ruleutils.c

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/*-------------------------------------------------------------------------
 *
 * ruleutils.c
 *	  Functions to convert stored expressions/querytrees back to
 *	  source text
 *
 * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.269.2.2 2008/06/06 17:59:37 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <unistd.h>
#include <fcntl.h>

#include "access/genam.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_depend.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_trigger.h"
#include "commands/defrem.h"
#include "commands/tablespace.h"
#include "executor/spi.h"
#include "funcapi.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/tlist.h"
#include "parser/gramparse.h"
#include "parser/keywords.h"
#include "parser/parse_expr.h"
#include "parser/parse_func.h"
#include "parser/parse_oper.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteHandler.h"
#include "rewrite/rewriteManip.h"
#include "rewrite/rewriteSupport.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/typcache.h"
#include "utils/xml.h"


/* ----------
 * Pretty formatting constants
 * ----------
 */

/* Indent counts */
#define PRETTYINDENT_STD		8
#define PRETTYINDENT_JOIN	   13
#define PRETTYINDENT_JOIN_ON	(PRETTYINDENT_JOIN-PRETTYINDENT_STD)
#define PRETTYINDENT_VAR		4

/* Pretty flags */
#define PRETTYFLAG_PAREN		1
#define PRETTYFLAG_INDENT		2

/* macro to test if pretty action needed */
#define PRETTY_PAREN(context)	((context)->prettyFlags & PRETTYFLAG_PAREN)
#define PRETTY_INDENT(context)	((context)->prettyFlags & PRETTYFLAG_INDENT)


/* ----------
 * 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 */
	int			prettyFlags;	/* enabling of pretty-print functions */
	int			indentLevel;	/* current indent level for prettyprint */
	bool		varprefix;		/* TRUE to print prefixes on Vars */
} deparse_context;

/*
 * Each level of query context around a subtree needs a level of Var namespace.
 * A Var having varlevelsup=N refers to the N'th item (counting from 0) in
 * the current context's namespaces list.
 *
 * The rangetable is the list of actual RTEs from the query tree.
 *
 * For deparsing plan trees, we provide for outer and inner subplan nodes.
 * The tlists of these nodes are used to resolve OUTER and INNER varnos.
 */
typedef struct
{
	List	   *rtable;			/* List of RangeTblEntry nodes */
	Plan	   *outer_plan;		/* OUTER subplan, or NULL if none */
	Plan	   *inner_plan;		/* INNER subplan, or NULL if none */
} deparse_namespace;


/* ----------
 * Global data
 * ----------
 */
static SPIPlanPtr plan_getrulebyoid = NULL;
static const char *query_getrulebyoid = "SELECT * FROM pg_catalog.pg_rewrite WHERE oid = $1";
static SPIPlanPtr plan_getviewrule = NULL;
static const char *query_getviewrule = "SELECT * FROM pg_catalog.pg_rewrite WHERE ev_class = $1 AND rulename = $2";


/* ----------
 * 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 char *deparse_expression_pretty(Node *expr, List *dpcontext,
						  bool forceprefix, bool showimplicit,
						  int prettyFlags, int startIndent);
static char *pg_get_viewdef_worker(Oid viewoid, int prettyFlags);
static void decompile_column_index_array(Datum column_index_array, Oid relId,
							 StringInfo buf);
static char *pg_get_ruledef_worker(Oid ruleoid, int prettyFlags);
static char *pg_get_indexdef_worker(Oid indexrelid, int colno, bool showTblSpc,
					   int prettyFlags);
static char *pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
							int prettyFlags);
static char *pg_get_expr_worker(text *expr, Oid relid, char *relname,
				   int prettyFlags);
static void make_ruledef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
			 int prettyFlags);
static void make_viewdef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
			 int prettyFlags);
static void get_query_def(Query *query, StringInfo buf, List *parentnamespace,
			  TupleDesc resultDesc, int prettyFlags, int startIndent);
static void get_values_def(List *values_lists, deparse_context *context);
static void get_select_query_def(Query *query, deparse_context *context,
					 TupleDesc resultDesc);
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,
					   TupleDesc resultDesc);
static void get_target_list(List *targetList, deparse_context *context,
				TupleDesc resultDesc);
static void get_setop_query(Node *setOp, Query *query,
				deparse_context *context,
				TupleDesc resultDesc);
static Node *get_rule_sortgroupclause(SortClause *srt, List *tlist,
						 bool force_colno,
						 deparse_context *context);
static char *get_variable(Var *var, int levelsup, bool showstar,
			 deparse_context *context);
static RangeTblEntry *find_rte_by_refname(const char *refname,
					deparse_context *context);
static const char *get_simple_binary_op_name(OpExpr *expr);
static bool isSimpleNode(Node *node, Node *parentNode, int prettyFlags);
static void appendStringInfoSpaces(StringInfo buf, int count);
static void appendContextKeyword(deparse_context *context, const char *str,
					 int indentBefore, int indentAfter, int indentPlus);
static void get_rule_expr(Node *node, deparse_context *context,
			  bool showimplicit);
static void get_oper_expr(OpExpr *expr, deparse_context *context);
static void get_func_expr(FuncExpr *expr, deparse_context *context,
			  bool showimplicit);
static void get_agg_expr(Aggref *aggref, deparse_context *context);
static void get_coercion_expr(Node *arg, deparse_context *context,
				  Oid resulttype, int32 resulttypmod,
				  Node *parentNode);
static void get_const_expr(Const *constval, deparse_context *context,
			   int showtype);
static void get_sublink_expr(SubLink *sublink, deparse_context *context);
static void get_from_clause(Query *query, const char *prefix,
				deparse_context *context);
static void get_from_clause_item(Node *jtnode, Query *query,
					 deparse_context *context);
static void get_from_clause_alias(Alias *alias, RangeTblEntry *rte,
					  deparse_context *context);
static void get_from_clause_coldeflist(List *names, List *types, List *typmods,
						   deparse_context *context);
static void get_opclass_name(Oid opclass, Oid actual_datatype,
				 StringInfo buf);
static Node *processIndirection(Node *node, deparse_context *context,
				   bool printit);
static void printSubscripts(ArrayRef *aref, deparse_context *context);
static char *generate_relation_name(Oid relid);
static char *generate_function_name(Oid funcid, int nargs, Oid *argtypes);
static char *generate_operator_name(Oid operid, Oid arg1, Oid arg2);
static text *string_to_text(char *str);
static char *flatten_reloptions(Oid relid);

#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)
{
	Oid			ruleoid = PG_GETARG_OID(0);

	PG_RETURN_TEXT_P(string_to_text(pg_get_ruledef_worker(ruleoid, 0)));
}


Datum
pg_get_ruledef_ext(PG_FUNCTION_ARGS)
{
	Oid			ruleoid = PG_GETARG_OID(0);
	bool		pretty = PG_GETARG_BOOL(1);
	int			prettyFlags;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
	PG_RETURN_TEXT_P(string_to_text(pg_get_ruledef_worker(ruleoid, prettyFlags)));
}


static char *
pg_get_ruledef_worker(Oid ruleoid, int prettyFlags)
{
	Datum		args[1];
	char		nulls[1];
	int			spirc;
	HeapTuple	ruletup;
	TupleDesc	rulettc;
	StringInfoData buf;

	/*
	 * Do this first so that string is alloc'd in outer context not SPI's.
	 */
	initStringInfo(&buf);

	/*
	 * Connect to SPI manager
	 */
	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "SPI_connect failed");

	/*
	 * On the first call prepare the plan to lookup pg_rewrite. We read
	 * pg_rewrite over the SPI manager instead of using the syscache to be
	 * checked for read access on pg_rewrite.
	 */
	if (plan_getrulebyoid == NULL)
	{
		Oid			argtypes[1];
		SPIPlanPtr	plan;

		argtypes[0] = OIDOID;
		plan = SPI_prepare(query_getrulebyoid, 1, argtypes);
		if (plan == NULL)
			elog(ERROR, "SPI_prepare failed for \"%s\"", query_getrulebyoid);
		plan_getrulebyoid = SPI_saveplan(plan);
	}

	/*
	 * Get the pg_rewrite tuple for this rule
	 */
	args[0] = ObjectIdGetDatum(ruleoid);
	nulls[0] = ' ';
	spirc = SPI_execute_plan(plan_getrulebyoid, args, nulls, true, 1);
	if (spirc != SPI_OK_SELECT)
		elog(ERROR, "failed to get pg_rewrite tuple for rule %u", ruleoid);
	if (SPI_processed != 1)
		appendStringInfo(&buf, "-");
	else
	{
		/*
		 * Get the rule's definition and put it into executor's memory
		 */
		ruletup = SPI_tuptable->vals[0];
		rulettc = SPI_tuptable->tupdesc;
		make_ruledef(&buf, ruletup, rulettc, prettyFlags);
	}

	/*
	 * Disconnect from SPI manager
	 */
	if (SPI_finish() != SPI_OK_FINISH)
		elog(ERROR, "SPI_finish failed");

	return buf.data;
}


/* ----------
 * get_viewdef			- Mainly the same thing, but we
 *				  only return the SELECT part of a view
 * ----------
 */
Datum
pg_get_viewdef(PG_FUNCTION_ARGS)
{
	/* By OID */
	Oid			viewoid = PG_GETARG_OID(0);

	PG_RETURN_TEXT_P(string_to_text(pg_get_viewdef_worker(viewoid, 0)));
}


Datum
pg_get_viewdef_ext(PG_FUNCTION_ARGS)
{
	/* By OID */
	Oid			viewoid = PG_GETARG_OID(0);
	bool		pretty = PG_GETARG_BOOL(1);
	int			prettyFlags;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
	PG_RETURN_TEXT_P(string_to_text(pg_get_viewdef_worker(viewoid, prettyFlags)));
}

Datum
pg_get_viewdef_name(PG_FUNCTION_ARGS)
{
	/* By qualified name */
	text	   *viewname = PG_GETARG_TEXT_P(0);
	RangeVar   *viewrel;
	Oid			viewoid;

	viewrel = makeRangeVarFromNameList(textToQualifiedNameList(viewname));
	viewoid = RangeVarGetRelid(viewrel, false);

	PG_RETURN_TEXT_P(string_to_text(pg_get_viewdef_worker(viewoid, 0)));
}


Datum
pg_get_viewdef_name_ext(PG_FUNCTION_ARGS)
{
	/* By qualified name */
	text	   *viewname = PG_GETARG_TEXT_P(0);
	bool		pretty = PG_GETARG_BOOL(1);
	int			prettyFlags;
	RangeVar   *viewrel;
	Oid			viewoid;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
	viewrel = makeRangeVarFromNameList(textToQualifiedNameList(viewname));
	viewoid = RangeVarGetRelid(viewrel, false);

	PG_RETURN_TEXT_P(string_to_text(pg_get_viewdef_worker(viewoid, prettyFlags)));
}

/*
 * Common code for by-OID and by-name variants of pg_get_viewdef
 */
static char *
pg_get_viewdef_worker(Oid viewoid, int prettyFlags)
{
	Datum		args[2];
	char		nulls[2];
	int			spirc;
	HeapTuple	ruletup;
	TupleDesc	rulettc;
	StringInfoData buf;

	/*
	 * Do this first so that string is alloc'd in outer context not SPI's.
	 */
	initStringInfo(&buf);

	/*
	 * Connect to SPI manager
	 */
	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "SPI_connect failed");

	/*
	 * On the first call prepare the plan to lookup pg_rewrite. We read
	 * pg_rewrite over the SPI manager instead of using the syscache to be
	 * checked for read access on pg_rewrite.
	 */
	if (plan_getviewrule == NULL)
	{
		Oid			argtypes[2];
		SPIPlanPtr	plan;

		argtypes[0] = OIDOID;
		argtypes[1] = NAMEOID;
		plan = SPI_prepare(query_getviewrule, 2, argtypes);
		if (plan == NULL)
			elog(ERROR, "SPI_prepare failed for \"%s\"", query_getviewrule);
		plan_getviewrule = SPI_saveplan(plan);
	}

	/*
	 * Get the pg_rewrite tuple for the view's SELECT rule
	 */
	args[0] = ObjectIdGetDatum(viewoid);
	args[1] = PointerGetDatum(ViewSelectRuleName);
	nulls[0] = ' ';
	nulls[1] = ' ';
	spirc = SPI_execute_plan(plan_getviewrule, args, nulls, true, 2);
	if (spirc != SPI_OK_SELECT)
		elog(ERROR, "failed to get pg_rewrite tuple for view %u", viewoid);
	if (SPI_processed != 1)
		appendStringInfo(&buf, "Not a view");
	else
	{
		/*
		 * Get the rule's definition and put it into executor's memory
		 */
		ruletup = SPI_tuptable->vals[0];
		rulettc = SPI_tuptable->tupdesc;
		make_viewdef(&buf, ruletup, rulettc, prettyFlags);
	}

	/*
	 * Disconnect from SPI manager
	 */
	if (SPI_finish() != SPI_OK_FINISH)
		elog(ERROR, "SPI_finish failed");

	return buf.data;
}

/* ----------
 * get_triggerdef			- Get the definition of a trigger
 * ----------
 */
Datum
pg_get_triggerdef(PG_FUNCTION_ARGS)
{
	Oid			trigid = PG_GETARG_OID(0);
	HeapTuple	ht_trig;
	Form_pg_trigger trigrec;
	StringInfoData buf;
	Relation	tgrel;
	ScanKeyData skey[1];
	SysScanDesc tgscan;
	int			findx = 0;
	char	   *tgname;

	/*
	 * Fetch the pg_trigger tuple by the Oid of the trigger
	 */
	tgrel = heap_open(TriggerRelationId, AccessShareLock);

	ScanKeyInit(&skey[0],
				ObjectIdAttributeNumber,
				BTEqualStrategyNumber, F_OIDEQ,
				ObjectIdGetDatum(trigid));

	tgscan = systable_beginscan(tgrel, TriggerOidIndexId, true,
								SnapshotNow, 1, skey);

	ht_trig = systable_getnext(tgscan);

	if (!HeapTupleIsValid(ht_trig))
		elog(ERROR, "could not find tuple for trigger %u", trigid);

	trigrec = (Form_pg_trigger) GETSTRUCT(ht_trig);

	/*
	 * Start the trigger definition. Note that the trigger's name should never
	 * be schema-qualified, but the trigger rel's name may be.
	 */
	initStringInfo(&buf);

	tgname = NameStr(trigrec->tgname);
	appendStringInfo(&buf, "CREATE %sTRIGGER %s ",
					 trigrec->tgisconstraint ? "CONSTRAINT " : "",
					 quote_identifier(tgname));

	if (TRIGGER_FOR_BEFORE(trigrec->tgtype))
		appendStringInfo(&buf, "BEFORE");
	else
		appendStringInfo(&buf, "AFTER");
	if (TRIGGER_FOR_INSERT(trigrec->tgtype))
	{
		appendStringInfo(&buf, " INSERT");
		findx++;
	}
	if (TRIGGER_FOR_DELETE(trigrec->tgtype))
	{
		if (findx > 0)
			appendStringInfo(&buf, " OR DELETE");
		else