1 files changed, 175 insertions, 0 deletions
diff --git a/pre_commit/commands/install_uninstall.py b/pre_commit/commands/install_uninstall.py
new file mode 100644
index 0000000..c8b7633
--- /dev/null
+++ b/pre_commit/commands/install_uninstall.py
@@ -0,0 +1,175 @@
+import itertools
+import logging
+import os.path
+import shutil
+import sys
+from typing import Optional
+from typing import Sequence
+from typing import Tuple
+
+from pre_commit import git
+from pre_commit import output
+from pre_commit.clientlib import load_config
+from pre_commit.repository import all_hooks
+from pre_commit.repository import install_hook_envs
+from pre_commit.store import Store
+from pre_commit.util import make_executable
+from pre_commit.util import resource_text
+
+
+logger = logging.getLogger(__name__)
+
+# This is used to identify the hook file we install
+PRIOR_HASHES = (
+    '4d9958c90bc262f47553e2c073f14cfe',
+    'd8ee923c46731b42cd95cc869add4062',
+    '49fd668cb42069aa1b6048464be5d395',
+    '79f09a650522a87b0da915d0d983b2de',
+    'e358c9dae00eac5d06b38dfdb1e33a8c',
+)
+CURRENT_HASH = '138fd403232d2ddd5efb44317e38bf03'
+TEMPLATE_START = '# start templated\n'
+TEMPLATE_END = '# end templated\n'
+# Homebrew/homebrew-core#35825: be more timid about appropriate `PATH`
+# #1312 os.defpath is too restrictive on BSD
+POSIX_SEARCH_PATH = ('/usr/local/bin', '/usr/bin', '/bin')
+SYS_EXE = os.path.basename(os.path.realpath(sys.executable))
+
+
+def _hook_paths(
+        hook_type: str,
+        git_dir: Optional[str] = None,
+) -> Tuple[str, str]:
+    git_dir = git_dir if git_dir is not None else git.get_git_dir()
+    pth = os.path.join(git_dir, 'hooks', hook_type)
+    return pth, f'{pth}.legacy'
+
+
+def is_our_script(filename: str) -> bool:
+    if not os.path.exists(filename):  # pragma: win32 no cover (symlink)
+        return False
+    with open(filename) as f:
+        contents = f.read()
+    return any(h in contents for h in (CURRENT_HASH,) + PRIOR_HASHES)
+
+
+def shebang() -> str:
+    if sys.platform == 'win32':
+        py = SYS_EXE
+    else:
+        exe_choices = [
+            f'python{sys.version_info[0]}.{sys.version_info[1]}',
+            f'python{sys.version_info[0]}',
+        ]
+        # avoid searching for bare `python` as it's likely to be python 2
+        if SYS_EXE != 'python':
+            exe_choices.append(SYS_EXE)
+        for path, exe in itertools.product(POSIX_SEARCH_PATH, exe_choices):
+            if os.access(os.path.join(path, exe), os.X_OK):
+                py = exe
+                break
+        else:
+            py = SYS_EXE
+    return f'#!/usr/bin/env {py}'
+
+
+def _install_hook_script(
+        config_file: str,
+        hook_type: str,
+        overwrite: bool = False,
+        skip_on_missing_config: bool = False,
+        git_dir: Optional[str] = None,
+) -> None:
+    hook_path, legacy_path = _hook_paths(hook_type, git_dir=git_dir)
+
+    os.makedirs(os.path.dirname(hook_path), exist_ok=True)
+
+    # If we have an existing hook, move it to pre-commit.legacy
+    if os.path.lexists(hook_path) and not is_our_script(hook_path):
+        shutil.move(hook_path, legacy_path)
+
+    # If we specify overwrite, we simply delete the legacy file
+    if overwrite and os.path.exists(legacy_path):
+        os.remove(legacy_path)
+    elif os.path.exists(legacy_path):
+        output.write_line(
+            f'Running in migration mode with existing hooks at {legacy_path}\n'
+            f'Use -f to use only pre-commit.',
+        )
+
+    args = ['hook-impl', f'--config={config_file}', f'--hook-type={hook_type}']
+    if skip_on_missing_config:
+        args.append('--skip-on-missing-config')
+    params = {'INSTALL_PYTHON': sys.executable, 'ARGS': args}
+
+    with open(hook_path, 'w') as hook_file:
+        contents = resource_text('hook-tmpl')
+        before, rest = contents.split(TEMPLATE_START)
+        to_template, after = rest.split(TEMPLATE_END)
+
+        before = before.replace('#!/usr/bin/env python3', shebang())
+
+        hook_file.write(before + TEMPLATE_START)
+        for line in to_template.splitlines():
+            var = line.split()[0]
+            hook_file.write(f'{var} = {params[var]!r}\n')
+        hook_file.write(TEMPLATE_END + after)
+    make_executable(hook_path)
+
+    output.write_line(f'pre-commit installed at {hook_path}')
+
+
+def install(
+        config_file: str,
+        store: Store,
+        hook_types: Sequence[str],
+        overwrite: bool = False,
+        hooks: bool = False,
+        skip_on_missing_config: bool = False,
+        git_dir: Optional[str] = None,
+) -> int:
+    if git_dir is None and git.has_core_hookpaths_set():
+        logger.error(
+            'Cowardly refusing to install hooks with `core.hooksPath` set.\n'
+            'hint: `git config --unset-all core.hooksPath`',
+        )
+        return 1
+
+    for hook_type in hook_types:
+        _install_hook_script(
+            config_file, hook_type,
+            overwrite=overwrite,
+            skip_on_missing_config=skip_on_missing_config,
+            git_dir=git_dir,
+        )
+
+    if hooks:
+        install_hooks(config_file, store)
+
+    return 0
+
+
+def install_hooks(config_file: str, store: Store) -> int:
+    install_hook_envs(all_hooks(load_config(config_file), store), store)
+    return 0
+
+
+def _uninstall_hook_script(hook_type: str) -> None:
+    hook_path, legacy_path = _hook_paths(hook_type)
+
+    # If our file doesn't exist or it isn't ours, gtfo.
+    if not os.path.exists(hook_path) or not is_our_script(hook_path):
+        return
+
+    os.remove(hook_path)
+    output.write_line(f'{hook_type} uninstalled')
+
+    if os.path.exists(legacy_path):
+        os.rename(legacy_path, hook_path)
+        output.write_line(f'Restored previous hooks to {hook_path}')
+
+
+def uninstall(hook_types: Sequence[str]) -> int:
+    for hook_type in hook_types:
+        _uninstall_hook_script(hook_type)
+    return 0