Added generating hashCode() to javac's HandleData.

1 files changed, 117 insertions, 2 deletions

diff --git a/src/lombok/javac/handlers/HandleData.java b/src/lombok/javac/handlers/HandleData.java
index ea34cd55..2faf96fd 100644
--- a/src/lombok/javac/handlers/HandleData.java
+++ b/src/lombok/javac/handlers/HandleData.java
@@ -83,10 +83,124 @@ public class HandleData implements JavacAnnotationHandler<Data> {
 			injectMethod(typeNode, method);
 		}
 		
-		//TODO hashCode, toString.
+		if ( methodExists("hashCode", typeNode) == MethodExistsResult.NOT_EXISTS ) {
+			JCMethodDecl method = createHashCode(typeNode, nodesForEquality);
+			injectMethod(typeNode, method);
+		}
+		
+		//TODO toString.
 		return true;
 	}
 	
+	private JCMethodDecl createHashCode(Node typeNode, List<Node> fields) {
+		TreeMaker maker = typeNode.getTreeMaker();
+		
+		JCAnnotation overrideAnnotation = maker.Annotation(chainDots(maker, typeNode, "java", "lang", "Override"), List.<JCExpression>nil());
+		JCModifiers mods = maker.Modifiers(Flags.PUBLIC, List.of(overrideAnnotation));
+		JCExpression returnType = maker.TypeIdent(TypeTags.INT);
+		List<JCStatement> statements = List.nil();
+		
+		Name primeName = typeNode.toName("PRIME");
+		Name resultName = typeNode.toName("result");
+		/* final int PRIME = 31; */ {
+			if ( !fields.isEmpty() ) {
+				statements = statements.append(
+						maker.VarDef(maker.Modifiers(Flags.FINAL), primeName, maker.TypeIdent(TypeTags.INT), maker.Literal(31)));
+			}
+		}
+		
+		/* int result = 1; */ {
+			statements = statements.append(maker.VarDef(maker.Modifiers(0), resultName, maker.TypeIdent(TypeTags.INT), maker.Literal(1)));
+		}
+		
+		List<JCExpression> intoResult = List.nil();
+		
+		int tempCounter = 0;
+		for ( Node fieldNode : fields ) {
+			JCVariableDecl field = (JCVariableDecl) fieldNode.get();
+			JCExpression fType = field.vartype;
+			JCExpression thisDotField = maker.Select(maker.Ident(typeNode.toName("this")), field.name);
+			JCExpression thisDotFieldClone = maker.Select(maker.Ident(typeNode.toName("this")), field.name);
+			if ( fType instanceof JCPrimitiveTypeTree ) {
+				switch ( ((JCPrimitiveTypeTree)fType).getPrimitiveTypeKind() ) {
+				case BOOLEAN:
+					/* this.fieldName ? 1231 : 1237 */
+					intoResult = intoResult.append(maker.Conditional(thisDotField, maker.Literal(1231), maker.Literal(1237)));
+					break;
+				case LONG:
+					intoResult = intoResult.append(longToIntForHashCode(maker, thisDotField, thisDotFieldClone));
+					break;
+				case FLOAT:
+					/* Float.floatToIntBits(this.fieldName) */
+					intoResult = intoResult.append(maker.Apply(
+							List.<JCExpression>nil(),
+							chainDots(maker, typeNode, "java", "lang", "Float", "floatToIntBits"),
+							List.of(thisDotField)));
+					break;
+				case DOUBLE:
+					/* longToIntForHashCode(Double.doubleToLongBits(this.fieldName)) */
+					Name tempVar = typeNode.toName("temp" + (++tempCounter));
+					JCExpression init = maker.Apply(
+							List.<JCExpression>nil(),
+							chainDots(maker, typeNode, "java", "lang", "Double", "doubleToLongBits"),
+							List.of(thisDotField));
+					statements = statements.append(
+							maker.VarDef(maker.Modifiers(Flags.FINAL), tempVar, maker.TypeIdent(TypeTags.LONG), init));
+					intoResult = intoResult.append(longToIntForHashCode(maker, maker.Ident(tempVar), maker.Ident(tempVar)));
+					break;
+				default:
+				case BYTE:
+				case SHORT:
+				case INT:
+				case CHAR:
+					/* just the field */
+					intoResult = intoResult.append(thisDotField);
+					break;
+				}
+			} else if ( fType instanceof JCArrayTypeTree ) {
+				/* java.util.Arrays.deepHashCode(this.fieldName) //use just hashCode() for primitive arrays. */
+				boolean multiDim = ((JCArrayTypeTree)fType).elemtype instanceof JCArrayTypeTree;
+				boolean primitiveArray = ((JCArrayTypeTree)fType).elemtype instanceof JCPrimitiveTypeTree;
+				boolean useDeepEquals = multiDim || !primitiveArray;
+				
+				JCExpression hcMethod = chainDots(maker, typeNode, "java", "util", "Arrays", useDeepEquals ? "deepHashCode" : "hashCode");
+				intoResult = intoResult.append(
+						maker.Apply(List.<JCExpression>nil(), hcMethod, List.of(thisDotField)));
+			} else /* objects */ {
+				/* this.fieldName == null ? 0 : this.fieldName.hashCode() */
+				JCExpression hcCall = maker.Apply(List.<JCExpression>nil(), maker.Select(thisDotField, typeNode.toName("hashCode")),
+						List.<JCExpression>nil());
+				JCExpression thisEqualsNull = maker.Binary(JCTree.EQ, thisDotField, maker.Literal(TypeTags.BOT, null));
+				intoResult = intoResult.append(
+						maker.Conditional(thisEqualsNull, maker.Literal(0), hcCall));
+			}
+		}
+		
+		/* fold each intoResult entry into:
+		   result = result * PRIME + (item); */
+		for ( JCExpression expr : intoResult ) {
+			JCExpression mult = maker.Binary(JCTree.MUL, maker.Ident(resultName), maker.Ident(primeName));
+			JCExpression add = maker.Binary(JCTree.PLUS, mult, expr);
+			statements = statements.append(maker.Exec(maker.Assign(maker.Ident(resultName), add)));
+		}
+		
+		/* return result; */ {
+			statements = statements.append(maker.Return(maker.Ident(resultName)));
+		}
+		
+		JCBlock body = maker.Block(0, statements);
+		return maker.MethodDef(mods, typeNode.toName("hashCode"), returnType,
+				List.<JCTypeParameter>nil(), List.<JCVariableDecl>nil(), List.<JCExpression>nil(), body, null);
+	}
+	
+	/** The 2 references must be clones of each other. */
+	private JCExpression longToIntForHashCode(TreeMaker maker, JCExpression ref1, JCExpression ref2) {
+		/* (int)(ref >>> 32 ^ ref) */
+		JCExpression shift = maker.Binary(JCTree.USR, ref1, maker.Literal(32));
+		JCExpression xorBits = maker.Binary(JCTree.BITXOR, shift, ref2);
+		return maker.TypeCast(maker.TypeIdent(TypeTags.INT), xorBits);
+	}
+	
 	private JCMethodDecl createEquals(Node typeNode, List<Node> fields) {
 		TreeMaker maker = typeNode.getTreeMaker();
 		JCClassDecl type = (JCClassDecl) typeNode.get();
@@ -95,7 +209,8 @@ public class HandleData implements JavacAnnotationHandler<Data> {
 		Name otherName = typeNode.toName("other");
 		Name thisName = typeNode.toName("this");
 		
-		JCModifiers mods = maker.Modifiers(Flags.PUBLIC);
+		JCAnnotation overrideAnnotation = maker.Annotation(chainDots(maker, typeNode, "java", "lang", "Override"), List.<JCExpression>nil());
+		JCModifiers mods = maker.Modifiers(Flags.PUBLIC, List.of(overrideAnnotation));
 		JCExpression objectType = maker.Type(typeNode.getSymbolTable().objectType);
 		JCExpression returnType = maker.TypeIdent(TypeTags.BOOLEAN);