sander/java.rs
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added get_names for methods

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This commit is contained in:
Sander Hautvast 2023-09-20 13:24:07 +02:00
parent 739ea7da3e
commit 724b2f3eaa
3 changed files with 132 additions and 12 deletions
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24
src/lib.rs
View file

@ -1,5 +1,6 @@
pub mod types;
use std::rc::Rc;
use crate::types::{CpEntry, Class, Field, Attribute, Method};
pub fn get_class(bytecode: Vec<u8>) -> Option<Class> {
@ -12,6 +13,8 @@ pub fn get_class(bytecode: Vec<u8>) -> Option<Class> {
constant_pool.push(read_constant_pool_entry(&mut index, &bytecode));
}
let constant_pool = Rc::new(constant_pool);
let access_flags = get_u16(&bytecode, index);
let this_class = get_u16(&bytecode, index + 2);
let super_class = get_u16(&bytecode, index + 4);
@ -35,7 +38,7 @@ pub fn get_class(bytecode: Vec<u8>) -> Option<Class> {
index += 2;
let mut methods = vec![];
for _ in 0..methods_count {
methods.push(read_method(&mut index, &bytecode));
methods.push(read_method(constant_pool.clone(), &mut index, &bytecode));
}
let attributes_count = get_u16(&bytecode, index);
@ -61,7 +64,7 @@ pub fn get_class(bytecode: Vec<u8>) -> Option<Class> {
fn check_magic(bytecode: &Vec<u8>) {
if &bytecode[0..4] != [0xCA, 0xFE, 0xBA, 0xBE] {
panic!(); //must never happen
panic!("Invalid class file");
}
}
@ -97,12 +100,12 @@ fn read_constant_pool_entry(index: &mut usize, bytecode: &Vec<u8>) -> CpEntry {
7 => {
let name_index = get_u16(bytecode, *index + 1);
*index += 3;
CpEntry::Class(name_index)
CpEntry::ClassRef(name_index)
}
8 => {
let string_index = get_u16(bytecode, *index + 1);
*index += 3;
CpEntry::String(string_index)
CpEntry::StringRef(string_index)
}
9 => {
let class_index = get_u16(bytecode, *index + 1);
@ -127,7 +130,13 @@ fn read_constant_pool_entry(index: &mut usize, bytecode: &Vec<u8>) -> CpEntry {
let descriptor_index = get_u16(bytecode, *index + 3);
*index += 5;
CpEntry::NameAndType(name_index, descriptor_index)
}
},
// 15 MethodHandle,
// 16 MethodType,
// 17 Dynamic,
// 18 InvokeDynamic,
// 19 Module,
// 20 Package,
_ => panic!()
}
}
@ -151,9 +160,9 @@ fn read_field(index: &mut usize, bytecode: &Vec<u8>) -> Field {
}
}
fn read_method(index: &mut usize, bytecode: &Vec<u8>) -> Method {
fn read_method(constant_pool: Rc<Vec<CpEntry>>, index: &mut usize, bytecode: &Vec<u8>) -> Method {
let access_flags = get_u16(bytecode, *index);
let name_index = get_u16(bytecode, *index + 2);
let name_index = get_u16(bytecode, *index + 2) as usize;
let descriptor_index = get_u16(bytecode, *index + 4);
let attributes_count = get_u16(bytecode, *index + 6);
*index += 8;
@ -162,6 +171,7 @@ fn read_method(index: &mut usize, bytecode: &Vec<u8>) -> Method {
attributes.push(read_attribute(bytecode, index));
}
Method {
constant_pool,
access_flags,
name_index,
descriptor_index,

33
src/types.rs
View file

@ -1,9 +1,12 @@
use std::rc::Rc;
use crate::types::CpEntry::*;
#[derive(Debug)]
//TODO create factory function
pub struct Class {
pub minor_version: u16,
pub major_version: u16,
pub constant_pool: Vec<CpEntry>,
pub constant_pool: Rc<Vec<CpEntry>>,
pub access_flags: u16,
pub this_class: u16,
pub super_class: u16,
@ -13,6 +16,16 @@ pub struct Class {
pub attributes: Vec<Attribute>,
}
impl<'a> Class {
pub fn get_version(&self) -> (u16, u16) {
(self.major_version, self.minor_version)
}
pub fn get_methods(&self) -> &Vec<Method> {
&self.methods
}
}
#[derive(Debug)]
pub enum CpEntry {
@ -21,8 +34,8 @@ pub enum CpEntry {
Float(f32),
Long(i64),
Double(f64),
Class(u16),
String(u16),
ClassRef(u16),
StringRef(u16),
Fieldref(u16, u16),
MethodRef(u16, u16),
InterfaceMethodref(u16, u16),
@ -45,10 +58,20 @@ pub struct Attribute {
}
#[derive(Debug)]
pub struct Method{
pub struct Method {
pub constant_pool: Rc<Vec<CpEntry>>,
pub access_flags: u16,
pub name_index: u16,
pub name_index: usize,
pub descriptor_index: u16,
pub attributes_count: u16,
pub attributes: Vec<Attribute>,
}
impl Method {
pub fn name(&self) -> &str {
if let Utf8(s) = &self.constant_pool[self.name_index - 1] {
return &s;
}
panic!() // name must be utf8
}
}

87
tests/class_tests.rs Normal file
View file

@ -0,0 +1,87 @@
use std::rc::Rc;
use classfile_reader::types::{Attribute, Class, Field, Method};
use classfile_reader::types::CpEntry::*;
#[test]
fn get_version() {
assert_eq!((55, 0), get_class().get_version());
}
#[test]
fn get_methods() {
for m in get_class().get_methods() {
println!("{}", m.name());
}
}
fn get_class() -> Class {
let cp = Rc::new(vec![MethodRef(2, 3),
ClassRef(4),
NameAndType(5, 6),
Utf8("java/lang/Object".to_owned()),
Utf8("<init>".to_owned()),
Utf8("()V".to_owned()),
Fieldref(8, 9),
ClassRef(10),
NameAndType(11, 12),
Utf8("com/github/shautvast/reflective/MetaField".to_owned()),
Utf8("name".to_owned()),
Utf8("Ljava/lang/String;".to_owned()),
Fieldref(8, 14),
NameAndType(15, 16),
Utf8("modifiers".to_owned()),
Utf8("I".to_owned()),
Utf8("(Ljava/lang/String;I)V".to_owned()),
Utf8("Code".to_owned()),
Utf8("LineNumberTable".to_owned()),
Utf8("LocalVariableTable".to_owned()),
Utf8("this".to_owned()),
Utf8("Lcom/github/shautvast/reflective/MetaField;".to_owned()),
Utf8("getName".to_owned()),
Utf8("()Ljava/lang/String;".to_owned()),
Utf8("getModifiers".to_owned()),
Utf8("()I".to_owned()),
Utf8("SourceFile".to_owned()),
Utf8("MetaField.java".to_owned())]);
Class {
minor_version: 0,
major_version: 55,
constant_pool: cp.clone(),
interfaces: vec![],
super_class: 2,
access_flags: 33,
this_class: 8,
methods: vec![
Method {
constant_pool: cp.clone(),
access_flags: 1,
name_index: 5,
descriptor_index: 17,
attributes_count: 1,
attributes: vec![Attribute {
attribute_name_index: 18,
info: vec![0, 2, 0, 3, 0, 0, 0, 15, 42, 183, 0, 1, 42, 43, 181, 0, 7, 42, 28,
181, 0, 13, 177, 0, 0, 0, 2, 0, 19, 0, 0, 0,
18, 0, 4, 0, 0, 0, 8, 0, 4, 0, 9, 0, 9, 0, 10, 0, 14, 0, 11, 0, 20, 0, 0,
0, 32, 0, 3, 0, 0, 0, 15, 0, 21, 0, 22, 0, 0, 0, 0, 0, 15, 0, 11,
0, 12, 0, 1, 0, 0, 0, 15, 0, 15, 0, 16, 0, 2],
}],
},
Method {
constant_pool: cp,
access_flags: 1,
name_index: 23,
descriptor_index: 24,
attributes_count: 1,
attributes: vec![Attribute {
attribute_name_index: 18,
info: vec![0, 1, 0, 1, 0, 0, 0, 5, 42, 180, 0, 7, 176, 0, 0, 0, 2, 0, 19, 0, 0, 0, 6, 0,
1, 0, 0, 0, 14, 0, 20, 0, 0, 0, 12, 0, 1, 0, 0, 0, 5, 0, 21, 0, 22, 0, 0],
}],
}],
fields: vec![Field { access_flags: 18, name_index: 11, descriptor_index: 12, attributes_count: 0, attributes: vec![] },
Field { access_flags: 18, name_index: 15, descriptor_index: 16, attributes_count: 0, attributes: vec![] }],
attributes: vec![Attribute { attribute_name_index: 27, info: vec![0, 28] }],
}
}