Remove and later re-add brackets to simplify intermediate transforms

5 years ago · 7d959ed135
parent 578927d2f7
commit 7d959ed135
3 changed files with 201 additions and 1 deletions
--- a/deob-ast/src/main/java/dev/openrs2/deob/ast/AstDeobfuscator.java
+++ b/deob-ast/src/main/java/dev/openrs2/deob/ast/AstDeobfuscator.java
@ -15,19 +15,23 @@ import com.google.common.collect.ImmutableList;
 import dev.openrs2.deob.ast.transform.AddSubTransformer;
 import dev.openrs2.deob.ast.transform.BinaryExprOrderTransformer;
 import dev.openrs2.deob.ast.transform.ComplementTransformer;
+import dev.openrs2.deob.ast.transform.EncloseTransformer;
 import dev.openrs2.deob.ast.transform.IfElseTransformer;
 import dev.openrs2.deob.ast.transform.NegativeLiteralTransformer;
 import dev.openrs2.deob.ast.transform.TernaryTransformer;
 import dev.openrs2.deob.ast.transform.Transformer;
+import dev.openrs2.deob.ast.transform.UnencloseTransformer;

 public final class AstDeobfuscator {
 	private static final ImmutableList<Transformer> TRANSFORMERS = ImmutableList.of(
+		new UnencloseTransformer(),
 		new NegativeLiteralTransformer(),
 		new ComplementTransformer(),
 		new IfElseTransformer(),
 		new TernaryTransformer(),
 		new BinaryExprOrderTransformer(),
-		new AddSubTransformer()
+		new AddSubTransformer(),
+		new EncloseTransformer()
 	);

 	public static void main(String[] args) {
--- a/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/EncloseTransformer.java
+++ b/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/EncloseTransformer.java
@ -0,0 +1,183 @@
+package dev.openrs2.deob.ast.transform;
+
+import java.util.Optional;
+
+import com.github.javaparser.ast.CompilationUnit;
+import com.github.javaparser.ast.expr.EnclosedExpr;
+import com.github.javaparser.ast.expr.Expression;
+
+public final class EncloseTransformer extends Transformer {
+	private enum Associativity {
+		LEFT,
+		RIGHT,
+		NONE
+	}
+
+	private enum Op {
+		ACCESS_PARENS(Associativity.LEFT),
+		POSTFIX(Associativity.NONE),
+		UNARY(Associativity.RIGHT),
+		CAST_NEW(Associativity.RIGHT),
+		MULTIPLICATIVE(Associativity.LEFT),
+		ADDITIVE(Associativity.LEFT),
+		SHIFT(Associativity.LEFT),
+		RELATIONAL(Associativity.LEFT),
+		EQUALITY(Associativity.NONE),
+		BITWISE_AND(Associativity.LEFT),
+		BITWISE_XOR(Associativity.LEFT),
+		BITWISE_OR(Associativity.LEFT),
+		LOGICAL_AND(Associativity.LEFT),
+		LOGICAL_OR(Associativity.LEFT),
+		TERNARY(Associativity.RIGHT),
+		ASSIGNMENT(Associativity.RIGHT);
+
+		public static Optional<Op> from(Expression expr) {
+			if (expr.isArrayAccessExpr() || expr.isFieldAccessExpr() || expr.isMethodCallExpr() || expr.isEnclosedExpr()) {
+				return Optional.of(ACCESS_PARENS);
+			} else if (expr.isUnaryExpr()) {
+				return Optional.of(expr.asUnaryExpr().getOperator().isPostfix() ? POSTFIX : UNARY);
+			} else if (expr.isCastExpr() || expr.isObjectCreationExpr() || expr.isArrayCreationExpr()) {
+				return Optional.of(CAST_NEW);
+			} else if (expr.isBinaryExpr()) {
+				switch (expr.asBinaryExpr().getOperator()) {
+				case MULTIPLY:
+				case DIVIDE:
+				case REMAINDER:
+					return Optional.of(MULTIPLICATIVE);
+				case PLUS:
+				case MINUS:
+					return Optional.of(ADDITIVE);
+				case LEFT_SHIFT:
+				case SIGNED_RIGHT_SHIFT:
+				case UNSIGNED_RIGHT_SHIFT:
+					return Optional.of(SHIFT);
+				case LESS:
+				case LESS_EQUALS:
+				case GREATER:
+				case GREATER_EQUALS:
+					return Optional.of(RELATIONAL);
+				case EQUALS:
+				case NOT_EQUALS:
+					return Optional.of(EQUALITY);
+				case BINARY_AND:
+					return Optional.of(BITWISE_AND);
+				case XOR:
+					return Optional.of(BITWISE_XOR);
+				case BINARY_OR:
+					return Optional.of(BITWISE_OR);
+				case AND:
+					return Optional.of(LOGICAL_AND);
+				case OR:
+					return Optional.of(LOGICAL_OR);
+				}
+			} else if (expr.isInstanceOfExpr()) {
+				return Optional.of(RELATIONAL);
+			} else if (expr.isConditionalExpr()) {
+				return Optional.of(TERNARY);
+			} else if (expr.isAssignExpr()) {
+				return Optional.of(ASSIGNMENT);
+			}
+			return Optional.empty();
+		}
+
+		private final Associativity associativity;
+
+		Op(Associativity associativity) {
+			this.associativity = associativity;
+		}
+
+		public Associativity getAssociativity() {
+			return associativity;
+		}
+
+		public boolean isPrecedenceLess(Op other) {
+			return ordinal() > other.ordinal();
+		}
+
+		public boolean isPrecedenceLessEqual(Op other) {
+			return ordinal() >= other.ordinal();
+		}
+	}
+
+	private static void encloseLeft(Expression parent, Expression child) {
+		var parentOp = Op.from(parent).orElseThrow(IllegalArgumentException::new);
+		Op.from(child).ifPresent(childOp -> {
+			switch (parentOp.getAssociativity()) {
+			case LEFT:
+				if (childOp.isPrecedenceLess(parentOp)) {
+					parent.replace(child, new EnclosedExpr(child.clone()));
+				}
+				break;
+			case NONE:
+			case RIGHT:
+				if (childOp.isPrecedenceLessEqual(parentOp)) {
+					parent.replace(child, new EnclosedExpr(child.clone()));
+				}
+				break;
+			default:
+				throw new IllegalArgumentException();
+			}
+		});
+	}
+
+	private static void encloseRight(Expression parent, Expression child) {
+		var parentOp = Op.from(parent).orElseThrow(IllegalArgumentException::new);
+		Op.from(child).ifPresent(childOp -> {
+			switch (parentOp.getAssociativity()) {
+			case NONE:
+			case LEFT:
+				if (childOp.isPrecedenceLessEqual(parentOp)) {
+					parent.replace(child, new EnclosedExpr(child.clone()));
+				}
+				break;
+			case RIGHT:
+				if (childOp.isPrecedenceLess(parentOp)) {
+					parent.replace(child, new EnclosedExpr(child.clone()));
+				}
+				break;
+			default:
+				throw new IllegalArgumentException();
+			}
+		});
+	}
+
+	@Override
+	public void transform(CompilationUnit unit) {
+		unit.findAll(Expression.class).forEach(expr -> {
+			if (expr.isArrayAccessExpr()) {
+				var accessExpr = expr.asArrayAccessExpr();
+				encloseLeft(expr, accessExpr.getName());
+			} else if (expr.isFieldAccessExpr()) {
+				encloseLeft(expr, expr.asFieldAccessExpr().getScope());
+			} else if (expr.isMethodCallExpr()) {
+				expr.asMethodCallExpr().getScope().ifPresent(scope -> {
+					encloseLeft(expr, scope);
+				});
+			} else if (expr.isUnaryExpr()) {
+				var unaryExpr = expr.asUnaryExpr();
+				encloseRight(expr, unaryExpr.getExpression());
+			} else if (expr.isCastExpr()) {
+				encloseRight(expr, expr.asCastExpr().getExpression());
+			} else if (expr.isObjectCreationExpr()) {
+				expr.asObjectCreationExpr().getScope().ifPresent(scope -> {
+					encloseLeft(expr, scope);
+				});
+			} else if (expr.isBinaryExpr()) {
+				var binaryExpr = expr.asBinaryExpr();
+				encloseLeft(expr, binaryExpr.getLeft());
+				encloseRight(expr, binaryExpr.getRight());
+			} else if (expr.isInstanceOfExpr()) {
+				encloseLeft(expr, expr.asInstanceOfExpr().getExpression());
+			} else if (expr.isConditionalExpr()) {
+				var conditionalExpr = expr.asConditionalExpr();
+				encloseLeft(expr, conditionalExpr.getCondition());
+				encloseLeft(expr, conditionalExpr.getThenExpr());
+				encloseRight(expr, conditionalExpr.getElseExpr());
+			} else if (expr.isAssignExpr()) {
+				var assignExpr = expr.asAssignExpr();
+				encloseLeft(expr, assignExpr.getTarget());
+				encloseRight(expr, assignExpr.getValue());
+			}
+		});
+	}
+}
--- a/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/UnencloseTransformer.java
+++ b/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/UnencloseTransformer.java
@ -0,0 +1,13 @@
+package dev.openrs2.deob.ast.transform;
+
+import com.github.javaparser.ast.CompilationUnit;
+import com.github.javaparser.ast.expr.EnclosedExpr;
+
+public final class UnencloseTransformer extends Transformer {
+	@Override
+	public void transform(CompilationUnit unit) {
+		unit.findAll(EnclosedExpr.class).forEach(expr -> {
+			expr.replace(expr.getInner().clone());
+		});
+	}
+}