Move HashFunction out of FileSystem, and turn it into a class, instead of an enum.

Now that we aren't using enum names for the hash functions, we also accept the standard names, such as SHA-256.

RELNOTES: None.
PiperOrigin-RevId: 201624286

2 files changed, 71 insertions, 3 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/vfs/DigestHashFunctionTest.java b/src/test/java/com/google/devtools/build/lib/vfs/DigestHashFunctionTest.java
new file mode 100644
index 0000000000..e39b3c0a54
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/vfs/DigestHashFunctionTest.java
@@ -0,0 +1,67 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.vfs;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.hash.Hashing;
+import com.google.devtools.build.lib.vfs.DigestHashFunction.DigestFunctionConverter;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/**
+ * Tests for DigestHashFunction, notably that the static instances can be compared with reference
+ * equality.
+ */
+@RunWith(JUnit4.class)
+public class DigestHashFunctionTest {
+  private final DigestFunctionConverter converter = new DigestFunctionConverter();
+
+  @Test
+  public void convertReturnsTheSameValueAsTheConstant() throws Exception {
+    assertThat(converter.convert("sha-256")).isSameAs(DigestHashFunction.SHA256);
+    assertThat(converter.convert("SHA-256")).isSameAs(DigestHashFunction.SHA256);
+    assertThat(converter.convert("SHA256")).isSameAs(DigestHashFunction.SHA256);
+    assertThat(converter.convert("sha256")).isSameAs(DigestHashFunction.SHA256);
+
+    assertThat(converter.convert("SHA-1")).isSameAs(DigestHashFunction.SHA1);
+    assertThat(converter.convert("sha-1")).isSameAs(DigestHashFunction.SHA1);
+    assertThat(converter.convert("SHA1")).isSameAs(DigestHashFunction.SHA1);
+    assertThat(converter.convert("sha1")).isSameAs(DigestHashFunction.SHA1);
+
+    assertThat(converter.convert("MD5")).isSameAs(DigestHashFunction.MD5);
+    assertThat(converter.convert("md5")).isSameAs(DigestHashFunction.MD5);
+  }
+
+  @Test
+  public void lateRegistrationGetsPickedUpByConverter() throws Exception {
+    DigestHashFunction.register(Hashing.goodFastHash(32), "goodFastHash32");
+
+    assertThat(converter.convert("goodFastHash32")).isSameAs(converter.convert("GOODFASTHASH32"));
+  }
+
+  @Test
+  public void lateRegistrationWithAlternativeNamesGetsPickedUpByConverter() throws Exception {
+    DigestHashFunction.register(
+        Hashing.goodFastHash(64), "goodFastHash64", "goodFastHash-64", "good-fast-hash-64");
+
+    assertThat(converter.convert("goodFastHash64")).isSameAs(converter.convert("GOODFASTHASH64"));
+    assertThat(converter.convert("goodFastHash64")).isSameAs(converter.convert("goodFastHash-64"));
+    assertThat(converter.convert("goodFastHash64"))
+        .isSameAs(converter.convert("good-fast-hash-64"));
+    assertThat(converter.convert("goodFastHash64"))
+        .isSameAs(converter.convert("GOOD-fast-HASH-64"));
+  }
+}
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/FileSystemTest.java b/src/test/java/com/google/devtools/build/lib/vfs/FileSystemTest.java
index 39c75eaeaa..fdf94298d3 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/FileSystemTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/FileSystemTest.java
@@ -23,7 +23,6 @@ import com.google.devtools.build.lib.testutil.MoreAsserts;
 import com.google.devtools.build.lib.testutil.TestUtils;
 import com.google.devtools.build.lib.unix.NativePosixFiles;
 import com.google.devtools.build.lib.util.Fingerprint;
-import com.google.devtools.build.lib.vfs.FileSystem.HashFunction;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
@@ -1305,7 +1304,8 @@ public abstract class FileSystemTest {
     Fingerprint fp = new Fingerprint();
     fp.addBytes(new byte[0]);
     assertThat(fp.hexDigestAndReset())
-        .isEqualTo(BaseEncoding.base16().lowerCase().encode(xFile.getDigest(HashFunction.MD5)));
+        .isEqualTo(
+            BaseEncoding.base16().lowerCase().encode(xFile.getDigest(DigestHashFunction.MD5)));
   }
 
   @Test
@@ -1318,7 +1318,8 @@ public abstract class FileSystemTest {
     Fingerprint fp = new Fingerprint();
     fp.addBytes(buffer);
     assertThat(fp.hexDigestAndReset())
-        .isEqualTo(BaseEncoding.base16().lowerCase().encode(xFile.getDigest(HashFunction.MD5)));
+        .isEqualTo(
+            BaseEncoding.base16().lowerCase().encode(xFile.getDigest(DigestHashFunction.MD5)));
   }
 
   @Test