1 files changed, 106 insertions, 0 deletions
diff --git a/pre_commit/languages/rust.py b/pre_commit/languages/rust.py
new file mode 100644
index 0000000..7ea3f54
--- /dev/null
+++ b/pre_commit/languages/rust.py
@@ -0,0 +1,106 @@
+import contextlib
+import os.path
+from typing import Generator
+from typing import Sequence
+from typing import Set
+from typing import Tuple
+
+import toml
+
+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 cmd_output_b
+
+ENVIRONMENT_DIR = 'rustenv'
+get_default_version = helpers.basic_get_default_version
+healthy = helpers.basic_healthy
+
+
+def get_env_patch(target_dir: str) -> PatchesT:
+    return (
+        ('PATH', (os.path.join(target_dir, 'bin'), os.pathsep, Var('PATH'))),
+    )
+
+
+@contextlib.contextmanager
+def in_env(prefix: Prefix) -> Generator[None, None, None]:
+    target_dir = prefix.path(
+        helpers.environment_dir(ENVIRONMENT_DIR, C.DEFAULT),
+    )
+    with envcontext(get_env_patch(target_dir)):
+        yield
+
+
+def _add_dependencies(
+        cargo_toml_path: str,
+        additional_dependencies: Set[str],
+) -> None:
+    with open(cargo_toml_path, 'r+') as f:
+        cargo_toml = toml.load(f)
+        cargo_toml.setdefault('dependencies', {})
+        for dep in additional_dependencies:
+            name, _, spec = dep.partition(':')
+            cargo_toml['dependencies'][name] = spec or '*'
+        f.seek(0)
+        toml.dump(cargo_toml, f)
+        f.truncate()
+
+
+def install_environment(
+        prefix: Prefix,
+        version: str,
+        additional_dependencies: Sequence[str],
+) -> None:
+    helpers.assert_version_default('rust', version)
+    directory = prefix.path(
+        helpers.environment_dir(ENVIRONMENT_DIR, C.DEFAULT),
+    )
+
+    # There are two cases where we might want to specify more dependencies:
+    # as dependencies for the library being built, and as binary packages
+    # to be `cargo install`'d.
+    #
+    # Unlike e.g. Python, if we just `cargo install` a library, it won't be
+    # used for compilation. And if we add a crate providing a binary to the
+    # `Cargo.toml`, the binary won't be built.
+    #
+    # Because of this, we allow specifying "cli" dependencies by prefixing
+    # with 'cli:'.
+    cli_deps = {
+        dep for dep in additional_dependencies if dep.startswith('cli:')
+    }
+    lib_deps = set(additional_dependencies) - cli_deps
+
+    if len(lib_deps) > 0:
+        _add_dependencies(prefix.path('Cargo.toml'), lib_deps)
+
+    with clean_path_on_failure(directory):
+        packages_to_install: Set[Tuple[str, ...]] = {('--path', '.')}
+        for cli_dep in cli_deps:
+            cli_dep = cli_dep[len('cli:'):]
+            package, _, version = cli_dep.partition(':')
+            if version != '':
+                packages_to_install.add((package, '--version', version))
+            else:
+                packages_to_install.add((package,))
+
+        for args in packages_to_install:
+            cmd_output_b(
+                'cargo', 'install', '--bins', '--root', directory, *args,
+                cwd=prefix.prefix_dir,
+            )
+
+
+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)