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postgres/src/backend/utils/adt/ruleutils.c

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/**********************************************************************
* get_ruledef.c - Function to get a rules definition text
* out of its tuple
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.52 2000/06/10 05:17:23 tgl 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 <unistd.h>
#include <fcntl.h>
#include "postgres.h"
#include "catalog/pg_index.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 "utils/lsyscache.h"
/* ----------
* Local data types
* ----------
*/
typedef struct
{
StringInfo buf; /* output buffer to append to */
List *rangetables; /* List of List of RangeTblEntry */
bool varprefix; /* TRUE to print prefixes on Vars */
} deparse_context;
typedef struct
{
Index rt_index;
int levelsup;
} check_if_rte_used_context;
/* ----------
* 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 or rulename = $2";
static void *plan_getam = NULL;
static char *query_getam = "SELECT * FROM pg_am WHERE oid = $1";
static void *plan_getopclass = NULL;
static char *query_getopclass = "SELECT * FROM pg_opclass WHERE oid = $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 *parentrtables);
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 RangeTblEntry *get_rte_for_var(Var *var, deparse_context *context);
static void get_rule_expr(Node *node, deparse_context *context);
static void get_func_expr(Expr *expr, deparse_context *context);
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 char *quote_identifier(char *ident);
static char *get_relation_name(Oid relid);
static char *get_attribute_name(Oid relid, int2 attnum);
static bool check_if_rte_used(Node *node, Index rt_index, int levelsup);
static bool check_if_rte_used_walker(Node *node,
check_if_rte_used_context *context);
#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
* ----------
*/
text *
pg_get_ruledef(NameData *rname)
{
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 = 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 = SPI_palloc(VARHDRSZ + 1);
VARSIZE(ruledef) = VARHDRSZ + 1;
VARDATA(ruledef)[0] = '-';
return 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);
VARSIZE(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?
* ----------
*/
return ruledef;
}
/* ----------
* get_viewdef - Mainly the same thing, but we
* only return the SELECT part of a view
* ----------
*/
text *
pg_get_viewdef(NameData *rname)
{
text *ruledef;
Datum args[2];
char nulls[3];
int spirc;
HeapTuple ruletup;
TupleDesc rulettc;
StringInfoData buf;
int len;
char name1[NAMEDATALEN + 5];
char name2[NAMEDATALEN + 5];
/* ----------
* We need the rules name somewhere deep down
* ----------
*/
rulename = pstrdup(NameStr(*rname));
/* ----------
* 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[2];
void *plan;
argtypes[0] = NAMEOID;
argtypes[1] = NAMEOID;
plan = SPI_prepare(query_getview, 2, 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
* ----------
*/
sprintf(name1, "_RET%s", rulename);
sprintf(name2, "_ret%s", rulename);
args[0] = PointerGetDatum(name1);
args[1] = PointerGetDatum(name2);
nulls[0] = ' ';
nulls[1] = ' ';
nulls[2] = '\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);
VARSIZE(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_viewdef: SPI_finish() failed");
/* ----------
* Easy - isn't it?
* ----------
*/
return 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;
HeapTuple spi_tup;
TupleDesc spi_ttc;
int spi_fno;
Form_pg_index idxrec;
Form_pg_class idxrelrec;
Form_pg_class indrelrec;
Datum spi_args[1];
char spi_nulls[2];
int spirc;
int len;
int keyno;
StringInfoData buf;
StringInfoData keybuf;
char *sep;
/* ----------
* Connect to SPI manager
* ----------
*/
if (SPI_connect() != SPI_OK_CONNECT)
elog(ERROR, "get_indexdef: cannot connect to SPI manager");
/* ----------
* On the first call prepare the plans to lookup pg_am
* and pg_opclass.
* ----------
*/
if (plan_getam == NULL)
{
Oid argtypes[1];
void *plan;
argtypes[0] = OIDOID;
plan = SPI_prepare(query_getam, 1, argtypes);
if (plan == NULL)
elog(ERROR, "SPI_prepare() failed for \"%s\"", query_getam);
plan_getam = SPI_saveplan(plan);
argtypes[0] = OIDOID;
plan = SPI_prepare(query_getopclass, 1, argtypes);
if (plan == NULL)
elog(ERROR, "SPI_prepare() failed for \"%s\"", query_getopclass);
plan_getopclass = SPI_saveplan(plan);
}
/* ----------
* Fetch the pg_index tuple by the Oid of the index
* ----------
*/
ht_idx = SearchSysCacheTuple(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 = SearchSysCacheTuple(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 = SearchSysCacheTuple(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);
/* ----------
* Get the am name for the index relation
* ----------
*/
spi_args[0] = ObjectIdGetDatum(idxrelrec->relam);
spi_nulls[0] = ' ';
spi_nulls[1] = '\0';
spirc = SPI_execp(plan_getam, spi_args, spi_nulls, 1);
if (spirc != SPI_OK_SELECT)
elog(ERROR, "failed to get pg_am tuple for index %s",
NameStr(idxrelrec->relname));
if (SPI_processed != 1)
elog(ERROR, "failed to get pg_am tuple for index %s",
NameStr(idxrelrec->relname));
spi_tup = SPI_tuptable->vals[0];
spi_ttc = SPI_tuptable->tupdesc;
spi_fno = SPI_fnumber(spi_ttc, "amname");
/* ----------
* Start the index definition
* ----------
*/
initStringInfo(&buf);
appendStringInfo(&buf, "CREATE %sINDEX %s ON %s USING %s (",
idxrec->indisunique ? "UNIQUE " : "",
quote_identifier(pstrdup(NameStr(idxrelrec->relname))),
quote_identifier(pstrdup(NameStr(indrelrec->relname))),
quote_identifier(SPI_getvalue(spi_tup, spi_ttc,
spi_fno)));
/* ----------
* Collect the indexed attributes
* ----------
*/
initStringInfo(&keybuf);
sep = "";
for (keyno = 0; keyno < INDEX_MAX_KEYS; keyno++)
{
if (idxrec->indkey[keyno] == InvalidAttrNumber)
break;
appendStringInfo(&keybuf, sep);
sep = ", ";
/* ----------
* Add the indexed field name
* ----------
*/
appendStringInfo(&keybuf, "%s",
quote_identifier(get_attribute_name(idxrec->indrelid,
idxrec->indkey[keyno])));
/* ----------
* If not a functional index, add the operator class name
* ----------
*/
if (idxrec->indproc == InvalidOid)
{
spi_args[0] = ObjectIdGetDatum(idxrec->indclass[keyno]);
spi_nulls[0] = ' ';
spi_nulls[1] = '\0';
spirc = SPI_execp(plan_getopclass, spi_args, spi_nulls, 1);
if (spirc != SPI_OK_SELECT)
elog(ERROR, "failed to get pg_opclass tuple %u", idxrec->indclass[keyno]);
if (SPI_processed != 1)
elog(ERROR, "failed to get pg_opclass tuple %u", idxrec->indclass[keyno]);
spi_tup = SPI_tuptable->vals[0];
spi_ttc = SPI_tuptable->tupdesc;
spi_fno = SPI_fnumber(spi_ttc, "opcname");
appendStringInfo(&keybuf, " %s",
quote_identifier(SPI_getvalue(spi_tup, spi_ttc,
spi_fno)));
}
}
/* ----------
* For functional index say 'func (attrs) opclass'
* ----------
*/
if (idxrec->indproc != InvalidOid)
{
HeapTuple proctup;
Form_pg_proc procStruct;
proctup = SearchSysCacheTuple(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(pstrdup(NameStr(procStruct->proname))),
keybuf.data);
spi_args[0] = ObjectIdGetDatum(idxrec->indclass[0]);
spi_nulls[0] = ' ';
spi_nulls[1] = '\0';
spirc = SPI_execp(plan_getopclass, spi_args, spi_nulls, 1);
if (spirc != SPI_OK_SELECT)
elog(ERROR, "failed to get pg_opclass tuple %u", idxrec->indclass[0]);
if (SPI_processed != 1)
elog(ERROR, "failed to get pg_opclass tuple %u", idxrec->indclass[0]);
spi_tup = SPI_tuptable->vals[0];
spi_ttc = SPI_tuptable->tupdesc;
spi_fno = SPI_fnumber(spi_ttc, "opcname");
appendStringInfo(&buf, "%s",
quote_identifier(SPI_getvalue(spi_tup, spi_ttc,
spi_fno)));
}
else
/* ----------
* For the others say 'attr opclass [, ...]'
* ----------
*/
appendStringInfo(&buf, "%s", keybuf.data);
/* ----------
* Finish
* ----------
*/
appendStringInfo(&buf, ")");
/* ----------
* Create the result in upper executor memory
* ----------
*/
len = buf.len + VARHDRSZ;
indexdef = SPI_palloc(len);
VARSIZE(indexdef) = len;
memcpy(VARDATA(indexdef), buf.data, buf.len);
pfree(buf.data);
pfree(keybuf.data);
/* ----------
* Disconnect from SPI manager
* ----------
*/
if (SPI_finish() != SPI_OK_FINISH)
elog(ERROR, "get_viewdef: SPI_finish() failed");
PG_RETURN_TEXT_P(indexdef);
}
/* ----------
* get_userbyid - Get a user name by usesysid and
* fallback to 'unknown (UID=n)'
* ----------
*/
NameData *
pg_get_userbyid(int32 uid)
{
HeapTuple usertup;
Form_pg_shadow user_rec;
NameData *result;
/* ----------
* Allocate space for the result
* ----------
*/
result = (NameData *) palloc(NAMEDATALEN);
memset(NameStr(*result), 0, NAMEDATALEN);
/* ----------
* Get the pg_shadow entry and print the result
* ----------
*/
usertup = SearchSysCacheTuple(SHADOWSYSID,
ObjectIdGetDatum(uid), 0, 0, 0);
if (HeapTupleIsValid(usertup))
{
user_rec = (Form_pg_shadow) GETSTRUCT(usertup);
StrNCpy(NameStr(*result), NameStr(user_rec->usename), NAMEDATALEN);
}
else
sprintf((char *) result, "unknown (UID=%d)", uid);
return 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).
*
* rangetables is a List of Lists of RangeTblEntry nodes: first sublist is for
* varlevelsup = 0, next for varlevelsup = 1, etc. In each sublist the first
* item is for varno = 1, next varno = 2, etc. (Each sublist has the same
* format as the rtable list of a parsetree or query.)
*
* forceprefix is TRUE to force all Vars to be prefixed with their table names.
* Otherwise, a prefix is printed only if there's more than one table involved
* (and someday the code might try to print one only if there's ambiguity).
*
* The result is a palloc'd string.
* ----------
*/
char *
deparse_expression(Node *expr, List *rangetables, bool forceprefix)
{
StringInfoData buf;
deparse_context context;
initStringInfo(&buf);
context.buf = &buf;
context.rangetables = rangetables;
context.varprefix = (forceprefix ||
length(rangetables) != 1 ||
length((List *) lfirst(rangetables)) != 1);
rulename = ""; /* in case of errors */
get_rule_expr(expr, &context);
return buf.data;
}
/* ----------
* 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_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;
appendStringInfo(buf, " WHERE ");
qual = stringToNode(ev_qual);
query = (Query *) lfirst(actions);
context.buf = buf;
context.rangetables = lcons(query->rtable, NIL);
context.varprefix = (length(query->rtable) != 1);
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, "<>"))
{
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 *parentrtables)
{
deparse_context context;
context.buf = buf;
context.rangetables = lcons(query->rtable, parentrtables);
context.varprefix = (parentrtables != NIL ||
length(query->rtable) != 1);
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;
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;
char *sep;
TargetEntry *tle;
RangeTblEntry *rte;
bool *rt_used;
int rt_length;
int rt_numused = 0;
bool rt_constonly = TRUE;
int i;
List *l;
/* ----------
* First we need to know which and how many of the
* range table entries in the query are used in the target list
* or queries qualification
* ----------
*/
rt_length = length(query->rtable);
rt_used = palloc(sizeof(bool) * rt_length);
for (i = 0; i < rt_length; i++)
{
if (check_if_rte_used((Node *) (query->targetList), i + 1, 0) ||
check_if_rte_used(query->qual, i + 1, 0) ||
check_if_rte_used(query->havingQual, i + 1, 0))
{
rt_used[i] = TRUE;
rt_numused++;
}
else
rt_used[i] = FALSE;
}
/* ----------
* Now check if any of the used rangetable entries is different
* from *NEW* and *CURRENT*. If so we must provide the FROM clause
* later.
* ----------
*/
i = 0;
foreach(l, query->rtable)
{
if (!rt_used[i++])
continue;
rte = (RangeTblEntry *) lfirst(l);
if (rte->ref == NULL)
continue;
if (!strcmp(rte->ref->relname, "*NEW*"))
continue;
if (!strcmp(rte->ref->relname, "*CURRENT*"))
continue;
rt_constonly = FALSE;
break;
}
/* ----------
* Build up the query string - first we say SELECT
* ----------
*/
appendStringInfo(buf, "SELECT");
/* Then we tell what to select (the targetlist) */
sep = " ";
foreach(l, query->targetList)
{
bool tell_as = FALSE;
tle = (TargetEntry *) lfirst(l);
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?");
else
{
Var *var = (Var *) (tle->expr);
char *attname;
rte = get_rte_for_var(var, context);
attname = get_attribute_name(rte->relid, var->varattno);
if (strcmp(attname, tle->resdom->resname))
tell_as = TRUE;
}
/* and do if so */
if (tell_as)
appendStringInfo(buf, " AS %s",
quote_identifier(tle->resdom->resname));
}
/* If we need other tables than *NEW* or *CURRENT* add the FROM clause */
if (!rt_constonly && rt_numused > 0)
{
sep = " FROM ";
i = 0;
foreach(l, query->rtable)
{
if (rt_used[i++])
{
rte = (RangeTblEntry *) lfirst(l);
if (rte->ref == NULL)
continue;
if (!strcmp(rte->ref->relname, "*NEW*"))
continue;
if (!strcmp(rte->ref->relname, "*CURRENT*"))
continue;
appendStringInfo(buf, sep);
sep = ", ";
appendStringInfo(buf, "%s%s",
only_marker(rte),
quote_identifier(rte->relname));
/*
* NOTE: SQL92 says you can't write column aliases unless
* you write a table alias --- so, if there's an alias
* list, make sure we emit a table alias even if it's the
* same as the table's real name.
*/
if ((rte->ref != NULL)
&& ((strcmp(rte->relname, rte->ref->relname) != 0)
|| (rte->ref->attrs != NIL)))
{
appendStringInfo(buf, " %s",
quote_identifier(rte->ref->relname));
if (rte->ref->attrs != NIL)
{
List *col;
appendStringInfo(buf, " (");
foreach(col, rte->ref->attrs)
{
if (col != rte->ref->attrs)
appendStringInfo(buf, ", ");
appendStringInfo(buf, "%s",
quote_identifier(strVal(lfirst(col))));
}
appendStringInfoChar(buf, ')');
}
}
}
}
}
/* Add the WHERE clause if given */
if (query->qual != NULL)
{
appendStringInfo(buf, " WHERE ");
get_rule_expr(query->qual, context);
}
/* Add the GROUP BY CLAUSE */
if (query->groupClause != NULL)
{
appendStringInfo(buf, " GROUP BY ");
sep = "";
foreach(l, query->groupClause)
{
GroupClause *grp = (GroupClause *) lfirst(l);
Node *groupexpr;
groupexpr = get_sortgroupclause_expr(grp,
query->targetList);
appendStringInfo(buf, sep);
get_rule_expr(groupexpr, context);
sep = ", ";
}
}
}
/* ----------
* get_insert_query_def - Parse back an INSERT parsetree
* ----------
*/
static void
get_insert_query_def(Query *query, deparse_context *context)
{
StringInfo buf = context->buf;
char *sep;
TargetEntry *tle;
RangeTblEntry *rte;
bool *rt_used;
int rt_length;
int rt_numused = 0;
bool rt_constonly = TRUE;
int i;
List *l;
/* ----------
* We need to know if other tables than *NEW* or *CURRENT*
* are used in the query. If not, it's an INSERT ... VALUES,
* otherwise an INSERT ... SELECT.
* ----------
*/
rt_length = length(query->rtable);
rt_used = palloc(sizeof(bool) * rt_length);
for (i = 0; i < rt_length; i++)
{
if (check_if_rte_used((Node *) (query->targetList), i + 1, 0) ||
check_if_rte_used(query->qual, i + 1, 0) ||
check_if_rte_used(query->havingQual, i + 1, 0))
{
rt_used[i] = TRUE;
rt_numused++;
}
else
rt_used[i] = FALSE;
}
i = 0;
foreach(l, query->rtable)
{
if (!rt_used[i++])
continue;
rte = (RangeTblEntry *) lfirst(l);
if (rte->ref == NULL)
continue;
if (!strcmp(rte->ref->relname, "*NEW*"))
continue;
if (!strcmp(rte->ref->relname, "*CURRENT*"))
continue;
rt_constonly = FALSE;
break;
}
/* ----------
* 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 target list */
sep = " (";
foreach(l, query->targetList)
{
tle = (TargetEntry *) lfirst(l);
appendStringInfo(buf, sep);
sep = ", ";
appendStringInfo(buf, "%s", quote_identifier(tle->resdom->resname));
}
appendStringInfo(buf, ") ");
/* Add the VALUES or the SELECT */
if (rt_constonly && query->qual == NULL)
{
appendStringInfo(buf, "VALUES (");
sep = "";
foreach(l, query->targetList)
{
tle = (TargetEntry *) lfirst(l);
appendStringInfo(buf, sep);
sep = ", ";
get_tle_expr(tle, context);
}
appendStringInfoChar(buf, ')');
}
else
get_select_query_def(query, context);
}
/* ----------
* 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;
TargetEntry *tle;
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)
{
tle = (TargetEntry *) lfirst(l);
appendStringInfo(buf, sep);
sep = ", ";
appendStringInfo(buf, "%s = ",
quote_identifier(tle->resdom->resname));
get_tle_expr(tle, context);
}
/* Finally add a WHERE clause if given */
if (query->qual != NULL)
{
appendStringInfo(buf, " WHERE ");
get_rule_expr(query->qual, 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->qual != NULL)
{
appendStringInfo(buf, " WHERE ");
get_rule_expr(query->qual, context);
}
}
/*
* Find the RTE referenced by a (possibly nonlocal) Var.
*/
static RangeTblEntry *
get_rte_for_var(Var *var, deparse_context *context)
{
List *rtlist = context->rangetables;
int sup = var->varlevelsup;
while (sup-- > 0)
rtlist = lnext(rtlist);
return rt_fetch(var->varno, (List *) lfirst(rtlist));
}
/* ----------
* 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;
RangeTblEntry *rte = get_rte_for_var(var, context);
if (context->varprefix)
{
if (rte->ref == NULL)
appendStringInfo(buf, "%s.",
quote_identifier(rte->relname));
else if (!strcmp(rte->ref->relname, "*NEW*"))
appendStringInfo(buf, "new.");
else if (!strcmp(rte->ref->relname, "*CURRENT*"))
appendStringInfo(buf, "old.");
else
appendStringInfo(buf, "%s.",
quote_identifier(rte->ref->relname));
}
appendStringInfo(buf, "%s",
quote_identifier(get_attribute_name(rte->relid,
var->varattno)));
}
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 = SearchSysCacheTuple(OPEROID,
ObjectIdGetDatum(opno),
0, 0, 0);
Assert(HeapTupleIsValid(tp));
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");
}
}
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;
List *lowlist;
List *uplist;
get_rule_expr(aref->refexpr, context);
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, "]");
}
/* XXX need to do anything with refassgnexpr? */
}
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 = SearchSysCacheTuple(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);
}
break;
case T_CaseExpr:
{
CaseExpr *caseexpr = (CaseExpr *) node;
List *temp;
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_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);
HeapTuple proctup;
Form_pg_proc procStruct;
char *proname;
int32 coercedTypmod;
List *l;
char *sep;
/*
* Get the functions pg_proc tuple
*/
proctup = SearchSysCacheTuple(PROCOID,
ObjectIdGetDatum(func->funcid),
0, 0, 0);
if (!HeapTupleIsValid(proctup))
elog(ERROR, "cache lookup for proc %u failed", func->funcid);
procStruct = (Form_pg_proc) GETSTRUCT(proctup);
proname = pstrdup(NameStr(procStruct->proname));
/*
* nullvalue() and nonnullvalue() should get turned into special
* syntax
*/
if (procStruct->pronargs == 1 && procStruct->proargtypes[0] == InvalidOid)
{
if (!strcmp(proname, "nullvalue"))
{
appendStringInfoChar(buf, '(');
get_rule_expr((Node *) lfirst(expr->args), context);
appendStringInfo(buf, " ISNULL)");
return;
}
if (!strcmp(proname, "nonnullvalue"))
{
appendStringInfoChar(buf, '(');
get_rule_expr((Node *) lfirst(expr->args), context);
appendStringInfo(buf, " NOTNULL)");
return;
}
}
/*
* 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);
/*
* Strip off any RelabelType on the input, so we don't print
* redundancies like x::bpchar::char(8). XXX Are there any cases
* where this is a bad idea?
*/
if (IsA(arg, RelabelType))
arg = ((RelabelType *) arg)->arg;
appendStringInfoChar(buf, '(');
get_rule_expr(arg, context);
appendStringInfo(buf, ")::");
/*
* Show typename with appropriate length decoration. Note that
* since exprIsLengthCoercion succeeded, the function name is the
* same as its output type name.
*/
if (strcmp(proname, "bpchar") == 0)
{
if (coercedTypmod > (int32) VARHDRSZ)
appendStringInfo(buf, "char(%d)", coercedTypmod - VARHDRSZ);
else
appendStringInfo(buf, "char");
}
else if (strcmp(proname, "varchar") == 0)
{
if (coercedTypmod > (int32) VARHDRSZ)
appendStringInfo(buf, "varchar(%d)", coercedTypmod - VARHDRSZ);
else
appendStringInfo(buf, "varchar");
}
else if (strcmp(proname, "numeric") == 0)
{
if (coercedTypmod >= (int32) VARHDRSZ)
appendStringInfo(buf, "numeric(%d,%d)",
((coercedTypmod - VARHDRSZ) >> 16) & 0xffff,
(coercedTypmod - VARHDRSZ) & 0xffff);
else
appendStringInfo(buf, "numeric");
}
else
appendStringInfo(buf, "%s", quote_identifier(proname));
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, ')');
}
/* ----------
* 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 = SearchSysCacheTuple(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);
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 (ch >= 0 && ch < ' ')
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;
}
}
/* ----------
* 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->rangetables);
if (need_paren)
appendStringInfo(buf, "))");
else
appendStringInfoChar(buf, ')');
}
/* ----------
* 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 <ctype.h> 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() expects an all-lower-case input, but
* we've already checked we have that.
*/
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;
classtup = SearchSysCacheTuple(RELOID,
ObjectIdGetDatum(relid), 0, 0, 0);
if (!HeapTupleIsValid(classtup))
elog(ERROR, "cache lookup of relation %u failed", relid);
classStruct = (Form_pg_class) GETSTRUCT(classtup);
return pstrdup(NameStr(classStruct->relname));
}
/* ----------
* get_attribute_name - Get an attribute name by its
* relations Oid and its attnum
* ----------
*/
static char *
get_attribute_name(Oid relid, int2 attnum)
{
HeapTuple atttup;
Form_pg_attribute attStruct;
atttup = SearchSysCacheTuple(ATTNUM,
ObjectIdGetDatum(relid), (Datum) attnum,
0, 0);
if (!HeapTupleIsValid(atttup))
elog(ERROR, "cache lookup of attribute %d in relation %u failed",
attnum, relid);
attStruct = (Form_pg_attribute) GETSTRUCT(atttup);
return pstrdup(NameStr(attStruct->attname));
}
/* ----------
* check_if_rte_used
* Check a targetlist or qual to see if a given rangetable entry
* is used in it
* ----------
*/
static bool
check_if_rte_used(Node *node, Index rt_index, int levelsup)
{
check_if_rte_used_context context;
context.rt_index = rt_index;
context.levelsup = levelsup;
return check_if_rte_used_walker(node, &context);
}
static bool
check_if_rte_used_walker(Node *node,
check_if_rte_used_context *context)
{
if (node == NULL)
return false;
if (IsA(node, Var))
{
Var *var = (Var *) node;
return var->varno == context->rt_index &&
var->varlevelsup == context->levelsup;
}
if (IsA(node, SubLink))
{
SubLink *sublink = (SubLink *) node;
Query *query = (Query *) sublink->subselect;
/* Recurse into subquery; expression_tree_walker will not */
if (check_if_rte_used((Node *) (query->targetList),
context->rt_index, context->levelsup + 1) ||
check_if_rte_used(query->qual,
context->rt_index, context->levelsup + 1) ||
check_if_rte_used(query->havingQual,
context->rt_index, context->levelsup + 1))
return true;
/*
* fall through to let expression_tree_walker examine lefthand
* args
*/
}
return expression_tree_walker(node, check_if_rte_used_walker,
(void *) context);
}
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