1 files changed, 208 insertions, 0 deletions
diff --git a/pre_commit/repository.py b/pre_commit/repository.py
new file mode 100644
index 0000000..77734ee
--- /dev/null
+++ b/pre_commit/repository.py
@@ -0,0 +1,208 @@
+import json
+import logging
+import os
+from typing import Any
+from typing import Dict
+from typing import List
+from typing import Optional
+from typing import Sequence
+from typing import Set
+from typing import Tuple
+
+import pre_commit.constants as C
+from pre_commit.clientlib import load_manifest
+from pre_commit.clientlib import LOCAL
+from pre_commit.clientlib import META
+from pre_commit.hook import Hook
+from pre_commit.languages.all import languages
+from pre_commit.languages.helpers import environment_dir
+from pre_commit.prefix import Prefix
+from pre_commit.store import Store
+from pre_commit.util import parse_version
+from pre_commit.util import rmtree
+
+
+logger = logging.getLogger('pre_commit')
+
+
+def _state(additional_deps: Sequence[str]) -> object:
+    return {'additional_dependencies': sorted(additional_deps)}
+
+
+def _state_filename(prefix: Prefix, venv: str) -> str:
+    return prefix.path(venv, f'.install_state_v{C.INSTALLED_STATE_VERSION}')
+
+
+def _read_state(prefix: Prefix, venv: str) -> Optional[object]:
+    filename = _state_filename(prefix, venv)
+    if not os.path.exists(filename):
+        return None
+    else:
+        with open(filename) as f:
+            return json.load(f)
+
+
+def _write_state(prefix: Prefix, venv: str, state: object) -> None:
+    state_filename = _state_filename(prefix, venv)
+    staging = f'{state_filename}staging'
+    with open(staging, 'w') as state_file:
+        state_file.write(json.dumps(state))
+    # Move the file into place atomically to indicate we've installed
+    os.rename(staging, state_filename)
+
+
+def _hook_installed(hook: Hook) -> bool:
+    lang = languages[hook.language]
+    venv = environment_dir(lang.ENVIRONMENT_DIR, hook.language_version)
+    return (
+        venv is None or (
+            (
+                _read_state(hook.prefix, venv) ==
+                _state(hook.additional_dependencies)
+            ) and
+            lang.healthy(hook.prefix, hook.language_version)
+        )
+    )
+
+
+def _hook_install(hook: Hook) -> None:
+    logger.info(f'Installing environment for {hook.src}.')
+    logger.info('Once installed this environment will be reused.')
+    logger.info('This may take a few minutes...')
+
+    lang = languages[hook.language]
+    assert lang.ENVIRONMENT_DIR is not None
+    venv = environment_dir(lang.ENVIRONMENT_DIR, hook.language_version)
+
+    # There's potentially incomplete cleanup from previous runs
+    # Clean it up!
+    if hook.prefix.exists(venv):
+        rmtree(hook.prefix.path(venv))
+
+    lang.install_environment(
+        hook.prefix, hook.language_version, hook.additional_dependencies,
+    )
+    # Write our state to indicate we're installed
+    _write_state(hook.prefix, venv, _state(hook.additional_dependencies))
+
+
+def _hook(
+        *hook_dicts: Dict[str, Any],
+        root_config: Dict[str, Any],
+) -> Dict[str, Any]:
+    ret, rest = dict(hook_dicts[0]), hook_dicts[1:]
+    for dct in rest:
+        ret.update(dct)
+
+    version = ret['minimum_pre_commit_version']
+    if parse_version(version) > parse_version(C.VERSION):
+        logger.error(
+            f'The hook `{ret["id"]}` requires pre-commit version {version} '
+            f'but version {C.VERSION} is installed.  '
+            f'Perhaps run `pip install --upgrade pre-commit`.',
+        )
+        exit(1)
+
+    lang = ret['language']
+    if ret['language_version'] == C.DEFAULT:
+        ret['language_version'] = root_config['default_language_version'][lang]
+    if ret['language_version'] == C.DEFAULT:
+        ret['language_version'] = languages[lang].get_default_version()
+
+    if not ret['stages']:
+        ret['stages'] = root_config['default_stages']
+
+    return ret
+
+
+def _non_cloned_repository_hooks(
+        repo_config: Dict[str, Any],
+        store: Store,
+        root_config: Dict[str, Any],
+) -> Tuple[Hook, ...]:
+    def _prefix(language_name: str, deps: Sequence[str]) -> Prefix:
+        language = languages[language_name]
+        # pygrep / script / system / docker_image do not have
+        # environments so they work out of the current directory
+        if language.ENVIRONMENT_DIR is None:
+            return Prefix(os.getcwd())
+        else:
+            return Prefix(store.make_local(deps))
+
+    return tuple(
+        Hook.create(
+            repo_config['repo'],
+            _prefix(hook['language'], hook['additional_dependencies']),
+            _hook(hook, root_config=root_config),
+        )
+        for hook in repo_config['hooks']
+    )
+
+
+def _cloned_repository_hooks(
+        repo_config: Dict[str, Any],
+        store: Store,
+        root_config: Dict[str, Any],
+) -> Tuple[Hook, ...]:
+    repo, rev = repo_config['repo'], repo_config['rev']
+    manifest_path = os.path.join(store.clone(repo, rev), C.MANIFEST_FILE)
+    by_id = {hook['id']: hook for hook in load_manifest(manifest_path)}
+
+    for hook in repo_config['hooks']:
+        if hook['id'] not in by_id:
+            logger.error(
+                f'`{hook["id"]}` is not present in repository {repo}.  '
+                f'Typo? Perhaps it is introduced in a newer version?  '
+                f'Often `pre-commit autoupdate` fixes this.',
+            )
+            exit(1)
+
+    hook_dcts = [
+        _hook(by_id[hook['id']], hook, root_config=root_config)
+        for hook in repo_config['hooks']
+    ]
+    return tuple(
+        Hook.create(
+            repo_config['repo'],
+            Prefix(store.clone(repo, rev, hook['additional_dependencies'])),
+            hook,
+        )
+        for hook in hook_dcts
+    )
+
+
+def _repository_hooks(
+        repo_config: Dict[str, Any],
+        store: Store,
+        root_config: Dict[str, Any],
+) -> Tuple[Hook, ...]:
+    if repo_config['repo'] in {LOCAL, META}:
+        return _non_cloned_repository_hooks(repo_config, store, root_config)
+    else:
+        return _cloned_repository_hooks(repo_config, store, root_config)
+
+
+def install_hook_envs(hooks: Sequence[Hook], store: Store) -> None:
+    def _need_installed() -> List[Hook]:
+        seen: Set[Tuple[Prefix, str, str, Tuple[str, ...]]] = set()
+        ret = []
+        for hook in hooks:
+            if hook.install_key not in seen and not _hook_installed(hook):
+                ret.append(hook)
+            seen.add(hook.install_key)
+        return ret
+
+    if not _need_installed():
+        return
+    with store.exclusive_lock():
+        # Another process may have already completed this work
+        for hook in _need_installed():
+            _hook_install(hook)
+
+
+def all_hooks(root_config: Dict[str, Any], store: Store) -> Tuple[Hook, ...]:
+    return tuple(
+        hook
+        for repo in root_config['repos']
+        for hook in _repository_hooks(repo, store, root_config)
+    )