Support package mappings

src/main/java/net/fabricmc/mappingio/FlatMappingVisitor.java

@@ -62,6 +62,14 @@ default boolean visitContent() throws IOException {
 		return true;
 	}
 
+	// TODO: Un-"default" in the next breaking release
+	default boolean visitPackage(String srcName, @Nullable String[] dstNames) throws IOException {
+		return false;
+	}
+
+	// TODO: Un-"default" in the next breaking release
+	default void visitPackageComment(String srcName, @Nullable String[] dstNames, String comment) throws IOException { }
+
 	boolean visitClass(String srcName, @Nullable String[] dstNames) throws IOException;
 	void visitClassComment(String srcName, @Nullable String[] dstNames, String comment) throws IOException;
 
@@ -149,6 +157,17 @@ default boolean visitMethodVar(String srcClsName, String srcMethodName, @Nullabl
 	}
 
 	// convenience / potentially higher efficiency visit methods for only one dst name
+	default boolean visitPackage(String srcName, String dstName) throws IOException {
+		return visitPackage(srcName, toArray(dstName));
+	}
+
+	default void visitPackageComment(String srcName, String comment) throws IOException {
+		visitPackageComment(srcName, (String) null, comment);
+	}
+
+	default void visitPackageComment(String srcName, @Nullable String dstName, String comment) throws IOException {
+		visitPackageComment(srcName, toArray(dstName), comment);
+	}
 
 	default boolean visitClass(String srcName, String dstName) throws IOException {
 		return visitClass(srcName, toArray(dstName));

src/main/java/net/fabricmc/mappingio/MappedElementKind.java

@@ -20,6 +20,7 @@
  * A kind of element that can be mapped.
  */
 public enum MappedElementKind {
+	PACKAGE(0),
 	CLASS(0),
 	FIELD(1),
 	METHOD(1),

src/main/java/net/fabricmc/mappingio/MappingVisitor.java

@@ -28,7 +28,8 @@
  * <p>The visitation order is as follows (omitting visit prefixes for brevity, lowercase for cross references):
  * <ul><li>overall: header -> content -> End -> overall
  * <li>header: Header -> Namespaces [-> Metadata]*
- * <li>content: Content [-> class|Metadata]*
+ * <li>content: Content [-> package|class|Metadata]*
+ * <li>package: Package [-> DstName]* -> ElementContent*
  * <li>class: Class [-> DstName]* -> ElementContent [-> field|method|Comment]*
  * <li>field: Field [-> DstName|DstDesc]* -> ElementContent [-> Comment]
  * <li>method: Method [-> DstName|DstDesc]* -> ElementContent [-> arg|var|Comment]*
@@ -85,6 +86,18 @@ default boolean visitContent() throws IOException {
 		return true;
 	}
 
+	/**
+	 * Visit a package.
+	 *
+	 * @param srcName The package path, with slashes instead of dots, and no trailing slash.
+	 * An empty string represents the default package.
+	 * @return Whether or not the package's content should be visited too.
+	 */
+	// TODO: Un-"default" in the next breaking release
+	default boolean visitPackage(String srcName) throws IOException {
+		return false;
+	}
+
 	/**
 	 * Visit a class.
 	 *

src/main/java/net/fabricmc/mappingio/adapter/FlatAsRegularMappingVisitor.java

@@ -64,10 +64,11 @@ public void visitNamespaces(String srcNamespace, List<String> dstNamespaces) thr
 		Set<MappingFlag> flags = next.getFlags();
 
 		if (flags.contains(MappingFlag.NEEDS_ELEMENT_UNIQUENESS)) {
+			dstPackageNames = new String[count];
 			dstClassNames = new String[count];
 			dstMemberNames = new String[count];
 		} else {
-			dstClassNames = dstMemberNames = null;
+			dstPackageNames = dstClassNames = dstMemberNames = null;
 		}
 
 		dstMemberDescs = flags.contains(MappingFlag.NEEDS_DST_FIELD_DESC) || flags.contains(MappingFlag.NEEDS_DST_METHOD_DESC) ? new String[count] : null;
@@ -83,6 +84,16 @@ public boolean visitContent() throws IOException {
 		return next.visitContent();
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		this.srcPkgName = srcName;
+
+		Arrays.fill(dstNames, null);
+		if (dstPackageNames != null) Arrays.fill(dstPackageNames, null);
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) {
 		this.srcClsName = srcName;
@@ -161,6 +172,10 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 		boolean relay;
 
 		switch (targetKind) {
+		case PACKAGE:
+			relay = next.visitPackage(srcPkgName, dstNames);
+			if (relay && dstPackageNames != null) System.arraycopy(dstNames, 0, dstPackageNames, 0, dstNames.length);
+			break;
 		case CLASS:
 			relay = next.visitClass(srcClsName, dstNames);
 			if (relay && dstClassNames != null) System.arraycopy(dstNames, 0, dstClassNames, 0, dstNames.length);
@@ -193,6 +208,9 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 	@Override
 	public void visitComment(MappedElementKind targetKind, String comment) throws IOException {
 		switch (targetKind) {
+		case PACKAGE:
+			next.visitPackageComment(srcPkgName, dstNames, comment);
+			break;
 		case CLASS:
 			next.visitClassComment(srcClsName, dstClassNames, comment);
 			break;
@@ -217,12 +235,14 @@ public void visitComment(MappedElementKind targetKind, String comment) throws IO
 
 	private final FlatMappingVisitor next;
 
+	private String srcPkgName;
 	private String srcClsName;
 	private String srcMemberName;
 	private String srcMemberDesc;
 	private String srcMemberSubName;
 	private int argIdx, lvIndex, startOpIdx, endOpIdx;
 	private String[] dstNames;
+	private String[] dstPackageNames;
 	private String[] dstClassNames;
 	private String[] dstMemberNames;
 	private String[] dstMemberDescs;

src/main/java/net/fabricmc/mappingio/adapter/ForwardingMappingVisitor.java

@@ -69,6 +69,11 @@ public boolean visitContent() throws IOException {
 		return next.visitContent();
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		return next.visitPackage(srcName);
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		return next.visitClass(srcName);

src/main/java/net/fabricmc/mappingio/adapter/MappingNsCompleter.java

@@ -115,6 +115,13 @@ public boolean visitContent() throws IOException {
 		return next.visitContent();
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		this.srcName = srcName;
+
+		return next.visitPackage(srcName);
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		this.srcName = srcName;

src/main/java/net/fabricmc/mappingio/adapter/MappingSourceNsSwitch.java

@@ -142,6 +142,15 @@ public boolean visitContent() throws IOException {
 		return next.visitContent();
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		if (passThrough) return next.visitPackage(srcName);
+
+		this.srcName = srcName;
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		if (passThrough) return next.visitClass(srcName);
@@ -256,6 +265,9 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 		boolean relay;
 
 		switch (targetKind) {
+		case PACKAGE:
+			relay = next.visitPackage(dstName);
+			break;
 		case CLASS:
 			relay = next.visitClass(dstName);
 			break;

src/main/java/net/fabricmc/mappingio/adapter/RegularAsFlatMappingVisitor.java

@@ -74,7 +74,38 @@ public boolean visitContent() throws IOException {
 	}
 
 	@Override
-	public boolean visitClass(String srcName, String[] dstNames) throws IOException {
+	public boolean visitPackage(String srcName, @Nullable String[] dstNames) throws IOException {
+		return visitPackage(srcName, dstNames, null);
+	}
+
+	@Override
+	public boolean visitPackage(String srcName, String dstName) throws IOException {
+		return visitPackage(srcName, null, dstName);
+	}
+
+	private boolean visitPackage(String srcName, @Nullable String[] dstNames, @Nullable String dstName) throws IOException {
+		if (!srcName.equals(lastPackage)) {
+			lastPackage = srcName;
+			relayLastPackage = next.visitPackage(srcName) && visitDstNames(MappedElementKind.PACKAGE, dstNames, dstName);
+		}
+
+		return relayLastPackage;
+	}
+
+	@Override
+	public void visitPackageComment(String srcName, @Nullable String[] dstNames, String comment) throws IOException {
+		if (!visitPackage(srcName, dstNames, null)) return;
+		next.visitComment(MappedElementKind.PACKAGE, comment);
+	}
+
+	@Override
+	public void visitPackageComment(String srcName, @Nullable String dstName, String comment) throws IOException {
+		if (!visitPackage(srcName, null, dstName)) return;
+		next.visitComment(MappedElementKind.PACKAGE, comment);
+	}
+
+	@Override
+	public boolean visitClass(String srcName, @Nullable String[] dstNames) throws IOException {
 		return visitClass(srcName, dstNames, null);
 	}
 
@@ -367,6 +398,8 @@ private boolean visitDstNamesDescs(MappedElementKind targetKind, @Nullable Strin
 	private boolean relayDstFieldDescs;
 	private boolean relayDstMethodDescs;
 
+	private String lastPackage;
+	private boolean relayLastPackage;
 	private String lastClass;
 	private boolean relayLastClass;
 	private String lastMemberName, lastMemberDesc;

src/main/java/net/fabricmc/mappingio/format/FeatureSet.java

@@ -30,13 +30,11 @@ public interface FeatureSet {
 	boolean hasFileComments();
 
 	default boolean supportsPackages() {
-		return packages().srcNames() != FeaturePresence.ABSENT
-				|| packages().dstNames() != FeaturePresence.ABSENT;
+		return packages().srcNames() != FeaturePresence.ABSENT;
 	}
 
 	default boolean supportsClasses() {
-		return classes().srcNames() != FeaturePresence.ABSENT
-				|| classes().dstNames() != FeaturePresence.ABSENT;
+		return classes().srcNames() != FeaturePresence.ABSENT;
 	}
 
 	default boolean supportsFields() {

src/main/java/net/fabricmc/mappingio/format/MappingFormat.java

@@ -116,9 +116,6 @@ public enum MappingFormat {
 
 	/**
 	 * The {@code SRG} ("Searge RetroGuard") mapping format, as specified <a href="https://github.com/MinecraftForge/SrgUtils/blob/67f30647ece29f18256ca89a23cda6216d6bd21e/src/main/java/net/minecraftforge/srgutils/InternalUtils.java#L69-L81">here</a>.
-	 *
-	 * <h2>Implementation notes</h2>
-	 * Package mappings are currently not supported.
 	 */
 	SRG_FILE("SRG file", "srg", true, FeatureSetBuilder.create()
 			.withPackages(p -> p
@@ -141,9 +138,6 @@ public enum MappingFormat {
 	 * The {@code XSRG} ("Extended SRG") mapping format, as specified <a href="https://github.com/MinecraftForge/SrgUtils/blob/67f30647ece29f18256ca89a23cda6216d6bd21e/src/main/java/net/minecraftforge/srgutils/InternalUtils.java#L69-L84">here</a>.
 	 *
 	 * <p>Same as SRG, but with field descriptors.
-	 *
-	 * <h2>Implementation notes</h2>
-	 * Package mappings are currently not supported.
 	 */
 	XSRG_FILE("XSRG file", "xsrg", true, FeatureSetBuilder.createFrom(SRG_FILE.features)
 			.withFields(f -> f
@@ -168,9 +162,6 @@ public enum MappingFormat {
 
 	/**
 	 * The {@code CSRG} ("Compact SRG", since it saves disk space over SRG) mapping format, as specified <a href="https://github.com/MinecraftForge/SrgUtils/blob/67f30647ece29f18256ca89a23cda6216d6bd21e/src/main/java/net/minecraftforge/srgutils/InternalUtils.java#L196-L207">here</a>.
-	 *
-	 * <h2>Implementation notes</h2>
-	 * Package mappings are currently not supported.
 	 */
 	CSRG_FILE("CSRG file", "csrg", true, FeatureSetBuilder.createFrom(SRG_FILE.features)
 			.withMethods(m -> m
@@ -180,17 +171,11 @@ public enum MappingFormat {
 	 * The {@code TSRG} ("Tiny SRG", since it saves disk space over SRG) mapping format, as specified <a href="https://github.com/MinecraftForge/SrgUtils/blob/67f30647ece29f18256ca89a23cda6216d6bd21e/src/main/java/net/minecraftforge/srgutils/InternalUtils.java#L196-L213">here</a>.
 	 *
 	 * <p>Same as CSRG, but hierarchical instead of flat.
-	 *
-	 * <h2>Implementation notes</h2>
-	 * Package mappings are currently not supported.
 	 */
 	TSRG_FILE("TSRG file", "tsrg", true, FeatureSetBuilder.createFrom(CSRG_FILE.features)),
 
 	/**
 	 * The {@code TSRG v2} mapping format, as specified <a href="https://github.com/MinecraftForge/SrgUtils/blob/67f30647ece29f18256ca89a23cda6216d6bd21e/src/main/java/net/minecraftforge/srgutils/InternalUtils.java#L262-L285">here</a>.
-	 *
-	 * <h2>Implementation notes</h2>
-	 * Package mappings and static markers for methods are currently not supported.
 	 */
 	TSRG_2_FILE("TSRG v2 file", "tsrg", true, FeatureSetBuilder.createFrom(TSRG_FILE.features)
 			.withNamespaces(true)
@@ -255,9 +240,6 @@ public enum MappingFormat {
 
 	/**
 	 * The {@code JOBF} mapping format, as specified <a href="https://github.com/skylot/jadx/blob/2d5c0fda4a0c5d16207a5f48edb72e6efa7d5bbd/jadx-core/src/main/java/jadx/core/deobf/DeobfPresets.java">here</a>.
-	 *
-	 * <h2>Implementation notes</h2>
-	 * Package mappings are currently not supported.
 	 */
 	JOBF_FILE("JOBF file", "jobf", true, FeatureSetBuilder.create()
 			.withPackages(c -> c

src/main/java/net/fabricmc/mappingio/format/intellij/MigrationMapFileReader.java

@@ -122,22 +122,29 @@ private static void read0(BufferedReader reader, String sourceNs, String targetN
 							break;
 						case "entry":
 							String type = xmlReader.getAttributeValue(null, "type");
+							boolean isPackage;
 
 							if (type == null || type.isEmpty()) throw new IOException("missing/empty type attribute at line "+xmlReader.getLocation().getLineNumber());
-							if (type.equals("package")) continue; // TODO: support packages
-							if (!type.equals("class")) throw new IOException("unexpected entry type "+type+" at line "+xmlReader.getLocation().getLineNumber());
+
+							if (!(isPackage = type.equals("package")) && !type.equals("class")) {
+								throw new IOException("unexpected entry type "+type+" at line "+xmlReader.getLocation().getLineNumber());
+							}
 
 							String srcName = xmlReader.getAttributeValue(null, "oldName");
 							String dstName = xmlReader.getAttributeValue(null, "newName");
-							// String recursive = xmlReader.getAttributeValue(null, "recursive"); // only used for packages
+							// String recursive = xmlReader.getAttributeValue(null, "recursive"); // only used for packages, indicates if subpackages should also be renamed
 
 							if (srcName == null || srcName.isEmpty()) throw new IOException("missing/empty oldName attribute at line "+xmlReader.getLocation().getLineNumber());
 							if (dstName == null || dstName.isEmpty()) throw new IOException("missing/empty newName attribute at line "+xmlReader.getLocation().getLineNumber());
 
 							srcName = srcName.replace('.', '/');
 							dstName = dstName.replace('.', '/');
 
-							if (visitor.visitClass(srcName)) {
+							if (isPackage && visitor.visitPackage(srcName)) {
+								visitor.visitDstName(MappedElementKind.PACKAGE, 0, dstName);
+								visitor.visitElementContent(MappedElementKind.PACKAGE);
+								// TODO: visit "recursive" attribute as element metadata once https://github.com/FabricMC/mapping-io/pull/41 is merged
+							} else if (!isPackage && visitor.visitClass(srcName)) {
 								visitor.visitDstName(MappedElementKind.CLASS, 0, dstName);
 								visitor.visitElementContent(MappedElementKind.CLASS);
 							}

src/main/java/net/fabricmc/mappingio/format/intellij/MigrationMapFileWriter.java

@@ -117,10 +117,20 @@ public void visitMetadata(String key, @Nullable String value) throws IOException
 		}
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		this.srcName = srcName;
+		this.dstName = null;
+		this.isPackage = true;
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		this.srcName = srcName;
 		this.dstName = null;
+		this.isPackage = false;
 
 		return true;
 	}
@@ -161,7 +171,11 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 			xmlWriter.writeEmptyElement("entry");
 			xmlWriter.writeAttribute("oldName", srcName.replace('/', '.'));
 			xmlWriter.writeAttribute("newName", dstName.replace('/', '.'));
-			xmlWriter.writeAttribute("type", "class");
+			xmlWriter.writeAttribute("type", isPackage ? "package" : "class");
+
+			if (isPackage) {
+				xmlWriter.writeAttribute("recursive", "false"); // TODO: true or false?
+			}
 		} catch (XMLStreamException e) {
 			throw new IOException(e);
 		}
@@ -180,6 +194,7 @@ public void visitComment(MappedElementKind targetKind, String comment) throws IO
 	private XMLStreamWriter xmlWriter;
 	private boolean wroteName;
 	private boolean wroteOrder;
+	private boolean isPackage;
 	private String srcName;
 	private String dstName;
 }