windows_utils.bzl

# Copyright 2017 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Windows Utils

These functions help making rules work on Windows.
"""

BATCH_RLOCATION_FUNCTION = r"""
rem Usage of rlocation function:
rem        call :rlocation <runfile_path> <abs_path>
rem        The rlocation function maps the given <runfile_path> to its absolute
rem        path and stores the result in a variable named <abs_path>.
rem        This function fails if the <runfile_path> doesn't exist in mainifest
rem        file.
:: Start of rlocation
goto :rlocation_end
:rlocation
if "%~2" equ "" (
  echo>&2 ERROR: Expected two arguments for rlocation function.
  exit 1
)
if "%RUNFILES_MANIFEST_ONLY%" neq "1" (
  set %~2=%~1
  exit /b 0
)
if exist "%RUNFILES_DIR%" (
  set RUNFILES_MANIFEST_FILE=%RUNFILES_DIR%_manifest
)
if "%RUNFILES_MANIFEST_FILE%" equ "" (
  set RUNFILES_MANIFEST_FILE=%~f0.runfiles\MANIFEST
)
if not exist "%RUNFILES_MANIFEST_FILE%" (
  set RUNFILES_MANIFEST_FILE=%~f0.runfiles_manifest
)
set MF=%RUNFILES_MANIFEST_FILE:/=\%
if not exist "%MF%" (
  echo>&2 ERROR: Manifest file %MF% does not exist.
  exit 1
)
set runfile_path=%~1
for /F "tokens=2* usebackq" %%i in (`%SYSTEMROOT%\system32\findstr.exe /l /c:"!runfile_path! " "%MF%"`) do (
  set abs_path=%%i
)
if "!abs_path!" equ "" (
  echo>&2 ERROR: !runfile_path! not found in runfiles manifest
  exit 1
)
set %~2=!abs_path!
exit /b 0
:rlocation_end
:: End of rlocation
"""

def is_windows(ctx):
    """
    Check if we are building for Windows.
    """

    # Only on Windows the path separator would be ';'
    # We should switch to a proper API after
    # https://github.com/bazelbuild/bazel/issues/9209 is resolved.
    return ctx.configuration.host_path_separator == ";"

# Avoid using non-normalized paths (workspace/../other_workspace/path)
def _to_manifest_path(ctx, file):
    if file.short_path.startswith("../"):
        return file.short_path[3:]
    else:
        return ctx.workspace_name + "/" + file.short_path

def create_windows_native_launcher_script(ctx, shell_script):
    """
    Create a Windows Batch file to launch the given shell script.
    The rule should specify @bazel_tools//tools/sh:toolchain_type as a required toolchain.
    """
    name = shell_script.basename
    if name.endswith(".sh"):
        name = name[:-3]
    win_launcher = ctx.actions.declare_file(name + ".bat", sibling = shell_script)
    ctx.actions.write(
        output = win_launcher,
        content = r"""@echo off
SETLOCAL ENABLEEXTENSIONS
SETLOCAL ENABLEDELAYEDEXPANSION
set RUNFILES_MANIFEST_ONLY=1
{rlocation_function}
call :rlocation "{sh_script}" run_script
for %%a in ("{bash_bin}") do set "bash_bin_dir=%%~dpa"
set PATH=%bash_bin_dir%;%PATH%
set args=%*
rem Escape \ and * in args before passsing it with double quote
if defined args (
  set args=!args:\=\\\\!
  set args=!args:"=\"!
)
"{bash_bin}" -c "!run_script! !args!"
""".format(
            bash_bin = ctx.toolchains["@bazel_tools//tools/sh:toolchain_type"].path,
            sh_script = _to_manifest_path(ctx, shell_script),
            rlocation_function = BATCH_RLOCATION_FUNCTION,
        ),
        is_executable = True,
    )
    return win_launcher