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This patch will allow arbitrary levels of analyze / rewriting
by making the static variables extra_before and extra_after automatic so we can use recursion. It gets much easier to generate extra commands now, and one can rest assured that the extra commands will be properly analyzed/rewritten. Without this patch, if a command produced by transformation tries to use these static lists their first contents would be lost with unpredictable results. I know I could fix this by just using nconc() instead of assignments, but the resulting order of the commands would not be exactly what one could expect. -- Fernando Nasser
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‎src/backend/parser/analyze.c

Lines changed: 53 additions & 37 deletions
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
77
* Portions Copyright (c) 1994, Regents of the University of California
88
*
9-
* $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.213 2002/01/03 23:21:31 tgl Exp $
9+
* $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.214 2002/02/25 04:21:55 momjian Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
@@ -64,17 +64,22 @@ typedef struct
6464
} CreateStmtContext;
6565

6666

67-
static Query *transformStmt(ParseState *pstate, Node *stmt);
67+
static Query *transformStmt(ParseState *pstate, Node *stmt,
68+
List **extras_before, List **extras_after);
6869
static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
69-
static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt);
70+
static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt,
71+
List **extras_before, List **extras_after);
7072
static Query *transformIndexStmt(ParseState *pstate, IndexStmt *stmt);
71-
static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt);
73+
static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt,
74+
List **extras_before, List **extras_after);
7275
static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt);
7376
static Query *transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt);
7477
static Node *transformSetOperationTree(ParseState *pstate, SelectStmt *stmt);
7578
static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
76-
static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt);
77-
static Query *transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt);
79+
static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt,
80+
List **extras_before, List **extras_after);
81+
static Query *transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt,
82+
List **extras_before, List **extras_after);
7883
static void transformColumnDefinition(ParseState *pstate,
7984
CreateStmtContext *cxt,
8085
ColumnDef *column);
@@ -101,9 +106,6 @@ static Oid transformFkeyGetColType(CreateStmtContext *cxt, char *colname);
101106
static void release_pstate_resources(ParseState *pstate);
102107
static FromExpr *makeFromExpr(List *fromlist, Node *quals);
103108

104-
/* kluge to return extra info from transformCreateStmt() */
105-
static List *extras_before;
106-
static List *extras_after;
107109

108110

109111
/*
@@ -121,27 +123,24 @@ parse_analyze(Node *parseTree, ParseState *parentParseState)
121123
List *result = NIL;
122124
ParseState *pstate = make_parsestate(parentParseState);
123125
Query *query;
126+
/* Lists to return extra commands from transformation */
127+
List *extras_before = NIL;
128+
List *extras_after = NIL;
124129

125-
extras_before = extras_after = NIL;
126-
127-
query = transformStmt(pstate, parseTree);
130+
query = transformStmt(pstate, parseTree, &extras_before, &extras_after);
128131
release_pstate_resources(pstate);
129132

130133
while (extras_before != NIL)
131134
{
132-
result = lappend(result,
133-
transformStmt(pstate, lfirst(extras_before)));
134-
release_pstate_resources(pstate);
135+
result = nconc(result, parse_analyze(lfirst(extras_before), pstate));
135136
extras_before = lnext(extras_before);
136137
}
137138

138139
result = lappend(result, query);
139140

140141
while (extras_after != NIL)
141142
{
142-
result = lappend(result,
143-
transformStmt(pstate, lfirst(extras_after)));
144-
release_pstate_resources(pstate);
143+
result = nconc(result, parse_analyze(lfirst(extras_after), pstate));
145144
extras_after = lnext(extras_after);
146145
}
147146

@@ -164,7 +163,8 @@ release_pstate_resources(ParseState *pstate)
164163
* transform a Parse tree into a Query tree.
165164
*/
166165
static Query *
167-
transformStmt(ParseState *pstate, Node *parseTree)
166+
transformStmt(ParseState *pstate, Node *parseTree,
167+
List **extras_before, List **extras_after)
168168
{
169169
Query *result = NULL;
170170

@@ -174,22 +174,25 @@ transformStmt(ParseState *pstate, Node *parseTree)
174174
* Non-optimizable statements
175175
*/
176176
case T_CreateStmt:
177-
result = transformCreateStmt(pstate, (CreateStmt *) parseTree);
177+
result = transformCreateStmt(pstate, (CreateStmt *) parseTree,
178+
extras_before, extras_after);
178179
break;
179180

180181
case T_IndexStmt:
181182
result = transformIndexStmt(pstate, (IndexStmt *) parseTree);
182183
break;
183184

184185
case T_RuleStmt:
185-
result = transformRuleStmt(pstate, (RuleStmt *) parseTree);
186+
result = transformRuleStmt(pstate, (RuleStmt *) parseTree,
187+
extras_before, extras_after);
186188
break;
187189

188190
case T_ViewStmt:
189191
{
190192
ViewStmt *n = (ViewStmt *) parseTree;
191193

192-
n->query = transformStmt(pstate, (Node *) n->query);
194+
n->query = transformStmt(pstate, (Node *) n->query,
195+
extras_before, extras_after);
193196

194197
/*
195198
* If a list of column names was given, run through and
@@ -239,20 +242,23 @@ transformStmt(ParseState *pstate, Node *parseTree)
239242

240243
result = makeNode(Query);
241244
result->commandType = CMD_UTILITY;
242-
n->query = transformStmt(pstate, (Node *) n->query);
245+
n->query = transformStmt(pstate, (Node *) n->query,
246+
extras_before, extras_after);
243247
result->utilityStmt = (Node *) parseTree;
244248
}
245249
break;
246250

247251
case T_AlterTableStmt:
248-
result = transformAlterTableStmt(pstate, (AlterTableStmt *) parseTree);
252+
result = transformAlterTableStmt(pstate, (AlterTableStmt *) parseTree,
253+
extras_before, extras_after);
249254
break;
250255

251256
/*
252257
* Optimizable statements
253258
*/
254259
case T_InsertStmt:
255-
result = transformInsertStmt(pstate, (InsertStmt *) parseTree);
260+
result = transformInsertStmt(pstate, (InsertStmt *) parseTree,
261+
extras_before, extras_after);
256262
break;
257263

258264
case T_DeleteStmt:
@@ -337,7 +343,8 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
337343
* transform an Insert Statement
338344
*/
339345
static Query *
340-
transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
346+
transformInsertStmt(ParseState *pstate, InsertStmt *stmt,
347+
List **extras_before, List **extras_after)
341348
{
342349
Query *qry = makeNode(Query);
343350
List *sub_rtable;
@@ -402,7 +409,12 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
402409
sub_pstate->p_rtable = sub_rtable;
403410
sub_pstate->p_namespace = sub_namespace;
404411

405-
selectQuery = transformStmt(sub_pstate, stmt->selectStmt);
412+
/*
413+
* Note: we are not expecting that extras_before and extras_after
414+
* are going to be used by the transformation of the SELECT statement.
415+
*/
416+
selectQuery = transformStmt(sub_pstate, stmt->selectStmt,
417+
extras_before, extras_after);
406418

407419
release_pstate_resources(sub_pstate);
408420
pfree(sub_pstate);
@@ -658,7 +670,8 @@ CreateIndexName(char *table_name, char *column_name,
658670
* - thomas 1997-12-02
659671
*/
660672
static Query *
661-
transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
673+
transformCreateStmt(ParseState *pstate, CreateStmt *stmt,
674+
List **extras_before, List **extras_after)
662675
{
663676
CreateStmtContext cxt;
664677
Query *q;
@@ -728,8 +741,8 @@ transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
728741
q->utilityStmt = (Node *) stmt;
729742
stmt->tableElts = cxt.columns;
730743
stmt->constraints = cxt.ckconstraints;
731-
extras_before = cxt.blist;
732-
extras_after = cxt.alist;
744+
*extras_before = nconc (*extras_before, cxt.blist);
745+
*extras_after = nconc (cxt.alist, *extras_after);
733746

734747
return q;
735748
}
@@ -1668,7 +1681,8 @@ transformIndexStmt(ParseState *pstate, IndexStmt *stmt)
16681681
* trees which is transformed into a list of query trees.
16691682
*/
16701683
static Query *
1671-
transformRuleStmt(ParseState *pstate, RuleStmt *stmt)
1684+
transformRuleStmt(ParseState *pstate, RuleStmt *stmt,
1685+
List **extras_before, List **extras_after)
16721686
{
16731687
Query *qry;
16741688
RangeTblEntry *oldrte;
@@ -1797,7 +1811,8 @@ transformRuleStmt(ParseState *pstate, RuleStmt *stmt)
17971811
addRTEtoQuery(sub_pstate, newrte, false, true);
17981812

17991813
/* Transform the rule action statement */
1800-
top_subqry = transformStmt(sub_pstate, action);
1814+
top_subqry = transformStmt(sub_pstate, action,
1815+
extras_before, extras_after);
18011816

18021817
/*
18031818
* We cannot support utility-statement actions (eg NOTIFY)
@@ -2494,7 +2509,8 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
24942509
* transform an Alter Table Statement
24952510
*/
24962511
static Query *
2497-
transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt)
2512+
transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt,
2513+
List **extras_before, List **extras_after)
24982514
{
24992515
CreateStmtContext cxt;
25002516
Query *qry;
@@ -2534,8 +2550,8 @@ transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt)
25342550
transformFKConstraints(pstate, &cxt);
25352551

25362552
((ColumnDef *) stmt->def)->constraints = cxt.ckconstraints;
2537-
extras_before = cxt.blist;
2538-
extras_after = cxt.alist;
2553+
*extras_before = nconc(*extras_before, cxt.blist);
2554+
*extras_after = nconc(cxt.alist, *extras_after);
25392555
break;
25402556

25412557
case 'C':
@@ -2571,8 +2587,8 @@ transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt)
25712587

25722588
Assert(cxt.columns == NIL);
25732589
stmt->def = (Node *) nconc(cxt.ckconstraints, cxt.fkconstraints);
2574-
extras_before = cxt.blist;
2575-
extras_after = cxt.alist;
2590+
*extras_before = nconc(*extras_before, cxt.blist);
2591+
*extras_after = nconc(cxt.alist, *extras_after);
25762592
break;
25772593

25782594
default:

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