Initial public release of nearby library

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: I85d490e448375aa4eb7b09680757c02fff1420b4

cpp/core/internal/mediums/utils.cc

@@ -0,0 +1,87 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "core/internal/mediums/utils.h"
+
+#include <sstream>
+
+#include "platform/exception.h"
+#include "absl/strings/escaping.h"
+
+namespace location {
+namespace nearby {
+namespace connections {
+
+void Utils::closeSocket(Ptr<BluetoothServerSocket> socket,
+                        const std::string& type, const std::string& name) {
+  if (!socket.isNull()) {
+    Exception::Value e = socket->close();
+    if (Exception::NONE != e) {
+      if (Exception::IO == e) {
+        // TODO(reznor): log.atWarning().withCause(e).log("Failed to close
+        // %sSocket %s", type, name);
+      }
+      return;
+    }
+    // TODO(reznor): log.atVerbose().log("Closed %sSocket %s", type, name);
+  }
+}
+
+ConstPtr<ByteArray> Utils::sha256Hash(Ptr<HashUtils> hash_utils,
+                                      ConstPtr<ByteArray> source,
+                                      size_t length) {
+  if (source.isNull()) {
+    return ConstPtr<ByteArray>();
+  }
+
+  ScopedPtr<ConstPtr<ByteArray>> full_hash(
+      hash_utils->sha256(std::string(source->getData(), source->size())));
+  return MakeConstPtr(new ByteArray(full_hash->getData(), length));
+}
+
+ConstPtr<ByteArray> Utils::legacySha256HashOnlyForPrinting(
+    Ptr<HashUtils> hash_utils, ConstPtr<ByteArray> source, size_t length) {
+  if (source.isNull()) {
+    return ConstPtr<ByteArray>();
+  }
+
+  std::string formatted_hex_string = Utils::bytesToPrintableHexString(source);
+  ScopedPtr<ConstPtr<ByteArray>> formatted_hex_byte_array(MakeConstPtr(
+      new ByteArray(formatted_hex_string.data(), formatted_hex_string.size())));
+  return Utils::sha256Hash(hash_utils, formatted_hex_byte_array.get(), length);
+}
+
+std::string Utils::bytesToPrintableHexString(ConstPtr<ByteArray> bytes) {
+  std::string hex_string(
+      absl::BytesToHexString(std::string(bytes->getData(), bytes->size())));
+
+  // Print out the byte array as a space separated listing of hex bytes.
+  std::ostringstream formatted_hex_string_stream;
+  formatted_hex_string_stream << "[ ";
+  for (int i = 0; i < hex_string.size(); i += 2) {
+    formatted_hex_string_stream << "0x";
+    // This is safe because we have the guarantee that hex_string is of even
+    // length (because a hex encoding will always be double the size of its
+    // input).
+    formatted_hex_string_stream << hex_string[i] << hex_string[i + 1];
+    formatted_hex_string_stream << " ";
+  }
+  formatted_hex_string_stream << "]";
+
+  return formatted_hex_string_stream.str();
+}
+
+}  // namespace connections
+}  // namespace nearby
+}  // namespace location