RAW_OUTPUT not opening FIFO

[antiprism]

Hi Karl

I had an issue reported for mpd_oled yesterday that was introduced with the last cava commit: be7c5b8

http://moodeaudio.org/forum/showthread.php?tid=155&pid=34372#pid34372

mpd_oled creates a FIFO for cava to write to, and then runs cava with a configuration like

[output]
method = raw
data_format = binary
channels = mono
raw_target = /tmp/cava_fifo_307165
bit_format = 8bit

Which leads to this section of cava code being run

if (access(p.raw_target, F_OK) != -1) {
                          // testopening in case it's a fifo
                          fptest = open(p.raw_target, O_RDONLY | O_NONBLOCK, 0644);
  
                          if (fptest == -1) {
                              fprintf(stderr, "could not open file %s for writin  g\n", p.raw_target);
                              exit(1);
                          }
                      } else...

In the old code there was a later unconditional line

fp = open(p.raw_target, O_WRONLY | O_NONBLOCK | O_CREAT, 0644)  ;

This is removed and made conditional in the new code, which leads to no spectrum (and fp is being initialised to 0 for me, which is maybe standard input!)

I also noticed the commit left a printf

printf("creating fifo %s\n", p.raw_target);

Could the code be simplified to something like

case OUTPUT_RAW:
                  if (strcmp(p.raw_target, "/dev/stdout") != 0) {
                      // checking if file exists
                      if (access(p.raw_target, F_OK) == -1) {
                          fprintf(stderr, "creating fifo %s\n", p.raw_target);
                          if (mkfifo(p.raw_target, 0664) == -1) {
                              fprintf(stderr, "could not create fifo %s\n", p.raw_target);
                              exit(1);
                          }
                      }
                      fp = open(p.raw_target, O_RDWR | O_NONBLOCK, 0644);
                  } else {
                      fp = fileno(stdout);
                      fprintf(stderr, "Opening stdout\n");
                  }
                  if (fp == -1) {
                      fprintf(stderr, "could not open file %s for writing\n", p.raw_target);
                      exit(1);
                  }
                  fprintf(stderr, "open file %s for writing raw output\n", p.raw_target);

I checked this with mpd_oled creating the FIFO and then calling cava, and also letting cava create the FIFO and mpd_oled simply opening it, and it worked in both cases.

Adrian.

[karlstav]

should work now, I was a bit quick when merging the previous commit so the fifo was actually only opened when it did not already exist.

the code here is a bit confusing the fptest was needed in order to achieve something and I have forgotten what it was. I think it had to do with keeping it non_blocking.

[antiprism]

Hi Karl

All working well with mpd_oled.

Thanks for the quick update!

Adrian.