bugfix/signal_13_when_closing_read_pipe

Sources/ChessKitEngineCore/EngineMessenger/EngineMessenger.mm

@@ -5,6 +5,7 @@
 
 #import "EngineMessenger.h"
 #import "../Engines/AvailableEngines.h"
+#include <signal.h>
 
 @implementation EngineMessenger : NSObject
 
@@ -25,7 +26,8 @@ - (id)initWithEngineType: (EngineType_objc) type {
   self = [super init];
 
   if (self) {
-    _lock = [[NSLock alloc] init];
+    signal(SIGPIPE, SIG_IGN);
+   _lock = [[NSLock alloc] init];
     switch (type) {
       case EngineTypeStockfish:
         _engine = new StockfishEngine();
@@ -83,23 +85,53 @@ - (void)start {
 
 - (void)stop {
   [_lock lock];
-  [_pipeReadHandle closeFile];
-  [_pipeWriteHandle closeFile];
 
-  _readPipe = NULL;
-  _pipeReadHandle = NULL;
+  // Remove read notifications before closing any handles
+  if (_pipeReadHandle) {
+      [[NSNotificationCenter defaultCenter] removeObserver:self name:NSFileHandleReadCompletionNotification object:_pipeReadHandle];
+  }
+
+  // Close write side first to signal EOF to the reader and avoid further writes
+  if (_pipeWriteHandle) {
+      @try {
+          [_pipeWriteHandle closeAndReturnError:nil];
+      } @catch (NSException *exception) {
+          NSLog([exception description]);
+      }
+  }
 
-  _writePipe = NULL;
-  _pipeWriteHandle = NULL;
+  _pipeWriteHandle = nil;
+  _writePipe = nil;
+
+  // Close read side
+  if (_pipeReadHandle) {
+    @try {
+      [_pipeReadHandle closeAndReturnError:nil];
+    } @catch (NSException *exception) {
+      NSLog([exception description]);
+    }
+  }
+
+  _pipeReadHandle = nil;
+  _readPipe = nil;
 
-  [[NSNotificationCenter defaultCenter] removeObserver:self];
   [_lock unlock];
 }
 
 - (void)sendCommand: (NSString*) command {
   dispatch_sync(_queue, ^{
-    const char *cmd = [[command stringByAppendingString:@"\n"] UTF8String];
-    write([_pipeWriteHandle fileDescriptor], cmd, strlen(cmd));
+    if (!_pipeWriteHandle) { return; }
+    NSString *line = [command stringByAppendingString:@"\n"];
+    NSData *data = [line dataUsingEncoding:NSUTF8StringEncoding];
+
+    if (!data) { return; }
+
+    ssize_t fd = [_pipeWriteHandle fileDescriptor];
+
+    if (fd < 0) { return; }
+
+    ssize_t result = write(fd, [data bytes], [data length]);
+    (void)result;
   });
 }