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, 4 insertions, 4 deletions

diff --git a/modules/gdscript/gdscript.cpp b/modules/gdscript/gdscript.cpp
index 8bd29ffc55..cff3be76ae 100644
--- a/modules/gdscript/gdscript.cpp
+++ b/modules/gdscript/gdscript.cpp
@@ -730,7 +730,7 @@ Error GDScript::load_byte_code(const String &p_path) {
 		Vector<uint8_t> key;
 		key.resize(32);
 		for (int i = 0; i < key.size(); i++) {
-			key[i] = script_encryption_key[i];
+			key.write[i] = script_encryption_key[i];
 		}
 		Error err = fae->open_and_parse(fa, key, FileAccessEncrypted::MODE_READ);
 		ERR_FAIL_COND_V(err, err);
@@ -941,7 +941,7 @@ bool GDScriptInstance::set(const StringName &p_name, const Variant &p_value) {
 				if (!E->get().data_type.is_type(p_value)) {
 					return false; // Type mismatch
 				}
-				members[E->get().index] = p_value;
+				members.write[E->get().index] = p_value;
 			}
 			return true;
 		}
@@ -1270,7 +1270,7 @@ void GDScriptInstance::reload_members() {
 
 		if (member_indices_cache.has(E->key())) {
 			Variant value = members[member_indices_cache[E->key()]];
-			new_members[E->get().index] = value;
+			new_members.write[E->get().index] = value;
 		}
 	}
 
@@ -1320,7 +1320,7 @@ void GDScriptLanguage::_add_global(const StringName &p_name, const Variant &p_va
 
 	if (globals.has(p_name)) {
 		//overwrite existing
-		global_array[globals[p_name]] = p_value;
+		global_array.write[globals[p_name]] = p_value;
 		return;
 	}
 	globals[p_name] = global_array.size();