Consolidate DROP handling for some object types.

This gets rid of a significant amount of duplicative code.

KaiGai Kohei, reviewed in earlier versions by Dimitri Fontaine, with
further review and cleanup by me.

1 files changed, 147 insertions, 0 deletions

diff --git a/src/backend/commands/dropcmds.c b/src/backend/commands/dropcmds.c
new file mode 100644
index 00000000000..8297730e3cf
--- /dev/null
+++ b/src/backend/commands/dropcmds.c
@@ -0,0 +1,147 @@
+/*-------------------------------------------------------------------------
+ *
+ * dropcmds.c
+ *	  handle various "DROP" operations
+ *
+ * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/dropcmds.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/heapam.h"
+#include "catalog/dependency.h"
+#include "catalog/namespace.h"
+#include "catalog/objectaddress.h"
+#include "catalog/pg_class.h"
+#include "commands/defrem.h"
+#include "miscadmin.h"
+#include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
+#include "utils/acl.h"
+
+static void does_not_exist_skipping(ObjectType objtype, List *objname);
+
+/*
+ * Drop one or more objects.
+ *
+ * We don't currently handle all object types here.  Relations, for example,
+ * require special handling, because (for example) indexes have additional
+ * locking requirements.
+ *
+ * We look up all the objects first, and then delete them in a single
+ * performMultipleDeletions() call.  This avoids unnecessary DROP RESTRICT
+ * errors if there are dependencies between them.
+ */
+void
+RemoveObjects(DropStmt *stmt)
+{
+	ObjectAddresses *objects;
+	ListCell   *cell1;
+
+	objects = new_object_addresses();
+
+	foreach(cell1, stmt->objects)
+	{
+		ObjectAddress	address;
+		List	   *objname = lfirst(cell1);
+		Relation	relation = NULL;
+		Oid			namespaceId;
+
+		/* Get an ObjectAddress for the object. */
+		address = get_object_address(stmt->removeType,
+									 objname, NIL,
+									 &relation,
+									 AccessExclusiveLock,
+									 stmt->missing_ok);
+
+		/* Issue NOTICE if supplied object was not found. */
+		if (!OidIsValid(address.objectId))
+		{
+			does_not_exist_skipping(stmt->removeType, objname);
+			continue;
+		}
+
+		/* Check permissions. */
+		namespaceId = get_object_namespace(&address);
+		if (!OidIsValid(namespaceId) ||
+			!pg_namespace_ownercheck(namespaceId, GetUserId()))
+			check_object_ownership(GetUserId(), stmt->removeType, address,
+								   objname, NIL, relation);
+
+		/* Release any relcache reference count, but keep lock until commit. */
+		if (relation)
+			heap_close(relation, NoLock);
+
+		add_exact_object_address(&address, objects);
+	}
+
+	/* Here we really delete them. */
+	performMultipleDeletions(objects, stmt->behavior);
+
+	free_object_addresses(objects);
+}
+
+/*
+ * Generate a NOTICE stating that the named object was not found, and is
+ * being skipped.  This is only relevant when "IF EXISTS" is used; otherwise,
+ * get_object_address() will throw an ERROR.
+ */
+static void
+does_not_exist_skipping(ObjectType objtype, List *objname)
+{
+	const char *msg = NULL;
+	char	   *name = NULL;
+
+	switch (objtype)
+	{
+		case OBJECT_TYPE:
+		case OBJECT_DOMAIN:
+			msg = gettext_noop("type \"%s\" does not exist, skipping");
+			name = TypeNameToString(makeTypeNameFromNameList(objname));
+			break;
+		case OBJECT_COLLATION:
+			msg = gettext_noop("collation \"%s\" does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		case OBJECT_CONVERSION:
+			msg = gettext_noop("conversion \"%s\" does not exist, skipping");
+			name =  NameListToString(objname);
+			break;
+		case OBJECT_SCHEMA:
+			msg = gettext_noop("schema \"%s\" does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		case OBJECT_TSPARSER:
+			msg = gettext_noop("text search parser \"%s\" does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		case OBJECT_TSDICTIONARY:
+			msg = gettext_noop("text search dictionary \"%s\" does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		case OBJECT_TSTEMPLATE:
+			msg = gettext_noop("text search template \"%s\" does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		case OBJECT_TSCONFIGURATION:
+			msg = gettext_noop("text search configuration \"%s\" does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		case OBJECT_EXTENSION:
+			msg = gettext_noop("extension \"%s\" does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		default:
+			elog(ERROR, "unexpected object type (%d)", (int)objtype);
+			break;
+	}
+
+	ereport(NOTICE, (errmsg(msg, name)));
+}