README.Coding: add "Error and out logic"

[gd/samba-autobuild/.git] / README.Coding

diff --git a/README.Coding b/README.Coding
index 19a363fa1dd13d3f605fc9c009a55fae17cb79ac..e89925cad264fcf237fe8e06513fc7c6247e744c 100644 (file)
--- a/README.Coding
+++ b/README.Coding
@@ -445,6 +445,55 @@ The only exception is the test code that depends repeated use of calls
 like CHECK_STATUS, CHECK_VAL and others.
 
 
+Error and out logic
+-------------------
+
+Don't do this:
+
+       frame = talloc_stackframe();
+
+       if (ret == LDB_SUCCESS) {
+               if (result->count == 0) {
+                       ret = LDB_ERR_NO_SUCH_OBJECT;
+               } else {
+                       struct ldb_message *match =
+                               get_best_match(dn, result);
+                       if (match == NULL) {
+                               TALLOC_FREE(frame);
+                               return LDB_ERR_OPERATIONS_ERROR;
+                       }
+                       *msg = talloc_move(mem_ctx, &match);
+               }
+       }
+
+       TALLOC_FREE(frame);
+       return ret;
+
+It should be:
+
+       frame = talloc_stackframe();
+
+       if (ret != LDB_SUCCESS) {
+               TALLOC_FREE(frame);
+               return ret;
+       }
+
+       if (result->count == 0) {
+               TALLOC_FREE(frame);
+               return LDB_ERR_NO_SUCH_OBJECT;
+       }
+
+       match = get_best_match(dn, result);
+       if (match == NULL) {
+               TALLOC_FREE(frame);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       *msg = talloc_move(mem_ctx, &match);
+       TALLOC_FREE(frame);
+       return LDB_SUCCESS;
+
+
 DEBUG statements
 ----------------