Streamline the FileSignature api.

Author: nedtwigg

lib/src/main/java/com/diffplug/spotless/FileSignature.java

@@ -121,26 +121,10 @@ public static Promised promise(Iterable<File> files) {
 		return new Promised(MoreIterables.toNullHostileList(files), null);
 	}
 
-	public Promised roundTrippable() {
+	public Promised asPromise() {
 		return new Promised(files, this);
 	}
 
-	public static @Nullable Promised roundTrippableNullable(@Nullable FileSignature signature) {
-		if (signature != null) {
-			return signature.roundTrippable();
-		} else {
-			return null;
-		}
-	}
-
-	public static @Nullable FileSignature stripAbsolutePathsNullable(@Nullable Promised roundTrippable) throws IOException {
-		if (roundTrippable != null) {
-			return roundTrippable.get();
-		} else {
-			return null;
-		}
-	}
-
 	/** Returns all of the files in this signature, throwing an exception if there are more or less than 1 file. */
 	public Collection<File> files() {
 		return Collections.unmodifiableList(files);

lib/src/main/java/com/diffplug/spotless/JarState.java

@@ -51,7 +51,7 @@ public JarState get() {
 			try {
 				if (cached == null) {
 					JarState result = supplier.get();
-					cached = result.fileSignature.roundTrippable();
+					cached = result.fileSignature.asPromise();
 					return result;
 				}
 				return new JarState(cached.get());

lib/src/main/java/com/diffplug/spotless/kotlin/DiktatStep.java

@@ -34,7 +34,7 @@ public class DiktatStep implements Serializable {
 	private DiktatStep(JarState.Promised jarState, boolean isScript, @Nullable FileSignature config) {
 		this.jarState = jarState;
 		this.isScript = isScript;
-		this.config = FileSignature.roundTrippableNullable(config);
+		this.config = config != null ? config.asPromise() : null;
 	}
 
 	private static final String MIN_SUPPORTED_VERSION = "1.2.1";
@@ -72,7 +72,7 @@ public static FormatterStep create(String versionDiktat, Provisioner provisioner
 	}
 
 	private State equalityState() throws Exception {
-		return new State(jarState.get(), isScript, FileSignature.stripAbsolutePathsNullable(config));
+		return new State(jarState.get(), isScript, config != null ? config.get() : null);
 	}
 
 	static final class State implements Serializable {