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Minimal test - lines (93, 93)

Code

  struct stat buf;

Minimal test - lines (49, 131)

Code

bool mozilla::fallocate(PRFileDesc* aFD, int64_t aLength) {
#  if defined(HAVE_POSIX_FALLOCATE)
  return posix_fallocate(PR_FileDesc2NativeHandle(aFD), 0, aLength) == 0;
#  elif defined(XP_WIN)
  int64_t oldpos = PR_Seek64(aFD, 0, PR_SEEK_CUR);
  if (oldpos == -1) {
    return false;
  }

  if (PR_Seek64(aFD, aLength, PR_SEEK_SET) != aLength) {
    return false;
  }

  bool retval = (0 != SetEndOfFile((HANDLE)PR_FileDesc2NativeHandle(aFD)));

  PR_Seek64(aFD, oldpos, PR_SEEK_SET);
  return retval;
#  elif defined(XP_MACOSX)
  int fd = PR_FileDesc2NativeHandle(aFD);
  fstore_t store = {F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, aLength};
  // Try to get a continous chunk of disk space
  int ret = fcntl(fd, F_PREALLOCATE, &store);
  if (ret == -1) {
    // OK, perhaps we are too fragmented, allocate non-continuous
    store.fst_flags = F_ALLOCATEALL;
    ret = fcntl(fd, F_PREALLOCATE, &store);
    if (ret == -1) {
      return false;
    }
  }
  return ftruncate(fd, aLength) == 0;
#  elif defined(XP_UNIX)
  // The following is copied from fcntlSizeHint in sqlite
  /* If the OS does not have posix_fallocate(), fake it. First use
  ** ftruncate() to set the file size, then write a single byte to
  ** the last byte in each block within the extended region. This
  ** is the same technique used by glibc to implement posix_fallocate()
  ** on systems that do not have a real fallocate() system call.
  */
  int64_t oldpos = PR_Seek64(aFD, 0, PR_SEEK_CUR);
  if (oldpos == -1) {
    return false;
  }

  struct stat buf;
  int fd = PR_FileDesc2NativeHandle(aFD);
  if (fstat(fd, &buf)) {
    return false;
  }

  if (buf.st_size >= aLength) {
    return false;
  }

  const int nBlk = buf.st_blksize;

  if (!nBlk) {
    return false;
  }

  if (ftruncate(fd, aLength)) {
    return false;
  }

  int nWrite;  // Return value from write()
  int64_t iWrite = ((buf.st_size + 2 * nBlk - 1) / nBlk) * nBlk -
                   1;  // Next offset to write to
  while (iWrite < aLength) {
    nWrite = 0;
    if (PR_Seek64(aFD, iWrite, PR_SEEK_SET) == iWrite) {
      nWrite = PR_Write(aFD, "", 1);
    }
    if (nWrite != 1) {
      break;
    }
    iWrite += nBlk;
  }

  PR_Seek64(aFD, oldpos, PR_SEEK_SET);
  return nWrite == 1;
#  endif
  return false;
}