thodg/libgit2

diff --git a/script/release.py b/script/release.py
new file mode 100755
index 0000000..e0f2953
--- /dev/null
+++ b/script/release.py
@@ -0,0 +1,171 @@
+#!/usr/bin/env python
+
+from collections import namedtuple
+
+import argparse
+import base64
+import copy
+import json
+import subprocess
+import sys
+import urllib.parse
+import urllib.request
+import urllib.error
+
+class Error(Exception):
+    pass
+
+class Version(object):
+    def __init__(self, version):
+        versions = version.split(sep='.')
+        if len(versions) < 2 or len(versions) > 3:
+            raise Error("Invalid version string '{}'".format(version))
+        self.major = int(versions[0])
+        self.minor = int(versions[1])
+        self.revision = int(versions[2]) if len(versions) == 3 else 0
+
+    def __str__(self):
+        return '{}.{}.{}'.format(self.major, self.minor, self.revision)
+
+    def __eq__(self, other):
+        return self.major == other.major and self.minor == other.minor and self.revision == other.revision
+
+def verify_version(version):
+    expected = {
+        'VERSION':      [ '"{}"'.format(version), None ],
+        'VER_MAJOR':    [ str(version.major), None ],
+        'VER_MINOR':    [ str(version.minor), None ],
+        'VER_REVISION': [ str(version.revision), None ],
+        'VER_PATCH':    [ '0', None ],
+        'SOVERSION':    [ '"{}.{}"'.format(version.major, version.minor), None ],
+    }
+
+    with open('include/git2/version.h') as f:
+        lines = f.readlines()
+
+    for key in expected.keys():
+        define = '#define LIBGIT2_{} '.format(key)
+        for line in lines:
+            if line.startswith(define):
+                expected[key][1] = line[len(define):].strip()
+                break
+        else:
+            raise Error("version.h: missing define for '{}'".format(key))
+
+    for k, v in expected.items():
+        if v[0] != v[1]:
+            raise Error("version.h: define '{}' does not match (got '{}', expected '{}')".format(k, v[0], v[1]))
+
+def generate_relnotes(tree, version):
+    with open('docs/changelog.md') as f:
+        lines = f.readlines()
+
+    if not lines[0].startswith('v'):
+        raise Error("changelog.md: missing section for v{}".format(version))
+    try:
+        v = Version(lines[0][1:].strip())
+    except:
+        raise Error("changelog.md: invalid version string {}".format(lines[0].strip()))
+    if v != version:
+        raise Error("changelog.md: changelog version doesn't match (got {}, expected {})".format(v, version))
+    if not lines[1].startswith('----'):
+        raise Error("changelog.md: missing version header")
+    if lines[2] != '\n':
+        raise Error("changelog.md: missing newline after version header")
+
+    for i, line in enumerate(lines[3:]):
+        if not line.startswith('v'):
+            continue
+        try:
+            Version(line[1:].strip())
+            break
+        except:
+            continue
+    else:
+        raise Error("changelog.md: cannot find section header of preceding release")
+
+    return ''.join(lines[3:i + 3]).strip()
+
+def git(*args):
+    process = subprocess.run([ 'git', *args ], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    if process.returncode != 0:
+        raise Error('Failed executing git {}: {}'.format(' '.join(args),  process.stderr.decode()))
+    return process.stdout
+
+def post(url, data, contenttype, user, password):
+    request = urllib.request.Request(url, data=data)
+    request.add_header('Accept', 'application/json')
+    request.add_header('Content-Type', contenttype)
+    request.add_header('Content-Length', len(data))
+    request.add_header('Authorization', 'Basic ' + base64.b64encode('{}:{}'.format(user, password).encode()).decode())
+
+    try:
+        response = urllib.request.urlopen(request)
+        if response.getcode() != 201:
+            raise Error("POST to '{}' failed: {}".format(url, response.reason))
+    except urllib.error.URLError as e:
+        raise Error("POST to '{}' failed: {}".format(url, e))
+    data = json.load(response)
+
+    return data
+
+def generate_asset(version, tree, archive_format):
+    Asset = namedtuple('Asset', ['name', 'label', 'mimetype', 'data'])
+    mimetype = 'application/{}'.format('gzip' if archive_format == 'tar.gz' else 'zip')
+    return Asset(
+        "libgit2-{}.{}".format(version, archive_format), "Release sources: libgit2-{}.{}".format(version, archive_format), mimetype,
+        git('archive', '--format', archive_format, '--prefix', 'libgit2-{}/'.format(version), tree)
+    )
+
+def release(args):
+    params = {
+        "tag_name": 'v' + str(args.version),
+        "name": 'libgit2 v' + str(args.version),
+        "target_commitish": git('rev-parse', args.tree).decode().strip(),
+        "body": generate_relnotes(args.tree, args.version),
+    }
+    assets = [
+        generate_asset(args.version, args.tree, 'tar.gz'),
+        generate_asset(args.version, args.tree, 'zip'),
+    ]
+
+    if args.dryrun:
+        for k, v in params.items():
+            print('{}: {}'.format(k, v))
+        for asset in assets:
+            print('asset: name={}, label={}, mimetype={}, bytes={}'.format(asset.name, asset.label, asset.mimetype, len(asset.data)))
+        return
+
+    try:
+        url = 'https://api.github.com/repos/{}/releases'.format(args.repository)
+        response = post(url, json.dumps(params).encode(), 'application/json', args.user, args.password)
+    except Error as e:
+        raise Error('Could not create release: ' + str(e))
+
+    for asset in assets:
+        try:
+            url = list(urllib.parse.urlparse(response['upload_url'].split('{?')[0]))
+            url[4] = urllib.parse.urlencode({ 'name': asset.name, 'label': asset.label })
+            post(urllib.parse.urlunparse(url), asset.data, asset.mimetype, args.user, args.password)
+        except Error as e:
+            raise Error('Could not upload asset: ' + str(e))
+
+def main():
+    parser = argparse.ArgumentParser(description='Create a libgit2 release')
+    parser.add_argument('--tree', default='HEAD', help='tree to create release for (default: HEAD)')
+    parser.add_argument('--dryrun', action='store_true', help='generate release, but do not post it')
+    parser.add_argument('--repository', default='libgit2/libgit2', help='GitHub repository to create repository in')
+    parser.add_argument('--user', help='user to authenitcate as')
+    parser.add_argument('--password', help='password to authenticate with')
+    parser.add_argument('version', type=Version, help='version of the new release')
+    args = parser.parse_args()
+
+    verify_version(args.version)
+    release(args)
+
+if __name__ == '__main__':
+    try:
+        main()
+    except Error as e:
+        print(e)
+        sys.exit(1)