1 files changed, 109 insertions, 0 deletions
diff --git a/pre_commit/languages/dart.py b/pre_commit/languages/dart.py
new file mode 100644
index 0000000..16e7554
--- /dev/null
+++ b/pre_commit/languages/dart.py
@@ -0,0 +1,109 @@
+import contextlib
+import os.path
+import shutil
+import tempfile
+from typing import Generator
+from typing import Sequence
+from typing import Tuple
+
+import pre_commit.constants as C
+from pre_commit.envcontext import envcontext
+from pre_commit.envcontext import PatchesT
+from pre_commit.envcontext import Var
+from pre_commit.hook import Hook
+from pre_commit.languages import helpers
+from pre_commit.prefix import Prefix
+from pre_commit.util import clean_path_on_failure
+from pre_commit.util import win_exe
+from pre_commit.util import yaml_load
+
+ENVIRONMENT_DIR = 'dartenv'
+
+get_default_version = helpers.basic_get_default_version
+healthy = helpers.basic_healthy
+
+
+def get_env_patch(venv: str) -> PatchesT:
+    return (
+        ('PATH', (os.path.join(venv, 'bin'), os.pathsep, Var('PATH'))),
+    )
+
+
+@contextlib.contextmanager
+def in_env(prefix: Prefix) -> Generator[None, None, None]:
+    directory = helpers.environment_dir(ENVIRONMENT_DIR, C.DEFAULT)
+    envdir = prefix.path(directory)
+    with envcontext(get_env_patch(envdir)):
+        yield
+
+
+def install_environment(
+        prefix: Prefix,
+        version: str,
+        additional_dependencies: Sequence[str],
+) -> None:
+    helpers.assert_version_default('dart', version)
+
+    envdir = prefix.path(helpers.environment_dir(ENVIRONMENT_DIR, version))
+    bin_dir = os.path.join(envdir, 'bin')
+
+    def _install_dir(prefix_p: Prefix, pub_cache: str) -> None:
+        dart_env = {**os.environ, 'PUB_CACHE': pub_cache}
+
+        with open(prefix_p.path('pubspec.yaml')) as f:
+            pubspec_contents = yaml_load(f)
+
+        helpers.run_setup_cmd(prefix_p, ('dart', 'pub', 'get'), env=dart_env)
+
+        for executable in pubspec_contents['executables']:
+            helpers.run_setup_cmd(
+                prefix_p,
+                (
+                    'dart', 'compile', 'exe',
+                    '--output', os.path.join(bin_dir, win_exe(executable)),
+                    prefix_p.path('bin', f'{executable}.dart'),
+                ),
+                env=dart_env,
+            )
+
+    with clean_path_on_failure(envdir):
+        os.makedirs(bin_dir)
+
+        with tempfile.TemporaryDirectory() as tmp:
+            _install_dir(prefix, tmp)
+
+        for dep_s in additional_dependencies:
+            with tempfile.TemporaryDirectory() as dep_tmp:
+                dep, _, version = dep_s.partition(':')
+                if version:
+                    dep_cmd: Tuple[str, ...] = (dep, '--version', version)
+                else:
+                    dep_cmd = (dep,)
+
+                helpers.run_setup_cmd(
+                    prefix,
+                    ('dart', 'pub', 'cache', 'add', *dep_cmd),
+                    env={**os.environ, 'PUB_CACHE': dep_tmp},
+                )
+
+                # try and find the 'pubspec.yaml' that just got added
+                for root, _, filenames in os.walk(dep_tmp):
+                    if 'pubspec.yaml' in filenames:
+                        with tempfile.TemporaryDirectory() as copied:
+                            pkg = os.path.join(copied, 'pkg')
+                            shutil.copytree(root, pkg)
+                            _install_dir(Prefix(pkg), dep_tmp)
+                        break
+                else:
+                    raise AssertionError(
+                        f'could not find pubspec.yaml for {dep_s}',
+                    )
+
+
+def run_hook(
+        hook: Hook,
+        file_args: Sequence[str],
+        color: bool,
+) -> Tuple[int, bytes]:
+    with in_env(hook.prefix):
+        return helpers.run_xargs(hook, hook.cmd, file_args, color=color)