diff options
Diffstat (limited to 'backend/runloop.c')
| -rw-r--r-- | backend/runloop.c | 117 |
1 files changed, 111 insertions, 6 deletions
diff --git a/backend/runloop.c b/backend/runloop.c index fd0bb8f04..647c79488 100644 --- a/backend/runloop.c +++ b/backend/runloop.c @@ -1,7 +1,7 @@ /* - * "$Id: runloop.c 6498 2007-04-30 21:40:33Z mike $" + * "$Id: runloop.c 6591 2007-06-21 20:35:28Z mike $" * - * Common run loop API for the Common UNIX Printing System (CUPS). + * Common run loop APIs for the Common UNIX Printing System (CUPS). * * Copyright 2006-2007 by Easy Software Products, all rights reserved. * @@ -25,7 +25,8 @@ * * Contents: * - * backendRunLoop() - Read and write print and back-channel data. + * backendDrainOutput() - Drain pending print data to the device. + * backendRunLoop() - Read and write print and back-channel data. */ /* @@ -41,6 +42,109 @@ /* + * 'backendDrainOutput()' - Drain pending print data to the device. + */ + +int /* O - 0 on success, -1 on error */ +backendDrainOutput(int print_fd, /* I - Print file descriptor */ + int device_fd) /* I - Device file descriptor */ +{ + int nfds; /* Maximum file descriptor value + 1 */ + fd_set input; /* Input set for reading */ + ssize_t print_bytes, /* Print bytes read */ + bytes; /* Bytes written */ + char print_buffer[8192], /* Print data buffer */ + *print_ptr; /* Pointer into print data buffer */ + struct timeval timeout; /* Timeout for read... */ + + + fprintf(stderr, "DEBUG: backendDrainOutput(print_fd=%d, device_fd=%d)\n", + print_fd, device_fd); + + /* + * Figure out the maximum file descriptor value to use with select()... + */ + + nfds = (print_fd > device_fd ? print_fd : device_fd) + 1; + + /* + * Now loop until we are out of data from print_fd... + */ + + for (;;) + { + /* + * Use select() to determine whether we have data to copy around... + */ + + FD_ZERO(&input); + FD_SET(print_fd, &input); + + timeout.tv_sec = 0; + timeout.tv_usec = 0; + + if (select(nfds, &input, NULL, NULL, &timeout) < 0) + return (-1); + + if (!FD_ISSET(print_fd, &input)) + return (0); + + if ((print_bytes = read(print_fd, print_buffer, + sizeof(print_buffer))) < 0) + { + /* + * Read error - bail if we don't see EAGAIN or EINTR... + */ + + if (errno != EAGAIN || errno != EINTR) + { + perror("ERROR: Unable to read print data"); + return (-1); + } + + print_bytes = 0; + } + else if (print_bytes == 0) + { + /* + * End of file, return... + */ + + return (0); + } + + fprintf(stderr, "DEBUG: Read %d bytes of print data...\n", + (int)print_bytes); + + for (print_ptr = print_buffer; print_bytes > 0;) + { + if ((bytes = write(device_fd, print_ptr, print_bytes)) < 0) + { + /* + * Write error - bail if we don't see an error we can retry... + */ + + if (errno != ENOSPC && errno != ENXIO && errno != EAGAIN && + errno != EINTR && errno != ENOTTY) + { + fprintf(stderr, _("ERROR: Unable to write print data: %s\n"), + strerror(errno)); + return (-1); + } + } + else + { + fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes); + + print_bytes -= bytes; + print_ptr += bytes; + } + } + } +} + + +/* * 'backendRunLoop()' - Read and write print and back-channel data. */ @@ -69,8 +173,9 @@ backendRunLoop( fprintf(stderr, - "DEBUG: backendRunLoop(print_fd=%d, device_fd=%d, use_bc=%d)\n", - print_fd, device_fd, use_bc); + "DEBUG: backendRunLoop(print_fd=%d, device_fd=%d, use_bc=%d, " + "side_cb=%p)\n", + print_fd, device_fd, use_bc, side_cb); /* * If we are printing data from a print driver on stdin, ignore SIGTERM @@ -278,5 +383,5 @@ backendRunLoop( /* - * End of "$Id: runloop.c 6498 2007-04-30 21:40:33Z mike $". + * End of "$Id: runloop.c 6591 2007-06-21 20:35:28Z mike $". */ |