utils.py

import os
import subprocess
import pygit2

def is_overlayfs_mounted(directory):
    with open('/proc/mounts', 'r') as mount_file:
        for line in mount_file:
            if 'overlay' in line and directory in line:
                return True
    return False

def is_ogit_mounted(config):
    return os.path.exists(config["commit-graph-file-name"])

def is_ofs_nested(config):
    merge_directory = config["ogit-working-directory-name"] + "/" + config["intermediate-merge-directory-prefix"] + "0"
    with open('/proc/mounts', 'r') as mount_file:
        for line in mount_file:
            if 'overlay' in line and merge_directory in line:
                return True
    return False


def generate_layer_path(config, commit_hash):
    layer_path = commit_hash[:2] + "/" + commit_hash[2:config["hash-length"]]
    return layer_path

def get_current_commit_hash():
    try:
        with open("HEAD", 'r', encoding='utf-8') as head_file:
            return head_file.read()
    except Exception as e:
        print(f'Error: not found HEAD file')
        return None

def get_full_hash(config, short_hash):
    repository = pygit2.Repository(config["repository-path"])
    try:
        commit = repository[short_hash]
        return commit.id.__str__()
    except KeyError:
        print(f"commit not found: {short_hash}")
        return None

# full hashじゃなくてもいいが，fullじゃないと大規模リポジトリではhash衝突する可能性もある
def restore_hash_from_layer_name(config, layer_name):
    short_hash = layer_name[:2] + layer_name[3:config["hash-length"]+1]
    # return get_full_hash(config, short_hash)
    return short_hash

def umount(dir_name):
    try:
        cmd = ["sudo", "umount", dir_name]
        subprocess.run(cmd, check=True, text=True)
    except subprocess.CalledProcessError as e:
        print(f'Error: {e}')

def umount_all(config):
    if is_overlayfs_mounted(config["ogit-mount-directory-name"]):
        umount(config["ogit-mount-directory-name"])

    if not is_ofs_nested(config):
        return
    
    imd_dirs = os.listdir(config["ogit-working-directory-name"])
    imd_dir_prefix = config["intermediate-merge-directory-prefix"]
    imd_number = 0
    while ((imd_dir_prefix + str(imd_number)) in imd_dirs) and imd_number < 500:
        merge_directory = config["ogit-working-directory-name"] + "/" + imd_dir_prefix + str(imd_number)
        if is_overlayfs_mounted(merge_directory):
            umount(merge_directory)
        else:
            break
        imd_number += 1