avfilter/asubprocess: handle subprocess write errors

Signed-off-by: Stefan Westerfeld <stefan@space.twc.de>

libavfilter/af_asubprocess.c

@@ -137,7 +137,7 @@ sp_read (SP *sp, char *buffer, int count)
     }
 }
 
-static void
+static int
 sp_write (SP *sp, char *buffer, int count)
 {
   int offset = 0;
@@ -146,6 +146,8 @@ sp_write (SP *sp, char *buffer, int count)
       close (sp->input_pipe);
       sp->input_pipe = -1;
     }
+  if (count && sp->done)
+      return AVERROR_EXTERNAL;
   do
     {
       struct pollfd fds[2] = {
@@ -185,10 +187,13 @@ sp_write (SP *sp, char *buffer, int count)
               waitpid (sp->pid, &status, 0);
               printf ("wstatus=%d\n", WEXITSTATUS (status));
               sp->done = true;
-              return;
+              if (count)
+                  return AVERROR_EXTERNAL;
+              return 0;
             }
         }
     } while (count);
+  return 0;
 }
 
 static bool
@@ -260,12 +265,13 @@ static av_cold void uninit(AVFilterContext *ctx)
 
 #define NB_BUFFER_SAMPLES 4096
 
-static void write_wav_header (ASubProcessContext *s, int nb_channels, int sample_rate)
+static int write_wav_header (ASubProcessContext *s, int nb_channels, int sample_rate)
 {
     int bit_depth = s->in_bit_depth;
     AVIOContext *wav_header = NULL;
     uint8_t *buffer = NULL;
     int size;
+    int ret;
 
     avio_open_dyn_buf (&wav_header);
     ffio_wfourcc(wav_header, "RIFF");
@@ -285,8 +291,9 @@ static void write_wav_header (ASubProcessContext *s, int nb_channels, int sample
     ffio_wfourcc (wav_header, "data");
     avio_wl32 (wav_header, -1);
     size = avio_close_dyn_buf (wav_header, &buffer);
-    sp_write (s->sp, buffer, size);
+    ret = sp_write (s->sp, buffer, size);
     av_free (buffer);
+    return ret;
 }
 
 static int config_input(AVFilterLink *inlink)
@@ -356,7 +363,7 @@ static void read_samples(ASubProcessContext *s, int32_t *data, int count)
     }
 }
 
-static void write_samples(ASubProcessContext *s, int32_t *data, int count)
+static int write_samples(ASubProcessContext *s, int32_t *data, int count)
 {
     int sample_size = s->in_bit_depth / 8;
 
@@ -364,8 +371,7 @@ static void write_samples(ASubProcessContext *s, int32_t *data, int count)
     if (s->in_bit_depth == 32)
     {
         /* optimized case: on little endian systems we don't need any conversion */
-        sp_write(s->sp, (char *)data, sample_size * count);
-        return;
+        return sp_write(s->sp, (char *)data, sample_size * count);
     }
 #endif
     if (s->in_bit_depth == 16)
@@ -389,7 +395,7 @@ static void write_samples(ASubProcessContext *s, int32_t *data, int count)
         for (int k = 0; k < count; k++)
             AV_WL32(out + k, data[k]);
     }
-    sp_write(s->sp, s->sample_buffer, sample_size * count);
+    return sp_write(s->sp, s->sample_buffer, sample_size * count);
 }
 
 static int write_frame(ASubProcessContext *s, AVFilterLink *inlink, AVFrame *in)
@@ -397,7 +403,7 @@ static int write_frame(ASubProcessContext *s, AVFilterLink *inlink, AVFrame *in)
     int ret = 0;
 
     av_assert0(in->nb_samples <= NB_BUFFER_SAMPLES);
-    write_samples(s, (int32_t *)in->data[0], in->nb_samples * inlink->ch_layout.nb_channels);
+    ret = write_samples(s, (int32_t *)in->data[0], in->nb_samples * inlink->ch_layout.nb_channels);
     av_frame_free(&in);
     return ret;
 }