1 files changed, 142 insertions, 0 deletions
diff --git a/sync/src/main/scala/akka/serial/sync/SerialConnection.scala b/sync/src/main/scala/akka/serial/sync/SerialConnection.scala
new file mode 100644
index 0000000..7d80a4c
--- /dev/null
+++ b/sync/src/main/scala/akka/serial/sync/SerialConnection.scala
@@ -0,0 +1,142 @@
+package akka.serial
+package sync
+
+import java.nio.ByteBuffer
+import java.util.concurrent.atomic.AtomicBoolean
+
+/**
+ * Represents a serial connection in a more secure and object-oriented style than `UnsafeSerial`. In
+ * contrast to the latter, this class encapsulates and secures any pointers used to communicate with
+ * the native backend and is thread-safe.
+ *
+ * The underlying serial port is assumed open when this class is initialized.
+ */
+class SerialConnection private (
+  unsafe: UnsafeSerial,
+  val port: String
+) {
+
+  private var reading: Boolean = false
+  private val readLock = new Object
+
+  private var writing: Boolean = false
+  private val writeLock = new Object
+
+  private val closed = new AtomicBoolean(false)
+
+  /**
+   * Checks if this serial port is closed.
+   */
+  def isClosed = closed.get()
+
+  /**
+   * Closes the underlying serial connection. Any callers blocked on read or write will return.
+   * A call of this method has no effect if the serial port is already closed.
+   * @throws IOException on IO error
+   */
+  def close(): Unit = this.synchronized {
+    if (!closed.get) {
+      closed.set(true)
+      unsafe.cancelRead()
+      readLock.synchronized {
+        while (reading) this.wait()
+      }
+      writeLock.synchronized {
+        while (writing) this.wait()
+      }
+      unsafe.close()
+    }
+  }
+
+  /**
+   * Reads data from underlying serial connection into a ByteBuffer.
+   * Note that data is read into the buffer's memory, starting at the
+   * first position. The buffer's limit is set to the number of bytes
+   * read.
+   *
+   * A call to this method is blocking, however it is interrupted
+   * if the connection is closed.
+   *
+   * This method works only for direct buffers.
+   *
+   * @param buffer a ByteBuffer into which data is read
+   * @return the actual number of bytes read
+   * @throws PortInterruptedException if port is closed while reading
+   * @throws IOException on IO error
+   */
+  def read(buffer: ByteBuffer): Int = readLock.synchronized {
+    if (!closed.get) {
+      try {
+        reading = true
+        val n = unsafe.read(buffer)
+        buffer.limit(n)
+        n
+      } finally {
+        reading = false
+        if (closed.get) readLock.notify()
+      }
+    } else {
+      throw new PortClosedException(s"${port} is closed")
+    }
+  }
+
+  /**
+   * Writes data from a ByteBuffer to underlying serial connection.
+   * Note that data is read from the buffer's memory, its attributes
+   * such as position and limit are not modified.
+   *
+   * The write is non-blocking, this function returns as soon as the data is copied into the kernel's
+   * transmission buffer.
+   *
+   * This method works only for direct buffers.
+   *
+   * @param buffer a ByteBuffer from which data is taken
+   * @return the actual number of bytes written
+   * @throws IOException on IO error
+   */
+  def write(buffer: ByteBuffer): Int = writeLock.synchronized {
+    if (!closed.get) {
+      try {
+        writing = true
+        unsafe.write(buffer, buffer.position)
+      } finally {
+        writing = false
+        if (closed.get) writeLock.notify()
+      }
+    } else {
+      throw new PortClosedException(s"${port} is closed")
+    }
+  }
+
+}
+
+object SerialConnection {
+
+  /**
+   * Opens a new connection to a serial port.
+   * This method acts as a factory to creating serial connections.
+   *
+   * @param port name of serial port to open
+   * @param settings settings with which to initialize the connection
+   * @return an instance of the open serial connection
+   * @throws NoSuchPortException if the given port does not exist
+   * @throws AccessDeniedException if permissions of the current user are not sufficient to open port
+   * @throws PortInUseException if port is already in use
+   * @throws InvalidSettingsException if any of the specified settings are invalid
+   * @throws IOException on IO error
+   */
+  def open(
+    port: String,
+    settings: SerialSettings
+  ): SerialConnection = synchronized {
+    val pointer = UnsafeSerial.open(
+      port,
+      settings.baud,
+      settings.characterSize,
+      settings.twoStopBits,
+      settings.parity.id
+    )
+    new SerialConnection(new UnsafeSerial(pointer), port)
+  }
+
+}