[#340] Fix encode object acl

In the process of encode the acl of an object,
we use a map. As a result, when traversing the
map, we can get a different sequence of permissions
each time. Therefore, a list is used instead of a map.

Signed-off-by: Roman Loginov <r.loginov@yadro.com>

api/handler/acl.go

@@ -1630,6 +1630,26 @@ func isWriteOperation(op eacl.Operation) bool {
 	return op == eacl.OperationDelete || op == eacl.OperationPut
 }
 
+type access struct {
+	recipient  string
+	operations []eacl.Operation
+}
+
+type accessList struct {
+	list []access
+}
+
+func (c *accessList) addAccess(recipient string, operation eacl.Operation) {
+	for i, v := range c.list {
+		if v.recipient == recipient {
+			c.list[i].operations = append(c.list[i].operations, operation)
+			return
+		}
+	}
+
+	c.list = append(c.list, access{recipient, []eacl.Operation{operation}})
+}
+
 func (h *handler) encodeObjectACL(ctx context.Context, bucketACL *layer.BucketACL, bucketName, objectVersion string) *AccessControlPolicy {
 	res := &AccessControlPolicy{
 		Owner: Owner{
@@ -1638,7 +1658,7 @@ func (h *handler) encodeObjectACL(ctx context.Context, bucketACL *layer.BucketAC
 		},
 	}
 
-	m := make(map[string][]eacl.Operation)
+	m := &accessList{}
 
 	astList := tableToAst(bucketACL.EACL, bucketName)
 
@@ -1653,22 +1673,20 @@ func (h *handler) encodeObjectACL(ctx context.Context, bucketACL *layer.BucketAC
 			}
 
 			if len(op.Users) == 0 {
-				list := append(m[allUsersGroup], op.Op)
-				m[allUsersGroup] = list
+				m.addAccess(allUsersGroup, op.Op)
 			} else {
 				for _, user := range op.Users {
-					list := append(m[user], op.Op)
-					m[user] = list
+					m.addAccess(user, op.Op)
 				}
 			}
 		}
 	}
 
-	for key, val := range m {
+	for _, val := range m.list {
 		permission := aclFullControl
 		read := true
 		for op := eacl.OperationGet; op <= eacl.OperationRangeHash; op++ {
-			if !contains(val, op) && !isWriteOperation(op) {
+			if !contains(val.operations, op) && !isWriteOperation(op) {
 				read = false
 			}
 		}
@@ -1680,12 +1698,12 @@ func (h *handler) encodeObjectACL(ctx context.Context, bucketACL *layer.BucketAC
 		}
 
 		var grantee *Grantee
-		if key == allUsersGroup {
+		if val.recipient == allUsersGroup {
 			grantee = NewGrantee(acpGroup)
 			grantee.URI = allUsersGroup
 		} else {
 			grantee = NewGrantee(acpCanonicalUser)
-			grantee.ID = key
+			grantee.ID = val.recipient
 		}
 
 		grant := &Grant{