Rename DigestHashFunction.cloneOrCreateMessageDigest() to DigestHashFunction.newMessageDigest().

tjgq · copybara-github · commit 6760e80b342f · 2026-04-01T04:46:08.000-07:00
From the caller's perspective, the end result is always the same: a fresh MessageDigest instance is created. Whether we were able to do so via cloning is an implementation detail.

PiperOrigin-RevId: 892859698
Change-Id: I1644154095956b498aecf65aa5c7dfc74551df24
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
@@ -69,7 +69,7 @@ public final class Fingerprint implements BytesSink {
 
   /** Creates and initializes a new instance. */
   public Fingerprint(DigestHashFunction digestFunction) {
-    messageDigest = digestFunction.cloneOrCreateMessageDigest();
+    messageDigest = digestFunction.newMessageDigest();
     // This is a lot of indirection, but CodedOutputStream does a reasonable job of converting
     // strings to bytes without creating a whole bunch of garbage, which pays off.
     codedOut =
@@ -348,7 +348,6 @@ public static String getHexDigest(String input) {
     // use the value from DigestHashFunction.getDefault(). However, this gets called during class
     // loading in a few places, before setDefault() has been called, so these call-sites should be
     // removed before this can be done safely.
-    return hexDigest(
-        DigestHashFunction.SHA256.cloneOrCreateMessageDigest().digest(input.getBytes(UTF_8)));
+    return hexDigest(DigestHashFunction.SHA256.newMessageDigest().digest(input.getBytes(UTF_8)));
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/DigestHashFunction.java b/src/main/java/com/google/devtools/build/lib/vfs/DigestHashFunction.java
@@ -160,7 +160,8 @@ public HashFunction getHashFunction() {
     return hashFunction;
   }
 
-  public MessageDigest cloneOrCreateMessageDigest() {
+  /** Creates a new {@link MessageDigest} for this hash function. */
+  public MessageDigest newMessageDigest() {
     if (messageDigestPrototypeSupportsClone) {
       try {
         return (MessageDigest) messageDigestPrototype.clone();
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/DigestHashFunctionsTest.java b/src/test/java/com/google/devtools/build/lib/vfs/DigestHashFunctionsTest.java
@@ -45,7 +45,7 @@ public static Collection<DigestHashFunction[]> hashFunctions() {
 
   private void assertHashFunctionAndMessageDigestEquivalentForInput(byte[] input) {
     byte[] hashFunctionOutput = digestHashFunction.getHashFunction().hashBytes(input).asBytes();
-    byte[] messageDigestOutput = digestHashFunction.cloneOrCreateMessageDigest().digest(input);
+    byte[] messageDigestOutput = digestHashFunction.newMessageDigest().digest(input);
     assertThat(hashFunctionOutput).isEqualTo(messageDigestOutput);
   }
 

Original file line number	Diff line number	Diff line change
`@@ -160,7 +160,8 @@ public HashFunction getHashFunction() {`
`160`	`160`	`return hashFunction;`
`161`	`161`	`}`
`162`	`162`
`163`		`- public MessageDigest cloneOrCreateMessageDigest() {`
	`163`	`+ /** Creates a new {@link MessageDigest} for this hash function. */`
	`164`	`+ public MessageDigest newMessageDigest() {`
`164`	`165`	`if (messageDigestPrototypeSupportsClone) {`
`165`	`166`	`try {`
`166`	`167`	`return (MessageDigest) messageDigestPrototype.clone();`
Original file line number	Diff line number	Diff line change
`@@ -45,7 +45,7 @@ public static Collection<DigestHashFunction[]> hashFunctions() {`
`45`	`45`
`46`	`46`	`private void assertHashFunctionAndMessageDigestEquivalentForInput(byte[] input) {`
`47`	`47`	`byte[] hashFunctionOutput = digestHashFunction.getHashFunction().hashBytes(input).asBytes();`
`48`		`- byte[] messageDigestOutput = digestHashFunction.cloneOrCreateMessageDigest().digest(input);`
	`48`	`+ byte[] messageDigestOutput = digestHashFunction.newMessageDigest().digest(input);`
`49`	`49`	`assertThat(hashFunctionOutput).isEqualTo(messageDigestOutput);`
`50`	`50`	`}`
`51`	`51`