Reduce unnecessary COW on Vector by make writing explicit

This commit makes operator[] on Vector const and adds a write proxy to it.  From
now on writes to Vectors need to happen through the .write proxy. So for
instance:

Vector<int> vec;
vec.push_back(10);
std::cout << vec[0] << std::endl;
vec.write[0] = 20;

Failing to use the .write proxy will cause a compilation error.

In addition COWable datatypes can now embed a CowData pointer to their data.
This means that String, CharString, and VMap no longer use or derive from
Vector.

_ALWAYS_INLINE_ and _FORCE_INLINE_ are now equivalent for debug and non-debug
builds. This is a lot faster for Vector in the editor and while running tests.
The reason why this difference used to exist is because force-inlined methods
used to give a bad debugging experience. After extensive testing with modern
compilers this is no longer the case.

1 files changed, 3 insertions, 3 deletions

diff --git a/scene/animation/animation_player.cpp b/scene/animation/animation_player.cpp
index 111620dac1..b6988c08db 100644
--- a/scene/animation/animation_player.cpp
+++ b/scene/animation/animation_player.cpp
@@ -233,7 +233,7 @@ void AnimationPlayer::_ensure_node_caches(AnimationData *p_anim) {
 
 	for (int i = 0; i < a->get_track_count(); i++) {
 
-		p_anim->node_cache[i] = NULL;
+		p_anim->node_cache.write[i] = NULL;
 		RES resource;
 		Vector<StringName> leftover_path;
 		Node *child = parent->get_node_and_resource(a->track_get_path(i), resource, leftover_path);
@@ -265,12 +265,12 @@ void AnimationPlayer::_ensure_node_caches(AnimationData *p_anim) {
 
 		if (node_cache_map.has(key)) {
 
-			p_anim->node_cache[i] = &node_cache_map[key];
+			p_anim->node_cache.write[i] = &node_cache_map[key];
 		} else {
 
 			node_cache_map[key] = TrackNodeCache();
 
-			p_anim->node_cache[i] = &node_cache_map[key];
+			p_anim->node_cache.write[i] = &node_cache_map[key];
 			p_anim->node_cache[i]->path = a->track_get_path(i);
 			p_anim->node_cache[i]->node = child;
 			p_anim->node_cache[i]->resource = resource;