git-sql 0.0.1

Git on SQL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134

from hashlib import sha1
from argparse import ArgumentParser

import sys
import pygit2

obj_prepared = 'PREPARE obj(TEXT, TEXT) AS ' + \
               'INSERT INTO objects VALUES ($1, decode($2, \'hex\'))' + \
               ' ON CONFLICT DO NOTHING;'

parser = ArgumentParser()
parser.add_argument("repository")
parser.add_argument("output")

parser.add_argument(
    "--no-prepared-header",
    help="Disables the PREPARE statements.",
    action="store_true"
)

parser.add_argument(
    "--update",
    help="Disables Truncation",
    action="store_true"
)

parser.add_argument(
    "--total",
    help="Total Number of Objects"
)

total = 0

args = parser.parse_args()

if args.total:
    total = int(args.total)

repo = pygit2.Repository(args.repository)


def eprint(*args, **kwargs):
    print(*args, file=sys.stderr, **kwargs)


def show_info(cnt: int):
    if total == 0:
        eprint("{0} objects generated".format(cnt))
    else:
        percent = (cnt / total) * 100.0
        eprint("{0}% ({1} objects out of {2})".format(int(percent), cnt, total))


def translate_type_id(i):
    if i == 1:
        return "commit"
    elif i == 2:
        return "tree"
    elif i == 3:
        return "blob"
    elif i == 4:
        return "tag"
    else:
        raise Exception("Unknown Type: {}" % i)


def encode_git_object(oid: pygit2.Oid):
    type_id, data = repo.read(oid)
    type_name = translate_type_id(type_id)
    encoded = bytearray()
    encoded.extend(type_name.encode())
    encoded.extend(' '.encode())
    encoded.extend(str(len(data)).encode())
    encoded.extend(b'\x00')
    encoded.extend(data)
    sha = sha1()
    sha.update(encoded)
    calc_hash = sha.hexdigest()
    if str(oid) != calc_hash:
        raise Exception(
            "Invalid Object Encoding: expected {}, encoded {}" % oid % calc_hash)
    return encoded


def generate_sql_object(oid):
    data = encode_git_object(oid)
    sql = "EXECUTE obj('" + str(oid) + "', '" + data.hex() + "');"
    return sql


def generate_sql_objects():
    if not args.no_prepared_header:
        yield obj_prepared

    count = 0
    for oid in repo:
        yield generate_sql_object(oid)
        count += 1
        show_info(count)


def generate_sql_ref(ref):
    sql = 'INSERT INTO "refs" ("name", "target") VALUES ('
    sql += "'" + ref.name + "'"
    sql += ", '" + str(ref.target) + "'"
    sql += ') ON CONFLICT ("name") DO UPDATE SET "target" = '
    sql += "'" + str(ref.target) + "';"
    return sql


def generate_sql_refs():
    for ref in repo.references:
        yield generate_sql_ref(repo.references[ref])
    yield generate_sql_ref(repo.lookup_reference("HEAD"))


def generate_sql_file():
    if not args.update:
        yield 'TRUNCATE "objects";'
        yield 'TRUNCATE "refs";'

    yield from generate_sql_objects()
    yield from generate_sql_refs()


if args.output == '-':
    for line in generate_sql_file():
        print(line)
else:
    with open(args.output, mode='w+') as file:
        file.seek(0)
        for line in generate_sql_file():
            file.write(line)
            file.write('\n')