/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#include "AbstractDiskWriter.h"

#include <unistd.h>
#ifdef HAVE_MMAP
#  include <sys/mman.h>
#endif // HAVE_MMAP

#include <cerrno>
#include <cstring>
#include <cassert>

#include "File.h"
#include "util.h"
#include "message.h"
#include "DlAbortEx.h"
#include "a2io.h"
#include "fmt.h"
#include "DownloadFailureException.h"
#include "error_code.h"
#include "LogFactory.h"

namespace aria2 {

AbstractDiskWriter::AbstractDiskWriter(const std::string& filename)
  : filename_(filename),
    fd_(-1),
    readOnly_(false),
    enableMmap_(false),
    mapaddr_(0),
    maplen_(0)
{}

AbstractDiskWriter::~AbstractDiskWriter()
{
  closeFile();
}

void AbstractDiskWriter::openFile(int64_t totalLength)
{
  try {
    openExistingFile(totalLength);
  } catch(RecoverableException& e) {
    if(e.getErrNum() == ENOENT) {
      initAndOpenFile(totalLength);
    } else {
      throw;
    }
  }
}

void AbstractDiskWriter::closeFile()
{
#ifdef HAVE_MMAP
  if(mapaddr_) {
    int rv = munmap(mapaddr_, maplen_);
    if(rv == -1) {
      int errNum = errno;
      A2_LOG_ERROR(fmt("munmap for file %s failed: %s",
                       filename_.c_str(), strerror(errNum)));
    } else {
      A2_LOG_INFO(fmt("munmap for file %s succeeded", filename_.c_str()));
    }
    mapaddr_ = 0;
    maplen_ = 0;
  }
#endif // HAVE_MMAP
  if(fd_ != -1) {
    close(fd_);
    fd_ = -1;
  }
}

namespace {
int openFileWithFlags(const std::string& filename, int flags,
                      error_code::Value errCode)
{
  int fd;
  while((fd = a2open(utf8ToWChar(filename).c_str(), flags, OPEN_MODE)) == -1
        && errno == EINTR);
  if(fd < 0) {
    int errNum = errno;
    throw DL_ABORT_EX3(errNum, fmt(EX_FILE_OPEN,
                                   filename.c_str(),
                                   util::safeStrerror(errNum).c_str()),
                       errCode);
  }
#if defined(__APPLE__) && defined(__MACH__)
  fcntl(fd, F_GLOBAL_NOCACHE, 1);
#endif // __APPLE__ && __MACH__
  return fd;
}
} // namespace

void AbstractDiskWriter::openExistingFile(int64_t totalLength)
{
  int flags = O_BINARY;
  if(readOnly_) {
    flags |= O_RDONLY;
  } else {
    flags |= O_RDWR;
  }
  fd_ = openFileWithFlags(filename_, flags, error_code::FILE_OPEN_ERROR);
}

void AbstractDiskWriter::createFile(int addFlags)
{
  assert(!filename_.empty());
  util::mkdirs(File(filename_).getDirname());
  fd_ = openFileWithFlags(filename_, O_CREAT|O_RDWR|O_TRUNC|O_BINARY|addFlags,
                          error_code::FILE_CREATE_ERROR);
}

ssize_t AbstractDiskWriter::writeDataInternal(const unsigned char* data,
                                              size_t len, int64_t offset)
{
  if(mapaddr_) {
    memcpy(mapaddr_ + offset, data, len);
    return len;
  } else {
    ssize_t writtenLength = 0;
    seek(offset);
    while((size_t)writtenLength < len) {
      ssize_t ret = 0;
      while((ret = write(fd_, data+writtenLength, len-writtenLength)) == -1 &&
            errno == EINTR);
      if(ret == -1) {
        return -1;
      }
      writtenLength += ret;
    }
    return writtenLength;
  }
}

ssize_t AbstractDiskWriter::readDataInternal(unsigned char* data, size_t len,
                                             int64_t offset)
{
  if(mapaddr_) {
    ssize_t readlen;
    if(offset > maplen_) {
      readlen = 0;
    } else {
      readlen = std::min(static_cast<size_t>(maplen_ - offset), len);
    }
    memcpy(data, mapaddr_ + offset, readlen);
    return readlen;
  } else {
    ssize_t ret = 0;
    seek(offset);
    while((ret = read(fd_, data, len)) == -1 && errno == EINTR);
    return ret;
  }
}

void AbstractDiskWriter::seek(int64_t offset)
{
  if(a2lseek(fd_, offset, SEEK_SET) == (off_t)-1) {
    int errNum = errno;
    throw DL_ABORT_EX2(fmt(EX_FILE_SEEK,
                           filename_.c_str(),
                           util::safeStrerror(errNum).c_str()),
                       error_code::FILE_IO_ERROR);
  }
}

void AbstractDiskWriter::ensureMmapWrite(size_t len, int64_t offset)
{
#ifdef HAVE_MMAP
  if(enableMmap_) {
    if(mapaddr_) {
      if(static_cast<int64_t>(len + offset) > maplen_) {
        munmap(mapaddr_, maplen_);
        mapaddr_ = 0;
        maplen_ = 0;
        enableMmap_ = false;
      }
    } else {
      int64_t filesize = size();
      if(static_cast<int64_t>(len + offset) <= filesize) {
        mapaddr_ = reinterpret_cast<unsigned char*>
          (mmap(0, size(), PROT_READ | PROT_WRITE, MAP_SHARED, fd_, 0));
        if(mapaddr_) {
          A2_LOG_DEBUG(fmt("mmap for file %s succeeded, length=%" PRId64 "",
                           filename_.c_str(),
                           static_cast<uint64_t>(filesize)));
          maplen_ = filesize;
        } else {
          int errNum = errno;
          A2_LOG_INFO(fmt("mmap for file %s failed: %s",
                          filename_.c_str(), strerror(errNum)));
          enableMmap_ = false;
        }
      }
    }
  }
#endif // HAVE_MMAP
}

void AbstractDiskWriter::writeData(const unsigned char* data, size_t len, int64_t offset)
{
  ensureMmapWrite(len, offset);
  if(writeDataInternal(data, len, offset) < 0) {
    int errNum = errno;
    // If errno is ENOSPC(not enough space in device), throw
    // DownloadFailureException and abort download instantly.
    if(errNum == ENOSPC) {
      throw DOWNLOAD_FAILURE_EXCEPTION3
        (errNum,
         fmt(EX_FILE_WRITE,
             filename_.c_str(),
             util::safeStrerror(errNum).c_str()),
         error_code::NOT_ENOUGH_DISK_SPACE);
    } else {
      throw DL_ABORT_EX3
        (errNum,
         fmt(EX_FILE_WRITE,
             filename_.c_str(),
             util::safeStrerror(errNum).c_str()),
         error_code::FILE_IO_ERROR);
    }
  }
}

ssize_t AbstractDiskWriter::readData(unsigned char* data, size_t len, int64_t offset)
{
  ssize_t ret;
  if((ret = readDataInternal(data, len, offset)) < 0) {
    int errNum = errno;
    throw DL_ABORT_EX3
      (errNum,
       fmt(EX_FILE_READ,
           filename_.c_str(),
           util::safeStrerror(errNum).c_str()),
       error_code::FILE_IO_ERROR);
  }
  return ret;
}

void AbstractDiskWriter::truncate(int64_t length)
{
  if(fd_ == -1) {
    throw DL_ABORT_EX("File not opened.");
  }
#ifdef __MINGW32__
  // Since mingw32's ftruncate cannot handle over 2GB files, we use SetEndOfFile
  // instead.
  HANDLE handle = LongToHandle(_get_osfhandle(fd_));
  seek(length);
  if(SetEndOfFile(handle) == 0) {
    throw DL_ABORT_EX2(fmt("SetEndOfFile failed. cause: %lx",
                           GetLastError()),
                       error_code::FILE_IO_ERROR);
  }
#else
  if(ftruncate(fd_, length) == -1) {
    int errNum = errno;
    throw DL_ABORT_EX3(errNum,
                       fmt("ftruncate failed. cause: %s",
                           util::safeStrerror(errNum).c_str()),
                       error_code::FILE_IO_ERROR);
  }
#endif
}

void AbstractDiskWriter::allocate(int64_t offset, int64_t length)
{
#ifdef  HAVE_SOME_FALLOCATE
  if(fd_ == -1) {
    throw DL_ABORT_EX("File not yet opened.");
  }
# ifdef __MINGW32__
  LARGE_INTEGER fileLength;
  fileLength.QuadPart = offset+length;
  HANDLE handle = LongToHandle(_get_osfhandle(fd_));
  int r;
  r = SetFilePointerEx(handle, fileLength, 0, FILE_BEGIN);
  if(r == 0) {
    throw DL_ABORT_EX2(fmt("SetFilePointerEx failed. cause: %lx",
                           GetLastError()),
                       error_code::FILE_IO_ERROR);
  }
  r = SetEndOfFile(handle);
  if(r == 0) {
    throw DL_ABORT_EX2(fmt("SetEndOfFile failed. cause: %lx",
                           GetLastError()),
                       error_code::FILE_IO_ERROR);
  }
# elif HAVE_FALLOCATE
  // For linux, we use fallocate to detect file system supports
  // fallocate or not.
  int r;
  while((r = fallocate(fd_, 0, offset, length)) == -1 && errno == EINTR);
  int errNum = errno;
  if(r == -1) {
    throw DL_ABORT_EX3(errNum,
                       fmt("fallocate failed. cause: %s",
                           util::safeStrerror(errNum).c_str()),
                       error_code::FILE_IO_ERROR);
  }
# elif HAVE_POSIX_FALLOCATE
  int r = posix_fallocate(fd_, offset, length);
  if(r != 0) {
    throw DL_ABORT_EX3(r,
                       fmt("posix_fallocate failed. cause: %s",
                           util::safeStrerror(r).c_str()),
                       error_code::FILE_IO_ERROR);
  }
# else
#  error "no *_fallocate function available."
# endif
#endif // HAVE_SOME_FALLOCATE
}

int64_t AbstractDiskWriter::size()
{
  return File(filename_).size();
}

void AbstractDiskWriter::enableReadOnly()
{
  readOnly_ = true;
}

void AbstractDiskWriter::disableReadOnly()
{
  readOnly_ = false;
}

void AbstractDiskWriter::enableMmap()
{
  enableMmap_ = true;
}

} // namespace aria2