gbf_core/decompiler/ast/visitors/emitter.rs
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#![deny(missing_docs)]
use super::{
emit_context::{EmitContext, EmitVerbosity, IndentStyle},
AstVisitor,
};
use crate::decompiler::ast::meta::MetaNode;
use crate::decompiler::ast::statement::StatementNode;
use crate::decompiler::ast::unary_op::UnaryOperationNode;
use crate::decompiler::ast::{assignable::AssignableKind, expr::ExprKind};
use crate::decompiler::ast::{
bin_op::{BinOpType, BinaryOperationNode},
func_call::FunctionCallNode,
};
use crate::decompiler::ast::{function::FunctionNode, literal::LiteralNode};
use crate::decompiler::ast::{member_access::MemberAccessNode, ret::ReturnNode};
use crate::decompiler::ast::{AstKind, AstVisitable};
use crate::{decompiler::ast::identifier::IdentifierNode, utils::escape_string};
/// An emitter for the AST.
pub struct Gs2Emitter {
/// The output of the emitter.
output: String,
/// The context of the emitter.
context: EmitContext,
}
impl Gs2Emitter {
/// Creates a new `Gs2Emitter` with the given `context`.
pub fn new(context: EmitContext) -> Self {
Self {
output: String::new(),
context,
}
}
/// Returns the output of the emitter.
pub fn output(&self) -> &str {
&self.output
}
}
impl AstVisitor for Gs2Emitter {
fn visit_node(&mut self, node: &AstKind) {
match node {
AstKind::Expression(expr) => expr.accept(self),
AstKind::Meta(meta) => meta.accept(self),
AstKind::Statement(stmt) => stmt.accept(self),
AstKind::Function(func) => func.accept(self),
AstKind::Return(ret) => ret.accept(self),
AstKind::Empty => {}
}
}
fn visit_statement(&mut self, stmt_node: &StatementNode) {
// Step 0: Print the whitespace
let indent_level = self.context.indent;
for _ in 0..indent_level {
self.output.push(' ');
}
// Step 1: Visit and emit the LHS
stmt_node.lhs.accept(self);
let lhs_str = self.output.clone();
self.output.clear();
// Step 2: Handle RHS
if let ExprKind::BinOp(bin_op_node) = stmt_node.rhs.as_ref() {
// Check if the binary operation directly involves the LHS
let lhs_in_rhs =
bin_op_node.lhs.as_ref() == &ExprKind::Assignable(*stmt_node.lhs.clone());
if lhs_in_rhs {
match bin_op_node.op_type {
BinOpType::Add => {
// Handle increment (++), compound assignment (+=), or fall back to addition
if let ExprKind::Literal(LiteralNode::Number(num)) =
bin_op_node.rhs.as_ref()
{
if *num == 1 {
// Emit increment (++)
self.output.push_str(&format!("{}++;", lhs_str));
return;
} else {
// Emit compound assignment (+=)
bin_op_node.rhs.accept(self); // Visit the RHS to get the formatted number
let rhs_str = self.output.clone();
self.output.clear();
self.output
.push_str(&format!("{} += {};", lhs_str, rhs_str));
return;
}
}
}
BinOpType::Sub => {
// Handle decrement (--), compound assignment (-=), or fall back to subtraction
if let ExprKind::Literal(LiteralNode::Number(num)) =
bin_op_node.rhs.as_ref()
{
if *num == 1 {
// Emit decrement (--)
self.output.push_str(&format!("{}--;", lhs_str));
return;
} else {
// Emit compound assignment (-=)
bin_op_node.rhs.accept(self); // Visit the RHS to get the formatted number
let rhs_str = self.output.clone();
self.output.clear();
self.output
.push_str(&format!("{} -= {};", lhs_str, rhs_str));
return;
}
}
}
_ => {}
}
}
}
// Step 3: Handle default assignment
let prev_context = self.context;
self.context = self.context.with_expr_root(true);
stmt_node.rhs.accept(self); // Visit the RHS
let rhs_str = self.output.clone();
self.output.clear();
self.context = prev_context; // Restore the context
self.output.push_str(&format!("{} = {};", lhs_str, rhs_str));
}
fn visit_expr(&mut self, node: &ExprKind) {
match node {
ExprKind::Literal(literal) => literal.accept(self),
ExprKind::Assignable(assignable) => self.visit_assignable_expr(assignable),
ExprKind::BinOp(bin_op) => bin_op.accept(self),
ExprKind::UnaryOp(unary_op) => unary_op.accept(self),
ExprKind::FunctionCall(func_call) => func_call.accept(self),
}
}
fn visit_assignable_expr(&mut self, node: &AssignableKind) {
match node {
AssignableKind::MemberAccess(member_access) => {
if member_access.ssa_version.is_some() && self.context.include_ssa_versions {
self.output.push('{');
}
member_access.accept(self);
if self.context.include_ssa_versions {
if let Some(ssa_version) = member_access.ssa_version {
self.output.push_str(&format!("}}@{}", ssa_version));
}
}
}
AssignableKind::Identifier(identifier) => {
identifier.accept(self);
if self.context.include_ssa_versions {
if let Some(ssa_version) = identifier.ssa_version {
self.output.push_str(&format!("@{}", ssa_version));
}
}
}
}
}
fn visit_bin_op(&mut self, node: &BinaryOperationNode) {
// Save the current context and set expr_root to false for nested operations
let prev_context = self.context;
self.context = self.context.with_expr_root(false);
// Visit and emit the left-hand side
node.lhs.accept(self);
let lhs_str = self.output.clone(); // Capture emitted LHS
self.output.clear();
// Visit and emit the right-hand side
node.rhs.accept(self);
let rhs_str = self.output.clone(); // Capture emitted RHS
self.output.clear();
// Restore the previous context
self.context = prev_context;
// Determine the operator string
let op_str = node.op_type.to_string();
// Combine the emitted parts into the final binary operation string
if self.context.expr_root {
// Emit without parentheses for root expressions
self.output
.push_str(&format!("{} {} {}", lhs_str, op_str, rhs_str));
} else {
// Emit with parentheses for nested expressions
self.output
.push_str(&format!("({} {} {})", lhs_str, op_str, rhs_str));
}
}
fn visit_unary_op(&mut self, node: &UnaryOperationNode) {
// Save the current context and set expr_root to false for the operand
let prev_context = self.context;
self.context = self.context.with_expr_root(false);
// Visit and emit the operand
node.operand.accept(self);
let operand_str = self.output.clone(); // Capture emitted operand
self.output.clear();
// Restore the previous context
self.context = prev_context;
// Determine the operator string
let op_str = node.op_type.to_string();
// Combine the emitted parts into the final unary operation string
if self.context.expr_root {
self.output.push_str(&format!("{}{}", op_str, operand_str));
} else {
self.output
.push_str(&format!("({}{})", op_str, operand_str));
}
// self.output.push_str(&format!("{}{}", op_str, operand_str));
}
fn visit_identifier(&mut self, node: &IdentifierNode) {
// Append the identifier's ID directly to the output
self.output.push_str(node.id());
}
fn visit_literal(&mut self, node: &LiteralNode) {
let emitted_literal = match node {
LiteralNode::String(s) => format!("\"{}\"", escape_string(s)),
LiteralNode::Number(n) => {
if self.context.format_number_hex {
format!("0x{:X}", n)
} else {
n.to_string()
}
}
LiteralNode::Float(f) => f.clone(),
LiteralNode::Boolean(b) => b.to_string(),
};
self.output.push_str(&emitted_literal);
}
fn visit_member_access(&mut self, node: &MemberAccessNode) {
// Visit and emit the LHS
node.lhs.accept(self);
let lhs_str = self.output.clone(); // Capture emitted LHS
self.output.clear();
// Visit and emit the RHS
node.rhs.accept(self);
let rhs_str = self.output.clone(); // Capture emitted RHS
self.output.clear();
// Combine the LHS and RHS with a dot for member access
self.output.push_str(&format!("{}.{}", lhs_str, rhs_str));
}
fn visit_meta(&mut self, node: &MetaNode) {
// Handle minified verbosity
if self.context.verbosity == EmitVerbosity::Minified {
node.node().accept(self);
return;
}
let mut result = String::new();
// Add comment if available
if let Some(comment) = &node.comment() {
result.push_str(&format!("// {}\n", comment));
}
// Visit and emit the inner node
node.node().accept(self);
result.push_str(&self.output);
self.output.clear();
// Store the result in the visitor's output
self.output.push_str(&result);
}
fn visit_function_call(&mut self, node: &FunctionCallNode) {
// Visit and emit the base
self.output.push_str(node.name.id_string().as_str());
// Emit the arguments
self.output.push('(');
for (i, arg) in node.arguments.iter().enumerate() {
arg.accept(self);
if i < node.arguments.len() - 1 {
self.output.push_str(", ");
}
}
self.output.push(')');
}
fn visit_function(&mut self, node: &FunctionNode) {
let name = node.name().clone();
if name.is_none() {
// Just emit the function body if there is no name since we're
// in the entry point function
for stmt in node.body() {
stmt.accept(self);
self.output.push('\n');
}
return;
}
let name = name.unwrap();
// Emit the function parameters
self.output.push_str(format!("function {}(", name).as_str());
for (i, param) in node.params().iter().enumerate() {
param.accept(self);
if i < node.params().len() - 1 {
self.output.push_str(", ");
}
}
self.output.push(')');
// Check if we we are using allman or k&r style
if self.context.indent_style == IndentStyle::Allman {
self.output.push_str("\n{\n");
} else {
self.output.push_str(" {\n");
}
// Emit the function body, indented
let old_context = self.context;
self.context = self.context.with_indent();
for stmt in node.body() {
stmt.accept(self);
self.output.push('\n');
}
self.context = old_context;
self.output.push_str("}\n");
}
fn visit_return(&mut self, node: &ReturnNode) {
// return with indentation
for _ in 0..self.context.indent {
self.output.push(' ');
}
// Emit the return keyword
self.output.push_str("return ");
// Emit the return value
node.ret.accept(self);
// Emit the semicolon
self.output.push(';');
}
}