refactor(extmarks): use a more efficient representation

marktree.c was originally constructed as a "generic" datatype,
to make the prototyping of its internal logic as simple as possible
and also as the usecases for various kinds of extmarks/decorations was not yet decided.
As a consequence of this, various extra indirections and allocations was
needed to use marktree to implement extmarks (ns/id pairs) and
decorations of different kinds (some which is just a single highlight
id, other an allocated list of virtual text/lines)

This change removes a lot of indirection, by making Marktree specialized
for the usecase. In particular, the namespace id and mark id is stored
directly, instead of the 64-bit global id particular to the Marktree
struct. This removes the two maps needed to convert between global and
per-ns ids.

Also, "small" decorations are stored inline, i.e. those who
doesn't refer to external heap memory anyway. That is highlights (with
priority+flags) are stored inline, while virtual text, which anyway
occurs a lot of heap allocations, do not. (previously a hack was used
to elide heap allocations for highlights with standard prio+flags)

TODO(bfredl): the functionaltest-lua CI version of gcc is having
severe issues with uint16_t bitfields, so splitting up compound
assignments and redundant casts are needed. Clean this up once we switch
to a working compiler version.

1 files changed, 1 insertions, 9 deletions

diff --git a/src/nvim/map.h b/src/nvim/map.h
index dbd85a4e1f..5e56f4dd65 100644
--- a/src/nvim/map.h
+++ b/src/nvim/map.h
@@ -40,16 +40,8 @@ MAP_DECLS(ptr_t, ptr_t)
 MAP_DECLS(uint64_t, ptr_t)
 MAP_DECLS(uint64_t, ssize_t)
 MAP_DECLS(uint64_t, uint64_t)
+MAP_DECLS(uint32_t, uint32_t)
 
-// NB: this is the only way to define a struct both containing and contained
-// in a map...
-typedef struct ExtmarkNs {  // For namespacing extmarks
-  Map(uint64_t, uint64_t) map[1];  // For fast lookup
-  uint64_t free_id;         // For automatically assigning id's
-} ExtmarkNs;
-
-MAP_DECLS(uint64_t, ExtmarkNs)
-MAP_DECLS(uint64_t, ExtmarkItem)
 MAP_DECLS(handle_T, ptr_t)
 MAP_DECLS(String, MsgpackRpcRequestHandler)
 MAP_DECLS(HlEntry, int)