From 18fbdbb456c07a56b358bea2e392765fbcbb3283 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pedro=20J=2E=20Est=C3=A9banez?= <pedrojrulez@gmail.com>
Date: Wed, 26 Feb 2020 11:28:13 +0100
Subject: Reimplement Mutex with C++'s <mutex>

Main:
- It's now implemented thanks to `<mutex>`. No more platform-specific implementations.
- `BinaryMutex` (non-recursive) is added, as an alternative for special cases.
- Doesn't need allocation/deallocation anymore. It can live in the stack and be part of other classes.
- Because of that, it's methods are now `const` and the inner mutex is `mutable` so it can be easily used in `const` contexts.
- A no-op implementation is provided if `NO_THREADS` is defined. No more need to add `#ifdef NO_THREADS` just for this.
- `MutexLock` now takes a reference. At this point the cases of null `Mutex`es are rare. If you ever need that, just don't use `MutexLock`.
- Thread-safe utilities are therefore simpler now.

Misc.:
- `ScopedMutexLock` is dropped and replaced by `MutexLock`, because they were pretty much the same.
- Every case of lock, do-something, unlock is replaced by `MutexLock` (complex cases where it's not straightfoward are kept as as explicit lock and unlock).
- `ShaderRD` contained an `std::mutex`, which has been replaced by `Mutex`.
---
 scene/resources/dynamic_font.cpp | 59 ++++++++++++++++------------------------
 1 file changed, 24 insertions(+), 35 deletions(-)

(limited to 'scene/resources/dynamic_font.cpp')

diff --git a/scene/resources/dynamic_font.cpp b/scene/resources/dynamic_font.cpp
index 79a1500129..fc53dfe376 100644
--- a/scene/resources/dynamic_font.cpp
+++ b/scene/resources/dynamic_font.cpp
@@ -990,7 +990,7 @@ void DynamicFont::_bind_methods() {
 	BIND_ENUM_CONSTANT(SPACING_SPACE);
 }
 
-Mutex *DynamicFont::dynamic_font_mutex = NULL;
+Mutex DynamicFont::dynamic_font_mutex;
 
 SelfList<DynamicFont>::List *DynamicFont::dynamic_fonts = NULL;
 
@@ -1004,29 +1004,21 @@ DynamicFont::DynamicFont() :
 	spacing_char = 0;
 	spacing_space = 0;
 	outline_color = Color(1, 1, 1);
-	if (dynamic_font_mutex) {
-		dynamic_font_mutex->lock();
-		dynamic_fonts->add(&font_list);
-		dynamic_font_mutex->unlock();
-	}
+
+	MutexLock lock(dynamic_font_mutex);
+	dynamic_fonts->add(&font_list);
 }
 
 DynamicFont::~DynamicFont() {
-	if (dynamic_font_mutex) {
-		dynamic_font_mutex->lock();
-		dynamic_fonts->remove(&font_list);
-		dynamic_font_mutex->unlock();
-	}
+	MutexLock lock(dynamic_font_mutex);
+	dynamic_fonts->remove(&font_list);
 }
 
 void DynamicFont::initialize_dynamic_fonts() {
 	dynamic_fonts = memnew(SelfList<DynamicFont>::List());
-	dynamic_font_mutex = Mutex::create();
 }
 
 void DynamicFont::finish_dynamic_fonts() {
-	memdelete(dynamic_font_mutex);
-	dynamic_font_mutex = NULL;
 	memdelete(dynamic_fonts);
 	dynamic_fonts = NULL;
 }
@@ -1034,39 +1026,36 @@ void DynamicFont::finish_dynamic_fonts() {
 void DynamicFont::update_oversampling() {
 
 	Vector<Ref<DynamicFont> > changed;
+	{
+		MutexLock lock(dynamic_font_mutex);
 
-	if (dynamic_font_mutex)
-		dynamic_font_mutex->lock();
-
-	SelfList<DynamicFont> *E = dynamic_fonts->first();
-	while (E) {
+		SelfList<DynamicFont> *E = dynamic_fonts->first();
+		while (E) {
 
-		if (E->self()->data_at_size.is_valid()) {
-			E->self()->data_at_size->update_oversampling();
+			if (E->self()->data_at_size.is_valid()) {
+				E->self()->data_at_size->update_oversampling();
 
-			if (E->self()->outline_data_at_size.is_valid()) {
-				E->self()->outline_data_at_size->update_oversampling();
-			}
+				if (E->self()->outline_data_at_size.is_valid()) {
+					E->self()->outline_data_at_size->update_oversampling();
+				}
 
-			for (int i = 0; i < E->self()->fallback_data_at_size.size(); i++) {
-				if (E->self()->fallback_data_at_size[i].is_valid()) {
-					E->self()->fallback_data_at_size.write[i]->update_oversampling();
+				for (int i = 0; i < E->self()->fallback_data_at_size.size(); i++) {
+					if (E->self()->fallback_data_at_size[i].is_valid()) {
+						E->self()->fallback_data_at_size.write[i]->update_oversampling();
 
-					if (E->self()->has_outline() && E->self()->fallback_outline_data_at_size[i].is_valid()) {
-						E->self()->fallback_outline_data_at_size.write[i]->update_oversampling();
+						if (E->self()->has_outline() && E->self()->fallback_outline_data_at_size[i].is_valid()) {
+							E->self()->fallback_outline_data_at_size.write[i]->update_oversampling();
+						}
 					}
 				}
+
+				changed.push_back(Ref<DynamicFont>(E->self()));
 			}
 
-			changed.push_back(Ref<DynamicFont>(E->self()));
+			E = E->next();
 		}
-
-		E = E->next();
 	}
 
-	if (dynamic_font_mutex)
-		dynamic_font_mutex->unlock();
-
 	for (int i = 0; i < changed.size(); i++) {
 		changed.write[i]->emit_changed();
 	}
-- 
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