MacOS Thread Related Crash Fix

src/main/java/org/hid4java/jna/DarwinHidApiLibrary.java

@@ -1,24 +1,168 @@
 package org.hid4java.jna;
 
 import com.sun.jna.Native;
+import com.sun.jna.Pointer;
 import com.sun.jna.WString;
 
-public interface DarwinHidApiLibrary extends HidrawHidApiLibrary {
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 
-  DarwinHidApiLibrary INSTANCE = Native.load("hidapi", DarwinHidApiLibrary.class);
+/**
+ * This class provides a management layer for thread-sensitive operations within the HIDAPI library on macOS. Due to
+ * threading constraints in the underlying native library, certain functions must be called from the same thread. This
+ * includes {@code hid_init()} and {@code hid_exit()}, which must be invoked on a consistent thread to avoid runtime
+ * failures. See <a href="https://github.com/libusb/hidapi/issues/666">hidapi #666</a>
+ * <br>
+ * Additionally, certain functions such as {@code hid_open()}, {@code hid_enumerate()}, and {@code hid_open_path()} may
+ * implicitly call {@code hid_init()} if it has not been previously called. To prevent potential crashes due to these
+ * implicit calls, these functions are also managed in the same way.
+ * <br>
+ * This class utilizes a single-thread executor to wrap the thread-sensitive calls onto a single thread. Despite using
+ * an executor, the operations are executed in a blocking manner, ensuring they complete before returning.
+ */
+public class DarwinHidApiLibrary implements HidApiLibrary {
+  // WARNING:  This is NOT a JNA interface, but rather a wrapped instance
+  public static HidApiLibrary INSTANCE = new DarwinHidApiLibrary();
+  private static final RealDarwinHidApiLibrary REAL_INSTANCE = Native.load("hidapi", RealDarwinHidApiLibrary.class);
+  private static final ExecutorService executor = Executors.newSingleThreadExecutor();
 
-  /**
-   * Changes the behavior of all further calls to {@link #hid_open(short, short, WString)} or {@link #hid_open_path(String)}.
-   * <br>
-   * All devices opened by HIDAPI with {@link #hid_open(short, short, WString)} or {@link #hid_open_path(String)}
-   * are opened in exclusive mode per default.
-   * <br>
-   * Calling this function before {@link #hid_init()} or after {@link #hid_exit()} has no effect.
-   *
-   * @since hidapi 0.12.0
-   * @param openExclusive When set to 0 - all further devices will be opened in non-exclusive mode.
-   *                      Otherwise - all further devices will be opened in exclusive mode.
-   */
-  void hid_darwin_set_open_exclusive(int openExclusive);
+  private interface RealDarwinHidApiLibrary extends HidrawHidApiLibrary {
+    /**
+     * Changes the behavior of all further calls to {@link #hid_open(short, short, WString)} or {@link #hid_open_path(String)}.
+     * <br>
+     * All devices opened by HIDAPI with {@link #hid_open(short, short, WString)} or {@link #hid_open_path(String)}
+     * are opened in exclusive mode per default.
+     * <br>
+     * Calling this function before {@link #hid_init()} or after {@link #hid_exit()} has no effect.
+     *
+     * @since hidapi 0.12.0
+     * @param openExclusive When set to 0 - all further devices will be opened in non-exclusive mode.
+     *                      Otherwise - all further devices will be opened in exclusive mode.
+     */
+    void hid_darwin_set_open_exclusive(int openExclusive);
+  }
+  @Override
+  public void hid_init() {
+    try {
+      executor.submit(REAL_INSTANCE::hid_init).get();
+    } catch (InterruptedException | ExecutionException e) {
+      throw new RuntimeException(e);
+    }
+  }
 
+  @Override
+  public void hid_exit() {
+    try {
+      executor.submit(REAL_INSTANCE::hid_exit).get();
+    } catch (InterruptedException | ExecutionException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  @Override
+  public Pointer hid_open(short vendor_id, short product_id, WString serial_number) {
+    try {
+      return executor.submit(() -> REAL_INSTANCE.hid_open(vendor_id, product_id, serial_number)).get();
+    } catch (InterruptedException | ExecutionException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  @Override
+  public void hid_close(Pointer device) {
+    REAL_INSTANCE.hid_close(device);
+  }
+
+  @Override
+  public Pointer hid_error(Pointer device) {
+    return REAL_INSTANCE.hid_error(device);
+  }
+
+  @Override
+  public int hid_read(Pointer device, WideStringBuffer.ByReference bytes, int length) {
+    return REAL_INSTANCE.hid_read(device, bytes, length);
+  }
+
+  @Override
+  public int hid_read_timeout(Pointer device, WideStringBuffer.ByReference bytes, int length, int timeout) {
+    return REAL_INSTANCE.hid_read_timeout(device, bytes, length, timeout);
+  }
+
+  @Override
+  public int hid_write(Pointer device, WideStringBuffer.ByReference data, int len) {
+    return REAL_INSTANCE.hid_write(device, data, len);
+  }
+
+  @Override
+  public int hid_get_feature_report(Pointer device, WideStringBuffer.ByReference data, int length) {
+    return REAL_INSTANCE.hid_get_feature_report(device, data, length);
+  }
+
+  @Override
+  public int hid_send_feature_report(Pointer device, WideStringBuffer.ByReference data, int length) {
+    return REAL_INSTANCE.hid_send_feature_report(device, data, length);
+  }
+
+  @Override
+  public int hid_get_indexed_string(Pointer device, int idx, WideStringBuffer.ByReference string, int len) {
+    return REAL_INSTANCE.hid_get_indexed_string(device, idx, string, len);
+  }
+
+  @Override
+  public int hid_get_report_descriptor(Pointer device, byte[] buffer, int size) {
+    return REAL_INSTANCE.hid_get_report_descriptor(device, buffer, size);
+  }
+
+  @Override
+  public int hid_get_manufacturer_string(Pointer device, WideStringBuffer.ByReference str, int len) {
+    return REAL_INSTANCE.hid_get_manufacturer_string(device, str, len);
+  }
+
+  @Override
+  public int hid_get_product_string(Pointer device, WideStringBuffer.ByReference str, int len) {
+    return REAL_INSTANCE.hid_get_product_string(device, str, len);
+  }
+
+  @Override
+  public int hid_get_serial_number_string(Pointer device, WideStringBuffer.ByReference str, int len) {
+    return REAL_INSTANCE.hid_get_serial_number_string(device, str, len);
+  }
+
+  @Override
+  public int hid_set_nonblocking(Pointer device, int nonblock) {
+    return REAL_INSTANCE.hid_set_nonblocking(device, nonblock);
+  }
+
+  @Override
+  public HidDeviceInfoStructure hid_enumerate(short vendor_id, short product_id) {
+    try {
+      return executor.submit(() -> REAL_INSTANCE.hid_enumerate(vendor_id, product_id)).get();
+    } catch (InterruptedException | ExecutionException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  @Override
+  public void hid_free_enumeration(Pointer devs) {
+    REAL_INSTANCE.hid_free_enumeration(devs);
+  }
+
+  @Override
+  public Pointer hid_open_path(String path) {
+    try {
+      return executor.submit(() -> REAL_INSTANCE.hid_open_path(path)).get();
+    } catch (InterruptedException | ExecutionException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  @Override
+  public String hid_version_str() {
+    return REAL_INSTANCE.hid_version_str();
+  }
+
+  public void hid_darwin_set_open_exclusive(int openExclusive) {
+    REAL_INSTANCE.hid_darwin_set_open_exclusive(openExclusive);
+  }
 }