1 files changed, 138 insertions, 0 deletions
diff --git a/src/core/lombok/javac/handlers/HandleHelper.java b/src/core/lombok/javac/handlers/HandleHelper.java
new file mode 100644
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--- /dev/null
+++ b/src/core/lombok/javac/handlers/HandleHelper.java
@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2015 The Project Lombok Authors.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package lombok.javac.handlers;
+
+import static lombok.core.handlers.HandlerUtil.*;
+import static lombok.javac.handlers.JavacHandlerUtil.*;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
+
+import org.mangosdk.spi.ProviderFor;
+
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.TreeVisitor;
+import com.sun.source.util.TreeScanner;
+import com.sun.tools.javac.code.Flags;
+import com.sun.tools.javac.tree.JCTree.JCAnnotation;
+import com.sun.tools.javac.tree.JCTree.JCClassDecl;
+import com.sun.tools.javac.tree.JCTree.JCExpression;
+import com.sun.tools.javac.tree.JCTree.JCIdent;
+import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
+import com.sun.tools.javac.tree.JCTree.JCMethodInvocation;
+import com.sun.tools.javac.tree.JCTree.JCStatement;
+import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
+import com.sun.tools.javac.util.List;
+import com.sun.tools.javac.util.ListBuffer;
+import com.sun.tools.javac.util.Name;
+
+import lombok.ConfigurationKeys;
+import lombok.core.AST.Kind;
+import lombok.core.AnnotationValues;
+import lombok.experimental.Helper;
+import lombok.javac.JavacAnnotationHandler;
+import lombok.javac.JavacNode;
+import lombok.javac.JavacTreeMaker;
+
+@ProviderFor(JavacAnnotationHandler.class)
+public class HandleHelper extends JavacAnnotationHandler<Helper> {
+	@Override public void handle(AnnotationValues<Helper> annotation, JCAnnotation ast, JavacNode annotationNode) {
+		handleExperimentalFlagUsage(annotationNode, ConfigurationKeys.HELPER_FLAG_USAGE, "@Helper");
+		
+		deleteAnnotationIfNeccessary(annotationNode, Helper.class);
+		JavacNode annotatedType = annotationNode.up();
+		JavacNode containingMethod = annotatedType == null ? null : annotatedType.up();
+		
+		if (annotatedType == null || containingMethod == null || annotatedType.getKind() != Kind.TYPE || containingMethod.getKind() != Kind.METHOD) {
+			annotationNode.addError("@Helper is legal only on method-local classes.");
+			return;
+		}
+		
+		JCClassDecl annotatedType_ = (JCClassDecl) annotatedType.get();
+		JCMethodDecl amd = (JCMethodDecl) containingMethod.get();
+		List<JCStatement> origStatements = amd.body.stats;
+		Iterator<JCStatement> it = origStatements.iterator();
+		while (it.hasNext()) {
+			if (it.next() == annotatedType_) {
+				break;
+			}
+		}
+		
+		java.util.List<String> knownMethodNames = new ArrayList<String>();
+		
+		for (JavacNode ch : annotatedType.down()) {
+			if (ch.getKind() != Kind.METHOD) continue;
+			String n = ch.getName();
+			if (n == null || n.isEmpty() || n.charAt(0) == '<') continue;
+			knownMethodNames.add(n);
+		}
+		
+		Collections.sort(knownMethodNames);
+		final String[] knownMethodNames_ = knownMethodNames.toArray(new String[knownMethodNames.size()]);
+		
+		final Name helperName = annotationNode.toName("$" + annotatedType_.name);
+		final boolean[] helperUsed = new boolean[1];
+		final JavacTreeMaker maker = annotationNode.getTreeMaker();
+		
+		TreeVisitor<Void, Void> visitor = new TreeScanner<Void, Void>() {
+			@Override public Void visitMethodInvocation(MethodInvocationTree node, Void p) {
+				JCMethodInvocation jcmi = (JCMethodInvocation) node;
+				apply(jcmi);
+				return super.visitMethodInvocation(node, p);
+			}
+			
+			private void apply(JCMethodInvocation jcmi) {
+				if (!(jcmi.meth instanceof JCIdent)) return;
+				JCIdent jci = (JCIdent) jcmi.meth;
+				if (Arrays.binarySearch(knownMethodNames_, jci.name.toString()) < 0) return;
+				jcmi.meth = maker.Select(maker.Ident(helperName), jci.name);
+				helperUsed[0] = true;
+			}
+		};
+		
+		while (it.hasNext()) {
+			JCStatement stat = it.next();
+			stat.accept(visitor, null);
+		}
+		
+		if (!helperUsed[0]) {
+			annotationNode.addWarning("No methods of this helper class are ever used.");
+			return;
+		}
+		
+		ListBuffer<JCStatement> newStatements = new ListBuffer<JCStatement>();
+		
+		boolean mark = false;
+		for (JCStatement stat : origStatements) {
+			newStatements.append(stat);
+			if (mark || stat != annotatedType_) continue;
+			mark = true;
+			JCExpression init = maker.NewClass(null, List.<JCExpression>nil(), maker.Ident(annotatedType_.name), List.<JCExpression>nil(), null);
+			JCExpression varType = maker.Ident(annotatedType_.name);
+			JCVariableDecl decl = maker.VarDef(maker.Modifiers(Flags.FINAL), helperName, varType, init);
+			newStatements.append(decl);
+		}
+		amd.body.stats = newStatements.toList();
+	}
+}