From 5d6987210578f5f1c3151988b99a9411f9603374 Mon Sep 17 00:00:00 2001
From: bfredl <bjorn.linse@gmail.com>
Date: Wed, 8 Jun 2022 22:02:02 +0200
Subject: perf(ui): reduce allocation overhead when encoding "redraw" events

Note for external UIs: Nvim can now emit multiple "redraw" event batches
before a final "flush" event is received. To retain existing behavior,
clients should make sure to update visible state at an explicit "flush"
event, not just the end of a "redraw" batch of event.

* Get rid of copy_object() blizzard in the auto-generated ui_event layer
* Special case "grid_line" by encoding screen state directly to
  msgpack events with no intermediate API events.
* Get rid of the arcane notion of referring to the screen as the "shell"
* Array and Dictionary are kvec_t:s, so define them as such.
* Allow kvec_t:s, such as Arrays and Dictionaries, to be allocated with
  a predetermined size within an arena.
* Eliminate redundant capacity checking when filling such kvec_t:s
  with values.
---
 src/nvim/api/private/defs.h    | 15 ++++-----------
 src/nvim/api/private/helpers.c | 26 ++++++++++++++++++++++++++
 src/nvim/api/private/helpers.h | 14 ++++++++++++++
 3 files changed, 44 insertions(+), 11 deletions(-)

(limited to 'src/nvim/api/private')

diff --git a/src/nvim/api/private/defs.h b/src/nvim/api/private/defs.h
index 396fab721d..b1e0dd364c 100644
--- a/src/nvim/api/private/defs.h
+++ b/src/nvim/api/private/defs.h
@@ -6,9 +6,10 @@
 #include <string.h>
 
 #include "nvim/func_attr.h"
+#include "nvim/lib/kvec.h"
 #include "nvim/types.h"
 
-#define ARRAY_DICT_INIT { .size = 0, .capacity = 0, .items = NULL }
+#define ARRAY_DICT_INIT KV_INITIAL_VALUE
 #define STRING_INIT { .data = NULL, .size = 0 }
 #define OBJECT_INIT { .type = kObjectTypeNil }
 #define ERROR_INIT { .type = kErrorTypeNone, .msg = NULL }
@@ -84,18 +85,10 @@ REMOTE_TYPE(Window);
 REMOTE_TYPE(Tabpage);
 
 typedef struct object Object;
-
-typedef struct {
-  Object *items;
-  size_t size, capacity;
-} Array;
+typedef kvec_t(Object) Array;
 
 typedef struct key_value_pair KeyValuePair;
-
-typedef struct {
-  KeyValuePair *items;
-  size_t size, capacity;
-} Dictionary;
+typedef kvec_t(KeyValuePair) Dictionary;
 
 typedef enum {
   kObjectTypeNil = 0,
diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index ff6a4c37e8..693d946088 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -669,6 +669,32 @@ void api_free_string(String value)
   xfree(value.data);
 }
 
+Array arena_array(Arena *arena, size_t max_size)
+{
+  Array arr = ARRAY_DICT_INIT;
+  kv_fixsize_arena(arena, arr, max_size);
+  return arr;
+}
+
+Dictionary arena_dict(Arena *arena, size_t max_size)
+{
+  Dictionary dict = ARRAY_DICT_INIT;
+  kv_fixsize_arena(arena, dict, max_size);
+  return dict;
+}
+
+String arena_string(Arena *arena, String str)
+{
+  if (str.size) {
+    char *mem = arena_alloc(arena, str.size + 1, false);
+    memcpy(mem, str.data, str.size);
+    mem[str.size] = NUL;
+    return cbuf_as_string(mem, str.size);
+  } else {
+    return (String)STRING_INIT;
+  }
+}
+
 void api_free_object(Object value)
 {
   switch (value.type) {
diff --git a/src/nvim/api/private/helpers.h b/src/nvim/api/private/helpers.h
index 8423db4970..a4348d8b44 100644
--- a/src/nvim/api/private/helpers.h
+++ b/src/nvim/api/private/helpers.h
@@ -63,17 +63,31 @@
 #define PUT(dict, k, v) \
   kv_push(dict, ((KeyValuePair) { .key = cstr_to_string(k), .value = v }))
 
+#define PUT_C(dict, k, v) \
+  kv_push_c(dict, ((KeyValuePair) { .key = cstr_as_string(k), .value = v }))
+
 #define PUT_BOOL(dict, name, condition) PUT(dict, name, BOOLEAN_OBJ(condition));
 
 #define ADD(array, item) \
   kv_push(array, item)
 
+#define ADD_C(array, item) \
+  kv_push_c(array, item)
+
 #define FIXED_TEMP_ARRAY(name, fixsize) \
   Array name = ARRAY_DICT_INIT; \
   Object name##__items[fixsize]; \
   name.size = fixsize; \
   name.items = name##__items; \
 
+#define MAXSIZE_TEMP_ARRAY(name, maxsize) \
+  Array name = ARRAY_DICT_INIT; \
+  Object name##__items[maxsize]; \
+  name.capacity = maxsize; \
+  name.items = name##__items; \
+
+#define cbuf_as_string(d, s) ((String) { .data = d, .size = s })
+
 #define STATIC_CSTR_AS_STRING(s) ((String) { .data = s, .size = sizeof(s) - 1 })
 
 /// Create a new String instance, putting data in allocated memory
-- 
cgit