Mojo cpp bindings: report the reason of validation failure.

mojo/public/cpp/bindings/lib/validation_errors.cc

Index: mojo/public/cpp/bindings/lib/validation_errors.cc
diff --git a/mojo/public/cpp/bindings/lib/validation_errors.cc b/mojo/public/cpp/bindings/lib/validation_errors.cc
new file mode 100644
index 0000000000000000000000000000000000000000..03201b94c2432c9c93b7432d569744a473bc79c6
--- /dev/null
+++ b/mojo/public/cpp/bindings/lib/validation_errors.cc
@@ -0,0 +1,62 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "mojo/public/cpp/bindings/lib/validation_errors.h"
+
+#include <assert.h>
+#include <stdio.h>
+
+namespace mojo {
+namespace internal {
+namespace {
+
+ValidationErrorObserverForTesting* g_validation_error_observer = NULL;
+
+}  // namespace
+
+const char* ValidationErrorToString(ValidationError error) {
+  switch (error) {
+    case VALIDATION_ERROR_NONE:
+      return "VALIDATION_ERROR_NONE";
+    case VALIDATION_ERROR_MISALIGNED_OBJECT:
+      return "VALIDATION_ERROR_MISALIGNED_OBJECT";
+    case VALIDATION_ERROR_ILLEGAL_MEMORY_RANGE:
+      return "VALIDATION_ERROR_ILLEGAL_MEMORY_RANGE";
+    case VALIDATION_ERROR_UNEXPECTED_STRUCT_HEADER:
+      return "VALIDATION_ERROR_UNEXPECTED_STRUCT_HEADER";
+    case VALIDATION_ERROR_UNEXPECTED_ARRAY_HEADER:
+      return "VALIDATION_ERROR_UNEXPECTED_ARRAY_HEADER";
+    case VALIDATION_ERROR_ILLEGAL_HANDLE:
+      return "VALIDATION_ERROR_ILLEGAL_HANDLE";
+    case VALIDATION_ERROR_ILLEGAL_POINTER:
+      return "VALIDATION_ERROR_ILLEGAL_POINTER";
+    case VALIDATION_ERROR_MESSAGE_HEADER_INVALID_FLAG_COMBINAION:
+      return "VALIDATION_ERROR_MESSAGE_HEADER_INVALID_FLAG_COMBINAION";
+    case VALIDATION_ERROR_MESSAGE_HEADER_MISSING_REQUEST_ID:
+      return "VALIDATION_ERROR_MESSAGE_HEADER_MISSING_REQUEST_ID";
+  }
+
+  return "Unknown error";
+}
+
+void ReportValidationError(ValidationError error) {
+  // TODO(yzshen): Consider adding better logging support.
+  fprintf(stderr, "Invalid message: %s\n", ValidationErrorToString(error));
+  if (g_validation_error_observer)
+    g_validation_error_observer->set_last_error(error);
+}
+
+ValidationErrorObserverForTesting::ValidationErrorObserverForTesting()
+    : last_error_(VALIDATION_ERROR_NONE) {
+  assert(!g_validation_error_observer);
+  g_validation_error_observer = this;
+}
+
+ValidationErrorObserverForTesting::~ValidationErrorObserverForTesting() {
+  assert(g_validation_error_observer == this);
+  g_validation_error_observer = NULL;
+}
+
+}  // namespace internal
+}  // namespace mojo