Previous patch backed out.

Here is a patch against CVS (without my earlier patch)
to disallow

LOCK x

if x is a view.

It does not use the SPI interface.

--
Mark Hollomon

diff --git a/doc/TODO b/doc/TODO
index f903ba053df1fa178eb2a7f138be90747ab5cb5b..804d52a3a4b80750f811f4763131ba906ddfcaf4 100644 (file)
--- a/doc/TODO
+++ b/doc/TODO
@@ -35,7 +35,7 @@ VIEWS
 * Views containing aggregates sometimes fail(Jan)
 * Creating view and inheriting the view causes view* to show
   duplicates(inherit) 
-* Disallow LOCK on view
+* -Disallow LOCK on view(Mark Hollomon)
 
 MISC
 

diff --git a/src/backend/commands/command.c b/src/backend/commands/command.c
index 668858d07725094fbad3a55fc919160d3d20579d..d0de9e2e4de68b9181de841319e5475d77dfbd59 100644 (file)
--- a/src/backend/commands/command.c
+++ b/src/backend/commands/command.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.99 2000/09/12 04:30:08 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.100 2000/09/12 04:33:18 momjian Exp $
  *
  * NOTES
  *   The PerformAddAttribute() code, like most of the relation
@@ -26,6 +26,7 @@
 #include "catalog/indexing.h"
 #include "catalog/pg_attrdef.h"
 #include "catalog/pg_opclass.h"
+#include "catalog/pg_rewrite.h"
 #include "commands/command.h"
 #include "executor/spi.h"
 #include "catalog/heap.h"
@@ -55,7 +56,8 @@
 
 
 static bool needs_toast_table(Relation rel);
-static bool is_view(char *relname, char *command);
+static bool is_viewr(char *relname);
+static bool is_view(Relation rel);
 
 
 
@@ -1100,7 +1102,7 @@ AlterTableAddConstraint(char *relationName,
 #endif
 
    /* check to see if the table to be constrained is a view. */
-   if (is_view(relationName, "ALTER TABLE"))
+   if (is_viewr(relationName))
         elog(ERROR, "ALTER TABLE: Cannot add constraints to views.");
        
    switch (nodeTag(newConstraint))
@@ -1250,7 +1252,7 @@ AlterTableAddConstraint(char *relationName,
                }
 
                /* check to see if the referenced table is a view. */
-               if (is_view(fkconstraint->pktable_name, "ALTER TABLE"))
+               if (is_viewr(fkconstraint->pktable_name))
                 elog(ERROR, "ALTER TABLE: Cannot add constraints to views.");
 
                /*
@@ -1698,11 +1700,11 @@ LockTableCommand(LockStmt *lockstmt)
    Relation    rel;
    int         aclresult;
 
-   if (is_view(lockstmt->relname, "LOCK TABLE")) 
-           elog(ERROR, "LOCK TABLE: cannot lock a view");
-
    rel = heap_openr(lockstmt->relname, NoLock);
 
+   if (is_view(rel)) 
+           elog(ERROR, "LOCK TABLE: cannot lock a view");
+
    if (lockstmt->mode == AccessShareLock)
        aclresult = pg_aclcheck(lockstmt->relname, GetUserId(), ACL_RD);
    else
@@ -1719,26 +1721,63 @@ LockTableCommand(LockStmt *lockstmt)
 
 static
 bool
-is_view (char * relname, char *command)
+is_viewr(char *name)
 {
-   bool retval;
-   char rulequery[41+NAMEDATALEN]; 
-   void *qplan;
-   char nulls[1]="";
-
-   sprintf(rulequery, "select * from pg_views where viewname='%s'", relname);
-   if (SPI_connect()!=SPI_OK_CONNECT)
-       elog(ERROR, "%s: Unable to determine if %s is a view - SPI_connect failure..", command, relname);
-   qplan=SPI_prepare(rulequery, 0, NULL);
-   if (!qplan)
-       elog(ERROR, "%s: Unable to determine if %s is a view - SPI_prepare failure.", command, relname);
-   qplan=SPI_saveplan(qplan);
-   if (SPI_execp(qplan, NULL, nulls, 1)!=SPI_OK_SELECT) 
-       elog(ERROR, "%s: Unable to determine if %s is a view - SPI_execp failure.", command, relname);
-
-   retval = (SPI_processed != 0);
-  if (SPI_finish() != SPI_OK_FINISH)
-    elog(NOTICE, "SPI_finish() failed in %s", command);
+   Relation rel = heap_openr(name, NoLock);
+
+   bool retval = is_view(rel);
+
+   heap_close(rel, NoLock);
+
+   return retval;
+}
+
+static
+bool
+is_view (Relation rel)
+{
+   Relation    RewriteRelation;
+   HeapScanDesc scanDesc;
+   ScanKeyData scanKeyData;
+   HeapTuple   tuple;
+   Form_pg_rewrite data;
+
+
+   bool retval = 0;
+
+   /*
+    * Open the pg_rewrite relation.
+    */
+   RewriteRelation = heap_openr(RewriteRelationName, RowExclusiveLock);
+
+   /*
+    * Scan the RuleRelation ('pg_rewrite') for all the tuples that has
+    * the same ev_class as the relation being checked.
+    */
+   ScanKeyEntryInitialize(&scanKeyData,
+                          0,
+                          Anum_pg_rewrite_ev_class,
+                          F_OIDEQ,
+                          ObjectIdGetDatum(rel->rd_id));
+   scanDesc = heap_beginscan(RewriteRelation,
+                             0, SnapshotNow, 1, &scanKeyData);
+
+   while (HeapTupleIsValid(tuple = heap_getnext(scanDesc, 0)))
+   {
+       if (tuple->t_data != NULL) 
+       {
+           data = (Form_pg_rewrite) GETSTRUCT(tuple);
+           if (data->ev_type == '1')
+           {
+               retval = 1;
+               break;
+           }
+       }
+
+   }
 
+   heap_endscan(scanDesc);
+   heap_close(RewriteRelation, RowExclusiveLock);
+   
   return retval;
 }