core: Opaque: Improve reuse of file id data for PseudoFS innerInode

... and add Opaque#numBytes and #putBytes.

This simplifies the dance between public-facing and inner Inode objects,
allowing Opaque objects to be reused between these.

Related: #149
Signed-off-by: Christian Kohlschütter <[email protected]>

Author: kohlschuetter

core/src/main/java/org/dcache/nfs/util/Opaque.java

@@ -88,13 +88,29 @@ static boolean defaultEquals(Opaque obj, Object other) {
      */
     byte[] toBytes();
 
+    /**
+     * Returns the number of bytes in this opaque object;
+     * 
+     * @return The number of bytes;
+     */
+    int numBytes();
+
     /**
      * Returns a Base64 string representing this opaque object.
      * 
      * @return A Base64 string.
      */
     String toBase64();
 
+    /**
+     * Writes the bytes of this {@link Opaque} to the given {@link ByteBuffer}.
+     * 
+     * @param buf The target buffer.
+     */
+    default void putBytes(ByteBuffer buf) {
+        buf.put(toBytes());
+    }
+
     /**
      * Returns the hashCode based on the byte-representation of this instance.
      * <p>
@@ -136,6 +152,11 @@ public String toBase64() {
             return base64;
         }
 
+        @Override
+        public void putBytes(ByteBuffer buf) {
+            buf.put(_opaque);
+        }
+
         @Override
         public int hashCode() {
             return Arrays.hashCode(_opaque);
@@ -166,5 +187,10 @@ public boolean equals(Object o) {
         public String toString() {
             return super.toString() + "[" + toBase64() + "]";
         }
+
+        @Override
+        public int numBytes() {
+            return _opaque.length;
+        }
     }
 }

core/src/main/java/org/dcache/nfs/vfs/Inode.java

@@ -69,14 +69,18 @@ public Inode(FileHandle fh) {
      */
     @Deprecated
     public Inode(int generation, int exportIdx, int type, byte[] fs_opaque) {
+        this(generation, exportIdx, type, Opaque.forBytes(fs_opaque));
+    }
+
+    private Inode(int generation, int exportIdx, int type, Opaque fileIdKey) {
         this.version = VERSION;
         this.magic = MAGIC;
         this.generation = generation;
         this.exportIdx = exportIdx;
         this.type = type;
-        this.opaqueKey = Opaque.forBytes(fs_opaque);
+        this.opaqueKey = fileIdKey;
 
-        this.nfsHandle = buildNfsHandle(fs_opaque);
+        this.nfsHandle = buildNfsHandle();
     }
 
     /**
@@ -146,6 +150,10 @@ public static Inode forFileIdKey(Opaque key) {
         return forFile(key.toBytes());
     }
 
+    public static Inode innerInode(Inode outerInode) {
+        return new Inode(0, 0, 0, outerInode.getFileIdKey());
+    }
+
     @Deprecated(forRemoval = true)
     public byte[] getFileId() {
         return opaqueKey.toBytes();
@@ -178,8 +186,13 @@ public byte[] toNfsHandle() {
         return nfsHandle.clone();
     }
 
-    private byte[] buildNfsHandle(byte[] fs_opaque) {
-        int len = fs_opaque.length + MIN_LEN;
+    private byte[] buildNfsHandle() {
+        int opaqueLen = opaqueKey.numBytes();
+        if (opaqueLen < 0 || opaqueLen > 255) {
+            throw new IllegalStateException("Invalid opaque key length");
+        }
+
+        int len = MIN_LEN + opaqueLen;
         byte[] bytes = new byte[len];
         ByteBuffer b = ByteBuffer.wrap(bytes);
         b.order(ByteOrder.BIG_ENDIAN);
@@ -188,8 +201,8 @@ private byte[] buildNfsHandle(byte[] fs_opaque) {
         b.putInt(generation);
         b.putInt(exportIdx);
         b.put((byte) type);
-        b.put((byte) fs_opaque.length);
-        b.put(fs_opaque);
+        b.put((byte) opaqueLen);
+        opaqueKey.putBytes(b);
         return bytes;
     }
 

core/src/main/java/org/dcache/nfs/vfs/PseudoFs.java

@@ -748,6 +748,6 @@ private boolean inheritUidGid(Inode inode) {
      * @return The {@link Inode} as passed from {@link PseudoFs} to the underlying {@link VirtualFileSystem}.
      */
     private Inode innerInode(Inode inode) {
-        return Inode.forFile(inode.getFileId());
+        return Inode.innerInode(inode);
     }
 }