def __init__(self, cls_file_name):
self.cls_file_name = cls_file_name
self.result = ParsingResult(self.cls_file_name)
self.clsFile = None
class Parser:
def __init__(self, cls_file_name):
self.cls_file_name = cls_file_name
self.result = ParsingResult(self.cls_file_name)
self.clsFile = None
def __verify(self):
"""
Verify the given arguments.
"""
if not (os.path.exists(self.cls_file_name) and os.path.isfile(self.cls_file_name)):
raise ParsingException("Can't find the class file %s" % self.cls_file_name)
def __parseMagicNum(self):
"""
Parse the magic num (the first 4 bytes)
"""
assert self.clsFile is not None
# get first four bytes
magicNumBytes = self.clsFile.read(4)
self.result.setMagicNumber(magicNumBytes)
def __parseVersion(self):
"""
Parse the version of this class file.
Version is composed by minor version and major version.
Each will occupy 2 bytes.
"""
assert self.clsFile is not None
majorVerBytes = self.clsFile.read(2)
minorVerBytes = self.clsFile.read(2)
self.result.setVersion(ByteToDec(minorVerBytes), ByteToDec(majorVerBytes))
def __parseConstantPool(self):
"""
Parse the constant pool of class file
First 2 bytes of this section is the count.
Pay attention here. Constant index starts from 1, not 0.
"""
assert self.clsFile is not None
const_count = ByteToDec(self.clsFile.read(2)) - 1
self.result.setConstPoolCount(const_count)
constants = ConstantPool.parse(const_count, self.clsFile)
self.result.setConstants(constants)
def __parseAccessFlag(self):
"""
Parse the access flag
"""
assert self.clsFile is not None
accessFlag = ByteToDec(self.clsFile.read(2))
self.result.setAccessFlag(accessFlag)
def __parseThis(self):
"""
Parse "this" section
"""
assert self.clsFile is not None
thisIndex = ByteToDec(self.clsFile.read(2))
self.result.setThisIndex(thisIndex)
def __parseSuper(self):
"""
Parse "super" section
"""
assert self.clsFile is not None
superIndex = ByteToDec(self.clsFile.read(2))
self.result.setSuperIndex(superIndex)
def __parseInterface(self):
"""
Parse "interface" section
"""
assert self.clsFile is not None
interfaceCount = ByteToDec(self.clsFile.read(2))
interfaceIndex = []
if interfaceCount > 0:
for i in range(interfaceCount):
interfaceIndex.append(ByteToDec(self.clsFile.read(2)))
self.result.setInterfaces(interfaceCount, interfaceIndex)
def __parseFields(self):
"""
Parse fields sections.
"""
assert self.clsFile is not None
fieldCount = ByteToDec(self.clsFile.read(2))
fields = []
for index in range(fieldCount):
accessFlag = ByteToDec(self.clsFile.read(2))
name = self.result.getUtf8(ByteToDec(self.clsFile.read(2)))
descriptor = self.result.getUtf8(ByteToDec(self.clsFile.read(2)))
field = Field(name, descriptor, accessFlag)
attrCount = ByteToDec(self.clsFile.read(2))
if attrCount > 0:
for i in range(attrCount):
attributeName = self.result.getUtf8(ByteToDec(self.clsFile.read(2)))
attributeLength = ByteToDec(self.clsFile.read(4))
# for now, only parse the "Code Attribute
parser = Attribute.getParser(attributeName)
if parser is not None:
attribute = parser(self.clsFile, self.result)
field.addAttribute(attribute)
else:
self.clsFile.read(attributeLength)
fields.append(field)
self.result.setFields(fieldCount, fields)
def __parseMethods(self):
"""
Parse methods section.
"""
assert self.clsFile is not None
methodCount = ByteToDec(self.clsFile.read(2))
methods = []
for index in range(methodCount):
accessFlag = ByteToDec(self.clsFile.read(2))
name = self.result.getUtf8(ByteToDec(self.clsFile.read(2)))
descriptor = self.result.getUtf8(ByteToDec(self.clsFile.read(2)))
method = Method(name, descriptor, accessFlag)
attrCount = ByteToDec(self.clsFile.read(2))
if attrCount > 0:
for i in range(attrCount):
attributeName = self.result.getUtf8(ByteToDec(self.clsFile.read(2)))
attributeLength = ByteToDec(self.clsFile.read(4))
# for now, only parse the "Code Attribute
parser = Attribute.getParser(attributeName)
if parser is not None:
attribute = parser(self.clsFile, self.result)
method.addAttribute(attribute)
else:
self.clsFile.read(attributeLength)
methods.append(method)
self.result.setMethods(methodCount, methods)
def __parseAttribute(self):
"""
Parse the attributes of class file.
"""
attrCount = ByteToDec(self.clsFile.read(2))
if attrCount > 0:
for i in range(attrCount):
attributeName = self.result.getUtf8(ByteToDec(self.clsFile.read(2)))
attributeLength = ByteToDec(self.clsFile.read(4))
parser = Attribute.getParser(attributeName)
if parser is not None:
attribute = parser(self.clsFile, self.result)
self.result.addAttribute(attribute)
else:
self.clsFile.read(attributeLength)
def parse(self):
try:
self.__verify()
# parse the magic number of class file
self.clsFile = open(self.cls_file_name, 'rb')
# following functions' order is very important
self.__parseMagicNum()
self.__parseVersion()
self.__parseConstantPool()
self.__parseAccessFlag()
self.__parseThis()
self.__parseSuper()
self.__parseInterface()
self.__parseFields()
self.__parseMethods()
self.__parseAttribute()
except ParsingException,e:
raise e
finally:
