续上一篇文章
2.2.4.获取class文件访问权限，当前class，超类class
access_flags = 33 = 0x21 = 0x0020 + 0x0001
this_class = 5
super_class = 6
根据解释可以看出，[]interface里面存放的应该是一个下标，指向常量池；
func readMembers(count uint16, reader *ClassReader) []*MemberInfo {
members := make([]*MemberInfo, count)
for i := range members {
members[i] = readMember(reader)
}
return members
}
func readMember(reader *ClassReader) *MemberInfo {
access_flags := reader.readUint16()
name_index := reader.readUint16()
descriptor_index:=reader.readUint16()
attributes_count:=reader.readUint16()
return &MemberInfo{
access_flags: access_flags,
name_index: name_index,
descriptor_index: descriptor_index,
attributes_count: attributes_count,
attributes: readAttributes(attributes_count, reader),
}
}
func readAttributes(count uint16, reader *ClassReader) []AttributeInfo {
attributes := make([]AttributeInfo, count)
for i := range attributes {
attributes[i] = readAttribute(reader)
}
return attributes
}
func readAttribute(reader *ClassReader) AttributeInfo {
attrIndex := reader.readUint16()
attrLen := reader.readUint32()
attrInfo := newAttributeInfo(attrIndex, attrLen)
attrInfo.readInfo(reader)
return attrInfo
}
func newAttributeInfo(attribute_name_index uint16, attribute_length uint32) AttributeInfo {
attributeName := ConstantPoolInstance.getUtf8(attribute_name_index)
switch attributeName {
case Code_String:
return &CodeAttribute{attribute_name_index: attribute_name_index, attribute_length: attribute_length} //ok
case ConstantValue_String:
return &ConstantValueAttribute{attribute_name_index: attribute_name_index, attribute_length: attribute_length} //ok
case Deprecated_String:
return &DeprecatedAttribute{MarkerAttribute{attribute_name_index: attribute_name_index, attribute_length: attribute_length}} //ok
case Exceptions_String:
return &ExceptionsAttribute{attribute_name_index: attribute_name_index, attribute_length: attribute_length} //ok
case LineNumberTable_String:
return &LineNumberTableAttribute{attribute_name_index: attribute_name_index, attribute_length: attribute_length} //ok
case LocalVariableTable_String:
return &LocalVariableTableAttribute{attribute_name_index: attribute_name_index, attribute_length: attribute_length} //ok
case SourceFile_String:
return &SourceFileAttribute{attribute_name_index: attribute_name_index, attribute_length: attribute_length} //ok
case Synthetic_String:
return &SyntheticAttribute{MarkerAttribute{attribute_name_index: attribute_name_index, attribute_length: attribute_length}}
default:
return &UnparsedAttribute{attributeName, attribute_length, nil}
}
2.2.6.1.Code
type CodeAttribute struct {
attribute_name_index uint16
attribute_length uint32
max_stack uint16
max_locals uint16
code_length uint32
code []byte
exception_table_length uint16
exception_table []*ExceptionTableEntry
attribute_count uint16
attribute_info []AttributeInfo
}
type ExceptionTableEntry struct {
startPc uint16
endPc uint16
handlerPc uint16
catchType uint16
}
func (self *CodeAttribute) readInfo(reader *ClassReader) {
//self.attribute_name_index = reader.readUint16()
//self.attribute_length = reader.readUint32()
self.max_stack = reader.readUint16()
self.max_locals = reader.readUint16()
self.code_length = reader.readUint32()
self.code = reader.readBytes(self.code_length)
self.exception_table_length = reader.readUint16()
self.exception_table = readExceptionTable(self.exception_table_length, reader)
self.attribute_count = reader.readUint16()
self.attribute_info = readAttributes(self.attribute_count, reader)
}
func readExceptionTable(length uint16, reader *ClassReader) []*ExceptionTableEntry {
exceptionTable := make([]*ExceptionTableEntry, length)
for i := range exceptionTable {
exceptionTable[i] = &ExceptionTableEntry{
startPc: reader.readUint16(),
endPc: reader.readUint16(),
handlerPc: reader.readUint16(),
catchType: reader.readUint16(),
}
}
return exceptionTable
}
2.2.6.2.ConstantValue
type ConstantValueAttribute struct {
attribute_name_index uint16
attribute_length uint32
constantvalue_index uint16
}
func (self *ConstantValueAttribute) readInfo(reader *ClassReader) {
self.constantvalue_index = reader.readUint16()
}
2.2.6.3.Deprecated
type MarkerAttribute struct {
attribute_name_index uint16
attribute_length uint32
}
type DeprecatedAttribute struct {
MarkerAttribute
}
type SyntheticAttribute struct {
MarkerAttribute
}
func (self *MarkerAttribute) readInfo(reader *ClassReader) {
}
2.2.6.4.Exceptions
type ExceptionsAttribute struct {
attribute_name_index uint16
attribute_length uint32
number_of_exceptions uint16
exception_index_table []uint16
}
func (self *ExceptionsAttribute) readInfo(reader *ClassReader) {
//self.attribute_name_index = reader.readUint16()
//self.attribute_length = reader.readUint32()
self.number_of_exceptions = reader.readUint16()
self.exception_index_table = readExceptionIndexTable(self.number_of_exceptions, reader)
}
func readExceptionIndexTable(count uint16, reader *ClassReader) []uint16 {
ret := make([]uint16, count)
for i := range ret {
ret[i] = reader.readUint16()
}
return ret
}
2.2.6.5.LineNumberTable
type LineNumberTableAttribute struct {
attribute_name_index uint16
attribute_length uint32
line_number_table_length uint16
lineNumberTable []*LineNumberTableEntry
}
type LineNumberTableEntry struct {
startPc uint16
lineNumber uint16
}
func (self *LineNumberTableAttribute) readInfo(reader *ClassReader) {
//self.attribute_name_index = reader.readUint16()
self.line_number_table_length = reader.readUint16()
self.lineNumberTable = make([]*LineNumberTableEntry, self.line_number_table_length)
for i := range self.lineNumberTable {
self.lineNumberTable[i] = &LineNumberTableEntry{
startPc: reader.readUint16(),
lineNumber: reader.readUint16(),
}
}
}
2.2.6.6.LocalVariableTable
type LocalVariableTableAttribute struct {
attribute_name_index uint16
attribute_length uint32
local_variable_table_length uint16
localVariableTable []*LocalVariableTableEntry
}
type LocalVariableTableEntry struct {
startPc uint16
length uint16
name_index uint16
descriptor_index uint16
index uint16
}
func (self *LocalVariableTableAttribute) readInfo(reader *ClassReader) {
//self.attribute_name_index = reader.readUint16()
//self.attribute_length = reader.readUint32()
self.local_variable_table_length = reader.readUint16()
self.localVariableTable = make([]*LocalVariableTableEntry, self.local_variable_table_length)
for i := range self.localVariableTable {
self.localVariableTable[i] = &LocalVariableTableEntry{
startPc: reader.readUint16(),
length: reader.readUint16(),
name_index: reader.readUint16(),
descriptor_index: reader.readUint16(),
index: reader.readUint16(),
}
}
}
2.2.6.7.SourceFile
type SourceFileAttribute struct {
attribute_name_index uint16
attribute_length uint32
sourcefile_index uint16
}
func (self *SourceFileAttribute) readInfo(reader *ClassReader) {
//self.attribute_name_index = reader.readUint16()
//self.attribute_length = reader.readUint32()
self.sourcefile_index = reader.readUint16()
}
2.2.6.8.Synthetic
type MarkerAttribute struct {
attribute_name_index uint16
attribute_length uint32
}
type DeprecatedAttribute struct {
MarkerAttribute
}
type SyntheticAttribute struct {
MarkerAttribute
}
func (self *MarkerAttribute) readInfo(reader *ClassReader) {
}
2.2.6.9.Unparsed(未识别成功的)
type UnparsedAttribute struct {
name string
length uint32
info []byte
}
func (self *UnparsedAttribute) readInfo(reader *ClassReader) {
self.info = reader.readBytes(self.length)
}
2.2.7.获取方法数量及方法信息
//同获取字段数量及其信息
//从下我们可以看出字段信息和方法信息结构一致；
field_info {
u2 access_flags;
u2 name_index;
u2 descriptor_index;
u2 attributes_count;
attribute_info attributes[attributes_count];
}
method_info {
u2 access_flags;
u2 name_index;
u2 descriptor_index;
u2 attributes_count;
attribute_info attributes[attributes_count];
}
2.2.8.获取属性数量及属性信息
//同上的readAttributes，因为method_info, field_info中已经包含了attribute信息
