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CREATE OR REPLACE VIEW, CREATE OR REPLACE RULE.
Gavin Sherry, Neil Conway, and Tom Lane all got their hands dirty on this one ...
This commit is contained in:
Tom Lane
@ -6,43 +6,43 @@
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* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: view.c,v 1.68 2002/08/30 19:23:19 tgl Exp $
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/commands/view.c,v 1.69 2002/09/02 02:13:01 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/xact.h"
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#include "access/heapam.h"
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#include "catalog/dependency.h"
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#include "catalog/heap.h"
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#include "catalog/namespace.h"
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#include "commands/tablecmds.h"
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#include "commands/view.h"
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#include "miscadmin.h"
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#include "nodes/makefuncs.h"
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#include "parser/parse_relation.h"
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#include "parser/parse_type.h"
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#include "rewrite/rewriteDefine.h"
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#include "rewrite/rewriteManip.h"
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#include "rewrite/rewriteRemove.h"
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#include "rewrite/rewriteSupport.h"
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#include "utils/syscache.h"
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#include "utils/acl.h"
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#include "utils/lsyscache.h"
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/*---------------------------------------------------------------------
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* DefineVirtualRelation
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*
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* Create the "view" relation.
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* `DefineRelation' does all the work, we just provide the correct
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* arguments!
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*
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* If the relation already exists, then 'DefineRelation' will abort
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* the xact...
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* Create the "view" relation. `DefineRelation' does all the work,
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* we just provide the correct arguments ... at least when we're
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* creating a view. If we're updating an existing view, we have to
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* work harder.
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*---------------------------------------------------------------------
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*/
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static Oid
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DefineVirtualRelation(const RangeVar *relation, List *tlist)
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DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace)
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{
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Oid viewOid,
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namespaceId;
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CreateStmt *createStmt = makeNode(CreateStmt);
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List *attrList,
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*t;
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@ -52,7 +52,7 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist)
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* the (non-junk) targetlist items from the view's SELECT list.
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*/
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attrList = NIL;
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foreach(t, tlist)
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foreach (t, tlist)
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{
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TargetEntry *entry = lfirst(t);
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Resdom *res = entry->resdom;
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@ -83,23 +83,74 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist)
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elog(ERROR, "attempted to define virtual relation with no attrs");
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/*
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* now create the parameters for keys/inheritance etc. All of them are
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* nil...
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* Check to see if we want to replace an existing view.
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*/
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createStmt->relation = (RangeVar *) relation;
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createStmt->tableElts = attrList;
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createStmt->inhRelations = NIL;
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createStmt->constraints = NIL;
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createStmt->hasoids = false;
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namespaceId = RangeVarGetCreationNamespace(relation);
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viewOid = get_relname_relid(relation->relname, namespaceId);
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/*
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* finally create the relation...
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*/
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return DefineRelation(createStmt, RELKIND_VIEW);
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if (OidIsValid(viewOid) && replace)
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{
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Relation rel;
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TupleDesc descriptor;
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/*
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* Yes. Get exclusive lock on the existing view ...
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*/
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rel = relation_open(viewOid, AccessExclusiveLock);
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/*
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* Make sure it *is* a view, and do permissions checks.
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*/
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if (rel->rd_rel->relkind != RELKIND_VIEW)
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elog(ERROR, "%s is not a view",
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RelationGetRelationName(rel));
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if (!pg_class_ownercheck(viewOid, GetUserId()))
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aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
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/*
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* Create a tuple descriptor to compare against the existing view,
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* and verify it matches.
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*
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* XXX the error message is a bit cheesy here: would be useful to
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* give a more specific complaint about the difference in the
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* descriptors. No time for it at the moment though.
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*/
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descriptor = BuildDescForRelation(attrList);
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if (!equalTupleDescs(descriptor, rel->rd_att))
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elog(ERROR, "Cannot change column set of existing view %s",
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RelationGetRelationName(rel));
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/*
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* Seems okay, so return the OID of the pre-existing view.
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*/
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relation_close(rel, NoLock); /* keep the lock! */
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return viewOid;
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}
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else
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{
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/*
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* now create the parameters for keys/inheritance etc. All of them are
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* nil...
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*/
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createStmt->relation = (RangeVar *) relation;
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createStmt->tableElts = attrList;
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createStmt->inhRelations = NIL;
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createStmt->constraints = NIL;
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createStmt->hasoids = false;
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/*
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* finally create the relation (this will error out if there's
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* an existing view, so we don't need more code to complain
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* if "replace" is false).
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*/
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return DefineRelation(createStmt, RELKIND_VIEW);
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}
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}
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static RuleStmt *
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FormViewRetrieveRule(const RangeVar *view, Query *viewParse)
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FormViewRetrieveRule(const RangeVar *view, Query *viewParse, bool replace)
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{
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RuleStmt *rule;
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@ -114,12 +165,13 @@ FormViewRetrieveRule(const RangeVar *view, Query *viewParse)
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rule->event = CMD_SELECT;
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rule->instead = true;
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rule->actions = makeList1(viewParse);
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rule->replace = replace;
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return rule;
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}
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static void
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DefineViewRules(const RangeVar *view, Query *viewParse)
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DefineViewRules(const RangeVar *view, Query *viewParse, bool replace)
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{
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RuleStmt *retrieve_rule;
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@ -129,10 +181,9 @@ DefineViewRules(const RangeVar *view, Query *viewParse)
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RuleStmt *delete_rule;
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#endif
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retrieve_rule = FormViewRetrieveRule(view, viewParse);
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retrieve_rule = FormViewRetrieveRule(view, viewParse, replace);
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#ifdef NOTYET
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replace_rule = FormViewReplaceRule(view, viewParse);
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append_rule = FormViewAppendRule(view, viewParse);
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delete_rule = FormViewDeleteRule(view, viewParse);
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@ -221,16 +272,18 @@ UpdateRangeTableOfViewParse(Oid viewOid, Query *viewParse)
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*-------------------------------------------------------------------
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*/
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void
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DefineView(const RangeVar *view, Query *viewParse)
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DefineView(const RangeVar *view, Query *viewParse, bool replace)
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{
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Oid viewOid;
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/*
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* Create the view relation
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*
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* NOTE: if it already exists, the xact will be aborted.
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* NOTE: if it already exists and replace is false, the xact will
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* be aborted.
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*/
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viewOid = DefineVirtualRelation(view, viewParse->targetList);
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viewOid = DefineVirtualRelation(view, viewParse->targetList, replace);
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/*
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* The relation we have just created is not visible to any other
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@ -248,7 +301,7 @@ DefineView(const RangeVar *view, Query *viewParse)
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/*
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* Now create the rules associated with the view.
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*/
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DefineViewRules(view, viewParse);
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DefineViewRules(view, viewParse, replace);
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}
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/*
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