experimental/PdfViewer/generate_code.py

import sys

class PdfName:
  def __init__(self, name, abr=''):
    self.fName = name
    self.fAbr = abr

class PdfInteger:
  def __init__(self, value):
    self.fValue = value

class PdfReal:
  def __init__(self, value):
    self.fValue = value

class PdfString:
  def __init__(self, value):
    self.fValue = value

class PdfBoolean:
  def __init__(self, value):
    self.fValue = value

class PdfField:
  def __init__(self, parent, name, abr):
    self.fParent = parent
    self.fName = name
    self.fAbr = abr
    
    self.fDefault = ''
    self.fType = ''

  def must(self, value):
    return self.fParent
    
  def default(self, value):
    self.fDefault = value
    return self
    
  def number(self):
    self.fType = 'number'
    return self
    
  def integer(self):
    self.fType = 'integer'
    return self

  def real(self):
    self.fType = 'real'
    return self

  def name(self):
    self.fType = 'name'
    return self
    
  def string(self):
    self.fType = 'string'
    return self
    
  def multiple(self, options):
    self.fType = 'multiple'
    self.fOptions = options
    return self
    
  def done(self):
    return self.fParent


class PdfClassField:
  def __init__(self, parent, required):
    self.fFields = []
    self.fIncludes = []
    self.fCC = []
    self.fParent = parent
    self.fRequired = required
    
  def hasField(self, name, abr=''):
    return PdfField(self, name, abr)
    
  def done(self):
    return self.fParent

class PdfClass:
  def __init__(self, name, base):
    self.fFields = []
    self.fIncludes = []
    self.fCC = []
    self.fName = name
    self.fBase = base
    
    self.fEnumSubclasses = [] 
    
    self.fEnum = '!UNDEFINED'
    self.fEnumEnd = '!UNDEFINED'
    
  def required(self):
    field = PdfClassField(self, True)
    self.fFields.append(field)
    return field
    
  def optional(self):
    field = PdfClassField(self, False)
    self.fFields.append(field)
    return field
    
  def include(self, path):
    self.fIncludes.append(path)
    return self
    
  def carbonCopy(self, cc):
    self.fCC.append(cc)
    return self 

class PdfClassManager:
  def __init__(self):
    self.fClasses = {}

  def addClass(self, name, base=''):
    cls = PdfClass(name, base)
    self.fClasses[name] = cls
    return cls
  
  def longName(self, name):
    ret = ''
    while name != '':
      cls = self.fClasses[name]
      ret = name + ret
      name = cls.fBase
      
    return ret
  
  
  def writeEnum(self, enum, enumToCls):
    print('  ' + enum + ',')
    cls = enumToCls[enum]
    cls.fEnumSubclasses.sort()
    
    cnt = 0
    for sub in cls.fEnumSubclasses:
      self.writeEnum(cls.fEnumSubclasses[cnt], enumToCls)
      cnt = cnt + 1
      
    if cnt != 0:
       print('  ' + cls.fEnumEnd + ',')
  
  def write(self):
    # generate enum
    enumsRoot = []

    enumToCls = {}
    
    for name in self.fClasses:
      cls = self.fClasses[name]
      enum = self.longName(name)
      cls.fEnum = 'k' + enum + '_PdfObjectType'
      cls.fEnumEnd = 'k' + enum + '__End_PdfObjectType'
            
      if cls.fBase != '':
        self.fClasses[cls.fBase].fEnumSubclasses.append(cls.fEnum)

      if cls.fBase == '':
        enumsRoot.append(cls.fEnum)
       
      enumToCls[cls.fEnum] = cls
      
    enumsRoot.sort()
    
    # write enums
    print('enum PdfObjectType {')
    for enum in enumsRoot:
      self.writeEnum(enum, enumToCls)
    print('};')
      
    # generate each class
    # generate parser  
    return

def generateCode():
  all = PdfClassManager()
  
  all.addClass('Object')
  all.addClass('Null')
  all.addClass('Boolean')
  all.addClass('Integer')
  all.addClass('Real')
  all.addClass('Name')
  all.addClass('Stream')
  all.addClass('Reference')
  all.addClass('Array')
  all.addClass('Dictionary')

  all.addClass('XObject', 'Dictionary').required().hasField('/Type').must('/XObject')
  
  all.addClass('Image', 'XObject').required().hasField('/Type').must('/XObject').done()\
                                  .required().hasField('/Subtype').must('/Image').done()\
                                  .required().hasField('/Width', '/W').integer().done().done()\
                                  .required().hasField('/Height', '/H').integer().done().done()\
                                  .required().hasField('/ColorSpace').multiple([PdfName('/DeviceRGB', '/RGB'), PdfName('/DeviceGray', '/Gray')])\
                                                                                .done()\
                                                                     .done()\
                                  .optional().hasField('/BitsPerComponent', '/BPC').multiple([PdfInteger(1), PdfInteger(2), PdfInteger(4), PdfInteger(8)])\
                                                                                   .default(PdfInteger(1))\
                                                                                   .done().done()\
                                  .carbonCopy('SkBitmap bitmap;')

  all.addClass('Form', 'XObject').required().hasField('/Type').must('/XObject').done()\
                                 .required().hasField('/Subtype').must('/Form').done()


  all.write()
  
  return 1

if '__main__' == __name__:
  sys.exit(generateCode())