# SMB3 Lease Feature - Detailed Design Document

## 1. Overview

SMB3 leases provide a client caching mechanism that replaces the traditional oplock mechanism. Leases enable better performance through client-side caching while maintaining cache coherency across multiple clients.

## 2. Protocol Specification Reference

- **MS-SMB2 Section 2.2.13**: SMB2 CREATE Request with Lease Context
- **MS-SMB2 Section 2.2.14**: SMB2 CREATE Response with Lease State

 * behavior</a> when multiple threads attempt concurrent mutations. Its equivalent to {@code
 * CacheBuilder} is its <a
 * href="https://www.javadoc.io/doc/com.github.ben-manes.caffeine/caffeine/latest/com.github.benmanes.caffeine/com/github/benmanes/caffeine/cache/Caffeine.html">{@code
 * Caffeine}</a> class. Caffeine offers better performance, more features (including asynchronous

    
    // Second listing should use cache (much faster)
    long start2 = System.currentTimeMillis();
    SmbFile[] files2 = dir.listFiles();
    long time2 = System.currentTimeMillis() - start2;
    
    assertEquals(files1.length, files2.length);
    assertTrue(time2 < time1 / 2);  // Should be significantly faster
}

@Test
public void testDirectoryChangeNotification() throws Exception {

    testDecodes(ignoreCase, "666F6F626172", "foobar");
    testDecodes(ignoreCase, "666f6f626172", "foobar");
    testDecodes(ignoreCase, "666F6f626172", "foobar");
  }

  // order the methods are called should not matter
  public void testBase16IgnoreCaseLowerCase() {
    BaseEncoding ignoreCase = base16().ignoreCase().lowerCase();
    assertThat(ignoreCase).isNotSameInstanceAs(base16());

    b ^= b >>> 47;
    b *= K3;
    return b;
  }

  /**
   * Computes intermediate hash of 32 bytes of byte array from the given offset. Results are
   * returned in the output array - this is 12% faster than allocating new arrays every time.
   */
  private static void weakHashLength32WithSeeds(
      byte[] bytes, int offset, long seedA, long seedB, long[] output) {
    long part1 = load64(bytes, offset);

        assertNotNull(e.getMessage()); // Should have an error message
    }

    @Test
    void testGetters() {
        // Simple test for getter methods
        NtlmContext context = new NtlmContext(mockAuth, true);
        assertFalse(context.isEstablished());
        assertNull(context.getServerChallenge());
        assertNull(context.getSigningKey());

![Events Diagram](../assets/images/******@****.***)

Here’s a [sample event listener](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEventsNonConcurrent.java) that prints each event with a timestamp.

```java
class PrintingEventListener extends EventListener {
  private long callStartNanos;

        assertSame(buffer, released);
        assertEquals(0x42, released[0]);

        // After release, getting buffer again should return null
        assertNull(transaction.releaseBuffer());
    }

    @Test
    @DisplayName("Test subCommand getter and setter")
    void testSubCommand() {
        assertEquals(SmbComTransaction.TRANS2_FIND_FIRST2, transaction.getSubCommand());

            if (config.isEncryptionEnabled()) {
                // Build cipher list based on AES-256 support
                List<Integer> ciphers = new ArrayList<>();

                // Prefer GCM over CCM for better performance
                if (config.isAES256Enabled()) {
                    ciphers.add(EncryptionNegotiateContext.CIPHER_AES256_GCM);
                    ciphers.add(EncryptionNegotiateContext.CIPHER_AES256_CCM);

    private SmbFile createMockSmbFile(String url, NtlmPasswordAuthentication auth) throws MalformedURLException {
        // This is complex due to the class structure. A better approach would be
        // to refactor SmbFile to be more testable (e.g., dependency injection).
        // For now, we test methods that don't require deep mocks.
        return new SmbFile(url, auth);
    }