Initial public release of nearby library

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

cpp/platform/pipe.h

@@ -0,0 +1,89 @@
+// 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.
+
+#ifndef PLATFORM_PIPE_H_
+#define PLATFORM_PIPE_H_
+
+#include <cstdint>
+#include <deque>
+
+#include "platform/api/condition_variable.h"
+#include "platform/api/input_stream.h"
+#include "platform/api/lock.h"
+#include "platform/api/output_stream.h"
+#include "platform/byte_array.h"
+#include "platform/exception.h"
+#include "platform/ptr.h"
+
+namespace location {
+namespace nearby {
+
+namespace pipe {
+
+template <typename>
+class PipeInputStream;
+template <typename>
+class PipeOutputStream;
+
+}  // namespace pipe
+
+template <typename Platform>
+class Pipe {
+ public:
+  Pipe();
+  ~Pipe();
+
+  // The returned InputStream is auto-destroyed when no longer referenced.
+  static Ptr<InputStream> createInputStream(Ptr<Pipe>);
+  // The returned OutputStream is auto-destroyed when no longer referenced.
+  static Ptr<OutputStream> createOutputStream(Ptr<Pipe>);
+
+ private:
+  //////////////////////////////////////////////////////////////////////////////
+  // Everything in this first private: section is only used by PipeInputStream
+  // and PipeOutputStream, thus forming the interface presented to those 2
+  // classes.
+  //////////////////////////////////////////////////////////////////////////////
+
+  template <typename>
+  friend class pipe::PipeInputStream;
+  template <typename>
+  friend class pipe::PipeOutputStream;
+
+  ExceptionOr<ConstPtr<ByteArray> > read(std::int64_t size);
+  Exception::Value write(ConstPtr<ByteArray> data);
+
+  void markInputStreamClosed();
+  void markOutputStreamClosed();
+
+ private:
+  Exception::Value writeLocked(ConstPtr<ByteArray> data);
+
+  bool eitherStreamClosed() const;
+
+  ScopedPtr<Ptr<Lock> > lock_;
+  ScopedPtr<Ptr<ConditionVariable> > cond_;
+  typedef std::deque<ConstPtr<ByteArray> > BufferType;
+  BufferType buffer_;
+  bool input_stream_closed_;
+  bool output_stream_closed_;
+  bool read_all_chunks_;
+};
+
+}  // namespace nearby
+}  // namespace location
+
+#include "platform/pipe.cc"
+
+#endif  // PLATFORM_PIPE_H_