Code snippets from my youtube series: Implementing a file system.

part_2.py

"""
A file system is the interface between a user and their storage device.

features:
Non-contiguous
Single-level directory

Storage device
Block
File system
Files
"""

class Storage:
    """
    storage:
        btyearray
            binary file
    
    methods:
        create

        read
        write
    """


    def __init__(self, path, capacity):
        self.path = path
        self.capacity = capacity
    
    def create(self):

        with open(self.path, "wb") as f:
            data = bytearray([0] * self.capacity)
            f.write(data)

        print(f"Binary file '{self.path}' with {self.capacity} bytes has been created.")

    def write(self, position, content):

        with open(self.path, "r+b") as f:
            f.seek(position)
            f.write(content)

    def read(self, position, size):

        with open(self.path, "rb") as f:
            f.seek(position)
            data = f.read(size)

        return data


storage = Storage("store.bin", 10)
storage.create()

storage.write(5, b"Hello world")
data = storage.read(5, 5)
print(data)


class Block:
    pass

class FileSystem:
    pass

class File:
    pass

part_3.py

"""
A file system is the interface between a user and their storage device.

features:
Non-contiguous
Single-level directory

Storage device
Block
File system
Files
"""


from dataclasses import dataclass
from typing import Optional

class Storage:
    """
    storage:
        btyearray
            binary file
    
    methods:
        create

        read
        write
    """


    def __init__(self, path, capacity):
        self.path = path
        self.capacity = capacity
    
    def create(self):

        with open(self.path, "wb") as f:
            data = bytearray([0] * self.capacity)
            f.write(data)

        print(f"Binary file '{self.path}' with {self.capacity} bytes has been created.")

    def write(self, position, content):

        with open(self.path, "r+b") as f:
            f.seek(position)
            f.write(content)

    def read(self, position, size):

        with open(self.path, "rb") as f:
            f.seek(position)
            data = f.read(size)

        return data


storage = Storage("store.bin", 10)
storage.create()

storage.write(5, b"Hello world")
data = storage.read(5, 5)
print(data)

@dataclass
class Block:
    id: int
    start: int
    empty: bool
    next: Optional["Block"] = None


class FileSystem:
    pass

class File:
    pass

part_4.py

"""
A file system is the interface between a user and their storage device.

features:
Non-contiguous
Single-level directory

Storage device
Block
File system
Files
"""


from dataclasses import dataclass
from typing import Optional

from datetime import datetime

class Storage:
    """
    storage:
        btyearray
            binary file
    
    methods:
        create

        read
        write
    """


    def __init__(self, path, capacity):
        self.path = path
        self.capacity = capacity
    
    def create(self):

        with open(self.path, "wb") as f:
            data = bytearray([0] * self.capacity)
            f.write(data)

        print(f"Binary file '{self.path}' with {self.capacity} bytes has been created.")

    def write(self, position, content):

        with open(self.path, "r+b") as f:
            f.seek(position)
            f.write(content)

    def read(self, position, size):

        with open(self.path, "rb") as f:
            f.seek(position)
            data = f.read(size)

        return data

@dataclass
class Block:
    id: int
    start: int
    empty: bool
    next: Optional["Block"] = None


@dataclass
class MetaData:
    file_size: float
    created: datetime
    last_modified: datetime
    last_accessed: datetime


@dataclass
class File:
    name: str
    start_block: Block
    meta_data: MetaData

    def get_metadata(self):
        print(f"File size: {self.meta_data.file_size} bytes")
        print(f"Last accessed: {self.meta_data.last_accessed}")
        print(f"Last modified: {self.meta_data.last_modified}")
        print(f"Created: {self.meta_data.created}")

part_5.py

"""
A file system is the interface between a user and their storage device.

features:
Non-contiguous
Single-level directory

Storage device
Block
File system
Files
"""

from dataclasses import dataclass, field
from typing import Optional, List

from datetime import datetime

class Storage:
    """
    storage:
        btyearray
            binary file
    
    methods:
        create

        read
        write
    """


    def __init__(self, path, capacity):
        self.path = path
        self.capacity = capacity
    
    def create(self):

        with open(self.path, "wb") as f:
            data = bytearray([0] * self.capacity)
            f.write(data)

        print(f"Binary file '{self.path}' with {self.capacity} bytes has been created.")

    def write(self, position, content):

        with open(self.path, "r+b") as f:
            f.seek(position)
            f.write(content)

    def read(self, position, size):

        with open(self.path, "rb") as f:
            f.seek(position)
            data = f.read(size)

        return data

@dataclass
class Block:
    id: int
    start: int
    empty: bool
    next: Optional["Block"] = None
@dataclass
class MetaData:
    file_size: float
    created: datetime
    last_modified: datetime
    last_accessed: datetime
@dataclass
class File:
    name: str
    start_block: Block
    meta_data: MetaData

    def get_metadata(self):
        print(f"File size: {self.meta_data.file_size} bytes")
        print(f"Last accessed: {self.meta_data.last_accessed}")
        print(f"Last modified: {self.meta_data.last_modified}")
        print(f"Created: {self.meta_data.created}")



@dataclass
class FileSystem:
    storage: Storage
    block_size: int = 5
    blocks: List[Block] = field(default_factory=list)

    def create(self, content):
        """
        Create new file.
        """

        pass

    def open(self, file_name) -> File:
        """
        Get access to an existing file.
        """
        pass

    def read(self, file: File):
        """
        Get the content of a file.
        """
        pass

    def write(self, file: File, content):
        """
        Write content to file.
        """
        
        pass

    def append(self, file: File, new_content):
        """
        Add content to file.
        """
        
        pass

    def ls(self):
        """
        List files.
        """

        pass

    def delete(self, filename):
        """
        Delete file
        """

        pass

part_6.py

"""
A file system is the interface between a user and their storage device.

features:
Non-contiguous
Single-level directory

Storage device
Block
File system
Files
"""

from dataclasses import dataclass, field
from typing import Optional, List, Dict

import random

from datetime import datetime

class Storage:
    """
    storage:
        btyearray
            binary file
    
    methods:
        create

        read
        write
    """


    def __init__(self, path, capacity):
        self.path = path
        self.capacity = capacity
    
    def create(self):

        with open(self.path, "wb") as f:
            data = bytearray([0] * self.capacity)
            f.write(data)

        print(f"Binary file '{self.path}' with {self.capacity} bytes has been created.")

    def write(self, position, content):

        with open(self.path, "r+b") as f:
            f.seek(position)
            f.write(content)

    def read(self, position, size):

        with open(self.path, "rb") as f:
            f.seek(position)
            data = f.read(size)

        return data

@dataclass
class Block:
    id: int
    start: int
    empty: bool
    next: Optional["Block"] = None
@dataclass
class MetaData:
    file_size: float
    created: datetime
    last_modified: datetime
    last_accessed: datetime
@dataclass
class File:
    name: str
    start_block: Block
    meta_data: MetaData

    def get_metadata(self):
        print(f"File size: {self.meta_data.file_size} bytes")
        print(f"Last accessed: {self.meta_data.last_accessed}")
        print(f"Last modified: {self.meta_data.last_modified}")
        print(f"Created: {self.meta_data.created}")



@dataclass
class FileSystem:
    storage: Storage
    block_size: int = 5
    blocks: List[Block] = field(default_factory=list)
    root_dir: Dict[str, File] = field(default_factory=dict)

    def __post_init__(self):
        num_block = int(self.total_space / self.block_size)
        
        for i in range(num_block):
            self.blocks.append(Block(id=i, start=i * self.block_size, empty=True))

    @property
    def total_space(self):
        return self.storage.capacity

    @property
    def free_space(self):
        free_blocks = [block for block in self.blocks if block.empty]
        return len(free_blocks) * self.block_size

    def info(self):
        print(f"Total space: {self.total_space} bytes")
        print(f"Free space: {self.free_space} bytes")



    def open(self, file_name) -> File:
        """
        Get access to an existing file.
        """
        pass

    def read(self, file: File):
        """
        Get the content of a file.
        """
        pass

    def write(self, file: File, content):
        """
        Write content to file.
        """
        
        pass

    def append(self, file: File, new_content):
        """
        Add content to file.
        """
        
        pass

    def ls(self):
        """
        List files.
        """

        pass

    def delete(self, filename):

        """
        Delete file
        """

        pass

storage = Storage("store.bin", 50)
storage.create()
fs = FileSystem(storage)
fs.info()