diff options
Diffstat (limited to 'erts/emulator/sys/win32')
| -rwxr-xr-x | erts/emulator/sys/win32/sys.c | 77 |
1 files changed, 74 insertions, 3 deletions
diff --git a/erts/emulator/sys/win32/sys.c b/erts/emulator/sys/win32/sys.c index 1c9f8ebf43..6c69fecbf3 100755 --- a/erts/emulator/sys/win32/sys.c +++ b/erts/emulator/sys/win32/sys.c @@ -420,6 +420,8 @@ typedef struct async_io { HANDLE ioAllowed; /* The thread will wait for this event * before starting a new read or write. */ + HANDLE flushEvent; /* Used to signal that a flush should be done. */ + HANDLE flushReplyEvent; /* Used to signal that a flush has been done. */ DWORD pendingError; /* Used to delay presentating an error to Erlang * until the check_io function is entered. */ @@ -878,6 +880,8 @@ init_async_io(AsyncIo* aio, int use_threads) aio->ov.Offset = 0L; aio->ov.OffsetHigh = 0L; aio->ioAllowed = NULL; + aio->flushEvent = NULL; + aio->flushReplyEvent = NULL; aio->pendingError = 0; aio->bytesTransferred = 0; #ifdef ERTS_SMP @@ -890,6 +894,12 @@ init_async_io(AsyncIo* aio, int use_threads) aio->ioAllowed = CreateAutoEvent(FALSE); if (aio->ioAllowed == NULL) return -1; + aio->flushEvent = CreateAutoEvent(FALSE); + if (aio->flushEvent == NULL) + return -1; + aio->flushReplyEvent = CreateAutoEvent(FALSE); + if (aio->flushReplyEvent == NULL) + return -1; } return 0; } @@ -923,6 +933,14 @@ release_async_io(AsyncIo* aio, ErlDrvPort port_num) if (aio->ioAllowed != NULL) CloseHandle(aio->ioAllowed); aio->ioAllowed = NULL; + + if (aio->flushEvent != NULL) + CloseHandle(aio->flushEvent); + aio->flushEvent = NULL; + + if (aio->flushReplyEvent != NULL) + CloseHandle(aio->flushReplyEvent); + aio->flushReplyEvent = NULL; } /* ---------------------------------------------------------------------- @@ -2083,16 +2101,26 @@ threaded_writer(LPVOID param) AsyncIo* aio = (AsyncIo *) param; HANDLE thread = GetCurrentThread(); char* buf; - DWORD numToWrite; + DWORD numToWrite, handle; int ok; + HANDLE handles[2]; + handles[0] = aio->ioAllowed; + handles[1] = aio->flushEvent; for (;;) { - WaitForSingleObject(aio->ioAllowed, INFINITE); + handle = WaitForMultipleObjects(2, handles, FALSE, INFINITE); if (aio->flags & DF_EXIT_THREAD) break; + buf = OV_BUFFER_PTR(aio); numToWrite = OV_NUM_TO_READ(aio); aio->pendingError = 0; + + if (handle == (WAIT_OBJECT_0 + 1) && numToWrite == 0) { + SetEvent(aio->flushReplyEvent); + continue; + } + ok = WriteFile(aio->fd, buf, numToWrite, &aio->bytesTransferred, NULL); if (!ok) { aio->pendingError = GetLastError(); @@ -2127,7 +2155,11 @@ threaded_writer(LPVOID param) } } } - SetEvent(aio->ov.hEvent); + OV_NUM_TO_READ(aio) = 0; + if (handle == (WAIT_OBJECT_0 + 1)) + SetEvent(aio->flushReplyEvent); + else + SetEvent(aio->ov.hEvent); if (aio->pendingError != NO_ERROR || aio->bytesTransferred == 0) break; if (aio->flags & DF_EXIT_THREAD) @@ -2193,6 +2225,43 @@ fd_start(ErlDrvPort port_num, char* name, SysDriverOpts* opts) if ((dp = new_driver_data(port_num, opts->packet_bytes, 2, TRUE)) == NULL) return ERL_DRV_ERROR_GENERAL; + /** + * Here is a brief description about how the fd driver works on windows. + * + * fd_init: + * For each in/out fd pair a threaded_reader and threaded_writer thread is + * created. Within the DriverData struct each of the threads have an AsyncIO + * sctruct associated with it. Within AsyncIO there are two important HANDLEs, + * ioAllowed and ov.hEvent. ioAllowed is used to signal the threaded_* threads + * should read/write some data, and ov.hEvent is driver_select'ed to be used to + * signal that the thread is done reading/writing. + * + * The reason for the driver being threaded like this is because once the FD is open + * on windows, it is not possible to set the it in overlapped mode. So we have to + * simulate this using threads. + * + * output: + * When an output occurs the data to be outputted is copied to AsyncIO.ov. Then + * the ioAllowed HANDLE is set, ov.hEvent is cleared and the port is marked as busy. + * The threaded_writer thread is lying in WaitForMultipleObjects on ioAllowed, and + * when signalled it writes all data in AsyncIO.ov and then sets ov.hEvent so that + * ready_output gets triggered and (potentially) sends the reply to the port and + * marks the port an non-busy. + * + * input: + * The threaded_reader is lying waiting in ReadFile on the in fd and when a new + * line is written it sets ov.hEvent that new data is available and then goes + * and waits for ioAllowed to be set. ready_input is run when ov.hEvent is set and + * delivers the data to the port. Then ioAllowed is signalled again and threaded_reader + * goes back to ReadFile. + * + * shutdown: + * In order to guarantee that all io is outputted before the driver is stopped, + * fd_stop uses flushEvent and flushReplyEvent to make sure that there is no data + * in ov which needs writing before returning from fd_stop. + * + **/ + if (!create_file_thread(&dp->in, DO_READ)) { dp->port_num = PORT_FREE; return ERL_DRV_ERROR_GENERAL; @@ -2241,6 +2310,8 @@ static void fd_stop(ErlDrvData d) (void) driver_select(dp->port_num, (ErlDrvEvent)dp->out.ov.hEvent, ERL_DRV_WRITE, 0); + SetEvent(dp->out.flushEvent); + WaitForSingleObject(dp->out.flushReplyEvent, INFINITE); } } |