bluetooth: Use WebBluetoothDeviceId instead of string

content/common/bluetooth/web_bluetooth_device_id.cc

Index: content/common/bluetooth/web_bluetooth_device_id.cc
diff --git a/content/common/bluetooth/web_bluetooth_device_id.cc b/content/common/bluetooth/web_bluetooth_device_id.cc
new file mode 100644
index 0000000000000000000000000000000000000000..823ed0fd979cd6736a587d525848457153e084b2
--- /dev/null
+++ b/content/common/bluetooth/web_bluetooth_device_id.cc
@@ -0,0 +1,87 @@
+// Copyright 2016 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 "content/common/bluetooth/web_bluetooth_device_id.h"
+
+#include "base/base64.h"
+#include "base/strings/string_util.h"
+#include "crypto/random.h"
+
+namespace content {
+
+namespace {
+
+enum { kDeviceIdLength = 16 /* 128 bits */ };
+
+}  // namespace
+
+WebBluetoothDeviceId::WebBluetoothDeviceId() {}
+
+WebBluetoothDeviceId::WebBluetoothDeviceId(std::string device_id)
+    : device_id_(std::move(device_id)) {
+  CHECK(IsValid(device_id_));
+}
+
+WebBluetoothDeviceId::~WebBluetoothDeviceId() {}
+
+const std::string& WebBluetoothDeviceId::str() const {
+  CHECK(IsValid(device_id_));
+  return device_id_;
+}
+
+// static
+WebBluetoothDeviceId WebBluetoothDeviceId::Create() {
+  std::string bytes(
+      kDeviceIdLength + 1 /* to avoid bytes being reallocated by WriteInto */,
+      '\0');
+
+  crypto::RandBytes(base::WriteInto(&bytes /* str */,
+                                    kDeviceIdLength + 1 /* length_with_null */),
+                    kDeviceIdLength);
+
+  base::Base64Encode(bytes, &bytes);
+
+  return WebBluetoothDeviceId(std::move(bytes));
+}
+
+// static
+bool WebBluetoothDeviceId::IsValid(const std::string& device_id) {
+  std::string decoded;
+  if (!base::Base64Decode(device_id, &decoded)) {
+    return false;
+  }
+
+  if (decoded.size() != kDeviceIdLength) {
+    return false;
+  }
+
+  // When base64-encoding a 128bit string, only the two MSB are used for
+  // the 3rd-to-last character. Because of this, the 3rd-to-last character
+  // can only be one of this four characters.
+  if (!(device_id[device_id.size() - 3] == 'A' ||
+        device_id[device_id.size() - 3] == 'Q' ||
+        device_id[device_id.size() - 3] == 'g' ||
+        device_id[device_id.size() - 3] == 'w')) {
+    return false;
+  }
+
+  return true;
+}
+
+bool WebBluetoothDeviceId::operator==(
+    const WebBluetoothDeviceId& device_id) const {
+  return str() == device_id.str();
+}
+
+bool WebBluetoothDeviceId::operator!=(
+    const WebBluetoothDeviceId& device_id) const {
+  return !(*this == device_id);
+}
+
+std::ostream& operator<<(std::ostream& out,
+                         const WebBluetoothDeviceId& device_id) {
+  return out << device_id.str();
+}
+
+}  // namespace content