Allow arbitrary levels of analyze/rewriting - Mailing list pgsql-patches

Hi,

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
Red Hat Canada Ltd.                     E-Mail:  fnasser@redhat.com
2323 Yonge Street, Suite #300
Toronto, Ontario   M4P 2C9Index: src/backend/parser/analyze.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/parser/analyze.c,v
retrieving revision 1.213
diff -c -p -r1.213 analyze.c
*** src/backend/parser/analyze.c    2002/01/03 23:21:31    1.213
--- src/backend/parser/analyze.c    2002/02/12 15:35:58
*************** typedef struct
*** 64,80 ****
  } CreateStmtContext;


! static Query *transformStmt(ParseState *pstate, Node *stmt);
  static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
! static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt);
  static Query *transformIndexStmt(ParseState *pstate, IndexStmt *stmt);
! static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt);
  static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt);
  static Query *transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt);
  static Node *transformSetOperationTree(ParseState *pstate, SelectStmt *stmt);
  static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
! static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt);
! static Query *transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt);
  static void transformColumnDefinition(ParseState *pstate,
                            CreateStmtContext *cxt,
                            ColumnDef *column);
--- 64,85 ----
  } CreateStmtContext;


! static Query *transformStmt(ParseState *pstate, Node *stmt,
!                         List **extras_before, List **extras_after);
  static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
! static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt,
!                         List **extras_before, List **extras_after);
  static Query *transformIndexStmt(ParseState *pstate, IndexStmt *stmt);
! static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt,
!                         List **extras_before, List **extras_after);
  static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt);
  static Query *transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt);
  static Node *transformSetOperationTree(ParseState *pstate, SelectStmt *stmt);
  static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
! static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt,
!                         List **extras_before, List **extras_after);
! static Query *transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt,
!                         List **extras_before, List **extras_after);
  static void transformColumnDefinition(ParseState *pstate,
                            CreateStmtContext *cxt,
                            ColumnDef *column);
*************** static Oid    transformFkeyGetColType(Creat
*** 101,109 ****
  static void release_pstate_resources(ParseState *pstate);
  static FromExpr *makeFromExpr(List *fromlist, Node *quals);

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


  /*
--- 106,111 ----
*************** parse_analyze(Node *parseTree, ParseStat
*** 121,137 ****
      List       *result = NIL;
      ParseState *pstate = make_parsestate(parentParseState);
      Query       *query;

!     extras_before = extras_after = NIL;
!
!     query = transformStmt(pstate, parseTree);
      release_pstate_resources(pstate);

      while (extras_before != NIL)
      {
!         result = lappend(result,
!                          transformStmt(pstate, lfirst(extras_before)));
!         release_pstate_resources(pstate);
          extras_before = lnext(extras_before);
      }

--- 123,138 ----
      List       *result = NIL;
      ParseState *pstate = make_parsestate(parentParseState);
      Query       *query;
+     /* Lists to return extra commands from transformation */
+     List *extras_before = NIL;
+     List *extras_after = NIL;

!     query = transformStmt(pstate, parseTree, &extras_before, &extras_after);
      release_pstate_resources(pstate);

      while (extras_before != NIL)
      {
!         result = nconc(result, parse_analyze(lfirst(extras_before), pstate));
          extras_before = lnext(extras_before);
      }

*************** parse_analyze(Node *parseTree, ParseStat
*** 139,147 ****

      while (extras_after != NIL)
      {
!         result = lappend(result,
!                          transformStmt(pstate, lfirst(extras_after)));
!         release_pstate_resources(pstate);
          extras_after = lnext(extras_after);
      }

--- 140,146 ----

      while (extras_after != NIL)
      {
!         result = nconc(result, parse_analyze(lfirst(extras_after), pstate));
          extras_after = lnext(extras_after);
      }

*************** release_pstate_resources(ParseState *pst
*** 164,170 ****
   *      transform a Parse tree into a Query tree.
   */
  static Query *
! transformStmt(ParseState *pstate, Node *parseTree)
  {
      Query       *result = NULL;

--- 163,170 ----
   *      transform a Parse tree into a Query tree.
   */
  static Query *
! transformStmt(ParseState *pstate, Node *parseTree,
!               List **extras_before,    List **extras_after)
  {
      Query       *result = NULL;

*************** transformStmt(ParseState *pstate, Node *
*** 174,180 ****
               * Non-optimizable statements
               */
          case T_CreateStmt:
!             result = transformCreateStmt(pstate, (CreateStmt *) parseTree);
              break;

          case T_IndexStmt:
--- 174,181 ----
               * Non-optimizable statements
               */
          case T_CreateStmt:
!             result = transformCreateStmt(pstate, (CreateStmt *) parseTree,
!                                     extras_before, extras_after);
              break;

          case T_IndexStmt:
*************** transformStmt(ParseState *pstate, Node *
*** 182,195 ****
              break;

          case T_RuleStmt:
!             result = transformRuleStmt(pstate, (RuleStmt *) parseTree);
              break;

          case T_ViewStmt:
              {
                  ViewStmt   *n = (ViewStmt *) parseTree;

!                 n->query = transformStmt(pstate, (Node *) n->query);

                  /*
                   * If a list of column names was given, run through and
--- 183,198 ----
              break;

          case T_RuleStmt:
!             result = transformRuleStmt(pstate, (RuleStmt *) parseTree,
!                                     extras_before, extras_after);
              break;

          case T_ViewStmt:
              {
                  ViewStmt   *n = (ViewStmt *) parseTree;

!                 n->query = transformStmt(pstate, (Node *) n->query,
!                                     extras_before, extras_after);

                  /*
                   * If a list of column names was given, run through and
*************** transformStmt(ParseState *pstate, Node *
*** 239,258 ****

                  result = makeNode(Query);
                  result->commandType = CMD_UTILITY;
!                 n->query = transformStmt(pstate, (Node *) n->query);
                  result->utilityStmt = (Node *) parseTree;
              }
              break;

          case T_AlterTableStmt:
!             result = transformAlterTableStmt(pstate, (AlterTableStmt *) parseTree);
              break;

              /*
               * Optimizable statements
               */
          case T_InsertStmt:
!             result = transformInsertStmt(pstate, (InsertStmt *) parseTree);
              break;

          case T_DeleteStmt:
--- 242,264 ----

                  result = makeNode(Query);
                  result->commandType = CMD_UTILITY;
!                 n->query = transformStmt(pstate, (Node *) n->query,
!                                 extras_before, extras_after);
                  result->utilityStmt = (Node *) parseTree;
              }
              break;

          case T_AlterTableStmt:
!             result = transformAlterTableStmt(pstate, (AlterTableStmt *) parseTree,
!                                         extras_before, extras_after);
              break;

              /*
               * Optimizable statements
               */
          case T_InsertStmt:
!             result = transformInsertStmt(pstate, (InsertStmt *) parseTree,
!                                         extras_before, extras_after);
              break;

          case T_DeleteStmt:
*************** transformDeleteStmt(ParseState *pstate,
*** 337,343 ****
   *      transform an Insert Statement
   */
  static Query *
! transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
  {
      Query       *qry = makeNode(Query);
      List       *sub_rtable;
--- 343,350 ----
   *      transform an Insert Statement
   */
  static Query *
! transformInsertStmt(ParseState *pstate, InsertStmt *stmt,
!                     List **extras_before, List **extras_after)
  {
      Query       *qry = makeNode(Query);
      List       *sub_rtable;
*************** transformInsertStmt(ParseState *pstate,
*** 402,408 ****
          sub_pstate->p_rtable = sub_rtable;
          sub_pstate->p_namespace = sub_namespace;

!         selectQuery = transformStmt(sub_pstate, stmt->selectStmt);

          release_pstate_resources(sub_pstate);
          pfree(sub_pstate);
--- 409,420 ----
          sub_pstate->p_rtable = sub_rtable;
          sub_pstate->p_namespace = sub_namespace;

!         /*
!          * Note: we are not expecting that extras_before and extras_after
!          * are going to be used by the transformation of the SELECT statement.
!           */
!         selectQuery = transformStmt(sub_pstate, stmt->selectStmt,
!                                 extras_before, extras_after);

          release_pstate_resources(sub_pstate);
          pfree(sub_pstate);
*************** CreateIndexName(char *table_name, char *
*** 658,664 ****
   *      - thomas 1997-12-02
   */
  static Query *
! transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
  {
      CreateStmtContext cxt;
      Query       *q;
--- 670,677 ----
   *      - thomas 1997-12-02
   */
  static Query *
! transformCreateStmt(ParseState *pstate, CreateStmt *stmt,
!                     List **extras_before, List **extras_after)
  {
      CreateStmtContext cxt;
      Query       *q;
*************** transformCreateStmt(ParseState *pstate,
*** 728,735 ****
      q->utilityStmt = (Node *) stmt;
      stmt->tableElts = cxt.columns;
      stmt->constraints = cxt.ckconstraints;
!     extras_before = cxt.blist;
!     extras_after = cxt.alist;

      return q;
  }
--- 741,748 ----
      q->utilityStmt = (Node *) stmt;
      stmt->tableElts = cxt.columns;
      stmt->constraints = cxt.ckconstraints;
!     *extras_before = nconc (*extras_before, cxt.blist);
!     *extras_after = nconc (cxt.alist, *extras_after);

      return q;
  }
*************** transformIndexStmt(ParseState *pstate, I
*** 1668,1674 ****
   *      trees which is transformed into a list of query trees.
   */
  static Query *
! transformRuleStmt(ParseState *pstate, RuleStmt *stmt)
  {
      Query       *qry;
      RangeTblEntry *oldrte;
--- 1681,1688 ----
   *      trees which is transformed into a list of query trees.
   */
  static Query *
! transformRuleStmt(ParseState *pstate, RuleStmt *stmt,
!                 List **extras_before, List **extras_after)
  {
      Query       *qry;
      RangeTblEntry *oldrte;
*************** transformRuleStmt(ParseState *pstate, Ru
*** 1797,1803 ****
              addRTEtoQuery(sub_pstate, newrte, false, true);

              /* Transform the rule action statement */
!             top_subqry = transformStmt(sub_pstate, action);

              /*
               * We cannot support utility-statement actions (eg NOTIFY)
--- 1811,1818 ----
              addRTEtoQuery(sub_pstate, newrte, false, true);

              /* Transform the rule action statement */
!             top_subqry = transformStmt(sub_pstate, action,
!                                 extras_before, extras_after);

              /*
               * We cannot support utility-statement actions (eg NOTIFY)
*************** transformUpdateStmt(ParseState *pstate,
*** 2494,2500 ****
   *    transform an Alter Table Statement
   */
  static Query *
! transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt)
  {
      CreateStmtContext cxt;
      Query       *qry;
--- 2509,2516 ----
   *    transform an Alter Table Statement
   */
  static Query *
! transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt,
!                         List **extras_before, List **extras_after)
  {
      CreateStmtContext cxt;
      Query       *qry;
*************** transformAlterTableStmt(ParseState *psta
*** 2534,2541 ****
              transformFKConstraints(pstate, &cxt);

              ((ColumnDef *) stmt->def)->constraints = cxt.ckconstraints;
!             extras_before = cxt.blist;
!             extras_after = cxt.alist;
              break;

          case 'C':
--- 2550,2557 ----
              transformFKConstraints(pstate, &cxt);

              ((ColumnDef *) stmt->def)->constraints = cxt.ckconstraints;
!             *extras_before = nconc(*extras_before, cxt.blist);
!             *extras_after = nconc(cxt.alist, *extras_after);
              break;

          case 'C':
*************** transformAlterTableStmt(ParseState *psta
*** 2571,2578 ****

              Assert(cxt.columns == NIL);
              stmt->def = (Node *) nconc(cxt.ckconstraints, cxt.fkconstraints);
!             extras_before = cxt.blist;
!             extras_after = cxt.alist;
              break;

          default:
--- 2587,2594 ----

              Assert(cxt.columns == NIL);
              stmt->def = (Node *) nconc(cxt.ckconstraints, cxt.fkconstraints);
!             *extras_before = nconc(*extras_before, cxt.blist);
!             *extras_after = nconc(cxt.alist, *extras_after);
              break;

          default: