Update mojo sdk to rev 9fbbc4f0fef1187312316c0ed992342474e139f1

mojo/edk/system/unique_identifier.h

+// 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.
+
+#ifndef MOJO_EDK_SYSTEM_UNIQUE_IDENTIFIER_H_
+#define MOJO_EDK_SYSTEM_UNIQUE_IDENTIFIER_H_
+
+#include <stdint.h>
+#include <string.h>
+
+#include <iosfwd>
+
+#include "base/compiler_specific.h"
+#include "base/containers/hash_tables.h"
+#include "mojo/edk/system/system_impl_export.h"
+
+namespace mojo {
+namespace system {
+
+class UniqueIdentifier;
+
+}  // namespace system
+}  // namespace mojo
+
+namespace BASE_HASH_NAMESPACE {
+
+// Declare this before |UniqueIdentifier|, so that it can be friended.
+template <>
+struct hash<mojo::system::UniqueIdentifier>;
+
+}  // BASE_HASH_NAMESPACE
+
+namespace mojo {
+namespace system {
+
+// Declare this before |UniqueIdentifier|, so that it can be friended.
+MOJO_SYSTEM_IMPL_EXPORT std::ostream& operator<<(
+    std::ostream& out,
+    const UniqueIdentifier& unique_identifier);
+
+// |UniqueIdentifier| is a POD class whose value is used to uniquely identify
+// things.
+class MOJO_SYSTEM_IMPL_EXPORT UniqueIdentifier {
+ public:
+  // This generates a new identifier. Uniqueness is "guaranteed" (i.e.,
+  // probabilistically) for identifiers.
+  static UniqueIdentifier Generate();
+
+  bool operator==(const UniqueIdentifier& other) const {
+    return memcmp(data_, other.data_, sizeof(data_)) == 0;
+  }
+  bool operator!=(const UniqueIdentifier& other) const {
+    return !operator==(other);
+  }
+  bool operator<(const UniqueIdentifier& other) const {
+    return memcmp(data_, other.data_, sizeof(data_)) < 0;
+  }
+
+ private:
+  friend BASE_HASH_NAMESPACE::hash<mojo::system::UniqueIdentifier>;
+  friend std::ostream& operator<<(std::ostream&, const UniqueIdentifier&);
+
+  explicit UniqueIdentifier() {}
+
+  char data_[16];
+
+  // Copying and assignment allowed.
+};
+static_assert(sizeof(UniqueIdentifier) == 16,
+              "UniqueIdentifier has wrong size.");
+// We want to be able to take any buffer and cast it to a |UniqueIdentifier|.
+static_assert(ALIGNOF(UniqueIdentifier) == 1,
+              "UniqueIdentifier requires nontrivial alignment.");
+
+}  // namespace system
+}  // namespace mojo
+
+namespace BASE_HASH_NAMESPACE {
+
+template <>
+struct hash<mojo::system::UniqueIdentifier> {
+  size_t operator()(mojo::system::UniqueIdentifier unique_identifier) const {
+    return base::HashInts64(
+        *reinterpret_cast<uint64_t*>(unique_identifier.data_),
+        *reinterpret_cast<uint64_t*>(unique_identifier.data_ +
+                                     sizeof(uint64_t)));
+  }
+};
+
+}  // BASE_HASH_NAMESPACE
+
+#endif  // MOJO_EDK_SYSTEM_UNIQUE_IDENTIFIER_H_