diff options
| -rw-r--r-- | winsup/cygwin/fhandler_fifo.cc | 66 |
1 files changed, 60 insertions, 6 deletions
diff --git a/winsup/cygwin/fhandler_fifo.cc b/winsup/cygwin/fhandler_fifo.cc index 017d44e54..a33c32b73 100644 --- a/winsup/cygwin/fhandler_fifo.cc +++ b/winsup/cygwin/fhandler_fifo.cc @@ -1318,17 +1318,30 @@ fhandler_fifo::raw_read (void *in_ptr, size_t& len) if (take_ownership (10) < 0) goto maybe_retry; - /* Poll the connected clients for input. Make two passes. On - the first pass, just try to read from the client from which - we last read successfully. This should minimize - interleaving of writes from different clients. */ fifo_client_lock (); + /* Poll the connected clients for input. Make three passes. + + On the first pass, just try to read from the client from + which we last read successfully. This should minimize + interleaving of writes from different clients. + + On the second pass, just try to read from the clients in the + state fc_input_avail. This should be more efficient if + select has been called and detected input available. + + On the third pass, try to read from all connected clients. */ + /* First pass. */ int j; for (j = 0; j < nhandlers; j++) if (fc_handler[j].last_read) break; - if (j < nhandlers && fc_handler[j].get_state () >= fc_connected) + if (j < nhandlers && fc_handler[j].get_state () < fc_connected) + { + fc_handler[j].last_read = false; + j = nhandlers; + } + if (j < nhandlers) { NTSTATUS status; IO_STATUS_BLOCK io; @@ -1349,6 +1362,8 @@ fhandler_fifo::raw_read (void *in_ptr, size_t& len) } break; case STATUS_PIPE_EMPTY: + /* Update state in case it's fc_input_avail. */ + fc_handler[j].set_state (fc_connected); break; case STATUS_PIPE_BROKEN: fc_handler[j].set_state (fc_disconnected); @@ -1358,11 +1373,48 @@ fhandler_fifo::raw_read (void *in_ptr, size_t& len) fc_handler[j].set_state (fc_error); break; } - fc_handler[j].last_read = false; } /* Second pass. */ for (int i = 0; i < nhandlers; i++) + if (fc_handler[i].get_state () == fc_input_avail) + { + NTSTATUS status; + IO_STATUS_BLOCK io; + + status = NtReadFile (fc_handler[i].h, NULL, NULL, NULL, + &io, in_ptr, len, NULL, NULL); + switch (status) + { + case STATUS_SUCCESS: + case STATUS_BUFFER_OVERFLOW: + if (io.Information > 0) + { + len = io.Information; + if (j < nhandlers) + fc_handler[j].last_read = false; + fc_handler[i].last_read = true; + fifo_client_unlock (); + reading_unlock (); + return; + } + break; + case STATUS_PIPE_EMPTY: + /* No input available after all. */ + fc_handler[i].set_state (fc_connected); + break; + case STATUS_PIPE_BROKEN: + fc_handler[i].set_state (fc_disconnected); + break; + default: + debug_printf ("NtReadFile status %y", status); + fc_handler[i].set_state (fc_error); + break; + } + } + + /* Third pass. */ + for (int i = 0; i < nhandlers; i++) if (fc_handler[i].get_state () >= fc_connected) { NTSTATUS status; @@ -1378,6 +1430,8 @@ fhandler_fifo::raw_read (void *in_ptr, size_t& len) if (io.Information > 0) { len = io.Information; + if (j < nhandlers) + fc_handler[j].last_read = false; fc_handler[i].last_read = true; fifo_client_unlock (); reading_unlock (); |