FileHandle Class Reference

Generic file handle could be a file, or a socket or a device. More...

#include <FileHandle.h>

Inheritance diagram for FileHandle:

Collaboration diagram for FileHandle:

Public Types
typedef AutoLock< PthreadMutex >	ALock

Public Member Functions
	FileHandle ()
	Construct a closed FileHandle. More...
	FileHandle (int filed)
	Construct a FileHandle with filed as the open file descriptor. More...
virtual	~FileHandle ()
	Close the file descriptor. Use Reset if one wants to not close the file descriptor. More...
int	Poll (double timeout)
bool	Readable (bool r)
	Set that the file is currently readable or not. More...
bool	Readable () const
	Gives the current readability status of the file. More...
bool	Writeable (bool w)
	Set that this file is currently writeable or not. More...
bool	Writeable () const
	Gives the current writability status of the file. More...
int	FD () const
int	FD (int filed)
	Set the current file descriptor. More...
bool	Eof () const
bool	Eof (bool e)
	Set/reset the end of file condition. More...
bool	Good () const
	Convenience method for testing if the file this FileHandle has is open and not at end of file. More...
bool	Closed () const
void	SetBlocking (bool blocking)
	Manipulate how the current file handles blocking. More...
bool	IsBlocking () const
	Test if the current file is in blocking or non blocking mode. More...
void	Reset ()
	Clear all internal state including the file descriptor! WARNING does not close the file! More...
void	Close ()
	Close the file and reset the internal state. More...
unsigned	Read (void *ptr, unsigned len)
	Read data from the file descriptor. More...
unsigned	Readv (const iovec *iov, int iovcnt)
	scatter gather io version of Read More...
unsigned	Write (const void *ptr, unsigned len)
	Write data to the file descriptor. More...
unsigned	Writev (const iovec *iov, int iovcnt)
	scatter gather io version of Write More...
void	Flush ()
	Tell the OS to flush any buffers it has. May not be supported for all file types. More...

Static Public Member Functions
static int	Poll (IteratorRef< FileHandle * > begin, IteratorRef< FileHandle * > end, double timeout)
	poll a list of FileHandles for any activity and call the appropriate On method. More...
static void	SetBlocking (int fd, bool blocking)
	a convenience method that allows one to set the same blocking parameters for a file descriptor without setting it inside a FileHandle. More...
static bool	IsBlocking (int fd)
	Test the given file descriptor if it is in blocking mode. More...

Protected Member Functions
virtual void	OnReadable ()
	Called by Poll when it detects that the file is readable. More...
virtual void	OnWriteable ()
	Called by Poll when it detects that the file is writeable. More...

Protected Attributes
PthreadMutex	file_lock
int	fd
bool	readable
bool	writeable
bool	eof

Private Member Functions
	FileHandle (const FileHandle &)
FileHandle &	operator= (const FileHandle &)

Detailed Description

Generic file handle could be a file, or a socket or a device.

If needed wouldn't be very hard to add an open function here.

Definition at line 41 of file FileHandle.h.

Member Typedef Documentation

typedef AutoLock<PthreadMutex> FileHandle::ALock

Definition at line 43 of file FileHandle.h.

Constructor & Destructor Documentation

FileHandle::FileHandle

(

)

Construct a closed FileHandle.

Definition at line 91 of file FileHandle.cc.

    : fd(-1), readable(false), writeable(true), eof(false)
{
}

FileHandle::FileHandle

(

int

filed

)

Construct a FileHandle with filed as the open file descriptor.

Parameters

filed

the file descriptor to use

Definition at line 96 of file FileHandle.cc.

    : fd(filed), readable(false), writeable(true), eof(false)
{
}

FileHandle::~FileHandle ( )

virtual

Close the file descriptor. Use Reset if one wants to not close the file descriptor.

Definition at line 101 of file FileHandle.cc.

References fd, and Reset().

                        {
    if (fd != -1) { close(fd); }
    Reset();
}

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FileHandle::FileHandle ( const FileHandle &  )

private

Member Function Documentation

void FileHandle::Close

(

)

Close the file and reset the internal state.

Definition at line 146 of file FileHandle.cc.

References eof, fd, file_lock, readable, and writeable.

Referenced by CPN::ConnectionServer::Close(), CPN::RemoteContext::EntryPoint(), CPN::RemoteQueue::HandleError(), CPN::RemoteQueue::InternalCheckStatus(), and CPN::RemoteContextDaemon::Terminate().

                       {
    ALock al(file_lock);
    if (fd != -1) {
        if (close(fd) != 0) {
            throw ErrnoException();
        }
        fd = -1;
    }
    readable = false;
    writeable = false;
    eof = false;
}

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bool FileHandle::Closed ( ) const

inline

Returns

false if this FileHandle has an open file

Definition at line 128 of file FileHandle.h.

References fd, and file_lock.

Referenced by SocketHandle::Connect(), CPN::ConnectionServer::ConnectReader(), CPN::ConnectionServer::ConnectWriter(), CPN::RemoteQueue::FileThreadEntryPoint(), CPN::RemoteQueue::InternalCheckStatus(), CPN::RemoteQueue::LogState(), CPN::ConnectionServer::LogState(), CPN::RemoteContextDaemon::Run(), CPN::RemoteContextDaemon::Client::Send(), and CPN::RemoteContext::SendMessage().

{ ALock al(file_lock); return fd == -1; }

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bool FileHandle::Eof ( ) const

inline

Returns

the current end of file condition

Definition at line 115 of file FileHandle.h.

References eof, and file_lock.

Referenced by CPN::RemoteQueue::EnqueuePacket(), CPN::RemoteContext::EntryPoint(), CPN::RemoteQueue::InternalCheckStatus(), CPN::RemoteContextDaemon::Client::Read(), and CPN::RemoteQueue::Read().

{ ALock al(file_lock); return eof; }

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bool FileHandle::Eof ( bool  e )

inline

Set/reset the end of file condition.

Parameters

e	the new end of file condition

Returns

the new end of file condition

Definition at line 120 of file FileHandle.h.

References eof, and file_lock.

{ ALock al(file_lock); return eof = e; }

int FileHandle::FD ( ) const

inline

Returns

the current set file descriptor

Definition at line 106 of file FileHandle.h.

References fd, and file_lock.

Referenced by ServerSocketHandle::Accept(), CPN::RemoteContextDaemon::Client::Client(), SocketHandle::Connect(), CPN::ConnectionServer::ConnectWriter(), SocketHandle::CreatePair(), CPN::RemoteQueue::FileThreadEntryPoint(), Flush(), CPN::ConnectionServer::GetAddress(), SocketHandle::GetKeepAlive(), SocketHandle::GetLingerTimeout(), SocketHandle::GetNoDelay(), SocketHandle::GetPendingError(), SocketHandle::GetReceiveBufferSize(), SocketHandle::GetReceiveTimeout(), SocketHandle::GetSendBufferSize(), SocketHandle::GetSendTimeout(), IsBlocking(), ServerSocketHandle::Listen(), Poll(), CPN::RemoteContextDaemon::Run(), SetBlocking(), SocketHandle::SetKeepAlive(), SocketHandle::SetLingerTimeout(), SocketHandle::SetNoDelay(), SocketHandle::SetReceiveBufferSize(), SocketHandle::SetReceiveTimeout(), SocketHandle::SetSendBufferSize(), SocketHandle::SetSendTimeout(), SocketHandle::ShutdownRead(), SocketHandle::ShutdownWrite(), and WakeupHandle::WakeupHandle().

{ ALock al(file_lock); return fd; }

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int FileHandle::FD ( int  filed )

inline

Set the current file descriptor.

Parameters

filed

the new file descriptor

Returns

the new file descriptor

Definition at line 111 of file FileHandle.h.

References fd, and file_lock.

{ ALock al(file_lock); return fd = filed; }

void FileHandle::Flush

(

)

Tell the OS to flush any buffers it has. May not be supported for all file types.

Definition at line 293 of file FileHandle.cc.

References FD().

                       {
    if (fsync(FD()) != 0) {
        throw ErrnoException();
    }
}

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bool FileHandle::Good ( ) const

inline

Convenience method for testing if the file this FileHandle has is open and not at end of file.

Returns

true if open and not at end of file otherwise false

Definition at line 125 of file FileHandle.h.

References eof, fd, and file_lock.

Referenced by CPN::RemoteContext::EntryPoint(), and CPN::RemoteContextDaemon::Client::Read().

{ ALock al(file_lock); return !(eof || fd == -1); }

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bool FileHandle::IsBlocking

(

)

const

Test if the current file is in blocking or non blocking mode.

Returns

true if blocking or false if non blocking

Definition at line 128 of file FileHandle.cc.

References FD().

                                  {
    return IsBlocking(FD());
}

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bool FileHandle::IsBlocking ( int  fd )

static

Test the given file descriptor if it is in blocking mode.

Parameters

fd	the file descriptor to test

Returns

true if blocking or false if non blocking

Definition at line 132 of file FileHandle.cc.

                                  {
    int flags = fcntl(fd, F_GETFL, 0);
    if (-1 == flags) { throw ErrnoException(); }
    return !(flags & O_NONBLOCK);
}

virtual void FileHandle::OnReadable ( )

inlineprotectedvirtual

Called by Poll when it detects that the file is readable.

Reimplemented in WakeupHandle.

Definition at line 210 of file FileHandle.h.

References Readable().

Referenced by Poll().

{ Readable(true); }

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virtual void FileHandle::OnWriteable ( )

inlineprotectedvirtual

Called by Poll when it detects that the file is writeable.

Definition at line 212 of file FileHandle.h.

References Writeable().

Referenced by Poll().

{ Writeable(true); }

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FileHandle& FileHandle::operator= ( const FileHandle &  )

private

int FileHandle::Poll ( IteratorRef< FileHandle * >  begin, IteratorRef< FileHandle * >  end, double  timeout  )

static

poll a list of FileHandles for any activity and call the appropriate On method.

Definition at line 34 of file FileHandle.cc.

References FD(), fd, OnReadable(), OnWriteable(), Readable(), and Writeable().

Referenced by CPN::RemoteContext::EntryPoint(), CPN::RemoteQueue::FileThreadEntryPoint(), CPN::ConnectionServer::Poll(), Poll(), and CPN::RemoteContextDaemon::Run().

                                                                                                 {
    fd_set rfd;
    fd_set wfd;
    FD_ZERO(&rfd);
    FD_ZERO(&wfd);
    int maxfd = 0;
    IteratorRef<FileHandle*> itr = begin;
    while (itr != end) {
        FileHandle *han = *itr;
        int fd = han->FD();
        if (fd < 0) {
            return -1;
        } else {
            bool set = false;
            if (!han->Readable()) {
                FD_SET(fd, &rfd);
                set = true;
            }
            if (!han->Writeable()) {
                FD_SET(fd, &wfd);
                set = true;
            }
            if (set) { maxfd = std::max(maxfd, fd); }
        }
        ++itr;
    }
    timeval tv;
    timeval *ptv = 0;
    if (timeout >= 0) {
        tv.tv_sec = (int)timeout;
        tv.tv_usec = (int)((timeout - tv.tv_sec) * 1e6);
        ptv = &tv;
    }
    int ret = select(maxfd + 1, &rfd, &wfd, 0, ptv);
    if (ret < 0) {
        if (errno == EINTR) {
            return 0;
        }
        throw ErrnoException();
    }
    itr = begin;
    while (itr != end) {
        FileHandle *han = *itr;
        int fd = han->FD();
        if (fd >= 0) {
            if (FD_ISSET(fd, &rfd)) {
                han->OnReadable();
            }
            if (FD_ISSET(fd, &wfd)) {
                han->OnWriteable();
            }
        }
        ++itr;
    }
    return ret;
}

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int FileHandle::Poll

(

double

timeout

)

Poll the current file descriptor for activity specified by the current readable or writeable status, if false poll that value, and call one of OnWriteable or OnReadable whos default action is to set Readable or Writeable to true.

Parameters

timeout

-1 to wait forever for activity 0 to poll and return immediately or a time to wait in seconds.

Returns

zero if timed out, positive if an event occurred or negative if an error occurred.

Definition at line 106 of file FileHandle.cc.

References Poll().

                                   {
    FileHandle *fh = this;
    return Poll(&fh, &fh + 1, timeout);
}

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unsigned FileHandle::Read	(	void *	ptr,
		unsigned	len
	)

Read data from the file descriptor.

Will set the end of file condition if read detects end of file.

Note

All the read functions will set readable to false if they read less than the requested amount or we are non blocking and a would block condition happened.

Parameters

ptr	pointer to write data to
len	the maximum number of bytes to write to ptr

Returns

0 if no bytes read (check Eof) or the number of bytes read

Definition at line 159 of file FileHandle.cc.

References eof, fd, file_lock, Readable(), and readable.

Referenced by CPN::RemoteQueue::D4RTagPacket(), and WakeupHandle::Read().

                                                 {
    int filed;
    {
        ALock al(file_lock);
        if (eof || fd == -1) { return 0; }
        filed = fd;
    }
    unsigned bytesread = 0;
    int num = read(filed, ptr, len);
    if (num < 0) {
        int error = errno;
        switch (error) {
        case EAGAIN:
            Readable(false);
        case EINTR:
        case ENOMEM:
            break;
        default:
            throw ErrnoException(error);
        }
    } else if (num == 0 && len != 0) {
        ALock al(file_lock);
        eof = true;
        readable = false;
    } else {
        if (unsigned(num) < len) { Readable(false); }
        bytesread = num;
    }
    return bytesread;
}

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bool FileHandle::Readable ( bool  r )

inline

Set that the file is currently readable or not.

Parameters

r	true or false

Returns

the new readable status

Definition at line 86 of file FileHandle.h.

References file_lock, and readable.

Referenced by CPN::RemoteContext::EntryPoint(), Poll(), CPN::ConnectionServer::Poll(), and CPN::RemoteQueue::Read().

{ ALock al(file_lock); return readable = r; }

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bool FileHandle::Readable ( ) const

inline

Gives the current readability status of the file.

Returns

true if it is known that a read will not block

Definition at line 91 of file FileHandle.h.

References file_lock, and readable.

Referenced by ServerSocketHandle::Accept(), CPN::RemoteContextDaemon::Client::Client(), OnReadable(), CPN::RemoteContextDaemon::Read(), Read(), Readv(), SocketHandle::Recv(), CPN::RemoteContextDaemon::Run(), and WakeupHandle::WakeupHandle().

{ ALock al(file_lock); return readable; }

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unsigned FileHandle::Readv	(	const iovec *	iov,
		int	iovcnt
	)

scatter gather io version of Read

Returns

see Read

Definition at line 190 of file FileHandle.cc.

References eof, fd, file_lock, Readable(), and readable.

Referenced by CPN::RemoteQueue::EnqueuePacket().

                                                       {
    int filed;
    {
        ALock al(file_lock);
        if (eof || fd == -1) { return 0; }
        filed = fd;
    }
    unsigned len = 0;
    for (int i = 0; i < iovcnt; ++i) {
        len += iov[i].iov_len;
    }
    unsigned bytesread = 0;
    int num = readv(filed, iov, iovcnt);
    if (num < 0) {
        int error = errno;
        switch (error) {
        case EAGAIN:
            Readable(false);
        case EINTR:
        case ENOMEM:
            break;
        default:
            throw ErrnoException(error);
        }
    } else if (num == 0 && len != 0) {
        ALock al(file_lock);
        eof = true;
        readable = false;
    } else {
        if (unsigned(num) < len) { Readable(false); }
        bytesread = num;
    }
    return bytesread;
}

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void FileHandle::Reset

(

)

Clear all internal state including the file descriptor! WARNING does not close the file!

Definition at line 138 of file FileHandle.cc.

References eof, fd, file_lock, readable, and writeable.

Referenced by CPN::ConnectionServer::ConnectWriter(), CPN::RemoteQueue::FileThreadEntryPoint(), and ~FileHandle().

                       {
    ALock al(file_lock);
    readable = false;
    writeable = false;
    eof = false;
    fd = -1;
}

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void FileHandle::SetBlocking

(

bool

blocking

)

Manipulate how the current file handles blocking.

Parameters

blocking

true to set to blocking mode (default) false to set to non blocking mode.

In non blocking mode all reads and writes will not block. Use Poll to block.

Definition at line 111 of file FileHandle.cc.

References FD().

Referenced by WakeupHandle::WakeupHandle().

                                          {
    SetBlocking(FD(), blocking);
}

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void FileHandle::SetBlocking ( int  fd, bool  blocking  )

static

a convenience method that allows one to set the same blocking parameters for a file descriptor without setting it inside a FileHandle.

Parameters

fd	the file descriptor
blocking	true or false see SetBlock

Definition at line 115 of file FileHandle.cc.

                                                  {
    int flags = fcntl(fd, F_GETFL, 0);
    if (-1 == flags) { throw ErrnoException(); }
    if (blocking) {
        flags &= ~O_NONBLOCK;
    } else {
        flags |= O_NONBLOCK;
    }
    if (fcntl(fd, F_SETFL, flags) != 0) {
        throw ErrnoException();
    }
}

unsigned FileHandle::Write	(	const void *	ptr,
		unsigned	len
	)

Write data to the file descriptor.

Note

All write functions will set Writeable to false if they write less than the amount requested or if the file is in non blocking mode and the write returned would block.

Parameters

ptr	pointer to beginning of data to write
len	length of data to write

Returns

number of bytes written

Definition at line 225 of file FileHandle.cc.

References fd, file_lock, and Writeable().

Referenced by CPN::ConnectionServer::ConnectWriter(), CPN::RemoteContextDaemon::Client::Send(), CPN::RemoteContext::SendMessage(), and CPN::RemoteQueue::WriteBytes().

                                                        {
    int filed;
    {
        ALock al(file_lock);
        if (fd == -1) { return 0; }
        filed = fd;
    }
    unsigned written = 0;
    int num = write(filed, ptr, len);
    if (num < 0) {
        int error = errno;
        switch (error) {
        case EAGAIN: // Would block
        //case EWOULDBLOCK:
            Writeable(false);
        case EINTR: // Returned because of signal
        case ENOMEM:
        case ENOBUFS: // Buffers are full
            break;
        case EPIPE:
        case EBADF:
        case EFAULT:
        case EFBIG:
        case EINVAL:
        case EIO:
        case ENOSPC:
        default:
            throw ErrnoException(error);
        }
    } else {
        if (unsigned(num) < len) { Writeable(false); }
        written = num;
    }
    return written;
}

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bool FileHandle::Writeable ( bool  w )

inline

Set that this file is currently writeable or not.

Parameters

w	true or false

Returns

the new writeable status

Definition at line 97 of file FileHandle.h.

References file_lock, and writeable.

Referenced by Poll().

{ ALock al(file_lock); return writeable = w; }

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bool FileHandle::Writeable ( ) const

inline

Gives the current writability status of the file.

Returns

true if it is known that a write will not block

Definition at line 102 of file FileHandle.h.

References file_lock, and writeable.

Referenced by OnWriteable(), SocketHandle::Send(), WakeupHandle::WakeupHandle(), Write(), and Writev().

{ ALock al(file_lock); return writeable; }

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unsigned FileHandle::Writev	(	const iovec *	iov,
		int	iovcnt
	)

scatter gather io version of Write

Returns

see Write

Definition at line 261 of file FileHandle.cc.

References fd, file_lock, and Writeable().

Referenced by CPN::RemoteQueue::WriteBytes().

                                                        {
    int filed;
    {
        ALock al(file_lock);
        if (fd == -1) { return 0; }
        filed = fd;
    }
    unsigned written = 0;
    int num = writev(filed, iov, iovcnt);
    if (num < 0) {
        int error = errno;
        switch (error) {
        case EAGAIN:
            Writeable(false);
        case EINTR:
        case ENOMEM:
        case ENOBUFS:
            break;
        default:
            throw ErrnoException(error);
        }
    } else {
        unsigned len = 0;
        for (int i = 0; i < iovcnt; ++i) {
            len += iov[i].iov_len;
        }
        if (unsigned(num) < len) { Writeable(false); }
        written = num;
    }
    return written;
}

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Member Data Documentation

bool FileHandle::eof

protected

Definition at line 217 of file FileHandle.h.

Referenced by Close(), Eof(), Good(), Read(), Readv(), SocketHandle::Recv(), and Reset().

int FileHandle::fd

protected

Definition at line 214 of file FileHandle.h.

Referenced by Close(), Closed(), FD(), Good(), Poll(), Read(), Readv(), SocketHandle::Recv(), Reset(), SocketHandle::Send(), Write(), Writev(), and ~FileHandle().

PthreadMutex FileHandle::file_lock

mutableprotected

Definition at line 213 of file FileHandle.h.

Referenced by Close(), Closed(), Eof(), FD(), Good(), Read(), Readable(), Readv(), SocketHandle::Recv(), Reset(), SocketHandle::Send(), WakeupHandle::SendWakeup(), Write(), Writeable(), and Writev().

bool FileHandle::readable

protected

Definition at line 215 of file FileHandle.h.

Referenced by Close(), Read(), Readable(), Readv(), SocketHandle::Recv(), and Reset().

bool FileHandle::writeable

protected

Definition at line 216 of file FileHandle.h.

Referenced by Close(), Reset(), and Writeable().

---

The documentation for this class was generated from the following files:

• include/cpn/io/FileHandle.h
• lib/io/FileHandle.cc