WIP keep mill server alive if you Ctrl-C during --watch (#339)

* wip

* Clean up more resources in the Mill client after every command

* catch and ignore SIGINT in Mill server to make it survive Ctrl-C on the client

3 files changed, 66 insertions, 45 deletions

diff --git a/main/client/src/mill/main/client/Lock.java b/main/client/src/mill/main/client/Lock.java
index 890a352b..6e5f18b0 100644
--- a/main/client/src/mill/main/client/Lock.java
+++ b/main/client/src/mill/main/client/Lock.java
@@ -1,7 +1,8 @@
 package mill.main.client;
-public abstract class Lock{
+public abstract class Lock implements AutoCloseable{
     abstract public Locked lock() throws Exception;
     abstract public Locked tryLock() throws Exception;
+
     public void await() throws Exception{
         lock().release();
     }
diff --git a/main/client/src/mill/main/client/Locks.java b/main/client/src/mill/main/client/Locks.java
index 2843973d..64259293 100644
--- a/main/client/src/mill/main/client/Locks.java
+++ b/main/client/src/mill/main/client/Locks.java
@@ -4,7 +4,7 @@ import java.io.RandomAccessFile;
 import java.nio.channels.FileChannel;
 import java.util.concurrent.locks.ReentrantLock;
 
-public class Locks{
+public class Locks implements AutoCloseable{
     public Lock processLock;
     public Lock serverLock;
     public Lock clientLock;
@@ -24,6 +24,13 @@ public class Locks{
             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;
@@ -61,6 +68,12 @@ class FileLock extends Lock{
             return true;
         }
     }
+
+    @Override
+    public void close() throws Exception {
+        raf.close();
+        chan.close();
+    }
 }
 class MemoryLocked implements Locked{
     java.util.concurrent.locks.Lock l;
@@ -86,4 +99,9 @@ class MemoryLock extends Lock{
         if (innerLock.tryLock()) return new MemoryLocked(innerLock);
         else return null;
     }
+
+    @Override
+    public void close() throws Exception {
+        innerLock.unlock();
+    }
 }
diff --git a/main/client/src/mill/main/client/Main.java b/main/client/src/mill/main/client/MillClientMain.java
index 98445d3c..17a043f6 100644
--- a/main/client/src/mill/main/client/Main.java
+++ b/main/client/src/mill/main/client/MillClientMain.java
@@ -9,10 +9,10 @@ import java.net.URL;
 import java.nio.channels.FileChannel;
 import java.util.*;
 
-public class Main {
+public class MillClientMain {
     static void initServer(String lockBase, boolean setJnaNoSys) throws IOException,URISyntaxException{
         ArrayList<String> selfJars = new ArrayList<String>();
-        ClassLoader current = Main.class.getClassLoader();
+        ClassLoader current = MillClientMain.class.getClassLoader();
         while(current != null){
             if (current instanceof java.net.URLClassLoader) {
                 URL[] urls = ((java.net.URLClassLoader) current).getURLs();
@@ -38,7 +38,7 @@ public class Main {
         }
         l.add("-cp");
         l.add(String.join(File.pathSeparator, selfJars));
-        l.add("mill.main.ServerMain");
+        l.add("mill.main.MillServerMain");
         l.add(lockBase);
 
         new java.lang.ProcessBuilder()
@@ -48,6 +48,9 @@ public class Main {
                 .start();
     }
     public static void main(String[] args) throws Exception{
+        System.exit(main0(args));
+    }
+    public static int main0(String[] args) throws Exception{
         boolean setJnaNoSys = System.getProperty("jna.nosys") == null;
         Map<String, String> env = System.getenv();
         if (setJnaNoSys) {
@@ -58,33 +61,35 @@ public class Main {
             index += 1;
             String lockBase = "out/mill-worker-" + index;
             new java.io.File(lockBase).mkdirs();
-            RandomAccessFile lockFile = new RandomAccessFile(lockBase + "/clientLock", "rw");
-            FileChannel channel = lockFile.getChannel();
-            java.nio.channels.FileLock tryLock = channel.tryLock();
-            if (tryLock == null) {
-                lockFile.close();
-                channel.close();
-            } else {
-                int exitCode = Main.run(
-                        lockBase,
-                        new Runnable() {
-                            @Override
-                            public void run() {
-                                try{
-                                    initServer(lockBase, setJnaNoSys);
-                                }catch(Exception e){
-                                    throw new RuntimeException(e);
+
+            try(RandomAccessFile lockFile = new RandomAccessFile(lockBase + "/clientLock", "rw");
+                FileChannel channel = lockFile.getChannel();
+                java.nio.channels.FileLock tryLock = channel.tryLock();
+                Locks locks = Locks.files(lockBase)){
+                if (tryLock != null) {
+                    int exitCode = MillClientMain.run(
+                            lockBase,
+                            new Runnable() {
+                                @Override
+                                public void run() {
+                                    try{
+                                        initServer(lockBase, setJnaNoSys);
+                                    }catch(Exception e){
+                                        throw new RuntimeException(e);
+                                    }
                                 }
-                            }
-                        },
-                        Locks.files(lockBase),
-                        System.in,
-                        System.out,
-                        System.err,
-                        args,
-                        env
-                );
-                System.exit(exitCode);
+                            },
+                            locks,
+                            System.in,
+                            System.out,
+                            System.err,
+                            args,
+                            env
+                    );
+                    return exitCode;
+                }
+            } finally{
+
             }
         }
         throw new Exception("Reached max process limit: " + 5);
@@ -99,12 +104,12 @@ public class Main {
                           String[] args,
                           Map<String, String> env) throws Exception{
 
-        FileOutputStream f = new FileOutputStream(lockBase + "/run");
-        f.write(System.console() != null ? 1 : 0);
-        Util.writeString(f, System.getProperty("MILL_VERSION"));
-        Util.writeArgs(args, f);
-        Util.writeMap(env, f);
-        f.close();
+        try(FileOutputStream f = new FileOutputStream(lockBase + "/run")){
+            f.write(System.console() != null ? 1 : 0);
+            Util.writeString(f, System.getProperty("MILL_VERSION"));
+            Util.writeArgs(args, f);
+            Util.writeMap(env, f);
+        }
 
         boolean serverInit = false;
         if (locks.processLock.probe()) {
@@ -120,6 +125,7 @@ public class Main {
         Socket ioSocket = null;
 
         long retryStart = System.currentTimeMillis();
+
         while(ioSocket == null && System.currentTimeMillis() - retryStart < 1000){
             try{
                 ioSocket = Util.isWindows?
@@ -146,16 +152,12 @@ public class Main {
 
         locks.serverLock.await();
 
-        try{
-            return Integer.parseInt(
-                new BufferedReader(
-                    new InputStreamReader(
-                        new FileInputStream(lockBase + "/exitCode")
-                    )
-                ).readLine()
-            );
+        try(FileInputStream fos = new FileInputStream(lockBase + "/exitCode")){
+            return Integer.parseInt(new BufferedReader(new InputStreamReader(fos)).readLine());
         } catch(Throwable e){
             return 1;
+        } finally{
+            ioSocket.close();
         }
     }
 }