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// Copyright 2019 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
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef dap_io_h
#define dap_io_h
#include <stddef.h> // size_t
#include <memory> // std::unique_ptr
#include <utility> // std::pair
namespace dap {
class Closable {
virtual ~Closable() = default;
// isOpen() returns true if the stream has not been closed.
virtual bool isOpen() = 0;
// close() closes the stream.
virtual void close() = 0;
// Reader is an interface for reading from a byte stream.
class Reader : virtual public Closable {
// read() attempts to read at most n bytes into buffer, returning the number
// of bytes read.
// read() will block until the stream is closed or at least one byte is read.
virtual size_t read(void* buffer, size_t n) = 0;
// Writer is an interface for writing to a byte stream.
class Writer : virtual public Closable {
// write() writes n bytes from buffer into the stream.
// Returns true on success, or false if there was an error or the stream was
// closed.
virtual bool write(const void* buffer, size_t n) = 0;
// ReaderWriter is an interface that combines the Reader and Writer interfaces.
class ReaderWriter : public Reader, public Writer {
// create() returns a ReaderWriter that delegates the interface methods on to
// the provided Reader and Writer.
// isOpen() returns true if the Reader and Writer both return true for
// isOpen().
// close() closes both the Reader and Writer.
static std::shared_ptr<ReaderWriter> create(const std::shared_ptr<Reader>&,
const std::shared_ptr<Writer>&);
// pipe() returns a ReaderWriter where the Writer streams to the Reader.
// Writes are internally buffered.
// Calling close() on either the Reader or Writer will close both ends of the
// stream.
std::shared_ptr<ReaderWriter> pipe();
// file() wraps file with a ReaderWriter.
// If closable is false, then a call to ReaderWriter::close() will not close the
// underlying file.
std::shared_ptr<ReaderWriter> file(FILE* file, bool closable = true);
// file() opens (or creates) the file with the given path.
std::shared_ptr<ReaderWriter> file(const char* path);
// spy() returns a Reader that copies all reads from the Reader r to the Writer
// s, using the given optional prefix.
std::shared_ptr<Reader> spy(const std::shared_ptr<Reader>& r,
const std::shared_ptr<Writer>& s,
const char* prefix = "\n->");
// spy() returns a Writer that copies all writes to the Writer w to the Writer
// s, using the given optional prefix.
std::shared_ptr<Writer> spy(const std::shared_ptr<Writer>& w,
const std::shared_ptr<Writer>& s,
const char* prefix = "\n<-");
// writef writes the printf style string to the writer w.
bool writef(const std::shared_ptr<Writer>& w, const char* msg, ...);
} // namespace dap
#endif // dap_io_h