V18.4.0 CAS plugin

Note that this version does not have Widevine Provisioning 4.0 support.
It is only suitable for device upgrades. A new patch with provisioning
4.0 support will be made later.

wvutil/include/file_utils.h

@@ -0,0 +1,29 @@
+// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine License
+// Agreement.
+
+#include <string>
+#include <vector>
+
+namespace wvutil {
+
+const char kCurrentDirectory[] = ".";
+const char kParentDirectory[] = "..";
+const char kDirectoryDelimiter = '/';
+const char kWildcard[] = "*";
+bool IsCurrentOrParentDirectory(const char* dir);
+
+class FileUtils {
+ public:
+  static bool Exists(const std::string& src);
+  static bool Exists(const std::string& src, int* errno_value);
+  // The caller may only specifying a single wildcard
+  static bool Remove(const std::string& src);
+  static bool Copy(const std::string& src, const std::string& dest);
+  static bool List(const std::string& path, std::vector<std::string>* files);
+  static bool IsRegularFile(const std::string& path);
+  static bool IsDirectory(const std::string& path);
+  static bool CreateDirectory(const std::string& path);
+};
+
+}  // namespace wvutil