Add aidl-format as a new builtin hook

aidl-format formats AIDL files.

Bug: 144540481
Test: Add `aidl_format = true` to /system/tools/aidl/REUPLOAD.cfg,
make a poorly formatted change in one of the AIDL file in the repo.
Creating a commit and executing `repo upload` caught it and did an
automatic fixup.

[FAILED] aidl_format
  FILES: ('tests/android/aidl/tests/ITestService.aidl',)    17,18d16
  ...
[RUNNING 5/5] aidl_format
An automatic fix can be attempted for the "aidl_format" hook. Do you
want to run it? (Yes/no)? yes
Fix successfully applied. Amend the current commit before attempting to
upload again.

[FAILED] repohooks for platform/system/tools/aidl failed in 10.274s

FATAL: Preupload failed due to above error(s).
Change-Id: I3081360840dfbe989908cdffe189573799fc29ab

3 files changed, 42 insertions, 4 deletions

diff --git a/README.md b/README.md
index dd6ffc6..1954d0a 100644
--- a/README.md
+++ b/README.md
@@ -170,6 +170,9 @@ some dog = tool --no-cat-in-commit-message ${PREUPLOAD_COMMIT_MESSAGE}
 This section allows for turning on common/builtin hooks.  There are a bunch of
 canned hooks already included geared towards AOSP style guidelines.
 
+* `aidl_format`: Run AIDL files (.aidl) through `aidl-format`.
+* `android_test_mapping_format`: Validate TEST_MAPPING files in Android source
+  code. Refer to go/test-mapping for more details.
 * `bpfmt`: Run Blueprint files (.bp) through `bpfmt`.
 * `checkpatch`: Run commits through the Linux kernel's `checkpatch.pl` script.
 * `clang_format`: Run git-clang-format against the commit. The default style is
@@ -195,8 +198,6 @@ canned hooks already included geared towards AOSP style guidelines.
 * `pylint3`: Run Python code through `pylint` using Python 3.
 * `rustfmt`: Run Rust code through `rustfmt`.
 * `xmllint`: Run XML code through `xmllint`.
-* `android_test_mapping_format`: Validate TEST_MAPPING files in Android source
-  code. Refer to go/test-mapping for more details.
 
 Note: Builtin hooks tend to match specific filenames (e.g. `.json`).  If no
 files match in a specific commit, then the hook will be skipped for that commit.
@@ -263,6 +264,9 @@ executables can be overridden through `[Tool Paths]`.  This is helpful to
 provide consistent behavior for developers across different OS and Linux
 distros/versions.  The following tools are recognized:
 
+* `aidl-format`: used for the `aidl_format` builtin hook.
+* `android-test-mapping-format`: used for the `android_test_mapping_format`
+  builtin hook.
 * `bpfmt`: used for the `bpfmt` builtin hook.
 * `clang-format`: used for the `clang_format` builtin hook.
 * `cpplint`: used for the `cpplint` builtin hook.
@@ -272,8 +276,6 @@ distros/versions.  The following tools are recognized:
 * `google-java-format-diff`: used for the `google_java_format` builtin hook.
 * `pylint`: used for the `pylint` builtin hook.
 * `rustfmt`: used for the `rustfmt` builtin hook.
-* `android-test-mapping-format`: used for the `android_test_mapping_format`
-  builtin hook.
 
 See [Placeholders](#Placeholders) for variables you can expand automatically.
 
diff --git a/rh/hooks.py b/rh/hooks.py
index 8cea251..0b3bb29 100644
--- a/rh/hooks.py
+++ b/rh/hooks.py
@@ -974,9 +974,30 @@ def check_android_test_mapping(project, commit, _desc, diff, options=None):
     return _check_cmd('android-test-mapping-format', project, commit, cmd)
 
 
+def check_aidl_format(project, commit, _desc, diff, options=None):
+    """Checks that AIDL files are formatted with aidl-format."""
+    # All *.aidl files except for those under aidl_api directory.
+    filtered = _filter_diff(diff, [r'\.aidl$'], [r'/aidl_api/'])
+    if not filtered:
+        return None
+    aidl_format = options.tool_path('aidl-format')
+    cmd = [aidl_format, '-d'] + options.args((), filtered)
+    ret = []
+    for d in filtered:
+        data = rh.git.get_file_content(commit, d.file)
+        result = _run(cmd, input=data)
+        if result.stdout:
+            fixup_func = _fixup_func_caller([aidl_format, '-w', d.file])
+            ret.append(rh.results.HookResult(
+                'aidl-format', project, commit, error=result.stdout,
+                files=(d.file,), fixup_func=fixup_func))
+    return ret
+
+
 # Hooks that projects can opt into.
 # Note: Make sure to keep the top level README.md up to date when adding more!
 BUILTIN_HOOKS = {
+    'aidl_format': check_aidl_format,
     'android_test_mapping_format': check_android_test_mapping,
     'bpfmt': check_bpfmt,
     'checkpatch': check_checkpatch,
@@ -1002,6 +1023,7 @@ BUILTIN_HOOKS = {
 # Additional tools that the hooks can call with their default values.
 # Note: Make sure to keep the top level README.md up to date when adding more!
 TOOL_PATHS = {
+    'aidl-format': 'aidl-format',
     'android-test-mapping-format':
         os.path.join(TOOLS_DIR, 'android_test_mapping_format.py'),
     'bpfmt': 'bpfmt',
diff --git a/rh/hooks_unittest.py b/rh/hooks_unittest.py
index 716e1da..8466319 100755
--- a/rh/hooks_unittest.py
+++ b/rh/hooks_unittest.py
@@ -823,6 +823,20 @@ class BuiltinHooksTests(unittest.TestCase):
             self.project, 'commit', 'desc', diff, options=self.options)
         self.assertIsNotNone(ret)
 
+    def test_aidl_format(self, mock_check, _mock_run):
+        """Verify the aidl_format builtin hook."""
+        # First call should do nothing as there are no files to check.
+        ret = rh.hooks.check_aidl_format(
+            self.project, 'commit', 'desc', (), options=self.options)
+        self.assertIsNone(ret)
+        self.assertFalse(mock_check.called)
+
+        # Second call will have some results.
+        diff = [rh.git.RawDiffEntry(file='IFoo.go')]
+        ret = rh.hooks.check_gofmt(
+            self.project, 'commit', 'desc', diff, options=self.options)
+        self.assertIsNotNone(ret)
+
 
 if __name__ == '__main__':
     unittest.main()