player: add experimental C plugin interface

This basically reuses the scripting infrastructure.

Note that this needs to be explicitly enabled at compilation. For one,
enabling export for certain symbols from an executable seems to be quite
toolchain-specific. It might not work outside of Linux and cause random
problems within Linux.

If C plugins actually become commonly used and this approach is starting
to turn out as a problem, we can build mpv CLI as a wrapper for libmpv,
which would remove the requirement that plugins pick up host symbols.

I'm being lazy, so implementation/documentation are parked in existing
files, even if that stuff doesn't necessarily belong there. Sue me, or
better send patches.

1 files changed, 34 insertions, 0 deletions

diff --git a/player/scripting.c b/player/scripting.c
index 4b92f7bf1b..2469b67678 100644
--- a/player/scripting.c
+++ b/player/scripting.c
@@ -37,11 +37,15 @@
 #include "libmpv/client.h"
 
 extern const struct mp_scripting mp_scripting_lua;
+extern const struct mp_scripting mp_scripting_cplugin;
 
 static const struct mp_scripting *const scripting_backends[] = {
 #if HAVE_LUA
     &mp_scripting_lua,
 #endif
+#if HAVE_CPLUGINS
+    &mp_scripting_cplugin,
+#endif
     NULL
 };
 
@@ -228,3 +232,33 @@ void mp_load_scripts(struct MPContext *mpctx)
     }
     talloc_free(tmp);
 }
+
+#if HAVE_CPLUGINS
+
+#include <dlfcn.h>
+
+#define MPV_DLOPEN_FN "mpv_open_cplugin"
+typedef int (*mpv_open_cplugin)(mpv_handle *handle);
+
+static int load_cplugin(struct mpv_handle *client, const char *fname)
+{
+    int r = -1;
+    void *lib = dlopen(fname, RTLD_NOW | RTLD_LOCAL);
+    if (!lib)
+        goto error;
+    mpv_open_cplugin sym = (mpv_open_cplugin)dlsym(lib, MPV_DLOPEN_FN);
+    if (!sym)
+        goto error;
+    r = sym(client) ? -1 : 0;
+error:
+    if (lib)
+        dlclose(lib);
+    return r;
+}
+
+const struct mp_scripting mp_scripting_cplugin = {
+    .file_ext = "so",
+    .load = load_cplugin,
+};
+
+#endif