Add nullable variants to Fingerprint.

--
MOS_MIGRATED_REVID=120325869

2 files changed, 65 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/util/Fingerprint.java b/src/main/java/com/google/devtools/build/lib/util/Fingerprint.java
index 443b8a02ea..eb053f9be6 100644
--- a/src/main/java/com/google/devtools/build/lib/util/Fingerprint.java
+++ b/src/main/java/com/google/devtools/build/lib/util/Fingerprint.java
@@ -25,6 +25,8 @@ import java.security.NoSuchAlgorithmException;
 import java.util.Map;
 import java.util.UUID;
 
+import javax.annotation.Nullable;
+
 /**
  * Simplified wrapper for MD5 message digests. See also
  * com.google.math.crypto.MD5HMAC for a similar interface.
@@ -139,6 +141,14 @@ public final class Fingerprint {
   }
 
   /**
+   * Updates the digest with a boolean value, correctly handling null.
+   */
+  public Fingerprint addNullableBoolean(Boolean input) {
+    addInt(input == null ? -1 : (input.booleanValue() ? 1 : 0));
+    return this;
+  }
+
+  /**
    * Updates the digest with the little-endian bytes of a given int value.
    *
    * @param input the integer with which to update the digest
@@ -175,6 +185,22 @@ public final class Fingerprint {
   }
 
   /**
+   * Updates the digest with the little-endian bytes of a given int value, correctly distinguishing
+   * between null and non-null values.
+   *
+   * @param input the integer with which to update the digest
+   */
+  public Fingerprint addNullableInt(@Nullable Integer input) {
+    if (input == null) {
+      addInt(0);
+    } else {
+      addInt(1);
+      addInt(input);
+    }
+    return this;
+  }
+
+  /**
    * Updates the digest with a UUID.
    *
    * @param uuid the UUID with which to update the digest. Must not be null.
@@ -199,6 +225,22 @@ public final class Fingerprint {
   }
 
   /**
+   * Updates the digest with a String using its length plus its UTF8 encoded bytes; if the string
+   * is null, then it uses -1 as the length.
+   *
+   * @param input the String with which to update the digest
+   * @see java.security.MessageDigest#update(byte[])
+   */
+  public Fingerprint addNullableString(@Nullable String input) {
+    if (input == null) {
+      addInt(-1);
+    } else {
+      addString(input);
+    }
+    return this;
+  }
+
+  /**
    * Updates the digest with a String using its length and content.
    *
    * @param input the String with which to update the digest
diff --git a/src/test/java/com/google/devtools/build/lib/util/FingerprintTest.java b/src/test/java/com/google/devtools/build/lib/util/FingerprintTest.java
index 5aeb9685fe..42fc24e943 100644
--- a/src/test/java/com/google/devtools/build/lib/util/FingerprintTest.java
+++ b/src/test/java/com/google/devtools/build/lib/util/FingerprintTest.java
@@ -134,4 +134,27 @@ public class FingerprintTest {
     assertThat("01cc3eeea3a2f58e447e824f9f62d3d1").isEqualTo(
         new Fingerprint().addPath(p).hexDigestAndReset());
   }
+
+  @Test
+  public void addNullableBoolean() throws Exception {
+    String f1 = new Fingerprint().addNullableBoolean(null).hexDigestAndReset();
+    assertThat(f1).isEqualTo(new Fingerprint().addNullableBoolean(null).hexDigestAndReset());
+    assertThat(f1).isNotEqualTo(new Fingerprint().addNullableBoolean(false).hexDigestAndReset());
+    assertThat(f1).isNotEqualTo(new Fingerprint().addNullableBoolean(true).hexDigestAndReset());
+  }
+
+  @Test
+  public void addNullableInteger() throws Exception {
+    String f1 = new Fingerprint().addNullableInt(null).hexDigestAndReset();
+    assertThat(f1).isEqualTo(new Fingerprint().addNullableInt(null).hexDigestAndReset());
+    assertThat(f1).isNotEqualTo(new Fingerprint().addNullableInt(0).hexDigestAndReset());
+    assertThat(f1).isNotEqualTo(new Fingerprint().addNullableInt(1).hexDigestAndReset());
+  }
+
+  @Test
+  public void addNullableString() throws Exception {
+    String f1 = new Fingerprint().addNullableString(null).hexDigestAndReset();
+    assertThat(f1).isEqualTo(new Fingerprint().addNullableString(null).hexDigestAndReset());
+    assertThat(f1).isNotEqualTo(new Fingerprint().addNullableString("").hexDigestAndReset());
+  }
 }