Merge branch 'stable-4.11'
* stable-4.11:
ObjectIdSerializer: Support serialization of known non-null ObjectId
Change-Id: Ie430fa2c5d13ae698d884a37d0d03884ebbf25ec
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectIdSerializerTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectIdSerializerTest.java
index 24bc40e..d98b792 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectIdSerializerTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectIdSerializerTest.java
@@ -79,10 +79,18 @@ private ObjectId writeAndReadBackFromTempFile(ObjectId objectId)
throws Exception {
File file = File.createTempFile("ObjectIdSerializerTest_", "");
try (OutputStream out = new FileOutputStream(file)) {
- ObjectIdSerializer.write(out, objectId);
+ if (objectId == null) {
+ ObjectIdSerializer.write(out, objectId);
+ } else {
+ ObjectIdSerializer.writeWithoutMarker(out, objectId);
+ }
}
try (InputStream in = new FileInputStream(file)) {
- return ObjectIdSerializer.read(in);
+ if (objectId == null) {
+ return ObjectIdSerializer.read(in);
+ } else {
+ return ObjectIdSerializer.readWithoutMarker(in);
+ }
}
}
}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectIdSerializer.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectIdSerializer.java
index 59da408..96c7cee 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectIdSerializer.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectIdSerializer.java
@@ -51,57 +51,110 @@
import java.io.InputStream;
import java.io.OutputStream;
+import org.eclipse.jgit.annotations.NonNull;
import org.eclipse.jgit.annotations.Nullable;
import org.eclipse.jgit.util.IO;
/**
* Helper to serialize {@link ObjectId} instances. {@link ObjectId} is already
- * serializable, but this class provides a more optimal implementation. It
- * writes out a flag (0 or 1) followed by the object's words, or nothing if it
- * was a null id.
+ * serializable, but this class provides methods to handle null and non-null
+ * instances.
*
* @since 4.11
*/
public class ObjectIdSerializer {
+ /*
+ * Marker to indicate a null ObjectId instance.
+ */
+ private static final byte NULL_MARKER = 0;
+
+ /*
+ * Marker to indicate a non-null ObjectId instance.
+ */
+ private static final byte NON_NULL_MARKER = 1;
+
/**
+ * Write a possibly null {@link ObjectId} to the stream, using markers to
+ * differentiate null and non-null instances.
+ *
+ * <p>
+ * If the id is non-null, writes a {@link #NON_NULL_MARKER} followed by the
+ * id's words. If it is null, writes a {@link #NULL_MARKER} and nothing
+ * else.
+ *
* @param out
* the output stream
* @param id
- * the object id to serialize
+ * the object id to serialize; may be null
* @throws IOException
* the stream writing failed
*/
public static void write(OutputStream out, @Nullable AnyObjectId id)
throws IOException {
if (id != null) {
- out.write((byte) 1);
- id.copyRawTo(out);
+ out.write(NON_NULL_MARKER);
+ writeWithoutMarker(out, id);
} else {
- out.write((byte) 0);
+ out.write(NULL_MARKER);
}
}
/**
+ * Write a non-null {@link ObjectId} to the stream.
+ *
+ * @param out
+ * the output stream
+ * @param id
+ * the object id to serialize; never null
+ * @throws IOException
+ * the stream writing failed
+ */
+ public static void writeWithoutMarker(OutputStream out, @NonNull AnyObjectId id)
+ throws IOException {
+ id.copyRawTo(out);
+ }
+
+ /**
+ * Read a possibly null {@link ObjectId} from the stream.
+ *
+ * Reads the first byte of the stream, which is expected to be either
+ * {@link #NON_NULL_MARKER} or {@link #NULL_MARKER}.
+ *
* @param in
* the input stream
- * @return the object id
+ * @return the object id, or null
* @throws IOException
* there was an error reading the stream
*/
@Nullable
public static ObjectId read(InputStream in) throws IOException {
- switch (in.read()) {
- case 0:
+ byte marker = (byte) in.read();
+ switch (marker) {
+ case NULL_MARKER:
return null;
- case 1:
- final byte[] b = new byte[OBJECT_ID_LENGTH];
- IO.readFully(in, b, 0, OBJECT_ID_LENGTH);
- return ObjectId.fromRaw(b);
+ case NON_NULL_MARKER:
+ return readWithoutMarker(in);
default:
- throw new IOException("Invalid flag before ObjectId"); //$NON-NLS-1$
+ throw new IOException("Invalid flag before ObjectId: " + marker); //$NON-NLS-1$
}
}
+ /**
+ * Read a non-null {@link ObjectId} from the stream.
+ *
+ * @param in
+ * the input stream
+ * @return the object id; never null
+ * @throws IOException
+ * there was an error reading the stream
+ */
+ @NonNull
+ public static ObjectId readWithoutMarker(InputStream in) throws IOException {
+ final byte[] b = new byte[OBJECT_ID_LENGTH];
+ IO.readFully(in, b, 0, OBJECT_ID_LENGTH);
+ return ObjectId.fromRaw(b);
+ }
+
private ObjectIdSerializer() {
}
}
