xref: /aosp_15_r20/bootable/libbootloader/gbl/bazel.py (revision 5225e6b173e52d2efc6bcf950c27374fd72adabc)
1# Copyright (C) 2024 The Android Open Source Project
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#       http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15import argparse
16import os
17import pathlib
18import sys
19from typing import Tuple, Optional
20
21_BAZEL_REL_PATH = "prebuilts/kernel-build-tools/bazel/linux-x86_64/bazel"
22
23
24def _partition(lst: list[str], index: Optional[int]) \
25        -> Tuple[list[str], Optional[str], list[str]]:
26    """Returns the triple split by index.
27
28    That is, return a tuple:
29    (everything before index, the element at index, everything after index)
30
31    If index is None, return (the list, None, empty list)
32    """
33    if index is None:
34        return lst[:], None, []
35    return lst[:index], lst[index], lst[index + 1:]
36
37
38class BazelWrapper(object):
39    def __init__(self, workspace_dir: pathlib.Path, bazel_args: list[str]):
40        """Splits arguments to the bazel binary based on the functionality.
41
42        bazel [startup_options] command         [command_args] --               [target_patterns]
43                                 ^- command_idx                ^- dash_dash_idx
44
45        See https://bazel.build/reference/command-line-reference
46
47        Args:
48            workspace_dir: root of workspace.
49            bazel_args: The list of arguments the user provides through command line
50            env: existing environment
51        """
52
53        self.workspace_dir = workspace_dir
54
55        self.bazel_path = self.workspace_dir / _BAZEL_REL_PATH
56
57        command_idx = None
58        for idx, arg in enumerate(bazel_args):
59            if not arg.startswith("-"):
60                command_idx = idx
61                break
62
63        self.startup_options, self.command, remaining_args = _partition(bazel_args,
64                                                                        command_idx)
65
66        # Split command_args into `command_args -- target_patterns`
67        dash_dash_idx = None
68        try:
69            dash_dash_idx = remaining_args.index("--")
70        except ValueError:
71            # If -- is not found, put everything in command_args. These arguments
72            # are not provided to the Bazel executable target.
73            pass
74
75        self.command_args, self.dash_dash, self.target_patterns = _partition(remaining_args,
76                                                                             dash_dash_idx)
77
78        self._parse_startup_options()
79        self._parse_command_args()
80        self._add_extra_startup_options()
81
82    def add_startup_option_to_parser(self, parser):
83        parser.add_argument(
84            "-h", "--help", action="store_true",
85            help="show this help message and exit"
86        )
87
88    def _parse_startup_options(self):
89        """Parses the given list of startup_options.
90
91        After calling this function, the following attributes are set:
92        - absolute_user_root: A path holding bazel build output location
93        - transformed_startup_options: The transformed list of startup_options to replace
94          existing startup_options to be fed to the Bazel binary
95        """
96
97        parser = argparse.ArgumentParser(add_help=False, allow_abbrev=False)
98        self.add_startup_option_to_parser(parser)
99
100        self.known_startup_options, self.user_startup_options = \
101            parser.parse_known_args(self.startup_options)
102
103        self.absolute_out_dir = self.workspace_dir / "out"
104        self.absolute_user_root = \
105            self.absolute_out_dir / "bazel/output_user_root"
106
107        if self.known_startup_options.help:
108            self.transformed_startup_options = [
109                "--help"
110            ]
111
112        if not self.known_startup_options.help:
113            javatmp = self.absolute_out_dir / "bazel/javatmp"
114            self.transformed_startup_options = [
115                f"--host_jvm_args=-Djava.io.tmpdir={javatmp}",
116            ]
117
118        # See _add_extra_startup_options for extra startup options
119
120    def _parse_command_args(self):
121        """Parses the given list of command_args.
122
123        After calling this function, the following attributes are set:
124        - known_args: A namespace holding options known by this Bazel wrapper script
125        - transformed_command_args: The transformed list of command_args to replace
126          existing command_args to be fed to the Bazel binary
127        - env: A dictionary containing the new environment variables for the subprocess.
128        """
129
130        parser = argparse.ArgumentParser(add_help=False, allow_abbrev=False)
131
132        # TODO: Delete these args once build bots no longer specify them
133        parser.add_argument(
134            "--make_jobs", metavar="JOBS", type=int, default=None,
135            help="unused")
136        parser.add_argument(
137            "--make_keep_going", action="store_true", default=False,
138            help="unused")
139        parser.add_argument(
140            "--repo_manifest", metavar="<repo_root>:<manifest.xml>",
141            help="unused")
142
143        # Skip startup options (before command) and target_patterns (after --)
144        _, self.transformed_command_args = parser.parse_known_args(
145            self.command_args)
146
147    def _add_extra_startup_options(self):
148        """Adds extra startup options after command args are parsed."""
149
150        self.transformed_startup_options += self.user_startup_options
151
152        if not self.known_startup_options.help:
153            self.transformed_startup_options.append(
154                f"--output_user_root={self.absolute_user_root}")
155
156    def _build_final_args(self) -> list[str]:
157        """Builds the final arguments for the subprocess."""
158        # final_args:
159        # bazel [startup_options] [additional_startup_options] command [transformed_command_args] -- [target_patterns]
160
161        final_args = [self.bazel_path] + self.transformed_startup_options
162
163        if self.command is not None:
164            final_args.append(self.command)
165        final_args += self.transformed_command_args
166        if self.dash_dash is not None:
167            final_args.append(self.dash_dash)
168        final_args += self.target_patterns
169
170        return final_args
171
172    def run(self) -> int:
173        """Runs the wrapper.
174
175        Returns:
176            doesn't return"""
177        final_args = self._build_final_args()
178
179        os.execve(path=self.bazel_path, argv=final_args, env=os.environ)
180
181
182def _bazel_wrapper_main():
183    # <workspace_dir>/bootable/libbootloader/gbl/bazel.py
184    workspace_dir = (
185        pathlib.Path(__file__).resolve().parent.parent.parent.parent)
186    return BazelWrapper(workspace_dir=workspace_dir,
187                        bazel_args=sys.argv[1:]).run()
188
189
190if __name__ == "__main__":
191    sys.exit(_bazel_wrapper_main())
192