From 8a567380df2680da2911fc9e279a2f2ab172b226 Mon Sep 17 00:00:00 2001
From: crschnick <crschnick@xpipe.io>
Date: Tue, 5 Dec 2023 20:17:44 +0000
Subject: [PATCH] Lock storage io

---
 .../java/io/xpipe/app/storage/DataStorage.java    | 15 +++++++++++++--
 .../io/xpipe/app/storage/StandardStorage.java     | 14 ++++++++++++--
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/app/src/main/java/io/xpipe/app/storage/DataStorage.java b/app/src/main/java/io/xpipe/app/storage/DataStorage.java
index 68ad3ff0a..51ee8213b 100644
--- a/app/src/main/java/io/xpipe/app/storage/DataStorage.java
+++ b/app/src/main/java/io/xpipe/app/storage/DataStorage.java
@@ -20,6 +20,7 @@ import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -58,6 +59,8 @@ public abstract class DataStorage {
     @Getter
     private final List<StorageListener> listeners = new CopyOnWriteArrayList<>();
 
+    protected final ReentrantLock busyIo = new ReentrantLock();
+
     public DataStorage() {
         this.dir = AppPrefs.get().storageDirectory().getValue();
         this.storeEntries = new ConcurrentHashMap<>();
@@ -146,8 +149,16 @@ public abstract class DataStorage {
     public abstract void load();
 
     public void saveAsync() {
-        // TODO: Don't make this a daemon thread to guarantee proper saving
-        ThreadHelper.unstarted(this::save).start();
+        // If we are already loading or saving, don't queue up another operation.
+        // This could otherwise lead to thread starvation with virtual threads
+        // Technically the load and save operations also return instantly if locked, but let's not even create new threads here
+        if (busyIo.isLocked()) {
+            return;
+        }
+
+        ThreadHelper.runAsync(() -> {
+            save();
+        });
     }
 
     public abstract void save();
diff --git a/app/src/main/java/io/xpipe/app/storage/StandardStorage.java b/app/src/main/java/io/xpipe/app/storage/StandardStorage.java
index ad241aac3..ce7b3fc2f 100644
--- a/app/src/main/java/io/xpipe/app/storage/StandardStorage.java
+++ b/app/src/main/java/io/xpipe/app/storage/StandardStorage.java
@@ -110,7 +110,11 @@ public class StandardStorage extends DataStorage {
         }
     }
 
-    public synchronized void load() {
+    public void load() {
+        if (!busyIo.tryLock()) {
+            return;
+        }
+
         this.gitStorageHandler.beforeStorageLoad();
 
         var storesDir = getStoresDir();
@@ -294,14 +298,19 @@ public class StandardStorage extends DataStorage {
         deleteLeftovers();
 
         loaded = true;
+        busyIo.unlock();
         this.gitStorageHandler.afterStorageLoad();
     }
 
-    public synchronized void save() {
+    public void save() {
         if (!loaded || disposed) {
             return;
         }
 
+        if (!busyIo.tryLock()) {
+            return;
+        }
+
         this.gitStorageHandler.beforeStorageSave();
 
         try {
@@ -354,6 +363,7 @@ public class StandardStorage extends DataStorage {
 
         deleteLeftovers();
         gitStorageHandler.afterStorageSave();
+        busyIo.unlock();
     }
 
     @Override