Change rule dumper to produce reasonable output for casts that assign
a specific length or precision, such as foo::char(8). Remove erroneous removal of user-written casts at the top level of a SELECT target item.
This commit is contained in:
Tom Lane
parent
7173c485c8
commit
baeef0e172
@ -3,7 +3,7 @@
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* out of its tuple
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.43 2000/02/21 20:18:10 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.44 2000/02/26 21:13:18 tgl Exp $
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*
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* This software is copyrighted by Jan Wieck - Hamburg.
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*
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@ -49,6 +49,7 @@
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#include "optimizer/clauses.h"
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#include "optimizer/tlist.h"
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#include "parser/keywords.h"
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#include "parser/parse_expr.h"
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#include "parser/parsetree.h"
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#include "utils/builtins.h"
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#include "utils/lsyscache.h"
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@ -947,7 +948,8 @@ get_select_query_def(Query *query, deparse_context *context)
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appendStringInfo(buf, sep);
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sep = ", ";
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get_tle_expr(tle, context);
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/* Do NOT use get_tle_expr here; see its comments! */
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get_rule_expr(tle->expr, context);
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/* Check if we must say AS ... */
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if (! IsA(tle->expr, Var))
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@ -1486,16 +1488,16 @@ static void
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get_func_expr(Expr *expr, deparse_context *context)
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{
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StringInfo buf = context->buf;
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Func *func = (Func *) (expr->oper);
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HeapTuple proctup;
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Form_pg_proc procStruct;
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char *proname;
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int32 coercedTypmod;
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List *l;
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char *sep;
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Func *func = (Func *) (expr->oper);
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char *proname;
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/* ----------
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/*
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* Get the functions pg_proc tuple
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* ----------
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*/
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proctup = SearchSysCacheTuple(PROCOID,
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ObjectIdGetDatum(func->funcid),
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@ -1527,9 +1529,59 @@ get_func_expr(Expr *expr, deparse_context *context)
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}
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}
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/* ----------
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* Build a string of proname(args)
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* ----------
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/*
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* Check to see if function is a length-coercion function for some
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* datatype. If so, display the operation as a type cast.
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*/
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if (exprIsLengthCoercion((Node *) expr, &coercedTypmod))
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{
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Node *arg = lfirst(expr->args);
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/*
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* Strip off any RelabelType on the input, so we don't print
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* redundancies like x::bpchar::char(8).
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* XXX Are there any cases where this is a bad idea?
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*/
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if (IsA(arg, RelabelType))
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arg = ((RelabelType *) arg)->arg;
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appendStringInfoChar(buf, '(');
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get_rule_expr(arg, context);
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appendStringInfo(buf, ")::");
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/*
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* Show typename with appropriate length decoration.
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* Note that since exprIsLengthCoercion succeeded, the function
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* name is the same as its output type name.
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*/
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if (strcmp(proname, "bpchar") == 0)
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{
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if (coercedTypmod > VARHDRSZ)
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appendStringInfo(buf, "char(%d)", coercedTypmod - VARHDRSZ);
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else
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appendStringInfo(buf, "char");
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}
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else if (strcmp(proname, "varchar") == 0)
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{
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if (coercedTypmod > VARHDRSZ)
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appendStringInfo(buf, "varchar(%d)", coercedTypmod - VARHDRSZ);
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else
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appendStringInfo(buf, "varchar");
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}
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else if (strcmp(proname, "numeric") == 0)
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{
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if (coercedTypmod >= VARHDRSZ)
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appendStringInfo(buf, "numeric(%d,%d)",
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((coercedTypmod - VARHDRSZ) >> 16) & 0xffff,
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(coercedTypmod - VARHDRSZ) & 0xffff);
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else
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appendStringInfo(buf, "numeric");
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}
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else
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appendStringInfo(buf, "%s", quote_identifier(proname));
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return;
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}
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/*
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* Normal function: display as proname(args)
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*/
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appendStringInfo(buf, "%s(", quote_identifier(proname));
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sep = "";
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@ -1546,99 +1598,37 @@ get_func_expr(Expr *expr, deparse_context *context)
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/* ----------
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* get_tle_expr
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*
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* A target list expression is a bit different from a normal expression.
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* If the target column has an atttypmod, the parser usually puts a
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* padding-/cut-function call around the expression itself.
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* We must get rid of it, otherwise dump/reload/dump... would blow up
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* the expressions.
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* In an INSERT or UPDATE targetlist item, the parser may have inserted
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* a length-coercion function call to coerce the value to the right
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* length for the target column. We want to suppress the output of
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* that function call, otherwise dump/reload/dump... would blow up the
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* expression by adding more and more layers of length-coercion calls.
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*
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* As of 7.0, this hack is no longer absolutely essential, because the parser
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* is now smart enough not to add a redundant length coercion function call.
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* But we still suppress the function call just for neatness of displayed
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* rules.
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*
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* Note that this hack must NOT be applied to SELECT targetlist items;
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* any length coercion appearing there is something the user actually wrote.
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* ----------
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*/
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static void
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get_tle_expr(TargetEntry *tle, deparse_context *context)
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{
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Expr *expr = (Expr *) (tle->expr);
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Func *func;
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HeapTuple tup;
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Form_pg_proc procStruct;
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Form_pg_type typeStruct;
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Const *second_arg;
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/* ----------
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* Check if the result has an atttypmod and if the
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* expression in the targetlist entry is a function call
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* ----------
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*/
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if (tle->resdom->restypmod < 0 ||
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! IsA(expr, Expr) ||
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expr->opType != FUNC_EXPR)
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{
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get_rule_expr(tle->expr, context);
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return;
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}
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func = (Func *) (expr->oper);
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/* ----------
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* Get the functions pg_proc tuple
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* ----------
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*/
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tup = SearchSysCacheTuple(PROCOID,
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ObjectIdGetDatum(func->funcid), 0, 0, 0);
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if (!HeapTupleIsValid(tup))
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elog(ERROR, "cache lookup for proc %u failed", func->funcid);
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procStruct = (Form_pg_proc) GETSTRUCT(tup);
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/* ----------
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* It must be a function with two arguments where the first
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* is of the same type as the return value and the second is
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* an int4.
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* ----------
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*/
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if (procStruct->pronargs != 2 ||
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procStruct->prorettype != procStruct->proargtypes[0] ||
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procStruct->proargtypes[1] != INT4OID)
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{
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get_rule_expr(tle->expr, context);
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return;
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}
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int32 coercedTypmod;
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/*
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* Furthermore, the name of the function must be the same
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* as the argument/result type name.
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* If top level is a length coercion to the correct length, suppress it;
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* else dump the expression normally.
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*/
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tup = SearchSysCacheTuple(TYPEOID,
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ObjectIdGetDatum(procStruct->prorettype),
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0, 0, 0);
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if (!HeapTupleIsValid(tup))
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elog(ERROR, "cache lookup for type %u failed",
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procStruct->prorettype);
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typeStruct = (Form_pg_type) GETSTRUCT(tup);
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if (strncmp(NameStr(procStruct->proname),
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NameStr(typeStruct->typname),
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NAMEDATALEN) != 0)
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{
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if (tle->resdom->restypmod >= 0 &&
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exprIsLengthCoercion((Node *) expr, &coercedTypmod) &&
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coercedTypmod == tle->resdom->restypmod)
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get_rule_expr((Node *) lfirst(expr->args), context);
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else
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get_rule_expr(tle->expr, context);
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return;
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}
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/* ----------
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* Finally (to be totally safe) the second argument must be a
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* const and match the value in the results atttypmod.
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* ----------
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*/
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second_arg = (Const *) lsecond(expr->args);
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if (! IsA(second_arg, Const) ||
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DatumGetInt32(second_arg->constvalue) != tle->resdom->restypmod)
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{
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get_rule_expr(tle->expr, context);
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return;
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}
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/* ----------
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* Whow - got it. Now get rid of the padding function
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* ----------
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*/
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get_rule_expr((Node *) lfirst(expr->args), context);
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}
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