Descriptor.h

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/*
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Descriptor.h
 * The Descriptor classes
 * Copyright (C) 2005 Simon Newton
 */

#ifndef INCLUDE_OLA_IO_DESCRIPTOR_H_
#define INCLUDE_OLA_IO_DESCRIPTOR_H_

#include <stdint.h>
#include <unistd.h>
#include <ola/Callback.h>
#include <ola/base/Macro.h>
#include <ola/io/IOQueue.h>
#include <string>

namespace ola {
namespace io {

// The following section of code defines the various types and helper functions
// needed for the Descriptor infrastructure.
// On *nix, there's the "everything is a file" philosophy, so we can just use
// ints as handles.
// On Windows, the situation is more complicated, so we need to treat sockets,
// files, devices, pipes, etc. in special ways.
#ifdef _WIN32
// Internal use only. Semantic type of the descriptor.
enum DescriptorType {
  GENERIC_DESCRIPTOR = 0,  // Catch-all type without special handling
  SOCKET_DESCRIPTOR,  // WinSock socket
  PIPE_DESCRIPTOR  // Named Pipe handle
};

// Consider this to be an opaque type.
struct DescriptorHandle {
  // The actual OS handle
  union {
    int m_fd;
    void* m_handle;
  } m_handle;
  // Type of this descriptor's handle
  DescriptorType m_type;
  // Handler to an event for async I/O
  void* m_event;
  // Pointer to read result of an async I/O call
  uint8_t* m_async_data;
  // Pointer to size of read result data
  uint32_t* m_async_data_size;

  DescriptorHandle();
  ~DescriptorHandle();

  bool AllocAsyncBuffer();
  void FreeAsyncBuffer();

  bool IsValid() const;
};

void* ToHandle(const DescriptorHandle &handle);

static DescriptorHandle INVALID_DESCRIPTOR;
static const uint32_t ASYNC_DATA_BUFFER_SIZE = 1024;
bool operator!=(const DescriptorHandle &lhs, const DescriptorHandle &rhs);
bool operator==(const DescriptorHandle &lhs, const DescriptorHandle &rhs);
bool operator<(const DescriptorHandle &lhs, const DescriptorHandle &rhs);
std::ostream& operator<<(std::ostream &stream, const DescriptorHandle &data);
#else
typedef int DescriptorHandle;
static DescriptorHandle INVALID_DESCRIPTOR = -1;
#endif

int ToFD(const DescriptorHandle& handle);

/*
 * A FileDescriptor which can be read from.
 */

class ReadFileDescriptor {
 public:
  virtual ~ReadFileDescriptor() {}

  virtual DescriptorHandle ReadDescriptor() const = 0;

  bool ValidReadDescriptor() const {
    return ReadDescriptor() != INVALID_DESCRIPTOR;
  }

  virtual void PerformRead() = 0;
};


class WriteFileDescriptor {
 public:
  virtual ~WriteFileDescriptor() {}

  virtual DescriptorHandle WriteDescriptor() const = 0;

  bool ValidWriteDescriptor() const {
    return WriteDescriptor() != INVALID_DESCRIPTOR;
  }

  virtual void PerformWrite() = 0;
};


class BidirectionalFileDescriptor: public ReadFileDescriptor,
                                   public WriteFileDescriptor {
 public :
  BidirectionalFileDescriptor(): m_on_read(NULL), m_on_write(NULL) {}

  virtual ~BidirectionalFileDescriptor() {
    if (m_on_read)
      delete m_on_read;

    if (m_on_write)
      delete m_on_write;
  }

  void SetOnData(ola::Callback0<void> *on_read) {
    if (m_on_read)
      delete m_on_read;
    m_on_read = on_read;
  }

  void SetOnWritable(ola::Callback0<void> *on_write) {
    if (m_on_write)
      delete m_on_write;
    m_on_write = on_write;
  }

  void PerformRead();
  void PerformWrite();

 private:
  ola::Callback0<void> *m_on_read;
  ola::Callback0<void> *m_on_write;
};


class UnmanagedFileDescriptor: public BidirectionalFileDescriptor {
 public :
  explicit UnmanagedFileDescriptor(int fd);
  ~UnmanagedFileDescriptor() {}
  DescriptorHandle ReadDescriptor() const { return m_handle; }
  DescriptorHandle WriteDescriptor() const { return m_handle; }

 protected:
  // This is only protected because WIN32-specific subclasses need access.
  DescriptorHandle m_handle;

 private:
  DISALLOW_COPY_AND_ASSIGN(UnmanagedFileDescriptor);
};


struct UnmanagedFileDescriptor_lt {
  bool operator()(const ola::io::UnmanagedFileDescriptor *d1,
                  const ola::io::UnmanagedFileDescriptor *d2) const {
    return d1->ReadDescriptor() < d2->ReadDescriptor();
  }
};


class ConnectedDescriptor: public BidirectionalFileDescriptor {
 public:
  typedef ola::SingleUseCallback0<void> OnCloseCallback;

  ConnectedDescriptor(): BidirectionalFileDescriptor(), m_on_close(NULL) {}

  virtual ~ConnectedDescriptor() {
    if (m_on_close)
      delete m_on_close;
  }

  virtual ssize_t Send(const uint8_t *buffer, unsigned int size);

  virtual ssize_t Send(IOQueue *data);


  virtual int Receive(uint8_t *buffer,
                      unsigned int size,
                      unsigned int &data_read);  // NOLINT

  virtual bool SetReadNonBlocking() {
    return SetNonBlocking(ReadDescriptor());
  }

  virtual bool Close() = 0;

  int DataRemaining() const;

  bool IsClosed() const;

  void SetOnClose(OnCloseCallback *on_close) {
    if (m_on_close)
      delete m_on_close;
    m_on_close = on_close;
  }

  OnCloseCallback *TransferOnClose() {
    OnCloseCallback *on_close = m_on_close;
    m_on_close = NULL;
    return on_close;
  }

  static bool SetNonBlocking(DescriptorHandle fd);

 protected:
  virtual bool IsSocket() const = 0;

  bool SetNoSigPipe(DescriptorHandle fd);

 private:
  OnCloseCallback *m_on_close;
};


class LoopbackDescriptor: public ConnectedDescriptor {
 public:
  LoopbackDescriptor();
  ~LoopbackDescriptor() { Close(); }

  bool Init();
  DescriptorHandle ReadDescriptor() const { return m_handle_pair[0]; }
  DescriptorHandle WriteDescriptor() const { return m_handle_pair[1]; }

  bool Close();

  bool CloseClient();

 protected:
  bool IsSocket() const { return false; }

 private:
  DescriptorHandle m_handle_pair[2];


  DISALLOW_COPY_AND_ASSIGN(LoopbackDescriptor);
};


class PipeDescriptor: public ConnectedDescriptor {
 public:
  PipeDescriptor();
  ~PipeDescriptor() { Close(); }

  bool Init();

  PipeDescriptor *OppositeEnd();
  DescriptorHandle ReadDescriptor() const { return m_in_pair[0]; }
  DescriptorHandle WriteDescriptor() const { return m_out_pair[1]; }

  bool Close();

  bool CloseClient();

 protected:
  bool IsSocket() const { return false; }

 private:
  DescriptorHandle m_in_pair[2];
  DescriptorHandle m_out_pair[2];
  PipeDescriptor *m_other_end;

  PipeDescriptor(DescriptorHandle in_pair[2],
                 DescriptorHandle out_pair[2],
                 PipeDescriptor *other_end);


  DISALLOW_COPY_AND_ASSIGN(PipeDescriptor);
};

class UnixSocket: public ConnectedDescriptor {
 public:
  UnixSocket():
    m_other_end(NULL) {
    m_handle = INVALID_DESCRIPTOR;
  }
  ~UnixSocket() { Close(); }

  bool Init();

  UnixSocket *OppositeEnd();
  DescriptorHandle ReadDescriptor() const { return m_handle; }
  DescriptorHandle WriteDescriptor() const { return m_handle; }

  bool Close();


  bool CloseClient();

 protected:
  bool IsSocket() const { return true; }

 private:
  DescriptorHandle m_handle;
  UnixSocket *m_other_end;
  UnixSocket(int socket, UnixSocket *other_end);

  DISALLOW_COPY_AND_ASSIGN(UnixSocket);
};

class DeviceDescriptor: public ConnectedDescriptor {
 public:
  explicit DeviceDescriptor(int fd);
  ~DeviceDescriptor() { Close(); }

  DescriptorHandle ReadDescriptor() const { return m_handle; }
  DescriptorHandle WriteDescriptor() const { return m_handle; }

  bool Close();

 protected:
  bool IsSocket() const { return false; }

 private:
  DescriptorHandle m_handle;

  DISALLOW_COPY_AND_ASSIGN(DeviceDescriptor);
};

}  // namespace io
}  // namespace ola
#endif  // INCLUDE_OLA_IO_DESCRIPTOR_H_