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Convert IfElseTransformer to Kotlin

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Graham 5 years ago
parent 9b81c813dd
commit 53160e422d
2 changed files with 158 additions and 158 deletions
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  1. 158
      deob-ast/src/main/java/dev/openrs2/deob/ast/transform/IfElseTransformer.java
  2. 158
      deob-ast/src/main/java/dev/openrs2/deob/ast/transform/IfElseTransformer.kt

158
deob-ast/src/main/java/dev/openrs2/deob/ast/transform/IfElseTransformer.java
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@ -1,158 +0,0 @@
package dev.openrs2.deob.ast.transform;
import com.github.javaparser.ast.CompilationUnit;
import com.github.javaparser.ast.Node;
import com.github.javaparser.ast.stmt.BlockStmt;
import com.github.javaparser.ast.stmt.IfStmt;
import com.github.javaparser.ast.stmt.Statement;
import dev.openrs2.deob.ast.util.ExprUtils;
import dev.openrs2.deob.ast.util.NodeUtils;
public final class IfElseTransformer extends Transformer {
private static boolean isIf(Statement stmt) {
if (stmt.isIfStmt()) {
return true;
} else if (stmt.isBlockStmt()) {
var stmts = stmt.asBlockStmt().getStatements();
return stmts.size() == 1 && stmts.get(0).isIfStmt();
} else {
return false;
}
}
private static Statement getIf(Statement stmt) {
if (stmt.isIfStmt()) {
return stmt.clone();
} else if (stmt.isBlockStmt()) {
var stmts = stmt.asBlockStmt().getStatements();
if (stmts.size() == 1) {
Statement head = stmts.get(0);
if (head.isIfStmt()) {
return head.clone();
}
}
}
throw new IllegalArgumentException();
}
private static boolean isTailThrowOrReturn(Statement stmt) {
if (stmt.isThrowStmt() || stmt.isReturnStmt()) {
return true;
} else if (stmt.isBlockStmt()) {
var stmts = stmt.asBlockStmt().getStatements();
if (stmts.isEmpty()) {
return false;
}
var tail = stmts.get(stmts.size() - 1);
return tail.isThrowStmt() || tail.isReturnStmt();
} else {
return false;
}
}
@Override
public void transform(CompilationUnit unit) {
NodeUtils.walk(unit, Node.TreeTraversal.POSTORDER, IfStmt.class, stmt -> {
stmt.getElseStmt().ifPresent(elseStmt -> {
var condition = stmt.getCondition();
var thenStmt = stmt.getThenStmt();
if (isIf(thenStmt) && !isIf(elseStmt)) {
stmt.setCondition(ExprUtils.not(condition));
stmt.setThenStmt(elseStmt.clone());
stmt.setElseStmt(thenStmt.clone());
} else if (!isIf(thenStmt) && isIf(elseStmt)) {
/*
* Don't consider any more conditions for swapping the
* if/else branches, as it'll introduce another level of
* indentation.
*/
return;
}
/* Prefer fewer NOTs in the if condition. */
var notCondition = ExprUtils.not(condition);
if (ExprUtils.countNots(notCondition) < ExprUtils.countNots(condition)) {
stmt.setCondition(notCondition);
if (elseStmt.isIfStmt()) {
var block = new BlockStmt();
block.getStatements().add(elseStmt.clone());
stmt.setThenStmt(block);
} else {
stmt.setThenStmt(elseStmt.clone());
}
stmt.setElseStmt(thenStmt.clone());
}
});
});
NodeUtils.walk(unit, Node.TreeTraversal.POSTORDER, IfStmt.class, stmt -> {
stmt.getElseStmt().ifPresent(elseStmt -> {
if (isIf(elseStmt)) {
stmt.setElseStmt(getIf(elseStmt));
}
});
});
/*
* Rewrite:
*
* ...
* } else {
* if (x != 123) {
* ...
* throw ...;
* }
* ...
* }
*
* to:
*
* ...
* } else if (x == 123) {
* ...
* } else {
* ...
* throw ...;
* }
*/
NodeUtils.walk(unit, Node.TreeTraversal.POSTORDER, IfStmt.class, stmt -> {
stmt.getElseStmt().ifPresent(elseStmt -> {
/* match */
if (!elseStmt.isBlockStmt()) {
return;
}
var blockStmt = elseStmt.asBlockStmt();
var statements = blockStmt.getStatements();
if (statements.isEmpty()) {
return;
}
var head = statements.get(0);
if (!head.isIfStmt()) {
return;
}
var ifStmt = head.asIfStmt();
if (ifStmt.getElseStmt().isPresent()) {
return;
}
var thenStmt = ifStmt.getThenStmt();
if (!isTailThrowOrReturn(thenStmt)) {
return;
}
/* rewrite */
var condition = ExprUtils.not(ifStmt.getCondition());
var tail = blockStmt.clone();
tail.getStatements().remove(0);
elseStmt.replace(new IfStmt(condition, tail, thenStmt.clone()));
});
});
}
}

158
deob-ast/src/main/java/dev/openrs2/deob/ast/transform/IfElseTransformer.kt
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@ -0,0 +1,158 @@
package dev.openrs2.deob.ast.transform
import com.github.javaparser.ast.CompilationUnit
import com.github.javaparser.ast.Node
import com.github.javaparser.ast.stmt.BlockStmt
import com.github.javaparser.ast.stmt.IfStmt
import com.github.javaparser.ast.stmt.Statement
import dev.openrs2.deob.ast.util.ExprUtils
import dev.openrs2.deob.ast.util.NodeUtils
class IfElseTransformer : Transformer() {
override fun transform(unit: CompilationUnit) {
NodeUtils.walk(unit, Node.TreeTraversal.POSTORDER, IfStmt::class.java) { stmt ->
stmt.elseStmt.ifPresent { elseStmt: Statement ->
val condition = stmt.condition
val thenStmt = stmt.thenStmt
if (isIf(thenStmt) && !isIf(elseStmt)) {
stmt.condition = ExprUtils.not(condition)
stmt.thenStmt = elseStmt.clone()
stmt.setElseStmt(thenStmt.clone())
} else if (!isIf(thenStmt) && isIf(elseStmt)) {
/*
* Don't consider any more conditions for swapping the
* if/else branches, as it'll introduce another level of
* indentation.
*/
return@ifPresent
}
// Prefer fewer NOTs in the if condition
val notCondition = ExprUtils.not(condition)
if (ExprUtils.countNots(notCondition) < ExprUtils.countNots(condition)) {
stmt.condition = notCondition
if (elseStmt.isIfStmt) {
val block = BlockStmt()
block.statements.add(elseStmt.clone())
stmt.thenStmt = block
} else {
stmt.thenStmt = elseStmt.clone()
}
stmt.setElseStmt(thenStmt.clone())
}
}
}
NodeUtils.walk(unit, Node.TreeTraversal.POSTORDER, IfStmt::class.java) { stmt ->
stmt.elseStmt.ifPresent { elseStmt ->
if (isIf(elseStmt)) {
stmt.setElseStmt(getIf(elseStmt))
}
}
}
/*
* Rewrite:
*
* ...
* } else {
* if (x != 123) {
* ...
* throw ...;
* }
* ...
* }
*
* to:
*
* ...
* } else if (x == 123) {
* ...
* } else {
* ...
* throw ...;
* }
*/
NodeUtils.walk(unit, Node.TreeTraversal.POSTORDER, IfStmt::class.java) { stmt ->
stmt.elseStmt.ifPresent { elseStmt ->
// match
if (!elseStmt.isBlockStmt) {
return@ifPresent
}
val blockStmt = elseStmt.asBlockStmt()
val statements = blockStmt.statements
if (statements.isEmpty()) {
return@ifPresent
}
val head = statements[0]
if (!head.isIfStmt) {
return@ifPresent
}
val ifStmt = head.asIfStmt()
if (ifStmt.elseStmt.isPresent) {
return@ifPresent
}
val thenStmt = ifStmt.thenStmt
if (!isTailThrowOrReturn(thenStmt)) {
return@ifPresent
}
// rewrite
val condition = ExprUtils.not(ifStmt.condition)
val tail = blockStmt.clone()
tail.statements.removeAt(0)
elseStmt.replace(IfStmt(condition, tail, thenStmt.clone()))
}
}
}
companion object {
private fun isIf(stmt: Statement): Boolean {
return if (stmt.isIfStmt) {
true
} else if (stmt.isBlockStmt) {
val stmts = stmt.asBlockStmt().statements
stmts.size == 1 && stmts[0].isIfStmt
} else {
false
}
}
private fun getIf(stmt: Statement): Statement {
if (stmt.isIfStmt) {
return stmt.clone()
} else if (stmt.isBlockStmt) {
val stmts = stmt.asBlockStmt().statements
if (stmts.size == 1) {
val head = stmts[0]
if (head.isIfStmt) {
return head.clone()
}
}
}
throw IllegalArgumentException()
}
private fun isTailThrowOrReturn(stmt: Statement): Boolean {
return if (stmt.isThrowStmt || stmt.isReturnStmt) {
true
} else if (stmt.isBlockStmt) {
val stmts = stmt.asBlockStmt().statements
if (stmts.isEmpty()) {
return false
}
val tail = stmts[stmts.size - 1]
tail.isThrowStmt || tail.isReturnStmt
} else {
false
}
}
}
}
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