Support standard IO streams for several encryption tool commands

Useful for avoiding the need for intermediate files, such as when
piping the output of decryption to a Zstd decompressor.

Adds stdio support to:
 * Encryption input
 * Decryption input
 * Decryption output

Specified by substituting the file name with a single `-` character.

1 files changed, 27 insertions, 0 deletions

diff --git a/vespaclient-java/src/main/java/com/yahoo/vespa/security/tool/CliUtils.java b/vespaclient-java/src/main/java/com/yahoo/vespa/security/tool/CliUtils.java
index e9b348ab2a2..df199c00eda 100644
--- a/vespaclient-java/src/main/java/com/yahoo/vespa/security/tool/CliUtils.java
+++ b/vespaclient-java/src/main/java/com/yahoo/vespa/security/tool/CliUtils.java
@@ -3,6 +3,12 @@ package com.yahoo.vespa.security.tool;
 
 import org.apache.commons.cli.CommandLine;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
 /**
  * @author vekterli
  */
@@ -16,4 +22,25 @@ public class CliUtils {
         return value;
     }
 
+    public static InputStream inputStreamFromFileOrStream(String pathOrDash, InputStream stdIn) throws IOException {
+        if ("-".equals(pathOrDash)) {
+            return stdIn;
+        } else {
+            var inputPath = Paths.get(pathOrDash);
+            if (!inputPath.toFile().exists()) {
+                throw new IllegalArgumentException("Input file '%s' does not exist".formatted(inputPath.toString()));
+            }
+            return Files.newInputStream(inputPath);
+        }
+    }
+
+    public static OutputStream outputStreamToFileOrStream(String pathOrDash, OutputStream stdOut) throws IOException {
+        if ("-".equals(pathOrDash)) {
+            return stdOut;
+        } else {
+            // TODO fail if file already exists?
+            return Files.newOutputStream(Paths.get(pathOrDash));
+        }
+    }
+
 }