nix-store --tree to ncdu format

nix2ncdu.py

import sys
import os
import json
import time
import subprocess


def set_item(tree, items, info):
    item = items[0]

    if item not in tree:
        tree[item] = dict()

    if len(items) == 1:
        tree[item]['__info__'] = info
    else:
        set_item(tree[item], items[1:], info)


def get_size(folder):
    return int(subprocess.check_output(
        ['du','-s', '-B 1', path]).split()[0].decode('utf-8'))


if __name__ == '__main__':

    tree, items, prev_level = dict(), [], 0
    
    for line in sys.stdin.read().split('\n'):
        line = line.strip()
        if not line:
            continue

        level = line.find('/') / 4
        path = line[level * 4:]
        info = os.lstat(path)

        if level == 0:
            items = [ path ]
        elif level > prev_level:
            items.append(path)
        elif level < prev_level:
            items = items[:-(prev_level - level + 1)] + [ path ]

        set_item(tree, items, dict(
            name=path[44:],
            dsize=get_size(path),
            asize=info.st_size,
            dev=info.st_dev,
            ino=info.st_ino,
        ))

        prev_level = level

    data = [1, 0, {
      "progname"  : "ncdu",
      "progver"   : "1.9",
      "timestamp" : int(time.time())
    }]

    def tree2json(data, tree):
        for path in filter(lambda x: x != '__info__', tree.keys()):
            tmp = [tree[path]['__info__']]
            if len(tree[path].keys()) > 1:
                tree2json(tmp, tree[path])
            data.append(tmp)


    tree2json(data, tree)

    print json.dumps(data, indent=4)