### Locks

We have 3 different things that we synchronize on.

#### Http2Connection

This lock guards internal state of each connection. This lock is never held for blocking operations. That means that we acquire the lock, read or write a few fields and release the lock. No I/O and no application-layer callbacks.

#### Http2Stream

    private NetworkExplorer networkExplorer;

    @Mock
    private ServletConfig servletConfig;

    @Mock
    private ServletContext servletContext;

    @Mock
    private HttpServletRequest request;

    @Mock
    private HttpServletResponse response;

    @Mock
    private HttpSession session;

    @Mock
    private SmbFile smbFile;

    @Mock
    private SmbResourceLocator locator;

	c.mu.Lock()
	bucketIdx := c.nextCleanupBucket
	timeToExpire := time.Until(c.buckets[bucketIdx].newestEntry)
	// wait for newest entry to expire before cleanup without holding lock
	if timeToExpire > 0 {
		c.mu.Unlock()
		time.Sleep(timeToExpire)
		c.mu.Lock()
	}
	for _, ent := range c.buckets[bucketIdx].entries {
		c.removeElement(ent)
	}
	c.nextCleanupBucket = (c.nextCleanupBucket + 1) % numBuckets

    MockExecutor mock = new MockExecutor();
    TestExecutor testExecutor = new TestExecutor(mock);
    assertFalse(testExecutor.awaitTermination(10, MILLISECONDS));
    mock.assertLastMethodCalled("awaitTermination");
    assertFalse(testExecutor.isTerminated());
    mock.assertLastMethodCalled("isTerminated");
    assertFalse(testExecutor.isShutdown());
    mock.assertLastMethodCalled("isShutdown");

@ExtendWith(MockitoExtension.class)
@MockitoSettings(strictness = Strictness.LENIENT)
class SmbPipeHandleImplTest {

    @Mock
    SmbNamedPipe pipe;

    @Mock
    SmbTreeHandleImpl tree;

    @Mock
    SmbFileHandleImpl fileHandle;

    @Mock
    Configuration config;

    private SmbPipeHandleImpl target;

    @BeforeEach
    void setUp() throws SmbException {

import jcifs.util.transport.Request;

@ExtendWith(MockitoExtension.class)
@MockitoSettings(strictness = Strictness.LENIENT)
class SmbTransportImplTest {

    @Mock
    private CIFSContext ctx;
    @Mock
    private Configuration cfg;
    @Mock
    private Address address;

    private SmbTransportImpl transport;

    @BeforeEach
    void setUp() throws Exception {
        when(ctx.getConfig()).thenReturn(cfg);

   *
   * Lock lockA = factory1.newReentrantLock(MyLockOrder.FIRST);
   * Lock lockB = factory1.newReentrantLock(MyLockOrder.FIRST);
   * Lock lockC = factory2.newReentrantLock(MyLockOrder.FIRST);
   *
   * lockA.lock();
   *
   * lockB.lock();  // will throw an IllegalStateException
   * lockC.lock();  // will throw an IllegalStateException
   *
   * lockA.lock();  // reentrant acquisition is okay
   * }

package jcifs.internal.smb2.lock;

import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.Mockito.mock;

import java.lang.reflect.Field;
import java.util.Arrays;

	dm1st := NewDRWMutex(ds, "aap")
	dm2nd := NewDRWMutex(ds, "aap")

	dm1st.Lock(id, source)

	// Release lock after 10 seconds
	go func() {
		time.Sleep(5 * testDrwMutexAcquireTimeout)
		// fmt.Println("Unlocking dm1")

		dm1st.Unlock(t.Context())
	}()

	dm2nd.Lock(id, source)

	// fmt.Printf("2nd lock obtained after 1st lock is released\n")
	time.Sleep(testDrwMutexRefreshCallTimeout * 2)

	// ErrIsNotEmpty is returned when the buffer is not empty and not blocking.
	ErrIsNotEmpty = errors.New("ringbuffer is not empty")

	// ErrAcquireLock is returned when the lock is not acquired on Try operations.
	ErrAcquireLock = errors.New("unable to acquire lock")

	// ErrWriteOnClosed is returned when write on a closed ringbuffer.
	ErrWriteOnClosed = errors.New("write on closed ringbuffer")
)