Add initial files

libwyag.py

@@ -0,0 +1,148 @@
+import argparse
+import collections
+import configparser
+from datetime import datetime
+from fnmatch import fnmatch
+import hashlib
+from math import ceil
+import os
+import re
+import sys
+import zlib
+
+argparser = argparse.ArgumentParser(description="The stupidest content tracker")
+
+argsubparsers = argparser.add_subparsers(title="Commands", dest="command")
+argsubparsers.required = True
+
+def main(argv=sys.argv[1:]):
+    args = argparser.parse_args(argv)
+    match args.command:
+        case "add"          : cmd_add(args)
+        case "cat-file"     : cmd_cat_file(args)
+        case "check-ignore" : cmd_check_ignore(args)
+        case "checkout"     : cmd_checkout(args)
+        case "commit"       : cmd_commit(args)
+        case "hash-object"  : cmd_hash_object(args)
+        case "init"         : cmd_init(args)
+        case "log"          : cmd_log(args)
+        case "ls-files"     : cmd_ls_files(args)
+        case "ls-tree"      : cmd_ls_tree(args)
+        case "rev-parse"    : cmd_rev_parse(args)
+        case "rm"           : cmd_rm(args)
+        case "show-ref"     : cmd_show_ref(args)
+        case "status"       : cmd_status(args)
+        case "tag"          : cmd_tag(args)
+        case _              : print("Bad command.")
+
+class GitRepository (object):
+    """A git repo"""
+
+    worktree = None
+    gitdir = None
+    conf = None
+
+    def __init__(self, path, force=False):
+        self.worktree = path
+        self.gitdir = os.path.join(path, ".git")
+
+        if not (force or os.path.isdir(self.gitdir)):
+            raise Exception(f"Not a git repository {path}")
+
+        # Read configuration file in .git/config
+        self.conf = configparser.ConfigParser()
+        cf = GitRepository.repo_file(self, "config")
+
+        if cf and os.path.exists(cf):
+            self.conf.read([cf])
+        elif not force:
+            raise Exception("Configuration file missing")
+
+        if not force:
+            vers = int(self.conf.get("core", "repositoryformatversion"))
+            if vers != 0:
+                raise Exception(f"Unsupported repositoryformatversion {vers}")
+
+    def repo_path(repo, *path):
+        """Compute path under repo's gitdir."""
+        return os.path.join(repo.gitdir, *path)
+
+    def repo_file(repo, *path, mkdir=False):
+        """Same as repo_path, but create dirname(*path) if absent. For
+        example, repo_file(r, \"refs\", \"remotes\", \"origin\", \"HEAD\") will create
+        .git/refs/remotes/origin."""
+
+        if GitRepository.repo_dir(repo, *path[:-1], mkdir=mkdir):
+            return GitRepository.repo_path(repo, *path)
+
+    def repo_dir(repo, *path, mkdir=False):
+        """Same as repo_path, bt mkdir *path if absent if mkdir"""
+
+        path = GitRepository.repo_path(repo, *path)
+
+        if (os.path.exists(path)):
+            if (os.path.isdir(path)):
+                return path
+            else:
+                raise Exception(f"Not a directory {path}")
+
+        if mkdir:
+            os.makedirs(path)
+            return path
+        else:
+            return None
+
+def repo_create(path):
+    """Create a new repository at path."""
+
+    repo = GitRepository(path, True)
+
+    # First, we make sure the path either doesn't exist or is an
+    # empty dir.
+
+    if os.path.exists(repo.worktree):
+        if not os.path.isdir(repo.worktree):
+            raise Exception(f"{path} is not a directory!")
+        if os.path.exists(repo.gitdir) and os.listdir(repo.gitdir):
+            raise Exception(f"{path} is not empty!")
+    else:
+        os.makedirs(repo.worktree)
+
+    assert GitRepository.repo_dir(repo, "branches", mkdir=True)
+    assert GitRepository.repo_dir(repo, "objects", mkdir=True)
+    assert GitRepository.repo_dir(repo, "refs", "tags", mkdir=True)
+    assert GitRepository.repo_dir(repo, "refs", "heads", mkdir=True)
+
+    # .git/description
+    with open(GitRepository.repo_file(repo, "description"), "w") as f:
+        f.write("Unnamed repository; edit this file 'description' to name the repository")
+
+    with open(GitRepository.repo_file(repo, "HEAD"), "w") as f:
+        f.write("ref: refs/heads/master\n")
+
+    with open(GitRepository.repo_file(repo, "config"), "w") as f:
+        config = repo_default_config()
+        config.write(f)
+
+    return repo
+
+def repo_default_config():
+    ret = configparser.ConfigParser()
+
+    ret.add_section("core")
+    ret.set("core", "repositoryformatVersion", "0")
+    ret.set("core", "filemode", "false")
+    ret.set("core", "bare", "false")
+
+    return ret
+
+argsp = argsubparsers.add_parser("init", help="Initialize a new, empty repository.")
+
+argsp.add_argument("path",
+                   metavar="directory",
+                   nargs="?",
+                   default=".",
+                   help="Where to create the repository.")
+
+def cmd_init(args):
+    repo_create(args.path)

wyag.py

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+#!/usr/bin/env python3
+
+import libwyag
+libwyag.main()