Add initial Lua scripting support

This is preliminary. There are still tons of issues, and any aspect
of scripting may change in the future. I decided to merge this
(preliminary) work now because it makes it easier to develop it, not
because it's done. lua.rst is clear enough about it (plus some
sarcasm).

This requires linking to Lua. Lua has no official pkg-config file, but
there are distribution specific .pc files, all with different names.
Adding a non-pkg-config based configure test was considered, but we'd
rather not.

One major complication is that libquvi links against Lua too, and if
the Lua version is different from mpv's, you will get a crash as soon
as libquvi uses Lua. (libquvi by design always runs when a file is
opened.) I would consider this the problem of distros and whoever
builds mpv, but to make things easier for users, we add a terrible
runtime test to the configure script, which probes whether libquvi
will crash. This is disabled when cross-compiling, but in that case
we hope the user knows what he is doing.

1 files changed, 72 insertions, 0 deletions

diff --git a/mpvcore/command.c b/mpvcore/command.c
index b30a5299e0..35e72cb3ad 100644
--- a/mpvcore/command.c
+++ b/mpvcore/command.c
@@ -68,6 +68,8 @@
 
 #include "mpvcore/mp_core.h"
 
+#include "mp_lua.h"
+
 static int edit_filters(struct MPContext *mpctx, enum stream_type mediatype,
                         const char *cmd, const char *arg);
 static int set_filters(struct MPContext *mpctx, enum stream_type mediatype,
@@ -1913,6 +1915,11 @@ static const m_option_t mp_properties[] = {
     {0},
 };
 
+const struct m_option *mp_get_property_list(void)
+{
+    return mp_properties;
+}
+
 int mp_property_do(const char *name, int action, void *val,
                    struct MPContext *ctx)
 {
@@ -2729,6 +2736,15 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
                          cmd->args[1].v.s, msg_osd);
         break;
 
+    case MP_CMD_SCRIPT_DISPATCH:
+        if (mpctx->lua_ctx) {
+#ifdef CONFIG_LUA
+            mp_lua_script_dispatch(mpctx, cmd->args[0].v.s, cmd->args[1].v.i,
+                            cmd->key_up_follows ? "keyup_follows" : "press");
+#endif
+        }
+        break;
+
     case MP_CMD_COMMAND_LIST: {
         for (struct mp_cmd *sub = cmd->args[0].v.p; sub; sub = sub->queue_next)
             run_command(mpctx, sub);
@@ -2755,3 +2771,59 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
         break;
     }
 }
+
+struct command_ctx {
+    int events;
+};
+
+void command_init(struct MPContext *mpctx)
+{
+    mpctx->command_ctx = talloc_zero(mpctx, struct command_ctx);
+}
+
+// Notify that a property might have changed.
+void mp_notify_property(struct MPContext *mpctx, const char *property)
+{
+    mp_notify(mpctx, MP_EVENT_PROPERTY, (void *)property);
+}
+
+void mp_notify(struct MPContext *mpctx, enum mp_event event, void *arg)
+{
+    struct command_ctx *ctx = mpctx->command_ctx;
+    ctx->events |= 1u << event;
+}
+
+static void handle_script_event(struct MPContext *mpctx, const char *name,
+                                const char *arg)
+{
+#ifdef CONFIG_LUA
+    mp_lua_event(mpctx, name, arg);
+#endif
+}
+
+void mp_flush_events(struct MPContext *mpctx)
+{
+    struct command_ctx *ctx = mpctx->command_ctx;
+
+    ctx->events |= (1u << MP_EVENT_TICK);
+
+    for (int n = 0; n < 16; n++) {
+        enum mp_event event = n;
+        unsigned mask = 1 << event;
+        if (ctx->events & mask) {
+            // The event handler could set event flags again; in this case let
+            // the next mp_flush_events() call handle it to avoid infinite loops.
+            ctx->events &= ~mask;
+            const char *name = NULL;
+            switch (event) {
+            case MP_EVENT_TICK:             name = "tick"; break;
+            case MP_EVENT_TRACKS_CHANGED:   name = "track-layout"; break;
+            case MP_EVENT_START_FILE:       name = "start"; break;
+            case MP_EVENT_END_FILE:         name = "end"; break;
+            default: ;
+            }
+            if (name)
+                handle_script_event(mpctx, name, "");
+        }
+    }
+}