1 files changed, 107 insertions, 0 deletions
diff --git a/main/client/src/Locks.java b/main/client/src/Locks.java
new file mode 100644
index 00000000..64259293
--- /dev/null
+++ b/main/client/src/Locks.java
@@ -0,0 +1,107 @@
+package mill.main.client;
+
+import java.io.RandomAccessFile;
+import java.nio.channels.FileChannel;
+import java.util.concurrent.locks.ReentrantLock;
+
+public class Locks implements AutoCloseable{
+    public Lock processLock;
+    public Lock serverLock;
+    public Lock clientLock;
+    public static Locks files(String lockBase) throws Exception{
+        return new Locks(){{
+            processLock = new FileLock(lockBase + "/pid");
+
+            serverLock = new FileLock(lockBase + "/serverLock");
+
+            clientLock = new FileLock(lockBase + "/clientLock");
+        }};
+    }
+    public static Locks memory(){
+        return new Locks(){{
+            this.processLock = new MemoryLock();
+            this.serverLock = new MemoryLock();
+            this.clientLock = new MemoryLock();
+        }};
+    }
+
+    @Override
+    public void close() throws Exception {
+        processLock.close();
+        serverLock.close();
+        clientLock.close();
+    }
+}
+class FileLocked implements Locked{
+    private java.nio.channels.FileLock lock;
+    public FileLocked(java.nio.channels.FileLock lock){
+        this.lock = lock;
+    }
+    public void release() throws Exception{
+        this.lock.release();
+    }
+}
+
+class FileLock extends Lock{
+    String path;
+    RandomAccessFile raf;
+    FileChannel chan;
+    public FileLock(String path) throws Exception{
+        this.path = path;
+        raf = new RandomAccessFile(path, "rw");
+        chan = raf.getChannel();
+    }
+
+    public Locked lock() throws Exception{
+        return new FileLocked(chan.lock());
+    }
+    public Locked tryLock() throws Exception{
+        java.nio.channels.FileLock l = chan.tryLock();
+        if (l == null) return null;
+        else return new FileLocked(l);
+    }
+    public boolean probe()throws Exception{
+        java.nio.channels.FileLock l = chan.tryLock();
+        if (l == null) return false;
+        else {
+            l.release();
+            return true;
+        }
+    }
+
+    @Override
+    public void close() throws Exception {
+        raf.close();
+        chan.close();
+    }
+}
+class MemoryLocked implements Locked{
+    java.util.concurrent.locks.Lock l;
+    public MemoryLocked(java.util.concurrent.locks.Lock l){
+        this.l = l;
+    }
+    public void release() throws Exception{
+        l.unlock();
+    }
+}
+
+class MemoryLock extends Lock{
+    ReentrantLock innerLock = new ReentrantLock(true);
+
+    public boolean probe(){
+          return !innerLock.isLocked();
+    }
+    public Locked lock() {
+        innerLock.lock();
+        return new MemoryLocked(innerLock);
+    }
+    public Locked tryLock() {
+        if (innerLock.tryLock()) return new MemoryLocked(innerLock);
+        else return null;
+    }
+
+    @Override
+    public void close() throws Exception {
+        innerLock.unlock();
+    }
+}