iOS代码瘦身实践之如何删除无用的类

#binary_file_arch: distinguish Big-Endian and Little-Endian#file -b output example: Mach-O 64-bit executable arm64binary_file_arch = os.popen('file -b ' + path).read().split(' ')[-1].strip()

def pointers_from_binary(line, binary_file_arch): line = line[16:].strip().split(' ') pointers = set() if binary_file_arch == 'x86_64':  #untreated line example:00000001030cec80	d8 75 15 03 01 00 00 00 68 77 15 03 01 00 00 00  pointers.add(''.join(line[4:8][::-1] + line[0:4][::-1]))  pointers.add(''.join(line[12:16][::-1] + line[8:12][::-1]))  return pointers #arm64 confirmed,armv7 arm7s unconfirmed if binary_file_arch.startswith('arm'):  #untreated line example:00000001030bcd20	03138580 00000001 03138878 00000001  pointers.add(line[1] + line[0])  pointers.add(line[3] + line[2])  return pointers return None

def class_ref_pointers(path, binary_file_arch):  ref_pointers = set()  lines = os.popen('/usr/bin/otool -v -s __DATA __objc_classrefs %s' % path).readlines()  for line in lines:    pointers = pointers_from_binary(line, binary_file_arch)    ref_pointers = ref_pointers.union(pointers)  return ref_pointers

def class_list_pointers(path, binary_file_arch):  list_pointers = set()  lines = os.popen('/usr/bin/otool -v -s __DATA __objc_classlist %s' % path).readlines()  for line in lines:    pointers = pointers_from_binary(line, binary_file_arch)    list_pointers = list_pointers.union(pointers)  return list_pointers

unref_pointers = class_list_pointers(path, binary_file_arch) - class_ref_pointers(path, binary_file_arch)

def class_symbols(path):  symbols = {}  #class symbol format from nm: 0000000103113f68 (__DATA,__objc_data) external _OBJC_CLASS_$_EpisodeStatusDetailItemView  re_class_name = re.compile('(/w{16}) .* _OBJC_CLASS_/$_(.+)')  lines = os.popen('nm -nm %s' % path).readlines()  for line in lines:    result = re_class_name.findall(line)    if result:      (address, symbol) = result[0]      symbols[address] = symbol  return symbols

def filter_super_class(unref_symbols):  re_subclass_name = re.compile("/w{16} 0x/w{9} _OBJC_CLASS_/$_(.+)")  re_superclass_name = re.compile("/s*superclass 0x/w{9} _OBJC_CLASS_/$_(.+)")  #subclass example: 0000000102bd8070 0x103113f68 _OBJC_CLASS_$_TTEpisodeStatusDetailItemView  #superclass example: superclass 0x10313bb80 _OBJC_CLASS_$_TTBaseControl  lines = os.popen("/usr/bin/otool -oV %s" % path).readlines()  subclass_name = ""  superclass_name = ""  for line in lines:    subclass_match_result = re_subclass_name.findall(line)    if subclass_match_result:      subclass_name = subclass_match_result[0]    superclass_match_result = re_superclass_name.findall(line)    if superclass_match_result:      superclass_name = superclass_match_result[0]    if len(subclass_name) > 0 and len(superclass_name) > 0:      if superclass_name in unref_symbols and subclass_name not in unref_symbols:        unref_symbols.remove(superclass_name)      superclass_name = ""      subclass_name = ""  return unref_symbols

 for unref_pointer in unref_pointers:    if unref_pointer in symbols:      unref_symbol = symbols[unref_pointer]      if len(reserved_prefix) > 0 and not unref_symbol.startswith(reserved_prefix):        continue      if len(filter_prefix) > 0 and unref_symbol.startswith(filter_prefix):        continue      unref_symbols.add(unref_symbol)

script_path = sys.path[0].strip()f = open(script_path+"/result.txt","w")f.write( "unref class number:  %d/n" % len(unref_symbles))f.write("/n")for unref_symble in unref_symbles:  f.write(unref_symble+"/n")f.close()