mplayer: fix idle mode regressions

Commit 89a17bcda6c16 simplified the idle loop to run any commands
mplayer receives, not just playlist related commands. Unfortunately, it
turns out many slave commands always assume the presence of a demuxer.
MPContext->demuxer is assumed not to be NULL. This made the player
crash when receiving slave commands like pause/unpause, chapter
control, subtitle selection.

We want mplayer being able to handle this. Any slave command or
property, as long as it's backed by a persistent setting, should be run
successfully, even if no file is being played. If the slave command
doesn't make sense in this state, it shouldn't crash the player.

Insert some NULL checks when accessing demuxers. If sh_video or
sh_audio are not NULL, assume demuxer can't be NULL.

(There actually aren't that many properties which need to be changed. If
it gets too complicated, we could employ alternative mechanisms instead,
such as explicitly marking safe properties with a flag.)

1 files changed, 24 insertions, 13 deletions

diff --git a/command.c b/command.c
index 8fad64170e..bf3acba5c6 100644
--- a/command.c
+++ b/command.c
@@ -155,6 +155,12 @@ static void update_global_sub_size(MPContext *mpctx)
     int i;
     int cnt = 0;
 
+    if (!mpctx->demuxer) {
+        mpctx->global_sub_size = -1;
+        mpctx->global_sub_pos = -1;
+        return;
+    }
+
     // update number of demuxer sub streams
     for (i = 0; i < MAX_S_STREAMS; i++)
         if (mpctx->d_sub->demuxer->s_streams[i])
@@ -1042,6 +1048,9 @@ static int mp_property_program(m_option_t *prop, int action, void *arg,
 {
     demux_program_t prog;
 
+    if (!mpctx->demuxer)
+        return M_PROPERTY_UNAVAILABLE;
+
     switch (action) {
     case M_PROPERTY_STEP_UP:
     case M_PROPERTY_SET:
@@ -2041,6 +2050,8 @@ static int mp_property_tv_color(m_option_t *prop, int action, void *arg,
                                 MPContext *mpctx)
 {
     int r, val;
+    if (!mpctx->demuxer)
+        return M_PROPERTY_UNAVAILABLE;
     tvi_handle_t *tvh = mpctx->demuxer->priv;
     if (mpctx->demuxer->type != DEMUXER_TYPE_TV || !tvh)
         return M_PROPERTY_UNAVAILABLE;
@@ -3005,7 +3016,7 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
 
 #ifdef CONFIG_RADIO
     case MP_CMD_RADIO_STEP_CHANNEL:
-        if (mpctx->demuxer->stream->type == STREAMTYPE_RADIO) {
+        if (mpctx->demuxer && mpctx->demuxer->stream->type == STREAMTYPE_RADIO) {
             int v = cmd->args[0].v.i;
             if (v > 0)
                 radio_step_channel(mpctx->demuxer->stream,
@@ -3022,7 +3033,7 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
         break;
 
     case MP_CMD_RADIO_SET_CHANNEL:
-        if (mpctx->demuxer->stream->type == STREAMTYPE_RADIO) {
+        if (mpctx->demuxer && mpctx->demuxer->stream->type == STREAMTYPE_RADIO) {
             radio_set_channel(mpctx->demuxer->stream, cmd->args[0].v.s);
             if (radio_get_channel_name(mpctx->demuxer->stream)) {
                 set_osd_tmsg(OSD_MSG_RADIO_CHANNEL, 1, osd_duration,
@@ -3033,23 +3044,23 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
         break;
 
     case MP_CMD_RADIO_SET_FREQ:
-        if (mpctx->demuxer->stream->type == STREAMTYPE_RADIO)
+        if (mpctx->demuxer && mpctx->demuxer->stream->type == STREAMTYPE_RADIO)
             radio_set_freq(mpctx->demuxer->stream, cmd->args[0].v.f);
         break;
 
     case MP_CMD_RADIO_STEP_FREQ:
-        if (mpctx->demuxer->stream->type == STREAMTYPE_RADIO)
+        if (mpctx->demuxer && mpctx->demuxer->stream->type == STREAMTYPE_RADIO)
             radio_step_freq(mpctx->demuxer->stream, cmd->args[0].v.f);
         break;
 #endif
 
 #ifdef CONFIG_TV
     case MP_CMD_TV_START_SCAN:
-        if (mpctx->file_format == DEMUXER_TYPE_TV)
+        if (mpctx->demuxer && mpctx->file_format == DEMUXER_TYPE_TV)
             tv_start_scan((tvi_handle_t *) (mpctx->demuxer->priv), 1);
         break;
     case MP_CMD_TV_SET_FREQ:
-        if (mpctx->file_format == DEMUXER_TYPE_TV)
+        if (mpctx->demuxer && mpctx->file_format == DEMUXER_TYPE_TV)
             tv_set_freq((tvi_handle_t *) (mpctx->demuxer->priv),
                         cmd->args[0].v.f * 16.0);
 #ifdef CONFIG_PVR
@@ -3063,7 +3074,7 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
         break;
 
     case MP_CMD_TV_STEP_FREQ:
-        if (mpctx->file_format == DEMUXER_TYPE_TV)
+        if (mpctx->demuxer && mpctx->file_format == DEMUXER_TYPE_TV)
             tv_step_freq((tvi_handle_t *) (mpctx->demuxer->priv),
                          cmd->args[0].v.f * 16.0);
 #ifdef CONFIG_PVR
@@ -3077,13 +3088,13 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
         break;
 
     case MP_CMD_TV_SET_NORM:
-        if (mpctx->file_format == DEMUXER_TYPE_TV)
+        if (mpctx->demuxer && mpctx->file_format == DEMUXER_TYPE_TV)
             tv_set_norm((tvi_handle_t *) (mpctx->demuxer->priv),
                         cmd->args[0].v.s);
         break;
 
     case MP_CMD_TV_STEP_CHANNEL:
-        if (mpctx->file_format == DEMUXER_TYPE_TV) {
+        if (mpctx->demuxer && mpctx->file_format == DEMUXER_TYPE_TV) {
             int v = cmd->args[0].v.i;
             if (v > 0) {
                 tv_step_channel((tvi_handle_t *) (mpctx->
@@ -3130,7 +3141,7 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
         break;
 
     case MP_CMD_TV_SET_CHANNEL:
-        if (mpctx->file_format == DEMUXER_TYPE_TV) {
+        if (mpctx->demuxer && mpctx->file_format == DEMUXER_TYPE_TV) {
             tv_set_channel((tvi_handle_t *) (mpctx->demuxer->priv),
                            cmd->args[0].v.s);
             if (tv_channel_list) {
@@ -3164,7 +3175,7 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
 #endif /* CONFIG_DVBIN */
 
     case MP_CMD_TV_LAST_CHANNEL:
-        if (mpctx->file_format == DEMUXER_TYPE_TV) {
+        if (mpctx->demuxer && mpctx->file_format == DEMUXER_TYPE_TV) {
             tv_last_channel((tvi_handle_t *) (mpctx->demuxer->priv));
             if (tv_channel_list) {
                 set_osd_tmsg(OSD_MSG_TV_CHANNEL, 1, osd_duration,
@@ -3183,12 +3194,12 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
         break;
 
     case MP_CMD_TV_STEP_NORM:
-        if (mpctx->file_format == DEMUXER_TYPE_TV)
+        if (mpctx->demuxer && mpctx->file_format == DEMUXER_TYPE_TV)
             tv_step_norm((tvi_handle_t *) (mpctx->demuxer->priv));
         break;
 
     case MP_CMD_TV_STEP_CHANNEL_LIST:
-        if (mpctx->file_format == DEMUXER_TYPE_TV)
+        if (mpctx->demuxer && mpctx->file_format == DEMUXER_TYPE_TV)
             tv_step_chanlist((tvi_handle_t *) (mpctx->demuxer->priv));
         break;
 #endif /* CONFIG_TV */