1 --[[

2

3 This file contains an alternative pfilter(...) implementation in pure Lua (utilizing moonbridge_io). This implementation is currently not used since extos already comes with a C implementation (extos.pfilter), which is independent of moonbridge_io and thus preferred to the implementation below.

4

5 data_out, -- string containing stdout data, or nil in case of error

6 data_err, -- string containing error or stderr data

7 status = -- exit code, or negative code in case of abnormal termination

8 pfilter(

9 data_in, -- string containing stdin data

10 filename, -- executable

11 arg1, -- first (non-zero) argument to executable

12 arg2, -- second argument to executable

13 ...

14 )

15

16 Executes the executable given by "filename", passing optional arguments. A given string may be fed into the program as stdin. On success 3 values are returned: A string containing all stdout data of the sub-process, a string containing all stderr data of the sub-process, and a status code. The status code is negative, if the program didn't terminate normally. By convention a status code of zero indicates success, while positive status codes indicate error conditions. If program execution was not possible at all, then nil is returned as first value and an error string as second value.

17

18 --]]

19

20 return function(data_in, ...)

21 local process, errmsg = moonbridge_io.exec(...)

22 if not process then return nil, errmsg end

23 local read_fds = {[process.stdout] = true, [process.stderr] = true}

24 local write_fds = {[process.stdin] = true}

25 local function read(socket, chunks)

26 if read_fds[socket] then

27 local chunk, status = socket:read_nb()

28 if not chunk then

29 socket:close()

30 read_fds[socket] = nil

31 else

32 chunks[#chunks+1] = chunk

33 if status == "eof" then

34 socket:close()

35 read_fds[socket] = nil

36 end

37 end

38 end

39 end

40 local function write(...)

41 if write_fds[process.stdin] then

42 local buffered = process.stdin:flush_nb(...)

43 if not buffered or buffered == 0 then

44 process.stdin:close()

45 write_fds[process.stdin] = nil

46 end

47 end

48 end

49 write(data_in or "")

50 local stdout_chunks, stderr_chunks = {}, {}

51 while next(read_fds) or next(write_fds) do

52 moonbridge_io.poll(read_fds, write_fds)

53 read(process.stdout, stdout_chunks)

54 read(process.stderr, stderr_chunks)

55 write()

56 end

57 return

58 table.concat(stdout_chunks),

59 table.concat(stderr_chunks),

60 process:wait()

61 end

62