|
|
@@ -51,57 +51,110 @@ import java.io.IOException; |
|
|
|
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() { |
|
|
|
} |
|
|
|
} |