Amazon OO Design Linux Find Command

filesys.py

"""
implemnet linux find command as an api ,the api willl support finding files that has given size requirements and a file with a certain format like

    find all file >5mb
    find all xml
    Assume file class
    {
    get name()
    directorylistfile()
    getFile()
    create a library flexible that is flexible
    Design clases,interfaces.
"""
from abc import ABC, abstractmethod

# FileObject and FileSystems are copied directly from LC 588

class FileObject:
    def __init__(self, path=None):
        self.path = path
        # handles subdirectories
        self.children = dict()
        self.is_file = False
        self.contents = []
        self.size = 0

class FileSystem:

    def __init__(self):
        self.rootdir = FileObject()

    @property
    def root_dir(self):
        return self.rootdir

    # create directory or file
    def create_file(self, path: str) -> None:
        paths = path.split('/')
        itr = self.rootdir
        for p in paths:
            if not p:
                continue
            if p not in itr.children:
                itr.children[p] = FileObject(p)
            itr = itr.children[p]
        itr.is_file = True
        itr.type = itr.path.split('.')[-1]

class Filter(ABC):

    @abstractmethod
    def apply(self, fileobj):
        pass

class SizeFilter(Filter):
    def __init__(self, size_limit=0) -> None:
        self.size_limit = size_limit

    def apply(self, fileobj):
        return fileobj.size < self.size_limit

class TypeFilter(Filter):
    def __init__(self, filetypes=[]) -> None:
        self.filetypes = filetypes
    
    def apply(self, fileobj):
        return fileobj.type in self.filetypes

class Finder:
    def __init__(self, filterobj, rootdir):
        self.filter = filterobj
        self.rootdir = rootdir
    
    def find(self):
        results = []
        self.dfs(self.rootdir, [], results)
        return results
    
    def dfs(self, node, prefix, results):
        if node.is_file and self.filter.apply(node):
            results.append('/'.join(prefix))
            return
        
        for c in node.children:
            prefix.append(c)
            self.dfs(node.children[c], prefix, results)
            prefix.pop()

"""
example usage
"""
filesys = FileSystem()
filesys.create_file('/rongrong/coding/soln.cpp')
filesys.create_file('/rongrong/company/amz.cpp')
filesys.create_file('/rongrong/design/ood.ipynb')
filesys.create_file('/rongrong/entertain/photo.jpg')

type_finder = Finder(TypeFilter(filetypes=['cpp']), filesys.root_dir)
# output: ['rongrong/coding/soln.cpp', 'rongrong/company/amz.cpp']
type_finder.find()