Pipe.h

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef PIPE_H
#define PIPE_H

#include "File.h"
#include "pedigree/kernel/Log.h"
#include "pedigree/kernel/compiler.h"
#include "pedigree/kernel/process/Semaphore.h"
#include "pedigree/kernel/processor/types.h"
#include "pedigree/kernel/time/Time.h"
#include "pedigree/kernel/utilities/Buffer.h"
#include "pedigree/kernel/utilities/String.h"

#define PIPE_BUF_MAX 2048

class EXPORTED_PUBLIC Pipe : public File
{
    friend class Filesystem;
    friend class ZombiePipe;

  public:
    static Pipe *fromFile(File *pF)
    {
        if (!(pF->isPipe() || pF->isFifo()))
            FATAL("Casting non-pipe/fifo File to Pipe!");
        return reinterpret_cast<Pipe *>(pF);
    }

    Pipe();

    Pipe(const Pipe &file);

  private:
    Pipe &operator=(const Pipe &);

  public:
    Pipe(
        const String &name, Time::Timestamp accessedTime,
        Time::Timestamp modifiedTime, Time::Timestamp creationTime,
        uintptr_t inode, class Filesystem *pFs, size_t size, File *pParent,
        bool bIsAnonymous = false);
    virtual ~Pipe();

    virtual int select(bool bWriting = false, int timeout = 0);

    virtual uint64_t readBytewise(
        uint64_t location, uint64_t size, uintptr_t buffer,
        bool bCanBlock = true);
    virtual uint64_t writeBytewise(
        uint64_t location, uint64_t size, uintptr_t buffer,
        bool bCanBlock = true);

    virtual bool isPipe() const;
    virtual bool isFifo() const;

    virtual void increaseRefCount(bool bIsWriter);

    virtual void decreaseRefCount(bool bIsWriter);

    size_t getReaderCount() const
    {
        return m_nReaders;
    }

    size_t getWriterCount() const
    {
        return m_nWriters;
    }

    // Wait for a reader - returns false if interrupted before a reader arrived.
    bool waitForReader();

  protected:
    bool m_bIsAnonymous;

    volatile bool m_bIsEOF;

    Buffer<uint8_t> m_Buffer;

    Semaphore m_ReaderSem;

    virtual bool isBytewise() const
    {
        return true;
    }
};

#endif