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.

5 files changed, 24 insertions, 24 deletions

diff --git a/servers/physics_2d/body_2d_sw.h b/servers/physics_2d/body_2d_sw.h
index 7fe805b1f9..fef233a72b 100644
--- a/servers/physics_2d/body_2d_sw.h
+++ b/servers/physics_2d/body_2d_sw.h
@@ -141,7 +141,7 @@ public:
 	_FORCE_INLINE_ void add_area(Area2DSW *p_area) {
 		int index = areas.find(AreaCMP(p_area));
 		if (index > -1) {
-			areas[index].refCount += 1;
+			areas.write[index].refCount += 1;
 		} else {
 			areas.ordered_insert(AreaCMP(p_area));
 		}
@@ -150,7 +150,7 @@ public:
 	_FORCE_INLINE_ void remove_area(Area2DSW *p_area) {
 		int index = areas.find(AreaCMP(p_area));
 		if (index > -1) {
-			areas[index].refCount -= 1;
+			areas.write[index].refCount -= 1;
 			if (areas[index].refCount < 1)
 				areas.remove(index);
 		}
@@ -311,7 +311,7 @@ void Body2DSW::add_contact(const Vector2 &p_local_pos, const Vector2 &p_local_no
 	if (c_max == 0)
 		return;
 
-	Contact *c = &contacts[0];
+	Contact *c = contacts.ptrw();
 
 	int idx = -1;
 
diff --git a/servers/physics_2d/collision_object_2d_sw.cpp b/servers/physics_2d/collision_object_2d_sw.cpp
index 23084a4241..4dd5b2040f 100644
--- a/servers/physics_2d/collision_object_2d_sw.cpp
+++ b/servers/physics_2d/collision_object_2d_sw.cpp
@@ -50,7 +50,7 @@ void CollisionObject2DSW::set_shape(int p_index, Shape2DSW *p_shape) {
 
 	ERR_FAIL_INDEX(p_index, shapes.size());
 	shapes[p_index].shape->remove_owner(this);
-	shapes[p_index].shape = p_shape;
+	shapes.write[p_index].shape = p_shape;
 
 	p_shape->add_owner(this);
 	_update_shapes();
@@ -60,15 +60,15 @@ void CollisionObject2DSW::set_shape(int p_index, Shape2DSW *p_shape) {
 void CollisionObject2DSW::set_shape_metadata(int p_index, const Variant &p_metadata) {
 
 	ERR_FAIL_INDEX(p_index, shapes.size());
-	shapes[p_index].metadata = p_metadata;
+	shapes.write[p_index].metadata = p_metadata;
 }
 
 void CollisionObject2DSW::set_shape_transform(int p_index, const Transform2D &p_transform) {
 
 	ERR_FAIL_INDEX(p_index, shapes.size());
 
-	shapes[p_index].xform = p_transform;
-	shapes[p_index].xform_inv = p_transform.affine_inverse();
+	shapes.write[p_index].xform = p_transform;
+	shapes.write[p_index].xform_inv = p_transform.affine_inverse();
 	_update_shapes();
 	_shapes_changed();
 }
@@ -76,7 +76,7 @@ void CollisionObject2DSW::set_shape_transform(int p_index, const Transform2D &p_
 void CollisionObject2DSW::set_shape_as_disabled(int p_idx, bool p_disabled) {
 	ERR_FAIL_INDEX(p_idx, shapes.size());
 
-	CollisionObject2DSW::Shape &shape = shapes[p_idx];
+	CollisionObject2DSW::Shape &shape = shapes.write[p_idx];
 	if (shape.disabled == p_disabled)
 		return;
 
@@ -116,7 +116,7 @@ void CollisionObject2DSW::remove_shape(int p_index) {
 			continue;
 		//should never get here with a null owner
 		space->get_broadphase()->remove(shapes[i].bpid);
-		shapes[i].bpid = 0;
+		shapes.write[i].bpid = 0;
 	}
 	shapes[p_index].shape->remove_owner(this);
 	shapes.remove(p_index);
@@ -133,7 +133,7 @@ void CollisionObject2DSW::_set_static(bool p_static) {
 	if (!space)
 		return;
 	for (int i = 0; i < get_shape_count(); i++) {
-		Shape &s = shapes[i];
+		const Shape &s = shapes[i];
 		if (s.bpid > 0) {
 			space->get_broadphase()->set_static(s.bpid, _static);
 		}
@@ -144,7 +144,7 @@ void CollisionObject2DSW::_unregister_shapes() {
 
 	for (int i = 0; i < shapes.size(); i++) {
 
-		Shape &s = shapes[i];
+		Shape &s = shapes.write[i];
 		if (s.bpid > 0) {
 			space->get_broadphase()->remove(s.bpid);
 			s.bpid = 0;
@@ -159,7 +159,7 @@ void CollisionObject2DSW::_update_shapes() {
 
 	for (int i = 0; i < shapes.size(); i++) {
 
-		Shape &s = shapes[i];
+		Shape &s = shapes.write[i];
 
 		if (s.disabled)
 			continue;
@@ -187,7 +187,7 @@ void CollisionObject2DSW::_update_shapes_with_motion(const Vector2 &p_motion) {
 
 	for (int i = 0; i < shapes.size(); i++) {
 
-		Shape &s = shapes[i];
+		Shape &s = shapes.write[i];
 		if (s.disabled)
 			continue;
 
@@ -215,7 +215,7 @@ void CollisionObject2DSW::_set_space(Space2DSW *p_space) {
 
 		for (int i = 0; i < shapes.size(); i++) {
 
-			Shape &s = shapes[i];
+			Shape &s = shapes.write[i];
 			if (s.bpid) {
 				space->get_broadphase()->remove(s.bpid);
 				s.bpid = 0;
diff --git a/servers/physics_2d/collision_object_2d_sw.h b/servers/physics_2d/collision_object_2d_sw.h
index ab3e219ac0..393c4a6ed7 100644
--- a/servers/physics_2d/collision_object_2d_sw.h
+++ b/servers/physics_2d/collision_object_2d_sw.h
@@ -144,7 +144,7 @@ public:
 
 	_FORCE_INLINE_ void set_shape_as_one_way_collision(int p_idx, bool p_one_way_collision) {
 		ERR_FAIL_INDEX(p_idx, shapes.size());
-		shapes[p_idx].one_way_collision = p_one_way_collision;
+		shapes.write[p_idx].one_way_collision = p_one_way_collision;
 	}
 	_FORCE_INLINE_ bool is_shape_set_as_one_way_collision(int p_idx) const {
 		ERR_FAIL_INDEX_V(p_idx, shapes.size(), false);
diff --git a/servers/physics_2d/shape_2d_sw.cpp b/servers/physics_2d/shape_2d_sw.cpp
index 2b0eab5999..dc8ec23e69 100644
--- a/servers/physics_2d/shape_2d_sw.cpp
+++ b/servers/physics_2d/shape_2d_sw.cpp
@@ -891,8 +891,8 @@ int ConcavePolygonShape2DSW::_generate_bvh(BVH *p_bvh, int p_len, int p_depth) {
 
 	int l = _generate_bvh(p_bvh, median, p_depth + 1);
 	int r = _generate_bvh(&p_bvh[median], p_len - median, p_depth + 1);
-	bvh[node_idx].left = l;
-	bvh[node_idx].right = r;
+	bvh.write[node_idx].left = l;
+	bvh.write[node_idx].right = r;
 
 	return node_idx;
 }
@@ -953,20 +953,20 @@ void ConcavePolygonShape2DSW::set_data(const Variant &p_data) {
 		for (Map<Point2, int>::Element *E = pointmap.front(); E; E = E->next()) {
 
 			aabb.expand_to(E->key());
-			points[E->get()] = E->key();
+			points.write[E->get()] = E->key();
 		}
 
 		Vector<BVH> main_vbh;
 		main_vbh.resize(segments.size());
 		for (int i = 0; i < main_vbh.size(); i++) {
 
-			main_vbh[i].aabb.position = points[segments[i].points[0]];
-			main_vbh[i].aabb.expand_to(points[segments[i].points[1]]);
-			main_vbh[i].left = -1;
-			main_vbh[i].right = i;
+			main_vbh.write[i].aabb.position = points[segments[i].points[0]];
+			main_vbh.write[i].aabb.expand_to(points[segments[i].points[1]]);
+			main_vbh.write[i].left = -1;
+			main_vbh.write[i].right = i;
 		}
 
-		_generate_bvh(&main_vbh[0], main_vbh.size(), 1);
+		_generate_bvh(main_vbh.ptrw(), main_vbh.size(), 1);
 
 	} else {
 		//dictionary with arrays
diff --git a/servers/physics_2d/space_2d_sw.h b/servers/physics_2d/space_2d_sw.h
index 959e15e12d..1247317b03 100644
--- a/servers/physics_2d/space_2d_sw.h
+++ b/servers/physics_2d/space_2d_sw.h
@@ -188,7 +188,7 @@ public:
 	void set_debug_contacts(int p_amount) { contact_debug.resize(p_amount); }
 	_FORCE_INLINE_ bool is_debugging_contacts() const { return !contact_debug.empty(); }
 	_FORCE_INLINE_ void add_debug_contact(const Vector2 &p_contact) {
-		if (contact_debug_count < contact_debug.size()) contact_debug[contact_debug_count++] = p_contact;
+		if (contact_debug_count < contact_debug.size()) contact_debug.write[contact_debug_count++] = p_contact;
 	}
 	_FORCE_INLINE_ Vector<Vector2> get_debug_contacts() { return contact_debug; }
 	_FORCE_INLINE_ int get_debug_contact_count() { return contact_debug_count; }