Add Recaf Simple writer

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

@@ -26,6 +26,7 @@
 import net.fabricmc.mappingio.format.enigma.EnigmaDirWriter;
 import net.fabricmc.mappingio.format.enigma.EnigmaFileWriter;
 import net.fabricmc.mappingio.format.proguard.ProGuardFileWriter;
+import net.fabricmc.mappingio.format.simple.RecafSimpleFileWriter;
 import net.fabricmc.mappingio.format.tiny.Tiny1FileWriter;
 import net.fabricmc.mappingio.format.tiny.Tiny2FileWriter;
 
@@ -49,6 +50,7 @@ static MappingWriter create(Writer writer, MappingFormat format) throws IOExcept
 		case TINY_2_FILE: return new Tiny2FileWriter(writer, false);
 		case ENIGMA_FILE: return new EnigmaFileWriter(writer);
 		case PROGUARD_FILE: return new ProGuardFileWriter(writer);
+		case RECAF_SIMPLE_FILE: return new RecafSimpleFileWriter(writer);
 		default: throw new UnsupportedOperationException("format "+format+" is not implemented");
 		}
 	}

src/main/java/net/fabricmc/mappingio/format/simple/RecafSimpleFileWriter.java

@@ -0,0 +1,135 @@
+/*
+ * Copyright (c) 2023 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.mappingio.format.simple;
+
+import java.io.IOException;
+import java.io.Writer;
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Set;
+
+import net.fabricmc.mappingio.MappedElementKind;
+import net.fabricmc.mappingio.MappingFlag;
+import net.fabricmc.mappingio.MappingWriter;
+
+public final class RecafSimpleFileWriter implements MappingWriter {
+	public RecafSimpleFileWriter(Writer writer) {
+		this.writer = writer;
+	}
+
+	@Override
+	public void close() throws IOException {
+		writer.close();
+	}
+
+	@Override
+	public Set<MappingFlag> getFlags() {
+		return flags;
+	}
+
+	@Override
+	public void visitNamespaces(String srcNamespace, List<String> dstNamespaces) throws IOException {
+	}
+
+	@Override
+	public boolean visitClass(String srcName) throws IOException {
+		classSrcName = srcName;
+
+		return true;
+	}
+
+	@Override
+	public boolean visitField(String srcName, String srcDesc) throws IOException {
+		memberSrcName = srcName;
+		memberSrcDesc = srcDesc;
+
+		return true;
+	}
+
+	@Override
+	public boolean visitMethod(String srcName, String srcDesc) throws IOException {
+		memberSrcName = srcName;
+		memberSrcDesc = srcDesc;
+
+		return true;
+	}
+
+	@Override
+	public boolean visitMethodArg(int argPosition, int lvIndex, String srcName) throws IOException {
+		return false; // not supported, skip
+	}
+
+	@Override
+	public boolean visitMethodVar(int lvtRowIndex, int lvIndex, int startOpIdx, int endOpIdx, String srcName) throws IOException {
+		return false; // not supported, skip
+	}
+
+	@Override
+	public void visitDstName(MappedElementKind targetKind, int namespace, String name) {
+		if (namespace != 0) return;
+		dstName = name;
+	}
+
+	@Override
+	public boolean visitElementContent(MappedElementKind targetKind) throws IOException {
+		if (dstName == null) return true;
+		write(classSrcName);
+
+		if (targetKind != MappedElementKind.CLASS) {
+			if (memberSrcName == null) throw new IllegalArgumentException("member source name cannot be null!");
+			writer.write('.');
+			write(memberSrcName);
+
+			if (memberSrcDesc != null) {
+				if (targetKind == MappedElementKind.FIELD) writeSpace();
+				write(memberSrcDesc);
+			}
+		}
+
+		writeSpace();
+		write(dstName);
+		writeLn();
+		dstName = null;
+
+		return targetKind == MappedElementKind.CLASS; // only members are supported, skip anything but class contents
+	}
+
+	@Override
+	public void visitComment(MappedElementKind targetKind, String comment) throws IOException {
+		// not supported, skip
+	}
+
+	private void write(String str) throws IOException {
+		writer.write(str);
+	}
+
+	private void writeLn() throws IOException {
+		writer.write('\n');
+	}
+
+	private void writeSpace() throws IOException {
+		writer.write(' ');
+	}
+
+	private static final Set<MappingFlag> flags = EnumSet.of(MappingFlag.NEEDS_SRC_FIELD_DESC, MappingFlag.NEEDS_SRC_METHOD_DESC);
+
+	private final Writer writer;
+	private String classSrcName;
+	private String memberSrcName;
+	private String memberSrcDesc;
+	private String dstName;
+}

src/test/java/net/fabricmc/mappingio/write/WriteTest.java

@@ -58,6 +58,11 @@ public void tinyV2File() throws Exception {
 		write(MappingFormat.TINY_2_FILE);
 	}
 
+	@Test
+	public void recafSimpleFile() throws Exception {
+		write(MappingFormat.RECAF_SIMPLE_FILE);
+	}
+
 	private void write(MappingFormat format) throws Exception {
 		TestHelper.writeToDir(tree, format, dir);
 		TestHelper.writeToDir(treeWithHoles, format, dir);