View file File name : syncproc.sl Content :% synchronous process support %_debug_info = 1; private variable Filter_Processes = NULL; private define find_filter_process (pid) { variable s = Filter_Processes; while (s != NULL) { if (s.pid == pid) break; s = s.next; } return s; } private define delete_filter_process (s) { if (Filter_Processes == NULL) return; if (Filter_Processes == s) { Filter_Processes = s.next; s.next = NULL; return; } variable prev = Filter_Processes; variable next = prev.next; while (next != s) { if (next == NULL) return; prev = next; next = next.next; } prev.next = next.next; s.next = NULL; } private define process_signal_handler (pid, flags, status) { if (flags == 1) return; variable s = find_filter_process (pid); if (s == NULL) return; if (flags == 4) s.exit_status = status; else s.exit_status = -1; } private define allocate_filter_process (pid) { variable s = struct { pid, exit_status, next }; s.pid = pid; s.next = Filter_Processes; Filter_Processes = s; return s; } %!%+ %\function{open_filter_process} %\synopsis{Open a subprocess as a filter} %\usage{Int_Type pid = open_filter_process (String_Type argv[], String_Type output)} %\description % The \var{open_filter_process} function may be used to open an interactive % synchronous process. The first argument should be an array of strings % representing the program to be run in the subprocess, and the command line % parameters passed to it. The second argument specifies what to do with the % output generated by the process. It can be any value supported by the % "output" option of the \var{set_process} function. The process should be % closed using the \var{close_filter_process} function. %\seealso{close_filter_process, send_process, call_process_region} %!%- public define open_filter_process (argv, output) { if (typeof (argv) != Array_Type) argv = [argv]; variable nargs = length (argv); foreach (argv) ; variable args = __pop_args (nargs); variable pgm = argv[0]; variable pid = open_process_pipe (__push_args (args), nargs-1); if (-1 == pid) verror ("failed to execute %s", pgm); variable s = allocate_filter_process (pid); set_process (pid, "signal", &process_signal_handler); set_process (pid, "output", output); return pid; } %!%+ %\function{close_filter_process} %\synopsis{Close a filter process and return its status} %\usage{Int_Type close_filter_process (Int_Type pid)} %\description % The \var{close_filter_process} function waits for the specified process % to terminate and returns the exit status of the process. The process must % have been previously opened via the \var{open_filter_process} function. %\seealso{open_filter_process, send_process, get_process_input} %!%- public define close_filter_process (pid) { variable s = find_filter_process (pid); if (s == NULL) return -1; %send_process_eof (pid); get_process_input (0); variable next_signal = 2; while (s.exit_status == NULL) { update (0); ERROR_BLOCK { signal_process (pid, next_signal); if (next_signal != 9) _clear_error (); next_signal = 9; } get_process_input (5); } variable status = s.exit_status; delete_filter_process (s); return status; } public define call_process_region (cmd, output) { variable str = bufsubstr (); variable pid = open_filter_process (cmd, output); if (pid == -1) return; send_process (pid, str); send_process_eof (pid); vmessage ("Process returned %d", close_filter_process (pid)); }