player: use better way to wait for input and dispatching commands

Instead of using input_ctx for waiting, use the dispatch queue directly.
One big change is that the dispatch queue will just process commands
that come in (e.g. from client API) without returning. This should
reduce unnecessary playloop excutions (which is good since the playloop
got a bit fat from rechecking a lot of conditions every iteration).

Since this doesn't force a new playloop iteration on every access, this
has to be enforced manually in some cases.

Normal input (via terminal or VO window) still wakes up the playloop
every time, though that's not too important. It makes testing this
harder, though. If there are missing wakeup calls, it will be noticed
only when using the client API in some form.

At this point we could probably use a normal lock instead of the
dispatch queue stuff.

2 files changed, 19 insertions, 34 deletions

diff --git a/input/input.c b/input/input.c
index f820b8b174..90cd439779 100644
--- a/input/input.c
+++ b/input/input.c
@@ -22,6 +22,7 @@
 #include <stdio.h>
 #include <stdbool.h>
 #include <unistd.h>
+#include <math.h>
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -34,7 +35,6 @@
 #include <libavutil/common.h>
 
 #include "osdep/io.h"
-#include "osdep/semaphore.h"
 #include "misc/rendezvous.h"
 
 #include "input.h"
@@ -96,7 +96,6 @@ struct cmd_queue {
 
 struct input_ctx {
     pthread_mutex_t mutex;
-    sem_t wakeup;
     struct mp_log *log;
     struct mpv_global *global;
     struct m_config_cache *opts_cache;
@@ -147,6 +146,9 @@ struct input_ctx {
     struct cmd_queue cmd_queue;
 
     struct mp_cancel *cancel;
+
+    void (*wakeup_cb)(void *ctx);
+    void *wakeup_ctx;
 };
 
 static int parse_config(struct input_ctx *ictx, bool builtin, bstr data,
@@ -846,33 +848,18 @@ static mp_cmd_t *check_autorepeat(struct input_ctx *ictx)
     return NULL;
 }
 
-void mp_input_wait(struct input_ctx *ictx, double seconds)
+double mp_input_get_delay(struct input_ctx *ictx)
 {
     input_lock(ictx);
+    double seconds = INFINITY;
     adjust_max_wait_time(ictx, &seconds);
     input_unlock(ictx);
-    while (sem_trywait(&ictx->wakeup) == 0)
-        seconds = -1;
-    if (seconds > 0) {
-        MP_STATS(ictx, "start sleep");
-        struct timespec ts =
-            mp_time_us_to_timespec(mp_add_timeout(mp_time_us(), seconds));
-        sem_timedwait(&ictx->wakeup, &ts);
-        MP_STATS(ictx, "end sleep");
-    }
-}
-
-void mp_input_wakeup_nolock(struct input_ctx *ictx)
-{
-    // Some audio APIs discourage use of locking in their audio callback,
-    // and these audio callbacks happen to call mp_input_wakeup_nolock()
-    // when new data is needed. This is why we use semaphores here.
-    sem_post(&ictx->wakeup);
+    return seconds;
 }
 
 void mp_input_wakeup(struct input_ctx *ictx)
 {
-    mp_input_wakeup_nolock(ictx);
+    ictx->wakeup_cb(ictx->wakeup_ctx);
 }
 
 mp_cmd_t *mp_input_read_cmd(struct input_ctx *ictx)
@@ -1196,7 +1183,9 @@ done:
     return r;
 }
 
-struct input_ctx *mp_input_init(struct mpv_global *global)
+struct input_ctx *mp_input_init(struct mpv_global *global,
+                                void (*wakeup_cb)(void *ctx),
+                                void *wakeup_ctx)
 {
 
     struct input_ctx *ictx = talloc_ptrtype(NULL, ictx);
@@ -1206,15 +1195,12 @@ struct input_ctx *mp_input_init(struct mpv_global *global)
         .log = mp_log_new(ictx, global->log, "input"),
         .mouse_section = "default",
         .opts_cache = m_config_cache_alloc(ictx, global, &input_config),
+        .wakeup_cb = wakeup_cb,
+        .wakeup_ctx = wakeup_ctx,
     };
 
     ictx->opts = ictx->opts_cache->opts;
 
-    if (sem_init(&ictx->wakeup, 0, 0)) {
-        MP_FATAL(ictx, "mpv doesn't work on systems without POSIX semaphores.\n");
-        abort();
-    }
-
     mpthread_mutex_init_recursive(&ictx->mutex);
 
     // Setup default section, so that it does nothing.
@@ -1308,7 +1294,6 @@ void mp_input_uninit(struct input_ctx *ictx)
     clear_queue(&ictx->cmd_queue);
     talloc_free(ictx->current_down_cmd);
     pthread_mutex_destroy(&ictx->mutex);
-    sem_destroy(&ictx->wakeup);
     talloc_free(ictx);
 }
 
diff --git a/input/input.h b/input/input.h
index a5710b6065..cc523efc62 100644
--- a/input/input.h
+++ b/input/input.h
@@ -219,22 +219,22 @@ bool mp_input_test_dragging(struct input_ctx *ictx, int x, int y);
 
 // Initialize the input system
 struct mpv_global;
-struct input_ctx *mp_input_init(struct mpv_global *global);
+struct input_ctx *mp_input_init(struct mpv_global *global,
+                                void (*wakeup_cb)(void *ctx),
+                                void *wakeup_ctx);
 
 // Load config, options, and devices.
 void mp_input_load(struct input_ctx *ictx);
 
 void mp_input_uninit(struct input_ctx *ictx);
 
-// Sleep for the given amount of seconds, until mp_input_wakeup() is called,
-// or new input arrives. seconds<=0 returns immediately.
-void mp_input_wait(struct input_ctx *ictx, double seconds);
+// Return number of seconds until the next autorepeat event will be generated.
+// Returns INFINITY if no autorepeated key is active.
+double mp_input_get_delay(struct input_ctx *ictx);
 
 // Wake up sleeping input loop from another thread.
 void mp_input_wakeup(struct input_ctx *ictx);
 
-void mp_input_wakeup_nolock(struct input_ctx *ictx);
-
 // Used to asynchronously abort playback. Needed because the core still can
 // block on network in some situations.
 struct mp_cancel;