Avoid double encoding in PersistentStringIndexer

Strings using Bazel's internal encoding are already raw UTF-8 byte arrays.

Closes bazelbuild#27590.

PiperOrigin-RevId: 829517859
Change-Id: I558419f0a74c640c5d82e8b58c29943af226c7b3

Author: fmeum

src/main/java/com/google/devtools/build/lib/actions/cache/PersistentStringIndexer.java

@@ -14,10 +14,10 @@
 package com.google.devtools.build.lib.actions.cache;
 
 import static java.lang.Math.max;
-import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.devtools.build.lib.clock.Clock;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.ConditionallyThreadSafe;
+import com.google.devtools.build.lib.unsafe.StringUnsafe;
 import com.google.devtools.build.lib.util.MapCodec;
 import com.google.devtools.build.lib.util.PersistentMap;
 import com.google.devtools.build.lib.util.StringIndexer;
@@ -183,7 +183,7 @@ public void dump(PrintStream out) {
   }
 
   private static final MapCodec<String, Integer> CODEC =
-      new MapCodec<String, Integer>() {
+      new MapCodec<>() {
         @Override
         protected String readKey(DataInput in) throws IOException {
           int length = in.readInt();
@@ -192,7 +192,7 @@ protected String readKey(DataInput in) throws IOException {
           }
           byte[] content = new byte[length];
           in.readFully(content);
-          return new String(content, UTF_8);
+          return StringUnsafe.newInstance(content, StringUnsafe.LATIN1);
         }
 
         @Override
@@ -202,7 +202,7 @@ protected Integer readValue(DataInput in) throws IOException {
 
         @Override
         protected void writeKey(String key, DataOutput out) throws IOException {
-          byte[] content = key.getBytes(UTF_8);
+          byte[] content = StringUnsafe.getInternalStringBytes(key);
           out.writeInt(content.length);
           out.write(content);
         }
@@ -218,7 +218,7 @@ protected void writeValue(Integer value, DataOutput out) throws IOException {
    * metadata cache.
    */
   private static final class PersistentIndexMap extends PersistentMap<String, Integer> {
-    private static final int VERSION = 0x01;
+    private static final int VERSION = 0x02;
     private static final long SAVE_INTERVAL_NS = 3L * 1000 * 1000 * 1000;
 
     private final Clock clock;