def read(self, class_reader):
self.read_and_check_magic(class_reader)
self.read_and_check_version(class_reader)
self.constant_pool = ConstantPool()
self.constant_pool.read_constant_pool(class_reader)
self.access_flags = int.from_bytes(class_reader.read_unit16(), byteorder="big")
self.this_class = int.from_bytes(class_reader.read_unit16(), byteorder="big")
self.super_class = int.from_bytes(class_reader.read_unit16(), byteorder="big")
self.interfaces = class_reader.read_unit16s()
member_info = MemberInfo(self.constant_pool)
self.fields = member_info.read_members(class_reader, self.constant_pool)
self.methods = member_info.read_members(class_reader, self.constant_pool)
self.attributes = AttributeInfo.read_attributes(class_reader, self.constant_pool)
class ConstantMemberRefInfo(ConstantInfo):
def __init__(self, constant_pool):
from ch08.classfile.ConstantPool import ConstantPool
self.cp = ConstantPool(constant_pool)
self.class_index = 0
self.name_and_type_index = 0
def read_info(self, class_reader):
self.class_index = int.from_bytes(class_reader.read_unit16(), byteorder="big")
self.name_and_type_index = int.from_bytes(class_reader.read_unit16(), byteorder="big")
@property
def class_name(self):
return self.cp.get_class_name(self.class_index)
@property
def name_and_descriptor(self):
return self.cp.get_name_and_type(self.name_and_type_index)
class ConstantClassInfo(ConstantInfo):
def __init__(self, constant_pool):
from ch08.classfile.ConstantPool import ConstantPool
self.cp = ConstantPool(constant_pool)
self.name_index = 0
def read_info(self, class_reader):
self.name_index = int.from_bytes(class_reader.read_unit16(),
byteorder="big")
@property
def name(self):
return self.cp.get_utf8(self.name_index)
class ConstantStringInfo(ConstantInfo):
def __init__(self, constant_pool):
from ch08.classfile.ConstantPool import ConstantPool
self.cp = ConstantPool(constant_pool)
self.string_index = ""
# 读取常量池索引
def read_info(self, class_reader):
self.string_index = int.from_bytes(class_reader.read_unit16(),
byteorder="big")
# 按索引从常量池中查找字符串
def __str__(self):
return self.cp.get_utf8(self.string_index)
def new_constant_pool(clazz, cfConstantPool: ConstantPool):
from ch08.classfile.CpNumeric import ConstantDoubleInfo, ConstantLongInfo, ConstantFloatInfo, ConstantIntegerInfo
from ch08.classfile.ConstantStringInfo import ConstantStringInfo
from ch08.classfile.ConstantClassInfo import ConstantClassInfo
from ch08.classfile.ConstantMemberRefInfo import ConstantFieldRefInfo, ConstantMethodRefInfo, \
ConstantInterfaceMethodRefInfo
from ch08.rtda.heap.CpClassRef import ClassRef
from ch08.rtda.heap.CpFieldRef import FieldRef
from ch08.rtda.heap.CpMethodRef import MethodRef
from ch08.rtda.heap.CpInterfaceMethodRef import InterfaceMethodRef
cp_count = len(cfConstantPool.cp)
consts = [None for _ in range(cp_count)]
rt_constant_pool = ConstantPool(clazz, consts)
for i in range(1, cp_count):
cp_info = cfConstantPool.cp[i]
if isinstance(cp_info, ConstantIntegerInfo):
consts[i] = cp_info.val
elif isinstance(cp_info, ConstantFloatInfo):
consts[i] = cp_info.val
elif isinstance(cp_info, ConstantLongInfo):
consts[i] = cp_info.val
elif isinstance(cp_info, ConstantDoubleInfo):
consts[i] = cp_info.val
elif isinstance(cp_info, ConstantStringInfo):
consts[i] = str(cp_info)
elif isinstance(cp_info, ConstantClassInfo):
consts[i] = ClassRef(rt_constant_pool, cp_info)
elif isinstance(cp_info, ConstantFieldRefInfo):
consts[i] = FieldRef(rt_constant_pool, cp_info)
elif isinstance(cp_info, ConstantMethodRefInfo):
consts[i] = MethodRef(rt_constant_pool, cp_info)
elif isinstance(cp_info, ConstantInterfaceMethodRefInfo):
consts[i] = InterfaceMethodRef(rt_constant_pool, cp_info)
# rt_constant_pool.consts = consts
return rt_constant_pool
class ClassFile:
def __init__(self):
# 小版本号
self.minor_version = ""
# 主版本号
self.major_version = ""
# 常量池
self.constant_pool = None
# 类访问标志，用于指出class文件定义的是类还是接口，访问级别是public还是private
self.access_flags = ""
# 类索引
self.this_class = ""
# 超类索引
self.super_class = ""
# 接口索引表
self.interfaces = []
# 变量
self.fields = []
# 方法
self.methods = []
# 属性
self.attributes = []
def parse(self, class_data):
try:
class_reader = ClassReader(class_data)
self.read(class_reader)
return self, None
except Exception as err:
return self, err
def read(self, class_reader):
self.read_and_check_magic(class_reader)
self.read_and_check_version(class_reader)
self.constant_pool = ConstantPool()
self.constant_pool.read_constant_pool(class_reader)
self.access_flags = int.from_bytes(class_reader.read_unit16(), byteorder="big")
self.this_class = int.from_bytes(class_reader.read_unit16(), byteorder="big")
self.super_class = int.from_bytes(class_reader.read_unit16(), byteorder="big")
self.interfaces = class_reader.read_unit16s()
member_info = MemberInfo(self.constant_pool)
self.fields = member_info.read_members(class_reader, self.constant_pool)
self.methods = member_info.read_members(class_reader, self.constant_pool)
self.attributes = AttributeInfo.read_attributes(class_reader, self.constant_pool)
# 读取并检查Class文件的起始字节，必须以0xCAFEBABE固定字节开头
@staticmethod
def read_and_check_magic(class_reader):
magic = class_reader.read_unit32()
if magic != b'\xca\xfe\xba\xbe':
raise RuntimeError("java.lang.ClassFormatError: magic!")
# 读取并检查版本号，由于采用java1.8的编译器，故支持版本号为45.0~52.0的class文件
def read_and_check_version(self, class_reader):
self.minor_version = int.from_bytes(class_reader.read_unit16(), byteorder='big')
self.major_version = int.from_bytes(class_reader.read_unit16(), byteorder='big')
if self.major_version == 45:
return
elif self.major_version in {46, 47, 48, 49, 50, 51, 52}:
if self.minor_version == 0:
return
raise RuntimeError("java.lang.UnsupportedClassVersionError!")
# 从常量池中查找类名
@property
def class_name(self):
return self.constant_pool.get_class_name(self.this_class)
# 从常量池中查找超类类名
@property
def super_class_name(self):
if self.super_class > 0:
return self.constant_pool.get_class_name(self.super_class)
# 只有java.lang.Object没有超类
return ""
# 从常量池中查找接口名
@property
def interface_names(self):
return [self.constant_pool.get_class_name(cpName) for cpName in self.interfaces]
def __init__(self, constant_pool):
from ch08.classfile.ConstantPool import ConstantPool
self.cp = ConstantPool(constant_pool)
self.class_index = 0
self.name_and_type_index = 0
def __init__(self, constant_pool):
from ch08.classfile.ConstantPool import ConstantPool
self.cp = ConstantPool(constant_pool)
self.string_index = ""