player: add a --loop-file option

Unlike --loop, loops a file instead of the playlist.

DOCS/man/en/options.rst

@@ -1331,6 +1331,12 @@ OPTIONS
     disables looping. If several files are specified on command line, the
     entire playlist is looped.
 
+``--loop-file``
+    Loop a single file. The difference to ``--loop=inf`` is that this doesn't
+    loop the playlist, just the file itself. If the playlist contains only a
+    single file, the difference between the two option is that this option
+    performs a seek on loop, instead of reloading the file.
+
 ``--lua=<filename>``
     Load a Lua script. You can load multiple scripts by separating them with
     commas (``,``).

options/options.c

@@ -560,6 +560,7 @@ const m_option_t mp_opts[] = {
     OPT_CHOICE_OR_INT("loop", loop_times, M_OPT_GLOBAL, 2, 10000,
                       ({"no", -1}, {"1", -1},
                        {"inf", 0})),
+    OPT_FLAG("loop-file", loop_file, 0),
 
     OPT_FLAG("resume-playback", position_resume, 0),
     OPT_FLAG("save-position-on-quit", position_save_on_quit, 0),

options/options.h

@@ -100,6 +100,7 @@ typedef struct MPOpts {
     char *stream_capture;
     char *stream_dump;
     int loop_times;
+    int loop_file;
     int shuffle;
     int ordered_chapters;
     char *ordered_chapters_files;

player/command.c

@@ -2205,6 +2205,7 @@ static const m_option_t mp_properties[] = {
     M_OPTION_PROPERTY("osd-level"),
     M_OPTION_PROPERTY_CUSTOM("osd-scale", property_osd_helper),
     M_OPTION_PROPERTY("loop"),
+    M_OPTION_PROPERTY("loop-file"),
     M_OPTION_PROPERTY_CUSTOM("speed", mp_property_playback_speed),
     { "filename", mp_property_filename, CONF_TYPE_STRING,
       0, 0, 0, NULL },

player/playloop.c

@@ -825,6 +825,15 @@ static void handle_sstep(struct MPContext *mpctx)
     }
 }
 
+static void handle_loop_file(struct MPContext *mpctx)
+{
+    struct MPOpts *opts = mpctx->opts;
+    if (opts->loop_file && mpctx->stop_play == AT_END_OF_FILE) {
+        set_osd_function(mpctx, OSD_FFW);
+        queue_seek(mpctx, MPSEEK_ABSOLUTE, get_start_time(mpctx), 0, true);
+    }
+}
+
 static void handle_keep_open(struct MPContext *mpctx)
 {
     struct MPOpts *opts = mpctx->opts;
@@ -1282,6 +1291,8 @@ void run_playloop(struct MPContext *mpctx)
 
     handle_sstep(mpctx);
 
+    handle_loop_file(mpctx);
+
     handle_keep_open(mpctx);
 
     handle_force_window(mpctx, false);