Explicitly CHECK arguments in dbus::MessageWriter::AppendString/ObjectPath

dbus/string_util.cc

Index: dbus/string_util.cc
diff --git a/dbus/string_util.cc b/dbus/string_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4d4c9da96211f0cb1d9b56a2669d462561bd8745
--- /dev/null
+++ b/dbus/string_util.cc
@@ -0,0 +1,48 @@
+// Copyright (c) 2012 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 "dbus/string_util.h"
+
+#include "base/string_util.h"
+
+namespace dbus {
+
+bool IsValidObjectPath(const std::string& value) {
+  // This implementation is based upon D-Bus Specification Version 0.19.
+
+  const bool kCaseSensitive = true;
+
+  // A valid object path begins with '/'.
+  if (!StartsWithASCII(value, "/", kCaseSensitive))
+    return false;
+
+  // Elements are pieces delimited by '/'. For instance, "org", "chromium",
+  // "Foo" are elements of "/org/chromium/Foo".
+  int element_length = 0;
+  for (size_t i = 1; i < value.size(); ++i) {
+    const char c = value[i];
+    if (c == '/') {
+      // No element may be the empty string.
+      if (element_length == 0)
+        return false;
+      element_length = 0;
+    } else {
+      // Each element must only contain "[A-Z][a-z][0-9]_".
+      const bool is_valid_character =
+          ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z') ||
+          ('0' <= c && c <= '9') || c == '_';
+      if (!is_valid_character)
+        return false;
+      element_length++;
+    }
+  }
+
+  // A trailing '/' character is not allowed unless the path is the root path.
+  if (value.size() > 1 && EndsWith(value, "/", kCaseSensitive))
+    return false;
+
+  return true;
+}
+
+}  // namespace dbus