From 725d4195df78fa9efef29d4e162cdad1d69904a9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Thu, 16 Mar 2023 11:53:39 +0100
Subject: [PATCH] Small cleanup of purging code

---
 GPU/Common/ReplacedTexture.cpp | 40 ++++++++++++++++++++++++----------
 GPU/Common/ReplacedTexture.h   |  6 ++---
 GPU/Common/TextureReplacer.cpp |  2 +-
 3 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/GPU/Common/ReplacedTexture.cpp b/GPU/Common/ReplacedTexture.cpp
index fc5c1cde43..ed4915e1cd 100644
--- a/GPU/Common/ReplacedTexture.cpp
+++ b/GPU/Common/ReplacedTexture.cpp
@@ -95,9 +95,6 @@ private:
 
 ReplacedTexture::ReplacedTexture(VFSBackend *vfs, const ReplacementDesc &desc) : vfs_(vfs), desc_(desc) {
 	logId_ = desc.logId;
-	SetState(ReplacementState::POPULATED);
-
-	// TODO: What used to be here is now done on the thread task.
 }
 
 ReplacedTexture::~ReplacedTexture() {
@@ -115,19 +112,38 @@ ReplacedTexture::~ReplacedTexture() {
 	}
 }
 
-void ReplacedTexture::PurgeIfOlder(double t) {
-	if (threadWaitable_ && !threadWaitable_->WaitFor(0.0))
+void ReplacedTexture::PurgeIfNotUsedSinceTime(double t) {
+	if (State() != ReplacementState::ACTIVE) {
 		return;
-	if (lastUsed_ >= t)
+	}
+
+	// If there's some leftover threadWaitable, get rid of it.
+	if (threadWaitable_) {
+		if (threadWaitable_->WaitFor(0.0)) {
+			delete threadWaitable_;
+			threadWaitable_ = nullptr;
+			// Continue with purging.
+		} else {
+			// Try next time.
+			return;
+		}
+	}
+
+	// "atomic-enough" to not lock?
+	if (lastUsed_ >= t) {
 		return;
+	}
 
 	std::lock_guard<std::mutex> guard(lock_);
-	if (data_.size() && lastUsed < t) {
-		// We have to lock since multiple textures might reference this same data.
-		data_.clear();
-		// This means we have to reload.  If we never purge any, there's no need.
-		SetState(ReplacementState::POPULATED);
-	}
+
+	// We have to lock since multiple textures might reference this same data.
+	data_.clear();
+	levels_.clear();
+	fmt = Draw::DataFormat::UNDEFINED;
+	alphaStatus_ = ReplacedTextureAlpha::UNKNOWN;
+
+	// This means we have to reload.  If we never purge any, there's no need.
+	SetState(ReplacementState::POPULATED);
 }
 
 // This can only return true if ACTIVE or NOT_FOUND.
diff --git a/GPU/Common/ReplacedTexture.h b/GPU/Common/ReplacedTexture.h
index 138494594c..4b6657fee2 100644
--- a/GPU/Common/ReplacedTexture.h
+++ b/GPU/Common/ReplacedTexture.h
@@ -170,19 +170,19 @@ private:
 
 	void Prepare(VFSBackend *vfs);
 	LoadLevelResult LoadLevelData(VFSFileReference *fileRef, const std::string &filename, int level, Draw::DataFormat *pixelFormat);
-	void PurgeIfOlder(double t);
+	void PurgeIfNotUsedSinceTime(double t);
 
 	std::vector<std::vector<uint8_t>> data_;
 	std::vector<ReplacedTextureLevel> levels_;
 
-	ReplacedTextureAlpha alphaStatus_ = ReplacedTextureAlpha::UNKNOWN;
 	double lastUsed_ = 0.0;
 	LimitedWaitable *threadWaitable_ = nullptr;
 	std::mutex lock_;
 	Draw::DataFormat fmt = Draw::DataFormat::UNDEFINED;  // NOTE: Right now, the only supported format is Draw::DataFormat::R8G8B8A8_UNORM.
+	ReplacedTextureAlpha alphaStatus_ = ReplacedTextureAlpha::UNKNOWN;
 	double lastUsed = 0.0;
 
-	std::atomic<ReplacementState> state_ = ReplacementState::UNINITIALIZED;
+	std::atomic<ReplacementState> state_ = ReplacementState::POPULATED;
 
 	VFSBackend *vfs_ = nullptr;
 	ReplacementDesc desc_;
diff --git a/GPU/Common/TextureReplacer.cpp b/GPU/Common/TextureReplacer.cpp
index c2a7394709..432cf51c07 100644
--- a/GPU/Common/TextureReplacer.cpp
+++ b/GPU/Common/TextureReplacer.cpp
@@ -746,7 +746,7 @@ void TextureReplacer::Decimate(ReplacerDecimateMode mode) {
 	size_t totalSize = 0;
 	for (auto &item : levelCache_) {
 		std::lock_guard<std::mutex> guard(item.second->lock_);
-		item.second->PurgeIfOlder(threshold);
+		item.second->PurgeIfNotUsedSinceTime(threshold);
 		totalSize += item.second->GetTotalDataSize();  // TODO: Make something better.
 		// don't actually delete the items here, just clean out the data.
 	}