fixed race condition in InMemoryCache

gbcs-common/src/main/kotlin/net/woggioni/gbcs/common/GBCS.kt

@@ -1,7 +1,9 @@
 package net.woggioni.gbcs.common
 
+import net.woggioni.jwo.JWO
 import java.net.URI
 import java.net.URL
+import java.security.MessageDigest
 
 object GBCS {
     fun String.toUrl() : URL = URL.of(URI(this), null)
@@ -9,4 +11,19 @@ object GBCS {
     const val GBCS_NAMESPACE_URI: String = "urn:net.woggioni.gbcs.server"
     const val GBCS_PREFIX: String = "gbcs"
     const val XML_SCHEMA_NAMESPACE_URI = "http://www.w3.org/2001/XMLSchema-instance"
+
+    fun digest(
+        data: ByteArray,
+        md: MessageDigest = MessageDigest.getInstance("MD5")
+    ): ByteArray {
+        md.update(data)
+        return md.digest()
+    }
+
+    fun digestString(
+        data: ByteArray,
+        md: MessageDigest = MessageDigest.getInstance("MD5")
+    ): String {
+        return JWO.bytesToHex(digest(data, md))
+    }
 }

gbcs-server/src/main/kotlin/net/woggioni/gbcs/server/cache/CacheUtils.kt

@@ -1,21 +0,0 @@
-package net.woggioni.gbcs.server.cache
-
-import net.woggioni.jwo.JWO
-import java.security.MessageDigest
-
-object CacheUtils {
-    fun digest(
-        data: ByteArray,
-        md: MessageDigest = MessageDigest.getInstance("MD5")
-    ): ByteArray {
-        md.update(data)
-        return md.digest()
-    }
-
-    fun digestString(
-        data: ByteArray,
-        md: MessageDigest = MessageDigest.getInstance("MD5")
-    ): String {
-        return JWO.bytesToHex(digest(data, md))
-    }
-}

gbcs-server/src/main/kotlin/net/woggioni/gbcs/server/cache/FileSystemCache.kt

@@ -1,8 +1,8 @@
 package net.woggioni.gbcs.server.cache
 
 import net.woggioni.gbcs.api.Cache
+import net.woggioni.gbcs.common.GBCS.digestString
 import net.woggioni.gbcs.common.contextLogger
-import net.woggioni.gbcs.server.cache.CacheUtils.digestString
 import net.woggioni.jwo.LockFile
 import java.nio.channels.Channels
 import java.nio.channels.FileChannel

gbcs-server/src/main/kotlin/net/woggioni/gbcs/server/cache/InMemoryCache.kt

@@ -1,18 +1,15 @@
 package net.woggioni.gbcs.server.cache
 
 import net.woggioni.gbcs.api.Cache
-import net.woggioni.gbcs.server.cache.CacheUtils.digestString
+import net.woggioni.gbcs.common.GBCS.digestString
 import java.io.ByteArrayInputStream
 import java.io.ByteArrayOutputStream
-import java.nio.ByteBuffer
 import java.nio.channels.Channels
 import java.security.MessageDigest
 import java.time.Duration
 import java.time.Instant
 import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.PriorityBlockingQueue
-import java.util.concurrent.atomic.AtomicInteger
-import java.util.concurrent.atomic.AtomicReference
 import java.util.zip.Deflater
 import java.util.zip.DeflaterOutputStream
 import java.util.zip.Inflater
@@ -25,33 +22,27 @@ class InMemoryCache(
     val compressionLevel: Int
 ) : Cache {
 
-    private val map = ConcurrentHashMap<String, MapValue>()
+    private val map = ConcurrentHashMap<String, ByteArray>()
-
+    
-    private class MapValue(val rc: AtomicInteger, val payload : AtomicReference<ByteArray>)
+    private class RemovalQueueElement(val key: String, val value : ByteArray, val expiry : Instant) : Comparable<RemovalQueueElement> {
-
+        override fun compareTo(other: RemovalQueueElement) = expiry.compareTo(other.expiry)
-    private class RemovalQueueElement(val key: String, val expiry : Instant) : Comparable<RemovalQueueElement> {
-        override fun compareTo(other: RemovalQueueElement)= expiry.compareTo(other.expiry)
     }
 
     private val removalQueue = PriorityBlockingQueue<RemovalQueueElement>()
 
     private var running = true
-    private val garbageCollector = Thread({
+    private val garbageCollector = Thread {
         while(true) {
             val el = removalQueue.take()
             val now = Instant.now()
             if(now > el.expiry) {
-                val value = map[el.key] ?: continue
+                map.remove(el.key, el.value)
-                val rc = value.rc.decrementAndGet()
-                if(rc == 0) {
-                    map.remove(el.key)
-                }
             } else {
                 removalQueue.put(el)
                 Thread.sleep(minOf(Duration.between(now, el.expiry), Duration.ofSeconds(1)))
             }
         }
-    }).apply {
+    }.apply {
         start()
     }
 
@@ -68,8 +59,6 @@ class InMemoryCache(
             } ?: key
                 ).let { digest ->
                 map[digest]
-                    ?.let(MapValue::payload)
-                    ?.let(AtomicReference<ByteArray>::get)
                     ?.let { value ->
                     if (compressionEnabled) {
                         val inflater = Inflater()
@@ -96,11 +85,8 @@ class InMemoryCache(
             } else {
                 content
             }
-            val mapValue = map.computeIfAbsent(digest) {
+            map[digest] = value
-                MapValue(AtomicInteger(0), AtomicReference())
+            removalQueue.put(RemovalQueueElement(digest, value, Instant.now().plus(maxAge)))
-            }
-            mapValue.payload.set(value)
-            removalQueue.put(RemovalQueueElement(digest, Instant.now().plus(maxAge)))
         }
     }
 }

gradle.properties

@@ -2,9 +2,9 @@ org.gradle.configuration-cache=false
 org.gradle.parallel=true
 org.gradle.caching=true
 
-gbcs.version = 0.0.11
+gbcs.version = 0.1.1
 
-lys.version = 2025.01.25
+lys.version = 2025.01.31
 
 gitea.maven.url = https://gitea.woggioni.net/api/packages/woggioni/maven
 docker.registry.url=gitea.woggioni.net