Method net_read_io

src/iocore/net/UnixNetVConnection.cc:475–629

Read the data for a UnixNetVConnection. Rescheduling the UnixNetVConnection by moving the VC onto or off of the ready_list.

// Rescheduling the UnixNetVConnection by moving the VC
// onto or off of the ready_list.
void
UnixNetVConnection::net_read_io(NetHandler *nh)
{
  NetState *s = &this->read;
  int64_t   r = 0;

  MUTEX_TRY_LOCK(lock, s->vio.mutex, thread);

  if (!lock.is_locked()) {
    read_reschedule(nh, this);
    return;
  }

  // It is possible that the closed flag got set from HttpSessionManager in the
  // global session pool case.  If so, the closed flag should be stable once we get the
  // s->vio.mutex (the global session pool mutex).
  if (this->closed) {
    this->nh->free_netevent(this);
    return;
  }
  // if it is not enabled.
  if (!s->enabled || s->vio.op != VIO::READ || s->vio.is_disabled()) {
    read_disable(nh, this);
    return;
  }

  MIOBufferAccessor &buf = s->vio.buffer;
  ink_assert(buf.writer());

  // if there is nothing to do, disable connection
  int64_t ntodo = s->vio.ntodo();
  if (ntodo <= 0) {
    read_disable(nh, this);
    return;
  }
  int64_t toread = buf.writer()->write_avail();
  if (toread > ntodo) {
    toread = ntodo;
  }

  // read data
  int64_t  rattempted = 0, total_read = 0;
  unsigned niov = 0;
  IOVec    tiovec[NET_MAX_IOV];
  if (toread) {
    IOBufferBlock *b = buf.writer()->first_write_block();
    do {
      niov       = 0;
      rattempted = 0;
      while (b && niov < NET_MAX_IOV) {
        int64_t a = b->write_avail();
        if (a > 0) {
          tiovec[niov].iov_base = b->_end;
          int64_t togo          = toread - total_read - rattempted;
          if (a > togo) {
            a = togo;
          }
          tiovec[niov].iov_len  = a;