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.

11 files changed, 55 insertions, 55 deletions

diff --git a/scene/2d/animated_sprite.cpp b/scene/2d/animated_sprite.cpp
index b56eedabc7..85e7f8df92 100644
--- a/scene/2d/animated_sprite.cpp
+++ b/scene/2d/animated_sprite.cpp
@@ -235,7 +235,7 @@ void SpriteFrames::_set_frames(const Array &p_frames) {
 
 	E->get().frames.resize(p_frames.size());
 	for (int i = 0; i < E->get().frames.size(); i++)
-		E->get().frames[i] = p_frames[i];
+		E->get().frames.write[i] = p_frames[i];
 }
 Array SpriteFrames::_get_frames() const {
 
diff --git a/scene/2d/animated_sprite.h b/scene/2d/animated_sprite.h
index f6586aff36..cc49465403 100644
--- a/scene/2d/animated_sprite.h
+++ b/scene/2d/animated_sprite.h
@@ -113,7 +113,7 @@ public:
 		ERR_FAIL_COND(p_idx < 0);
 		if (p_idx >= E->get().frames.size())
 			return;
-		E->get().frames[p_idx] = p_frame;
+		E->get().frames.write[p_idx] = p_frame;
 	}
 	void remove_frame(const StringName &p_anim, int p_idx);
 	void clear(const StringName &p_anim);
diff --git a/scene/2d/collision_object_2d.cpp b/scene/2d/collision_object_2d.cpp
index cabd7fddc2..1e2184bd41 100644
--- a/scene/2d/collision_object_2d.cpp
+++ b/scene/2d/collision_object_2d.cpp
@@ -259,7 +259,7 @@ void CollisionObject2D::shape_owner_remove_shape(uint32_t p_owner, int p_shape)
 	for (Map<uint32_t, ShapeData>::Element *E = shapes.front(); E; E = E->next()) {
 		for (int i = 0; i < E->get().shapes.size(); i++) {
 			if (E->get().shapes[i].index > index_to_remove) {
-				E->get().shapes[i].index -= 1;
+				E->get().shapes.write[i].index -= 1;
 			}
 		}
 	}
diff --git a/scene/2d/collision_polygon_2d.cpp b/scene/2d/collision_polygon_2d.cpp
index 9d2a83fda7..9f19f56e75 100644
--- a/scene/2d/collision_polygon_2d.cpp
+++ b/scene/2d/collision_polygon_2d.cpp
@@ -102,11 +102,11 @@ Vector<Vector<Vector2> > CollisionPolygon2D::_decompose_in_convex() {
 
 		TriangulatorPoly &tp = I->get();
 
-		decomp[idx].resize(tp.GetNumPoints());
+		decomp.write[idx].resize(tp.GetNumPoints());
 
 		for (int i = 0; i < tp.GetNumPoints(); i++) {
 
-			decomp[idx][i] = tp.GetPoint(i);
+			decomp.write[idx].write[i] = tp.GetPoint(i);
 		}
 
 		idx++;
diff --git a/scene/2d/line_2d.cpp b/scene/2d/line_2d.cpp
index e9e895b5bb..ad9775c0b7 100644
--- a/scene/2d/line_2d.cpp
+++ b/scene/2d/line_2d.cpp
@@ -239,7 +239,7 @@ void Line2D::_draw() {
 	{
 		PoolVector<Vector2>::Read points_read = _points.read();
 		for (int i = 0; i < len; ++i) {
-			points[i] = points_read[i];
+			points.write[i] = points_read[i];
 		}
 	}
 
diff --git a/scene/2d/navigation2d.cpp b/scene/2d/navigation2d.cpp
index 16e0386952..e3b048fd74 100644
--- a/scene/2d/navigation2d.cpp
+++ b/scene/2d/navigation2d.cpp
@@ -74,7 +74,7 @@ void Navigation2D::_navpoly_link(int p_id) {
 			Vector2 ep = nm.xform.xform(r[idx]);
 			center += ep;
 			e.point = _get_point(ep);
-			p.edges[j] = e;
+			p.edges.write[j] = e;
 
 			int idxn = indices[(j + 1) % plen];
 			if (idxn < 0 || idxn >= len) {
@@ -119,17 +119,17 @@ void Navigation2D::_navpoly_link(int p_id) {
 					ConnectionPending pending;
 					pending.polygon = &p;
 					pending.edge = j;
-					p.edges[j].P = C->get().pending.push_back(pending);
+					p.edges.write[j].P = C->get().pending.push_back(pending);
 					continue;
 					//print_line(String()+_get_vertex(ek.a)+" -> "+_get_vertex(ek.b));
 				}
 
 				C->get().B = &p;
 				C->get().B_edge = j;
-				C->get().A->edges[C->get().A_edge].C = &p;
-				C->get().A->edges[C->get().A_edge].C_edge = j;
-				p.edges[j].C = C->get().A;
-				p.edges[j].C_edge = C->get().A_edge;
+				C->get().A->edges.write[C->get().A_edge].C = &p;
+				C->get().A->edges.write[C->get().A_edge].C_edge = j;
+				p.edges.write[j].C = C->get().A;
+				p.edges.write[j].C_edge = C->get().A_edge;
 				//connection successful.
 			}
 		}
@@ -167,10 +167,10 @@ void Navigation2D::_navpoly_unlink(int p_id) {
 			} else if (C->get().B) {
 				//disconnect
 
-				C->get().B->edges[C->get().B_edge].C = NULL;
-				C->get().B->edges[C->get().B_edge].C_edge = -1;
-				C->get().A->edges[C->get().A_edge].C = NULL;
-				C->get().A->edges[C->get().A_edge].C_edge = -1;
+				C->get().B->edges.write[C->get().B_edge].C = NULL;
+				C->get().B->edges.write[C->get().B_edge].C_edge = -1;
+				C->get().A->edges.write[C->get().A_edge].C = NULL;
+				C->get().A->edges.write[C->get().A_edge].C_edge = -1;
 
 				if (C->get().A == &E->get()) {
 
@@ -187,11 +187,11 @@ void Navigation2D::_navpoly_unlink(int p_id) {
 
 					C->get().B = cp.polygon;
 					C->get().B_edge = cp.edge;
-					C->get().A->edges[C->get().A_edge].C = cp.polygon;
-					C->get().A->edges[C->get().A_edge].C_edge = cp.edge;
-					cp.polygon->edges[cp.edge].C = C->get().A;
-					cp.polygon->edges[cp.edge].C_edge = C->get().A_edge;
-					cp.polygon->edges[cp.edge].P = NULL;
+					C->get().A->edges.write[C->get().A_edge].C = cp.polygon;
+					C->get().A->edges.write[C->get().A_edge].C_edge = cp.edge;
+					cp.polygon->edges.write[cp.edge].C = C->get().A;
+					cp.polygon->edges.write[cp.edge].C_edge = C->get().A_edge;
+					cp.polygon->edges.write[cp.edge].P = NULL;
 				}
 
 			} else {
@@ -339,8 +339,8 @@ Vector<Vector2> Navigation2D::get_simple_path(const Vector2 &p_start, const Vect
 
 		Vector<Vector2> path;
 		path.resize(2);
-		path[0] = begin_point;
-		path[1] = end_point;
+		path.write[0] = begin_point;
+		path.write[1] = end_point;
 		//print_line("Direct Path");
 		return path;
 	}
@@ -408,7 +408,7 @@ Vector<Vector2> Navigation2D::get_simple_path(const Vector2 &p_start, const Vect
 
 		for (int i = 0; i < es; i++) {
 
-			Polygon::Edge &e = p->edges[i];
+			Polygon::Edge &e = p->edges.write[i];
 
 			if (!e.C)
 				continue;
@@ -586,7 +586,7 @@ Vector<Vector2> Navigation2D::get_simple_path(const Vector2 &p_start, const Vect
 		if (!path.size() || path[path.size() - 1].distance_squared_to(begin_point) > CMP_EPSILON) {
 			path.push_back(begin_point); // Add the begin point
 		} else {
-			path[path.size() - 1] = begin_point; // Replace first midpoint by the exact begin point
+			path.write[path.size() - 1] = begin_point; // Replace first midpoint by the exact begin point
 		}
 
 		path.invert();
@@ -594,7 +594,7 @@ Vector<Vector2> Navigation2D::get_simple_path(const Vector2 &p_start, const Vect
 		if (path.size() <= 1 || path[path.size() - 1].distance_squared_to(end_point) > CMP_EPSILON) {
 			path.push_back(end_point); // Add the end point
 		} else {
-			path[path.size() - 1] = end_point; // Replace last midpoint by the exact end point
+			path.write[path.size() - 1] = end_point; // Replace last midpoint by the exact end point
 		}
 
 		return path;
diff --git a/scene/2d/navigation_polygon.cpp b/scene/2d/navigation_polygon.cpp
index 6e27bf1c1d..2d6679272a 100644
--- a/scene/2d/navigation_polygon.cpp
+++ b/scene/2d/navigation_polygon.cpp
@@ -91,7 +91,7 @@ void NavigationPolygon::_set_polygons(const Array &p_array) {
 
 	polygons.resize(p_array.size());
 	for (int i = 0; i < p_array.size(); i++) {
-		polygons[i].indices = p_array[i];
+		polygons.write[i].indices = p_array[i];
 	}
 }
 
@@ -110,7 +110,7 @@ void NavigationPolygon::_set_outlines(const Array &p_array) {
 
 	outlines.resize(p_array.size());
 	for (int i = 0; i < p_array.size(); i++) {
-		outlines[i] = p_array[i];
+		outlines.write[i] = p_array[i];
 	}
 	rect_cache_dirty = true;
 }
@@ -166,7 +166,7 @@ int NavigationPolygon::get_outline_count() const {
 
 void NavigationPolygon::set_outline(int p_idx, const PoolVector<Vector2> &p_outline) {
 	ERR_FAIL_INDEX(p_idx, outlines.size());
-	outlines[p_idx] = p_outline;
+	outlines.write[p_idx] = p_outline;
 	rect_cache_dirty = true;
 }
 
@@ -432,8 +432,8 @@ void NavigationPolygonInstance::_notification(int p_what) {
 				{
 					PoolVector<Vector2>::Read vr = verts.read();
 					for (int i = 0; i < vsize; i++) {
-						vertices[i] = vr[i];
-						colors[i] = color;
+						vertices.write[i] = vr[i];
+						colors.write[i] = color;
 					}
 				}
 
diff --git a/scene/2d/physics_body_2d.cpp b/scene/2d/physics_body_2d.cpp
index 7505aa4a94..9879f43877 100644
--- a/scene/2d/physics_body_2d.cpp
+++ b/scene/2d/physics_body_2d.cpp
@@ -1373,11 +1373,11 @@ Ref<KinematicCollision2D> KinematicBody2D::_get_slide_collision(int p_bounce) {
 	}
 
 	if (slide_colliders[p_bounce].is_null()) {
-		slide_colliders[p_bounce].instance();
-		slide_colliders[p_bounce]->owner = this;
+		slide_colliders.write[p_bounce].instance();
+		slide_colliders.write[p_bounce]->owner = this;
 	}
 
-	slide_colliders[p_bounce]->collision = colliders[p_bounce];
+	slide_colliders.write[p_bounce]->collision = colliders[p_bounce];
 	return slide_colliders[p_bounce];
 }
 
@@ -1475,7 +1475,7 @@ KinematicBody2D::~KinematicBody2D() {
 
 	for (int i = 0; i < slide_colliders.size(); i++) {
 		if (slide_colliders[i].is_valid()) {
-			slide_colliders[i]->owner = NULL;
+			slide_colliders.write[i]->owner = NULL;
 		}
 	}
 }
diff --git a/scene/2d/polygon_2d.cpp b/scene/2d/polygon_2d.cpp
index 81ed3c63c3..c9e5408f06 100644
--- a/scene/2d/polygon_2d.cpp
+++ b/scene/2d/polygon_2d.cpp
@@ -113,7 +113,7 @@ void Polygon2D::_notification(int p_what) {
 
 				PoolVector<Vector2>::Read polyr = polygon.read();
 				for (int i = 0; i < len; i++) {
-					points[i] = polyr[i] + offset;
+					points.write[i] = polyr[i] + offset;
 				}
 			}
 
@@ -153,18 +153,18 @@ void Polygon2D::_notification(int p_what) {
 					SWAP(ep[1], ep[4]);
 					SWAP(ep[2], ep[3]);
 					SWAP(ep[5], ep[0]);
-					SWAP(ep[6], points[highest_idx]);
+					SWAP(ep[6], points.write[highest_idx]);
 				}
 
 				points.resize(points.size() + 7);
 				for (int i = points.size() - 1; i >= highest_idx + 7; i--) {
 
-					points[i] = points[i - 7];
+					points.write[i] = points[i - 7];
 				}
 
 				for (int i = 0; i < 7; i++) {
 
-					points[highest_idx + i + 1] = ep[i];
+					points.write[highest_idx + i + 1] = ep[i];
 				}
 
 				len = points.size();
@@ -182,12 +182,12 @@ void Polygon2D::_notification(int p_what) {
 					PoolVector<Vector2>::Read uvr = uv.read();
 
 					for (int i = 0; i < len; i++) {
-						uvs[i] = texmat.xform(uvr[i]) / tex_size;
+						uvs.write[i] = texmat.xform(uvr[i]) / tex_size;
 					}
 
 				} else {
 					for (int i = 0; i < len; i++) {
-						uvs[i] = texmat.xform(points[i]) / tex_size;
+						uvs.write[i] = texmat.xform(points[i]) / tex_size;
 					}
 				}
 			}
@@ -262,10 +262,10 @@ void Polygon2D::_notification(int p_what) {
 			{
 				PoolVector<Color>::Read color_r = vertex_colors.read();
 				for (int i = 0; i < color_len && i < len; i++) {
-					colors[i] = color_r[i];
+					colors.write[i] = color_r[i];
 				}
 				for (int i = color_len; i < len; i++) {
-					colors[i] = color;
+					colors.write[i] = color;
 				}
 			}
 
@@ -333,13 +333,13 @@ void Polygon2D::_notification(int p_what) {
 					Vector<Vector2> vertices;
 					vertices.resize(loop.size());
 					for (int j = 0; j < vertices.size(); j++) {
-						vertices[j] = points[loop[j]];
+						vertices.write[j] = points[loop[j]];
 					}
 					Vector<int> sub_indices = Geometry::triangulate_polygon(vertices);
 					int from = indices.size();
 					indices.resize(from + sub_indices.size());
 					for (int j = 0; j < sub_indices.size(); j++) {
-						indices[from + j] = loop[sub_indices[j]];
+						indices.write[from + j] = loop[sub_indices[j]];
 					}
 				}
 
@@ -538,12 +538,12 @@ void Polygon2D::clear_bones() {
 
 void Polygon2D::set_bone_weights(int p_index, const PoolVector<float> &p_weights) {
 	ERR_FAIL_INDEX(p_index, bone_weights.size());
-	bone_weights[p_index].weights = p_weights;
+	bone_weights.write[p_index].weights = p_weights;
 	update();
 }
 void Polygon2D::set_bone_path(int p_index, const NodePath &p_path) {
 	ERR_FAIL_INDEX(p_index, bone_weights.size());
-	bone_weights[p_index].path = p_path;
+	bone_weights.write[p_index].path = p_path;
 	update();
 }
 
diff --git a/scene/2d/skeleton_2d.cpp b/scene/2d/skeleton_2d.cpp
index 8ceffb3c27..e6e9bde20a 100644
--- a/scene/2d/skeleton_2d.cpp
+++ b/scene/2d/skeleton_2d.cpp
@@ -191,13 +191,13 @@ void Skeleton2D::_update_bone_setup() {
 	bones.sort(); //sorty so they are always in the same order/index
 
 	for (int i = 0; i < bones.size(); i++) {
-		bones[i].rest_inverse = bones[i].bone->get_skeleton_rest().affine_inverse(); //bind pose
-		bones[i].bone->skeleton_index = i;
+		bones.write[i].rest_inverse = bones[i].bone->get_skeleton_rest().affine_inverse(); //bind pose
+		bones.write[i].bone->skeleton_index = i;
 		Bone2D *parent_bone = Object::cast_to<Bone2D>(bones[i].bone->get_parent());
 		if (parent_bone) {
-			bones[i].parent_index = parent_bone->skeleton_index;
+			bones.write[i].parent_index = parent_bone->skeleton_index;
 		} else {
-			bones[i].parent_index = -1;
+			bones.write[i].parent_index = -1;
 		}
 	}
 
@@ -230,9 +230,9 @@ void Skeleton2D::_update_transform() {
 
 		ERR_CONTINUE(bones[i].parent_index >= i);
 		if (bones[i].parent_index >= 0) {
-			bones[i].accum_transform = bones[bones[i].parent_index].accum_transform * bones[i].bone->get_transform();
+			bones.write[i].accum_transform = bones[bones[i].parent_index].accum_transform * bones[i].bone->get_transform();
 		} else {
-			bones[i].accum_transform = bones[i].bone->get_transform();
+			bones.write[i].accum_transform = bones[i].bone->get_transform();
 		}
 	}
 
diff --git a/scene/2d/tile_map.cpp b/scene/2d/tile_map.cpp
index 72c3ed7425..95fd4fff2c 100644
--- a/scene/2d/tile_map.cpp
+++ b/scene/2d/tile_map.cpp
@@ -529,8 +529,8 @@ void TileMap::update_dirty_quadrants() {
 								{
 									PoolVector<Vector2>::Read vr = navigation_polygon_vertices.read();
 									for (int i = 0; i < vsize; i++) {
-										vertices[i] = vr[i];
-										colors[i] = debug_navigation_color;
+										vertices.write[i] = vr[i];
+										colors.write[i] = debug_navigation_color;
 									}
 								}