sub: uglify OSD code path with locking

Do two things:
1. add locking to struct osd_state
2. make struct osd_state opaque

While 1. is somewhat simple, 2. is quite horrible. Lots of code accesses
lots of osd_state (and osd_object) members. To make sure everything is
accessed synchronously, I prefer making osd_state opaque, even if it
means adding pretty dumb accessors.

All of this is meant to allow running VO in their own threads.
Eventually, VOs will request OSD on their own, which means osd_state
will be accessed from foreign threads.

1 files changed, 34 insertions, 24 deletions

diff --git a/player/command.c b/player/command.c
index 2334e844b4..bb0e9789cf 100644
--- a/player/command.c
+++ b/player/command.c
@@ -87,6 +87,7 @@ struct command_ctx {
 
 #define OVERLAY_MAX_ID 64
     void *overlay_map[OVERLAY_MAX_ID];
+    struct sub_bitmaps external2;
 };
 
 static int edit_filters(struct MPContext *mpctx, enum stream_type mediatype,
@@ -1573,20 +1574,22 @@ static int mp_property_window_scale(m_option_t *prop, int action, void *arg,
 static int mp_property_osd_w(m_option_t *prop, int action, void *arg,
                              MPContext *mpctx)
 {
-    return m_property_int_ro(prop, action, arg, mpctx->osd->last_vo_res.w);
+    struct mp_osd_res vo_res = osd_get_vo_res(mpctx->osd, OSDTYPE_OSD);
+    return m_property_int_ro(prop, action, arg, vo_res.w);
 }
 
 static int mp_property_osd_h(m_option_t *prop, int action, void *arg,
                              MPContext *mpctx)
 {
-    return m_property_int_ro(prop, action, arg, mpctx->osd->last_vo_res.w);
+    struct mp_osd_res vo_res = osd_get_vo_res(mpctx->osd, OSDTYPE_OSD);
+    return m_property_int_ro(prop, action, arg, vo_res.w);
 }
 
 static int mp_property_osd_par(m_option_t *prop, int action, void *arg,
                                MPContext *mpctx)
 {
-    return m_property_double_ro(prop, action, arg,
-                                mpctx->osd->last_vo_res.display_par);
+    struct mp_osd_res vo_res = osd_get_vo_res(mpctx->osd, OSDTYPE_OSD);
+    return m_property_double_ro(prop, action, arg, vo_res.display_par);
 }
 
 /// Video fps (RO)
@@ -2348,7 +2351,7 @@ static int edit_filters_osd(struct MPContext *mpctx, enum stream_type mediatype,
 static int ext2_sub_find(struct MPContext *mpctx, int id)
 {
     struct command_ctx *cmd = mpctx->command_ctx;
-    struct sub_bitmaps *sub = &mpctx->osd->external2;
+    struct sub_bitmaps *sub = &cmd->external2;
     void *p = NULL;
     if (id >= 0 && id < OVERLAY_MAX_ID)
         p = cmd->overlay_map[id];
@@ -2363,10 +2366,10 @@ static int ext2_sub_find(struct MPContext *mpctx, int id)
 
 static int ext2_sub_alloc(struct MPContext *mpctx)
 {
-    struct osd_state *osd = mpctx->osd;
-    struct sub_bitmaps *sub = &osd->external2;
+    struct command_ctx *cmd = mpctx->command_ctx;
+    struct sub_bitmaps *sub = &cmd->external2;
     struct sub_bitmap b = {0};
-    MP_TARRAY_APPEND(osd, sub->parts, sub->num_parts, b);
+    MP_TARRAY_APPEND(cmd, sub->parts, sub->num_parts, b);
     return sub->num_parts - 1;
 }
 
@@ -2375,14 +2378,16 @@ static int overlay_add(struct MPContext *mpctx, int id, int x, int y,
                        int stride)
 {
     struct command_ctx *cmd = mpctx->command_ctx;
-    struct osd_state *osd = mpctx->osd;
+    int r = -1;
+    // Temporarily unmap them to avoid race condition with concurrent access.
+    osd_set_external2(mpctx->osd, NULL);
     if (strcmp(fmt, "bgra") != 0) {
         MP_ERR(mpctx, "overlay_add: unsupported OSD format '%s'\n", fmt);
-        return -1;
+        goto error;
     }
     if (id < 0 || id >= OVERLAY_MAX_ID) {
         MP_ERR(mpctx, "overlay_add: invalid id %d\n", id);
-        return -1;
+        goto error;
     }
     int fd = -1;
     bool close_fd = true;
@@ -2400,48 +2405,52 @@ static int overlay_add(struct MPContext *mpctx, int id, int x, int y,
         close(fd);
     if (!p) {
         MP_ERR(mpctx, "overlay_add: could not open or map '%s'\n", file);
-        return -1;
+        goto error;
     }
     int index = ext2_sub_find(mpctx, id);
     if (index < 0)
         index = ext2_sub_alloc(mpctx);
     if (index < 0) {
         munmap(p, h * stride);
-        return -1;
+        goto error;
     }
     cmd->overlay_map[id] = p;
-    osd->external2.parts[index] = (struct sub_bitmap) {
+    cmd->external2.parts[index] = (struct sub_bitmap) {
         .bitmap = p,
         .stride = stride,
         .x = x, .y = y,
         .w = w, .h = h,
         .dw = w, .dh = h,
     };
-    osd->external2.bitmap_id = osd->external2.bitmap_pos_id = 1;
-    osd->external2.format = SUBBITMAP_RGBA;
-    osd->want_redraw = true;
-    return 0;
+    cmd->external2.bitmap_id = cmd->external2.bitmap_pos_id = 1;
+    cmd->external2.format = SUBBITMAP_RGBA;
+    r = 0;
+error:
+    osd_set_external2(mpctx->osd, &cmd->external2);
+    return r;
 }
 
 static void overlay_remove(struct MPContext *mpctx, int id)
 {
     struct command_ctx *cmd = mpctx->command_ctx;
-    struct osd_state *osd = mpctx->osd;
+    osd_set_external2(mpctx->osd, NULL);
     int index = ext2_sub_find(mpctx, id);
     if (index >= 0) {
-        struct sub_bitmaps *sub = &osd->external2;
+        struct sub_bitmaps *sub = &cmd->external2;
         struct sub_bitmap *part = &sub->parts[index];
         munmap(part->bitmap, part->h * part->stride);
         MP_TARRAY_REMOVE_AT(sub->parts, sub->num_parts, index);
         cmd->overlay_map[id] = NULL;
         sub->bitmap_id = sub->bitmap_pos_id = 1;
     }
+    osd_set_external2(mpctx->osd, &cmd->external2);
 }
 
 static void overlay_uninit(struct MPContext *mpctx)
 {
     for (int id = 0; id < OVERLAY_MAX_ID; id++)
         overlay_remove(mpctx, id);
+    osd_set_external2(mpctx->osd, NULL);
 }
 
 #else
@@ -2739,12 +2748,13 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
 
     case MP_CMD_SUB_STEP:
     case MP_CMD_SUB_SEEK: {
-        struct osd_object *obj = mpctx->osd->objs[OSDTYPE_SUB];
-        if (obj->dec_sub) {
+        struct osd_sub_state state;
+        osd_get_sub(mpctx->osd, OSDTYPE_SUB, &state);
+        if (state.dec_sub) {
             double a[2];
-            a[0] = mpctx->video_pts - obj->video_offset - opts->sub_delay;
+            a[0] = mpctx->video_pts - state.video_offset - opts->sub_delay;
             a[1] = cmd->args[0].v.i;
-            if (sub_control(obj->dec_sub, SD_CTRL_SUB_STEP, a) > 0) {
+            if (sub_control(state.dec_sub, SD_CTRL_SUB_STEP, a) > 0) {
                 if (cmd->id == MP_CMD_SUB_STEP) {
                     opts->sub_delay -= a[0];
                     osd_changed_all(mpctx->osd);