Reject zero or negative BY step in plpgsql integer FOR-loops, and behave
sanely if the loop value overflows int32 on the way to the end value. Avoid useless computation of "SELECT 1" when BY is omitted. Avoid some type-punning between Datum and int4 that dates from the original coding.
This commit is contained in:
Tom Lane
parent
a69f9028b5
commit
816ff27f60
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@ -9,7 +9,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.102 2007/04/29 01:21:09 neilc Exp $
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.103 2007/07/15 02:15:04 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -876,7 +876,7 @@ stmt_for : opt_block_label K_FOR for_control loop_body
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}
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check_labels($1, $4.end_label);
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/* close namespace started in opt_label */
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/* close namespace started in opt_block_label */
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plpgsql_ns_pop();
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}
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;
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@ -968,39 +968,25 @@ for_control :
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PLpgSQL_stmt_fori *new;
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char *varname;
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/* First expression is well-formed */
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/* Check first expression is well-formed */
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check_sql_expr(expr1->query);
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expr2 = read_sql_construct(K_BY,
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K_LOOP,
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/* Read and check the second one */
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expr2 = read_sql_construct(K_LOOP,
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K_BY,
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"LOOP",
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"SELECT ",
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true,
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false,
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true,
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&tok);
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/* Get the BY clause if any */
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if (tok == K_BY)
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expr_by = plpgsql_read_expression(K_LOOP, "LOOP");
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else
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{
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/*
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* If there is no BY clause we will assume 1
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*/
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char buf[1024];
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PLpgSQL_dstring ds;
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expr_by = NULL;
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plpgsql_dstring_init(&ds);
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expr_by = palloc0(sizeof(PLpgSQL_expr));
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expr_by->dtype = PLPGSQL_DTYPE_EXPR;
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strcpy(buf, "SELECT 1");
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plpgsql_dstring_append(&ds, buf);
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expr_by->query = pstrdup(plpgsql_dstring_get(&ds));
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expr_by->plan = NULL;
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}
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/* should have had a single variable name */
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/* Should have had a single variable name */
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plpgsql_error_lineno = $2.lineno;
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if ($2.scalar && $2.row)
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ereport(ERROR,
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@ -1023,7 +1009,7 @@ for_control :
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new->reverse = reverse;
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new->lower = expr1;
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new->upper = expr2;
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new->by = expr_by;
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new->step = expr_by;
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$$ = (PLpgSQL_stmt *) new;
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}
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.197 2007/06/05 21:31:08 tgl Exp $
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.198 2007/07/15 02:15:04 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -1517,8 +1517,7 @@ exec_stmt_while(PLpgSQL_execstate *estate, PLpgSQL_stmt_while *stmt)
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/* ----------
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* exec_stmt_fori Iterate an integer variable
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* from a lower to an upper value
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* incrementing or decrementing in BY value
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* Loop can be left with exit.
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* incrementing or decrementing by the BY value
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* ----------
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*/
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static int
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@ -1526,16 +1525,18 @@ exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
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{
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PLpgSQL_var *var;
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Datum value;
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Datum by_value;
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Oid valtype;
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bool isnull;
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Oid valtype;
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int32 loop_value;
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int32 end_value;
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int32 step_value;
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bool found = false;
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int rc = PLPGSQL_RC_OK;
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var = (PLpgSQL_var *) (estate->datums[stmt->var->varno]);
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/*
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* Get the value of the lower bound into the loop var
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* Get the value of the lower bound
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*/
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value = exec_eval_expr(estate, stmt->lower, &isnull, &valtype);
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value = exec_cast_value(value, valtype, var->datatype->typoid,
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@ -1546,8 +1547,7 @@ exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
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ereport(ERROR,
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(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
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errmsg("lower bound of FOR loop cannot be NULL")));
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var->value = value;
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var->isnull = false;
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loop_value = DatumGetInt32(value);
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exec_eval_cleanup(estate);
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/*
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@ -1562,22 +1562,32 @@ exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
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ereport(ERROR,
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(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
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errmsg("upper bound of FOR loop cannot be NULL")));
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end_value = DatumGetInt32(value);
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exec_eval_cleanup(estate);
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/*
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* Get the by value
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* Get the step value
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*/
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by_value = exec_eval_expr(estate, stmt->by, &isnull, &valtype);
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by_value = exec_cast_value(by_value, valtype, var->datatype->typoid,
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&(var->datatype->typinput),
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var->datatype->typioparam,
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var->datatype->atttypmod, isnull);
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if (isnull)
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ereport(ERROR,
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(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
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errmsg("by value of FOR loop cannot be NULL")));
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exec_eval_cleanup(estate);
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if (stmt->step)
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{
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value = exec_eval_expr(estate, stmt->step, &isnull, &valtype);
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value = exec_cast_value(value, valtype, var->datatype->typoid,
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&(var->datatype->typinput),
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var->datatype->typioparam,
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var->datatype->atttypmod, isnull);
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if (isnull)
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ereport(ERROR,
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(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
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errmsg("BY value of FOR loop cannot be NULL")));
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step_value = DatumGetInt32(value);
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exec_eval_cleanup(estate);
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if (step_value <= 0)
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("BY value of FOR loop must be greater than zero")));
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}
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else
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step_value = 1;
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/*
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* Now do the loop
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@ -1585,21 +1595,27 @@ exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
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for (;;)
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{
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/*
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* Check bounds
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* Check against upper bound
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*/
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if (stmt->reverse)
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{
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if ((int4) (var->value) < (int4) value)
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if (loop_value < end_value)
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break;
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}
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else
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{
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if ((int4) (var->value) > (int4) value)
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if (loop_value > end_value)
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break;
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}
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found = true; /* looped at least once */
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/*
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* Assign current value to loop var
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*/
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var->value = Int32GetDatum(loop_value);
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var->isnull = false;
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/*
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* Execute the statements
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*/
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@ -1625,13 +1641,12 @@ exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
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* current statement's label, if any: return RC_EXIT so that the
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* EXIT continues to propagate up the stack.
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*/
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break;
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}
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else if (rc == PLPGSQL_RC_CONTINUE)
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{
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if (estate->exitlabel == NULL)
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/* anonymous continue, so re-run the current loop */
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/* unlabelled continue, so re-run the current loop */
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rc = PLPGSQL_RC_OK;
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else if (stmt->label != NULL &&
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strcmp(stmt->label, estate->exitlabel) == 0)
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@ -1652,12 +1667,21 @@ exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
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}
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/*
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* Increase/decrease loop var
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* Increase/decrease loop value, unless it would overflow, in which
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* case exit the loop.
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*/
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if (stmt->reverse)
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var->value -= by_value;
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{
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if ((int32) (loop_value - step_value) > loop_value)
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break;
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loop_value -= step_value;
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}
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else
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var->value += by_value;
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{
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if ((int32) (loop_value + step_value) < loop_value)
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break;
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loop_value += step_value;
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}
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}
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/*
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.59 2007/04/29 01:21:09 neilc Exp $
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.60 2007/07/15 02:15:04 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -701,8 +701,8 @@ dump_fori(PLpgSQL_stmt_fori *stmt)
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dump_expr(stmt->upper);
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printf("\n");
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dump_ind();
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printf(" by = ");
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dump_expr(stmt->by);
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printf(" step = ");
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dump_expr(stmt->step);
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printf("\n");
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dump_indent -= 2;
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.88 2007/04/29 01:21:09 neilc Exp $
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.89 2007/07/15 02:15:04 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -402,7 +402,7 @@ typedef struct
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PLpgSQL_var *var;
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PLpgSQL_expr *lower;
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PLpgSQL_expr *upper;
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PLpgSQL_expr *by;
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PLpgSQL_expr *step; /* NULL means default (ie, BY 1) */
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int reverse;
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List *body; /* List of statements */
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} PLpgSQL_stmt_fori;
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