From c39054a63da52ab266ed26d78e2329c48e4e0216 Mon Sep 17 00:00:00 2001
From: Romain Vimont <rom@rom1v.com>
Date: Thu, 2 Mar 2023 09:07:25 +0100
Subject: [PATCH] Introduce packet source trait

There was a packet sink trait, implemented by components able to
receive AVPackets, but each packet source had to manually send packets
to sinks.

In order to mutualise sink management, add a packet source trait.
---
 app/meson.build               |  1 +
 app/src/trait/packet_source.c | 70 +++++++++++++++++++++++++++++++++++
 app/src/trait/packet_source.h | 41 ++++++++++++++++++++
 3 files changed, 112 insertions(+)
 create mode 100644 app/src/trait/packet_source.c
 create mode 100644 app/src/trait/packet_source.h

diff --git a/app/meson.build b/app/meson.build
index 7749d664..82105876 100644
--- a/app/meson.build
+++ b/app/meson.build
@@ -30,6 +30,7 @@ src = [
     'src/server.c',
     'src/version.c',
     'src/video_buffer.c',
+    'src/trait/packet_source.c',
     'src/util/acksync.c',
     'src/util/bytebuf.c',
     'src/util/file.c',
diff --git a/app/src/trait/packet_source.c b/app/src/trait/packet_source.c
new file mode 100644
index 00000000..df678e16
--- /dev/null
+++ b/app/src/trait/packet_source.c
@@ -0,0 +1,70 @@
+#include "packet_source.h"
+
+void
+sc_packet_source_init(struct sc_packet_source *source) {
+    source->sink_count = 0;
+}
+
+void
+sc_packet_source_add_sink(struct sc_packet_source *source,
+                          struct sc_packet_sink *sink) {
+    assert(source->sink_count < SC_PACKET_SOURCE_MAX_SINKS);
+    assert(sink);
+    assert(sink->ops);
+    source->sinks[source->sink_count++] = sink;
+}
+
+static void
+sc_packet_source_sinks_close_firsts(struct sc_packet_source *source,
+                                    unsigned count) {
+    while (count) {
+        struct sc_packet_sink *sink = source->sinks[--count];
+        sink->ops->close(sink);
+    }
+}
+
+bool
+sc_packet_source_sinks_open(struct sc_packet_source *source,
+                            const AVCodec *codec) {
+    assert(source->sink_count);
+    for (unsigned i = 0; i < source->sink_count; ++i) {
+        struct sc_packet_sink *sink = source->sinks[i];
+        if (!sink->ops->open(sink, codec)) {
+            sc_packet_source_sinks_close_firsts(source, i);
+            return false;
+        }
+    }
+
+    return true;
+}
+
+void
+sc_packet_source_sinks_close(struct sc_packet_source *source) {
+    assert(source->sink_count);
+    sc_packet_source_sinks_close_firsts(source, source->sink_count);
+}
+
+bool
+sc_packet_source_sinks_push(struct sc_packet_source *source,
+                            const AVPacket *packet) {
+    assert(source->sink_count);
+    for (unsigned i = 0; i < source->sink_count; ++i) {
+        struct sc_packet_sink *sink = source->sinks[i];
+        if (!sink->ops->push(sink, packet)) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+void
+sc_packet_source_sinks_disable(struct sc_packet_source *source) {
+    assert(source->sink_count);
+    for (unsigned i = 0; i < source->sink_count; ++i) {
+        struct sc_packet_sink *sink = source->sinks[i];
+        if (sink->ops->disable) {
+            sink->ops->disable(sink);
+        }
+    }
+}
diff --git a/app/src/trait/packet_source.h b/app/src/trait/packet_source.h
new file mode 100644
index 00000000..c34aa5d3
--- /dev/null
+++ b/app/src/trait/packet_source.h
@@ -0,0 +1,41 @@
+#ifndef SC_PACKET_SOURCE_H
+#define SC_PACKET_SOURCE_H
+
+#include "common.h"
+
+#include "packet_sink.h"
+
+#define SC_PACKET_SOURCE_MAX_SINKS 2
+
+/**
+ * Packet source trait
+ *
+ * Component able to send AVPackets should implement this trait.
+ */
+struct sc_packet_source {
+    struct sc_packet_sink *sinks[SC_PACKET_SOURCE_MAX_SINKS];
+    unsigned sink_count;
+};
+
+void
+sc_packet_source_init(struct sc_packet_source *source);
+
+void
+sc_packet_source_add_sink(struct sc_packet_source *source,
+                          struct sc_packet_sink *sink);
+
+bool
+sc_packet_source_sinks_open(struct sc_packet_source *source,
+                            const AVCodec *codec);
+
+void
+sc_packet_source_sinks_close(struct sc_packet_source *source);
+
+bool
+sc_packet_source_sinks_push(struct sc_packet_source *source,
+                            const AVPacket *packet);
+
+void
+sc_packet_source_sinks_disable(struct sc_packet_source *source);
+
+#endif