lldb/source/Host/common/LockFileBase.cpp

//===-- LockFileBase.cpp ----------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "lldb/Host/LockFileBase.h"

using namespace lldb;
using namespace lldb_private;

namespace
{

Error
AlreadyLocked ()
{
    return Error ("Already locked");
}

Error
NotLocked ()
{
    return Error ("Not locked");
}

}

LockFileBase::LockFileBase (int fd) :
    m_fd (fd),
    m_locked (false),
    m_start (0),
    m_len (0)
{

}

bool
LockFileBase::IsLocked () const
{
    return m_locked;
}

Error
LockFileBase::WriteLock (const uint64_t start, const uint64_t len)
{
    return DoLock ([&] (const uint64_t start, const uint64_t len)
                   {
                       return DoWriteLock (start, len);
                   }, start, len);
}

Error
LockFileBase::TryWriteLock (const uint64_t start, const uint64_t len)
{
    return DoLock ([&] (const uint64_t start, const uint64_t len)
                   {
                        return DoTryWriteLock (start, len);
                   }, start, len);
}

Error
LockFileBase::ReadLock (const uint64_t start, const uint64_t len)
{
    return DoLock ([&] (const uint64_t start, const uint64_t len)
                   {
                        return DoReadLock (start, len);
                   }, start, len);
}

Error
LockFileBase::TryReadLock (const uint64_t start, const uint64_t len)
{
    return DoLock ([&] (const uint64_t start, const uint64_t len)
                   {
                       return DoTryReadLock (start, len);
                   }, start, len);

}

Error
LockFileBase::Unlock ()
{
    if (!IsLocked ())
        return NotLocked ();

    const auto error = DoUnlock ();
    if (error.Success ())
    {
        m_locked = false;
        m_start = 0;
        m_len = 0;
    }
    return error;
}

bool
LockFileBase::IsValidFile () const
{
    return m_fd != -1;
}

Error
LockFileBase::DoLock (const Locker &locker, const uint64_t start, const uint64_t len)
{
    if (!IsValidFile ())
        return Error("File is invalid");

    if (IsLocked ())
        return AlreadyLocked ();

    const auto error = locker (start, len);
    if (error.Success ())
    {
        m_locked = true;
        m_start = start;
        m_len = len;
    }

    return error;
}