[Spice-devel] [PATCH 2/5] DisplayChannel: add documentation for Ring types

[Jonathon Jongsma]

The Surface and Display channels each have a 'current_list' Ring, and
Surface also has a 'current' Ring. these names are confusing, so at
minimum, add a comment indicating the type of object they hold. The
DisplayChannel::current_list already had a comment, but it was
incorrect.
---
 server/display-channel-private.h | 6 +++++-
 server/display-channel.h         | 6 ++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/server/display-channel-private.h b/server/display-channel-private.h
index afb28b6..a727ddb 100644
--- a/server/display-channel-private.h
+++ b/server/display-channel-private.h
@@ -41,7 +41,11 @@ struct DisplayChannelPrivate
     int enable_jpeg;
     int enable_zlib_glz_wrap;
 
-    Ring current_list; // of TreeItem
+    /* A ring of pending drawables for this DisplayChannel, regardless of which
+     * surface they're associated with. This list is mainly used to flush older
+     * drawables when we need to make room for new drawables.  The ring is
+     * maintained in order of age, the tail being the oldest drawable */
+    Ring current_list;
 
     uint32_t drawable_count;
     _Drawable drawables[NUM_DRAWABLES];
diff --git a/server/display-channel.h b/server/display-channel.h
index 497f911..5c14017 100644
--- a/server/display-channel.h
+++ b/server/display-channel.h
@@ -162,7 +162,13 @@ typedef struct DrawContext {
 
 typedef struct RedSurface {
     uint32_t refs;
+    /* A Ring representing a hierarchical tree structure. This tree includes
+     * DrawItems, Containers, and Shadows. It is used to efficiently determine
+     * which drawables overlap, and to exclude regions of drawables that are
+     * obscured by other drawables */
     Ring current;
+    /* A ring of pending Drawables associated with this surface. This ring is
+     * actually used for drawing */
     Ring current_list;
     DrawContext context;
 
-- 
2.9.3