1 files changed, 271 insertions, 0 deletions
diff --git a/src/backend/commands/amcmds.c b/src/backend/commands/amcmds.c
new file mode 100644
index 00000000000..7a937543916
--- /dev/null
+++ b/src/backend/commands/amcmds.c
@@ -0,0 +1,271 @@
+/*-------------------------------------------------------------------------
+ *
+ * amcmds.c
+ *	  Routines for SQL commands that manipulate access methods.
+ *
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/commands/amcmds.c
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/heapam.h"
+#include "access/htup_details.h"
+#include "catalog/dependency.h"
+#include "catalog/indexing.h"
+#include "catalog/pg_am.h"
+#include "catalog/pg_proc.h"
+#include "catalog/pg_type.h"
+#include "commands/defrem.h"
+#include "miscadmin.h"
+#include "parser/parse_func.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+#include "utils/rel.h"
+#include "utils/syscache.h"
+
+
+static Oid	lookup_index_am_handler_func(List *handler_name, char amtype);
+static char *get_am_type_string(char amtype);
+
+
+/*
+ * CreateAcessMethod
+ *		Registers a new access method.
+ */
+ObjectAddress
+CreateAccessMethod(CreateAmStmt *stmt)
+{
+	Relation	rel;
+	ObjectAddress myself;
+	ObjectAddress referenced;
+	Oid			amoid;
+	Oid			amhandler;
+	bool		nulls[Natts_pg_am];
+	Datum		values[Natts_pg_am];
+	HeapTuple	tup;
+
+	rel = heap_open(AccessMethodRelationId, RowExclusiveLock);
+
+	/* Must be super user */
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("permission denied to create access method \"%s\"",
+						stmt->amname),
+				 errhint("Must be superuser to create an access method.")));
+
+	/* Check if name is used */
+	amoid = GetSysCacheOid1(AMNAME, CStringGetDatum(stmt->amname));
+	if (OidIsValid(amoid))
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_DUPLICATE_OBJECT),
+				 errmsg("access method \"%s\" already exists",
+						stmt->amname)));
+	}
+
+	/*
+	 * Get the handler function oid, verifying the AM type while at it.
+	 */
+	amhandler = lookup_index_am_handler_func(stmt->handler_name, stmt->amtype);
+
+	/*
+	 * Insert tuple into pg_am.
+	 */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+
+	values[Anum_pg_am_amname - 1] =
+		DirectFunctionCall1(namein, CStringGetDatum(stmt->amname));
+	values[Anum_pg_am_amhandler - 1] = ObjectIdGetDatum(amhandler);
+	values[Anum_pg_am_amtype - 1] = CharGetDatum(stmt->amtype);
+
+	tup = heap_form_tuple(RelationGetDescr(rel), values, nulls);
+
+	amoid = simple_heap_insert(rel, tup);
+	CatalogUpdateIndexes(rel, tup);
+	heap_freetuple(tup);
+
+	myself.classId = AccessMethodRelationId;
+	myself.objectId = amoid;
+	myself.objectSubId = 0;
+
+	/* Record dependency on handler function */
+	referenced.classId = ProcedureRelationId;
+	referenced.objectId = amhandler;
+	referenced.objectSubId = 0;
+
+	recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+
+	recordDependencyOnCurrentExtension(&myself, false);
+
+	heap_close(rel, RowExclusiveLock);
+
+	return myself;
+}
+
+/*
+ * Guts of access method deletion.
+ */
+void
+RemoveAccessMethodById(Oid amOid)
+{
+	Relation	relation;
+	HeapTuple	tup;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to drop access methods")));
+
+	relation = heap_open(AccessMethodRelationId, RowExclusiveLock);
+
+	tup = SearchSysCache1(AMOID, ObjectIdGetDatum(amOid));
+	if (!HeapTupleIsValid(tup))
+		elog(ERROR, "cache lookup failed for access method %u", amOid);
+
+	simple_heap_delete(relation, &tup->t_self);
+
+	ReleaseSysCache(tup);
+
+	heap_close(relation, RowExclusiveLock);
+}
+
+/*
+ * get_am_type_oid
+ * 		Worker for various get_am_*_oid variants
+ *
+ * If missing_ok is false, throw an error if access method not found.  If
+ * true, just return InvalidOid.
+ *
+ * If amtype is not '\0', an error is raised if the AM found is not of the
+ * given type.
+ */
+static Oid
+get_am_type_oid(const char *amname, char amtype, bool missing_ok)
+{
+	HeapTuple	tup;
+	Oid			oid = InvalidOid;
+
+	tup = SearchSysCache1(AMNAME, CStringGetDatum(amname));
+	if (HeapTupleIsValid(tup))
+	{
+		Form_pg_am	amform = (Form_pg_am) GETSTRUCT(tup);
+
+		if (amtype != '\0' &&
+			amform->amtype != amtype)
+			ereport(ERROR,
+					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					 errmsg("access method \"%s\" is not of type %s",
+							NameStr(amform->amname),
+							get_am_type_string(amtype))));
+
+		oid = HeapTupleGetOid(tup);
+		ReleaseSysCache(tup);
+	}
+
+	if (!OidIsValid(oid) && !missing_ok)
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("access method \"%s\" does not exist", amname)));
+	return oid;
+}
+
+/*
+ * get_index_am_oid - given an access method name, look up its OID
+ *		and verify it corresponds to an index AM.
+ */
+Oid
+get_index_am_oid(const char *amname, bool missing_ok)
+{
+	return get_am_type_oid(amname, AMTYPE_INDEX, missing_ok);
+}
+
+/*
+ * get_am_oid - given an access method name, look up its OID.
+ * 		The type is not checked.
+ */
+Oid
+get_am_oid(const char *amname, bool missing_ok)
+{
+	return get_am_type_oid(amname, '\0', missing_ok);
+}
+
+/*
+ * get_am_name - given an access method OID name and type, look up its name.
+ */
+char *
+get_am_name(Oid amOid)
+{
+	HeapTuple	tup;
+	char	   *result = NULL;
+
+	tup = SearchSysCache1(AMOID, ObjectIdGetDatum(amOid));
+	if (HeapTupleIsValid(tup))
+	{
+		Form_pg_am	amform = (Form_pg_am) GETSTRUCT(tup);
+
+		result = pstrdup(NameStr(amform->amname));
+		ReleaseSysCache(tup);
+	}
+	return result;
+}
+
+/*
+ * Convert single charater access method type into string for error reporting.
+ */
+static char *
+get_am_type_string(char amtype)
+{
+	switch (amtype)
+	{
+		case AMTYPE_INDEX:
+			return "INDEX";
+		default:
+			/* shouldn't happen */
+			elog(ERROR, "invalid access method type '%c'", amtype);
+	}
+}
+
+/*
+ * Convert a handler function name to an Oid.  If the return type of the
+ * function doesn't match the given AM type, an error is raised.
+ *
+ * This function either return valid function Oid or throw an error.
+ */
+static Oid
+lookup_index_am_handler_func(List *handler_name, char amtype)
+{
+	Oid			handlerOid;
+	static const Oid funcargtypes[1] = {INTERNALOID};
+
+	if (handler_name == NIL)
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_FUNCTION),
+				 errmsg("handler function is not specified")));
+
+	/* handlers have one argument of type internal */
+	handlerOid = LookupFuncName(handler_name, 1, funcargtypes, false);
+
+	/* check that handler has the correct return type */
+	switch (amtype)
+	{
+		case AMTYPE_INDEX:
+			if (get_func_rettype(handlerOid) != INDEX_AM_HANDLEROID)
+				ereport(ERROR,
+						(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+						 errmsg("function %s must return type \"%s\"",
+								NameListToString(handler_name),
+								"index_am_handler")));
+			break;
+		default:
+			elog(ERROR, "unrecognized access method type \"%c\"", amtype);
+	}
+
+	return handlerOid;
+}