCString(OidFunctionCall3(typeStruct->typoutput, constval->constvalue, ObjectIdGetDatum(typeStruct->typelem), Int32GetDatum(-1))); switch (constval->consttype) { case INT2OID: case INT4OID: case OIDOID: /* int types */ case FLOAT4OID: case FLOAT8OID: /* float types */ /* These types are printed without quotes */ appendStringInfo(buf, extval); break; default: /* * We must quote any funny characters in the constant's * representation. XXX Any MULTIBYTE considerations here? */ appendStringInfoChar(buf, '\''); for (valptr = extval; *valptr; valptr++) { char ch = *valptr; if (ch == '\'' || ch == '\\') { appendStringInfoChar(buf, '\\'); appendStringInfoChar(buf, ch); } else if (((unsigned char) ch) < ((unsigned char) ' ')) appendStringInfo(buf, "\\%03o", (int) ch); else appendStringInfoChar(buf, ch); } appendStringInfoChar(buf, '\''); break; } pfree(extval); switch (constval->consttype) { case INT4OID: case FLOAT8OID: case UNKNOWNOID: /* These types can be left unlabeled */ break; default: extval = pstrdup(NameStr(typeStruct->typname)); appendStringInfo(buf, "::%s", quote_identifier(extval)); pfree(extval); break; } ReleaseSysCache(typetup); } /* ---------- * get_sublink_expr - Parse back a sublink * ---------- */ static void get_sublink_expr(Node *node, deparse_context *context) { StringInfo buf = context->buf; SubLink *sublink = (SubLink *) node; Query *query = (Query *) (sublink->subselect); List *l; char *sep; Oper *oper; bool need_paren; appendStringInfoChar(buf, '('); if (sublink->lefthand != NIL) { need_paren = (length(sublink->lefthand) > 1); if (need_paren) appendStringInfoChar(buf, '('); sep = ""; foreach(l, sublink->lefthand) { appendStringInfo(buf, sep); sep = ", "; get_rule_expr((Node *) lfirst(l), context); } if (need_paren) appendStringInfo(buf, ") "); else appendStringInfoChar(buf, ' '); } need_paren = true; switch (sublink->subLinkType) { case EXISTS_SUBLINK: appendStringInfo(buf, "EXISTS "); break; case ANY_SUBLINK: oper = (Oper *) lfirst(sublink->oper); appendStringInfo(buf, "%s ANY ", get_opname(oper->opno)); break; case ALL_SUBLINK: oper = (Oper *) lfirst(sublink->oper); appendStringInfo(buf, "%s ALL ", get_opname(oper->opno)); break; case MULTIEXPR_SUBLINK: oper = (Oper *) lfirst(sublink->oper); appendStringInfo(buf, "%s ", get_opname(oper->opno)); break; case EXPR_SUBLINK: need_paren = false; break; default: elog(ERROR, "get_sublink_expr: unsupported sublink type %d", sublink->subLinkType); break; } if (need_paren) appendStringInfoChar(buf, '('); get_query_def(query, buf, context->namespaces); if (need_paren) appendStringInfo(buf, "))"); else appendStringInfoChar(buf, ')'); } /* ---------- * get_from_clause - Parse back a FROM clause * ---------- */ static void get_from_clause(Query *query, deparse_context *context) { StringInfo buf = context->buf; char *sep; List *l; /* * We use the query's jointree as a guide to what to print. However, * we must ignore auto-added RTEs that are marked not inFromCl. (These * can only appear at the top level of the jointree, so it's * sufficient to check here.) Also ignore the rule pseudo-RTEs for NEW * and OLD. */ sep = " FROM "; foreach(l, query->jointree->fromlist) { Node *jtnode = (Node *) lfirst(l); if (IsA(jtnode, RangeTblRef)) { int varno = ((RangeTblRef *) jtnode)->rtindex; RangeTblEntry *rte = rt_fetch(varno, query->rtable); if (!rte->inFromCl) continue; if (strcmp(rte->eref->relname, "*NEW*") == 0) continue; if (strcmp(rte->eref->relname, "*OLD*") == 0) continue; } appendStringInfo(buf, sep); get_from_clause_item(jtnode, query, context); sep = ", "; } } static void get_from_clause_item(Node *jtnode, Query *query, deparse_context *context) { StringInfo buf = context->buf; deparse_namespace *dpns; List *sv_namespace; /* * FROM-clause items have limited visibility of query's namespace. * Save and restore the outer namespace setting while we munge it. */ dpns = (deparse_namespace *) lfirst(context->namespaces); sv_namespace = dpns->namespace; dpns->namespace = NIL; if (IsA(jtnode, RangeTblRef)) { int varno = ((RangeTblRef *) jtnode)->rtindex; RangeTblEntry *rte = rt_fetch(varno, query->rtable); if (rte->relname) { /* Normal relation RTE */ appendStringInfo(buf, "%s%s", only_marker(rte), quote_identifier(rte->relname)); } else { /* Subquery RTE */ Assert(rte->subquery != NULL); appendStringInfoChar(buf, '('); get_query_def(rte->subquery, buf, context->namespaces); appendStringInfoChar(buf, ')'); } if (rte->alias != NULL) { appendStringInfo(buf, " %s", quote_identifier(rte->alias->relname)); if (rte->alias->attrs != NIL) { List *col; appendStringInfo(buf, "("); foreach(col, rte->alias->attrs) { if (col != rte->alias->attrs) appendStringInfo(buf, ", "); appendStringInfo(buf, "%s", quote_identifier(strVal(lfirst(col)))); } appendStringInfoChar(buf, ')'); } } } else if (IsA(jtnode, JoinExpr)) { JoinExpr *j = (JoinExpr *) jtnode; appendStringInfoChar(buf, '('); get_from_clause_item(j->larg, query, context); if (j->isNatural) appendStringInfo(buf, " NATURAL"); switch (j->jointype) { case JOIN_INNER: if (j->quals) appendStringInfo(buf, " JOIN "); else appendStringInfo(buf, " CROSS JOIN "); break; case JOIN_LEFT: appendStringInfo(buf, " LEFT JOIN "); break; case JOIN_FULL: appendStringInfo(buf, " FULL JOIN "); break; case JOIN_RIGHT: appendStringInfo(buf, " RIGHT JOIN "); break; case JOIN_UNION: appendStringInfo(buf, " UNION JOIN "); break; default: elog(ERROR, "get_from_clause_item: unknown join type %d", (int) j->jointype); } get_from_clause_item(j->rarg, query, context); if (!j->isNatural) { if (j->using) { List *col; appendStringInfo(buf, " USING ("); foreach(col, j->using) { if (col != j->using) appendStringInfo(buf, ", "); appendStringInfo(buf, "%s", quote_identifier(strVal(lfirst(col)))); } appendStringInfoChar(buf, ')'); } else if (j->quals) { dpns->namespace = makeList2(j->larg, j->rarg); appendStringInfo(buf, " ON ("); get_rule_expr(j->quals, context); appendStringInfoChar(buf, ')'); } } appendStringInfoChar(buf, ')'); /* Yes, it's correct to put alias after the right paren ... */ if (j->alias != NULL) { appendStringInfo(buf, " %s", quote_identifier(j->alias->relname)); if (j->alias->attrs != NIL) { List *col; appendStringInfo(buf, "("); foreach(col, j->alias->attrs) { if (col != j->alias->attrs) appendStringInfo(buf, ", "); appendStringInfo(buf, "%s", quote_identifier(strVal(lfirst(col)))); } appendStringInfoChar(buf, ')'); } } } else elog(ERROR, "get_from_clause_item: unexpected node type %d", nodeTag(jtnode)); dpns->namespace = sv_namespace; } /* ---------- * get_opclass_name - fetch name of an index operator class * * The opclass name is appended (after a space) to buf. * * Output is suppressed if the opclass is the default for the given * actual_datatype. (If you don't want this behavior, just pass * InvalidOid for actual_datatype.) * ---------- */ static void get_opclass_name(Oid opclass, Oid actual_datatype, StringInfo buf) { HeapTuple ht_opc; Form_pg_opclass opcrec; ht_opc = SearchSysCache(CLAOID, ObjectIdGetDatum(opclass), 0, 0, 0); if (!HeapTupleIsValid(ht_opc)) elog(ERROR, "cache lookup failed for opclass %u", opclass); opcrec = (Form_pg_opclass) GETSTRUCT(ht_opc); if (actual_datatype != opcrec->opcintype || !opcrec->opcdefault) appendStringInfo(buf, " %s", quote_identifier(NameStr(opcrec->opcname))); ReleaseSysCache(ht_opc); } /* ---------- * tleIsArrayAssign - check for array assignment * ---------- */ static bool tleIsArrayAssign(TargetEntry *tle) { ArrayRef *aref; if (tle->expr == NULL || !IsA(tle->expr, ArrayRef)) return false; aref = (ArrayRef *) tle->expr; if (aref->refassgnexpr == NULL) return false; /* * Currently, it should only be possible to see non-null refassgnexpr * if we are indeed looking at an "UPDATE array[n] = expr" situation. * So aref->refexpr ought to match the tle's target. */ if (aref->refexpr == NULL || !IsA(aref->refexpr, Var) || ((Var *) aref->refexpr)->varattno != tle->resdom->resno) elog(NOTICE, "tleIsArrayAssign: I'm confused ..."); return true; } /* ---------- * quote_identifier - Quote an identifier only if needed * * When quotes are needed, we palloc the required space; slightly * space-wasteful but well worth it for notational simplicity. * ---------- */ static char * quote_identifier(char *ident) { /* * Can avoid quoting if ident starts with a lowercase letter and * contains only lowercase letters, digits, and underscores, *and* is * not any SQL keyword. Otherwise, supply quotes. */ bool safe; char *result; /* * would like to use macros here, but they might yield * unwanted locale-specific results... */ safe = (ident[0] >= 'a' && ident[0] <= 'z'); if (safe) { char *ptr; for (ptr = ident + 1; *ptr; ptr++) { char ch = *ptr; safe = ((ch >= 'a' && ch <= 'z') || (ch >= '0' && ch <= '9') || (ch == '_')); if (!safe) break; } } if (safe) { /* * Check for keyword. This test is overly strong, since many of * the "keywords" known to the parser are usable as column names, * but the parser doesn't provide any easy way to test for whether * an identifier is safe or not... so be safe not sorry. * * Note: ScanKeywordLookup() does case-insensitive comparison, but * that's fine, since we already know we have all-lower-case. */ if (ScanKeywordLookup(ident) != NULL) safe = false; } if (safe) return ident; /* no change needed */ result = (char *) palloc(strlen(ident) + 2 + 1); sprintf(result, "\"%s\"", ident); return result; } /* ---------- * get_relation_name - Get a relation name by Oid * ---------- */ static char * get_relation_name(Oid relid) { HeapTuple classtup; Form_pg_class classStruct; char *result; classtup = SearchSysCache(RELOID, ObjectIdGetDatum(relid), 0, 0, 0); if (!HeapTupleIsValid(classtup)) elog(ERROR, "cache lookup of relation %u failed", relid); classStruct = (Form_pg_class) GETSTRUCT(classtup); result = pstrdup(NameStr(classStruct->relname)); ReleaseSysCache(classtup); return result; } /* ---------- * get_relid_attribute_name * Get an attribute name by its relations Oid and its attnum * * Same as underlying syscache routine get_attname(), except that error * is handled by elog() instead of returning NULL. * ---------- */ static char * get_relid_attribute_name(Oid relid, AttrNumber attnum) { char *attname; attname = get_attname(relid, attnum); if (attname == NULL) elog(ERROR, "cache lookup of attribute %d in relation %u failed", attnum, relid); return attname; }