WIP

links.c

@@ -0,0 +1,85 @@
+#include "device.h"
+#include "buffer.h"
+#include "buffer_list.h"
+#include "links.h"
+
+#define N_FDS 50
+
+int _build_fds(link_t *all_links, struct pollfd *fds, link_t **links, buffer_list_t **buf_lists, int max_n)
+{
+  int n;
+
+  for (int i = 0; all_links[i].capture; i++) {
+    link_t *link = &all_links[i];
+
+    if (!link->capture || !link->capture->capture_list || n >= max_n) {
+      return -EINVAL;
+    }
+    if (!link->capture->capture_list->do_mmap) {
+      continue;
+    }
+
+    struct pollfd fd = {link->capture->fd, POLLIN};
+    fds[n] = fd;
+    buf_lists[n] = link->capture->capture_list;
+    links[n] = link;
+    n++;
+
+    for (int j = 0; link->outputs[j]; j++) {
+      device_t *output = link->outputs[j];
+
+      if (!output || !output->output_list || n >= max_n) {
+        return -EINVAL;
+      }
+      if (!output->output_list->do_mmap) {
+        continue;
+      }
+
+      struct pollfd fd = {output->fd, POLLOUT};
+      fds[n] = fd;
+      buf_lists[n] = output->output_list;
+      links[n] = link;
+      n++;
+    }
+  }
+
+  return n;
+}
+
+int handle_links(link_t *all_links, int timeout)
+{
+  struct pollfd fds[N_FDS] = {0};
+  link_t *links[N_FDS];
+  buffer_list_t *buf_lists[N_FDS];
+  buffer_t *buf;
+  int n = _build_fds(all_links, fds, links, buf_lists, N_FDS);
+
+  if (poll(fds, n, timeout) < 0 && errno != EINTR) {
+    return errno;
+  }
+
+  for (int i = 0; i < n; i++) {
+    buffer_list_t *buf_list = buf_lists[n];
+    link_t *link = links[n];
+
+    if (fds[i].revents & POLLIN) {
+      if (buf = buffer_list_dequeue(buf_list, true)) {
+        for (int j = 0; link->outputs[j]; j++) {
+          buffer_list_enqueue(link->outputs[j]->output_list, buf);
+        }
+
+        if (link->on_buffer) {
+          link->on_buffer(buf);
+        }
+
+        buffer_consumed(buf);
+      }
+    }
+    if (fds[i].revents & POLLOUT) {
+      if (buf = buffer_list_dequeue(buf_list, false)) {
+        buffer_consumed(buf);
+      }
+    }
+  }
+  return 0;
+}

links.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include "v4l2.h"
+
+typedef struct link_s {
+  device_t *capture; // capture_list
+  device_t *outputs[10];
+  void (*on_buffer)(buffer_t *buf);
+} link_t;
+
+int handle_links(link_t *all_links, int timeout);

main.c

@@ -1,6 +1,7 @@
 #include "buffer.h"
 #include "buffer_list.h"
 #include "device.h"
+#include "links.h"
 #include "v4l2.h"
 
 int camera_width = 1920;