poco/Foundation/include/Poco/AsyncIOCommand.h

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2007-06-18 09:00:47 +02:00
//
// AsyncIOCommand.h
//
2008-01-28 18:23:19 +01:00
// $Id: //poco/svn/Foundation/include/Poco/AsyncIOCommand.h#2 $
2007-06-18 09:00:47 +02:00
//
// Library: Foundation
// Package: AsyncIO
// Module: AsyncIOCommand
//
// Definition of the AsyncIOCommand class and subclasses.
//
// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
//
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
#ifndef Foundation_AsyncIOCommand_INCLUDED
#define Foundation_AsyncIOCommand_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/RefCountedObject.h"
#include "Poco/AutoPtr.h"
#include "Poco/Event.h"
#include "Poco/BasicEvent.h"
#include "Poco/AsyncIOEvent.h"
#include "Poco/Exception.h"
#include <ios>
namespace Poco {
class AsyncIOChannel;
class Foundation_API AsyncIOCommand: public RefCountedObject
/// AsyncIOCommand is the base class for all asynchronous input/output
/// commands used with AsyncIOChannel.
///
/// See class AsyncIOChannel for more information about asynchronous input/output.
{
public:
typedef AutoPtr<AsyncIOCommand> Ptr;
enum State
{
CMD_PENDING, /// Command is queued for execution.
CMD_IN_PROGRESS, /// Command is currently being executed.
CMD_COMPLETED, /// Command has completed successfully.
CMD_FAILED /// Command has failed.
};
BasicEvent<AsyncIOEvent> commandCompleted;
/// Fired when the command has successfully completed.
BasicEvent<AsyncIOEvent> commandFailed;
/// Fired when the command has failed.
State state() const;
/// Returns the current state of the command.
void wait();
/// Waits for the completion of the command.
void wait(long milliseconds);
/// Waits at most the given timeout for the
/// completion of the command. Throws a
/// TimeoutException if the command does
/// not complete within the given timeout.
bool tryWait(long milliseconds);
/// Waits at most the given timeout for the
/// completion of the command.
///
/// Returns true if the command completes within
/// the given timeout, otherwise false.
bool succeeded() const;
/// Returns true iff the command completed successfully.
bool failed() const;
/// Returns true iff the command has completed with an error.
const Exception* exception() const;
/// If the command failed with an exception, returns a
/// clone of the exception. Otherwise, returns a null pointer.
int execute(AsyncIOChannel& channel);
/// Executes the command on the given AsyncIOChannel.
///
/// Sets the state to CMD_IN_PROGRESS, calls
/// executeImpl(), and, according to its result,
/// sets the state to CMD_COMPLETED or CMD_FAILED
/// and signals the event.
///
/// Returns the number of bytes processed by the
/// command.
int result() const;
/// Returns the result of the command.
protected:
AsyncIOCommand();
/// Creates the AsyncIOCommand.
~AsyncIOCommand();
/// Destroys the AsyncIOCommand.
virtual int executeImpl(AsyncIOChannel& channel) = 0;
/// Executes the command on the given AsyncIOChannel.
/// Must be overridded by subclasses.
///
/// Returns the number of bytes processed by the
/// command.
private:
State _state;
Event _completed;
int _result;
Exception* _pException;
};
class Foundation_API AsyncWriteCommand: public AsyncIOCommand
/// An asynchronous write command.
{
public:
AsyncWriteCommand(const void* buffer, int length);
/// Create an AsyncWriteCommand for writing length bytes
/// from the given buffer. The given buffer must be
/// valid until the command completes.
const void* buffer() const;
/// Returns the buffer's address.
int length() const;
/// Returns the buffer's size.
protected:
int executeImpl(AsyncIOChannel& channel);
~AsyncWriteCommand();
private:
AsyncWriteCommand();
const void* _buffer;
int _length;
};
class Foundation_API AsyncBufferedWriteCommand: public AsyncWriteCommand
/// An asynchronous write command. The difference to
/// AsyncWriteCommand is that AsyncBufferedWriteCommand
/// copies the data in the buffer into an internal buffer, thus
/// the given buffer can be deleted as soon as the constructor
/// returns.
{
public:
AsyncBufferedWriteCommand(const void* buffer, int length);
/// Create an AsyncBufferedWriteCommand for writing length bytes
/// from the given buffer and copies the data from the
/// given buffer into an internal buffer.
///
/// The internal buffer can be accessed via the buffer()
/// member function inherited from AsyncWriteCommand.
protected:
~AsyncBufferedWriteCommand();
};
class Foundation_API AsyncReadCommand: public AsyncIOCommand
/// An asynchronous read command.
{
public:
AsyncReadCommand(void* buffer, int length);
/// Create an AsyncReadCommand for reading up to length
/// bytes into the given buffer.
void* buffer() const;
/// Returns the buffer's address.
int length() const;
/// Returns the buffer's size.
protected:
int executeImpl(AsyncIOChannel& channel);
~AsyncReadCommand();
private:
AsyncReadCommand();
void* _buffer;
int _length;
};
class Foundation_API AsyncBufferedReadCommand: public AsyncReadCommand
/// An asynchronous read command. In contrast to
/// AsyncReadCommand, which requires an externally supplied
/// buffer that must be valid until the command completes,
/// AsyncBufferedReadCommand maintains an internal buffer.
{
public:
AsyncBufferedReadCommand(int length);
/// Create an AsyncReadCommand for reading up to length
/// bytes into an internal buffer.
///
/// The buffer can be accessed via the buffer() member
/// function inherited from AsyncReadCommand.
protected:
~AsyncBufferedReadCommand();
};
class Foundation_API AsyncSeekCommand: public AsyncIOCommand
/// An asynchronous seek command.
{
public:
AsyncSeekCommand(std::streamoff off, std::ios::seekdir dir = std::ios::beg);
/// Creates an AsyncSeekCommand for setting the current read/write position.
protected:
int executeImpl(AsyncIOChannel& channel);
~AsyncSeekCommand();
private:
AsyncSeekCommand();
std::streamoff _off;
std::ios::seekdir _dir;
};
//
// inlines
//
inline AsyncIOCommand::State AsyncIOCommand::state() const
{
return _state;
}
inline int AsyncIOCommand::result() const
{
return _result;
}
inline const Exception* AsyncIOCommand::exception() const
{
return _pException;
}
inline bool AsyncIOCommand::succeeded() const
{
return _state == CMD_COMPLETED;
}
inline bool AsyncIOCommand::failed() const
{
return _state == CMD_FAILED;
}
inline const void* AsyncWriteCommand::buffer() const
{
return _buffer;
}
inline int AsyncWriteCommand::length() const
{
return _length;
}
inline void* AsyncReadCommand::buffer() const
{
return _buffer;
}
inline int AsyncReadCommand::length() const
{
return _length;
}
} // namespace Poco
#endif // Foundation_AsyncIOCommand_INCLUDED