1 files changed, 187 insertions, 0 deletions
diff --git a/pre_commit/commands/hook_impl.py b/pre_commit/commands/hook_impl.py
new file mode 100644
index 0000000..5ff4555
--- /dev/null
+++ b/pre_commit/commands/hook_impl.py
@@ -0,0 +1,187 @@
+import argparse
+import os.path
+import subprocess
+import sys
+from typing import Optional
+from typing import Sequence
+from typing import Tuple
+
+from pre_commit.commands.run import run
+from pre_commit.envcontext import envcontext
+from pre_commit.parse_shebang import normalize_cmd
+from pre_commit.store import Store
+
+Z40 = '0' * 40
+
+
+def _run_legacy(
+        hook_type: str,
+        hook_dir: str,
+        args: Sequence[str],
+) -> Tuple[int, bytes]:
+    if os.environ.get('PRE_COMMIT_RUNNING_LEGACY'):
+        raise SystemExit(
+            f"bug: pre-commit's script is installed in migration mode\n"
+            f'run `pre-commit install -f --hook-type {hook_type}` to fix '
+            f'this\n\n'
+            f'Please report this bug at '
+            f'https://github.com/pre-commit/pre-commit/issues',
+        )
+
+    if hook_type == 'pre-push':
+        stdin = sys.stdin.buffer.read()
+    else:
+        stdin = b''
+
+    # not running in legacy mode
+    legacy_hook = os.path.join(hook_dir, f'{hook_type}.legacy')
+    if not os.access(legacy_hook, os.X_OK):
+        return 0, stdin
+
+    with envcontext((('PRE_COMMIT_RUNNING_LEGACY', '1'),)):
+        cmd = normalize_cmd((legacy_hook, *args))
+        return subprocess.run(cmd, input=stdin).returncode, stdin
+
+
+def _validate_config(
+        retv: int,
+        config: str,
+        skip_on_missing_config: bool,
+) -> None:
+    if not os.path.isfile(config):
+        if skip_on_missing_config or os.getenv('PRE_COMMIT_ALLOW_NO_CONFIG'):
+            print(f'`{config}` config file not found. Skipping `pre-commit`.')
+            raise SystemExit(retv)
+        else:
+            print(
+                f'No {config} file was found\n'
+                f'- To temporarily silence this, run '
+                f'`PRE_COMMIT_ALLOW_NO_CONFIG=1 git ...`\n'
+                f'- To permanently silence this, install pre-commit with the '
+                f'--allow-missing-config option\n'
+                f'- To uninstall pre-commit run `pre-commit uninstall`',
+            )
+            raise SystemExit(1)
+
+
+def _ns(
+        hook_type: str,
+        color: bool,
+        *,
+        all_files: bool = False,
+        from_ref: Optional[str] = None,
+        to_ref: Optional[str] = None,
+        remote_name: Optional[str] = None,
+        remote_url: Optional[str] = None,
+        commit_msg_filename: Optional[str] = None,
+        checkout_type: Optional[str] = None,
+) -> argparse.Namespace:
+    return argparse.Namespace(
+        color=color,
+        hook_stage=hook_type.replace('pre-', ''),
+        from_ref=from_ref,
+        to_ref=to_ref,
+        remote_name=remote_name,
+        remote_url=remote_url,
+        commit_msg_filename=commit_msg_filename,
+        all_files=all_files,
+        checkout_type=checkout_type,
+        files=(),
+        hook=None,
+        verbose=False,
+        show_diff_on_failure=False,
+    )
+
+
+def _rev_exists(rev: str) -> bool:
+    return not subprocess.call(('git', 'rev-list', '--quiet', rev))
+
+
+def _pre_push_ns(
+        color: bool,
+        args: Sequence[str],
+        stdin: bytes,
+) -> Optional[argparse.Namespace]:
+    remote_name = args[0]
+    remote_url = args[1]
+
+    for line in stdin.decode().splitlines():
+        _, local_sha, _, remote_sha = line.split()
+        if local_sha == Z40:
+            continue
+        elif remote_sha != Z40 and _rev_exists(remote_sha):
+            return _ns(
+                'pre-push', color,
+                from_ref=remote_sha, to_ref=local_sha,
+                remote_name=remote_name, remote_url=remote_url,
+            )
+        else:
+            # ancestors not found in remote
+            ancestors = subprocess.check_output((
+                'git', 'rev-list', local_sha, '--topo-order', '--reverse',
+                '--not', f'--remotes={remote_name}',
+            )).decode().strip()
+            if not ancestors:
+                continue
+            else:
+                first_ancestor = ancestors.splitlines()[0]
+                cmd = ('git', 'rev-list', '--max-parents=0', local_sha)
+                roots = set(subprocess.check_output(cmd).decode().splitlines())
+                if first_ancestor in roots:
+                    # pushing the whole tree including root commit
+                    return _ns(
+                        'pre-push', color,
+                        all_files=True,
+                        remote_name=remote_name, remote_url=remote_url,
+                    )
+                else:
+                    rev_cmd = ('git', 'rev-parse', f'{first_ancestor}^')
+                    source = subprocess.check_output(rev_cmd).decode().strip()
+                    return _ns(
+                        'pre-push', color,
+                        from_ref=source, to_ref=local_sha,
+                        remote_name=remote_name, remote_url=remote_url,
+                    )
+
+    # nothing to push
+    return None
+
+
+def _run_ns(
+        hook_type: str,
+        color: bool,
+        args: Sequence[str],
+        stdin: bytes,
+) -> Optional[argparse.Namespace]:
+    if hook_type == 'pre-push':
+        return _pre_push_ns(color, args, stdin)
+    elif hook_type in {'prepare-commit-msg', 'commit-msg'}:
+        return _ns(hook_type, color, commit_msg_filename=args[0])
+    elif hook_type in {'pre-merge-commit', 'pre-commit'}:
+        return _ns(hook_type, color)
+    elif hook_type == 'post-checkout':
+        return _ns(
+            hook_type, color,
+            from_ref=args[0], to_ref=args[1], checkout_type=args[2],
+        )
+    else:
+        raise AssertionError(f'unexpected hook type: {hook_type}')
+
+
+def hook_impl(
+        store: Store,
+        *,
+        config: str,
+        color: bool,
+        hook_type: str,
+        hook_dir: str,
+        skip_on_missing_config: bool,
+        args: Sequence[str],
+) -> int:
+    retv, stdin = _run_legacy(hook_type, hook_dir, args)
+    _validate_config(retv, config, skip_on_missing_config)
+    ns = _run_ns(hook_type, color, args, stdin)
+    if ns is None:
+        return retv
+    else:
+        return retv | run(config, store, ns)