feat: implement is_exec_platform_windows

lib/private/BUILD.bazel

@@ -1,4 +1,10 @@
 load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
+load(":windows_utils.bzl", "is_exec_platform_windows")
+
+is_exec_platform_windows(
+    name = "is_exec_platform_windows",
+    visibility = ["//visibility:public"],
+)
 
 exports_files(
     [

lib/private/windows_utils.bzl

@@ -0,0 +1,136 @@
+"Helpers for rules running on windows"
+
+load("//lib/private:paths.bzl", "paths")
+
+# cmd.exe function for looking up runfiles.
+# Equivalent of the BASH_RLOCATION_FUNCTION in paths.bzl.
+# Use this to write actions that don't require bash.
+# Originally by @meteorcloudy in
+# https://github.com/bazelbuild/rules_nodejs/commit/f06553a
+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 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.
+
+    Args:
+        ctx: Rule context
+        shell_script: The bash launcher script
+
+    Returns:
+        A windows launcher script
+    """
+    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 = paths.to_rlocation_path(ctx, shell_script),
+            rlocation_function = BATCH_RLOCATION_FUNCTION,
+        ),
+        is_executable = True,
+    )
+    return win_launcher
+
+def _is_exec_platform_windows(ctx):
+    is_windows = ctx.target_platform_has_constraint(ctx.attr._windows_constraint[platform_common.ConstraintValueInfo])
+    executable = ctx.actions.declare_file("windows_exec.bats")
+    ctx.actions.write(
+        executable,
+        content = "@noop",
+    )
+
+    return [
+        DefaultInfo(executable = executable),
+        OutputGroupInfo(windows = depset()) if is_windows else OutputGroupInfo(),
+    ]
+
+is_exec_platform_windows = rule(
+    implementation = _is_exec_platform_windows,
+    attrs = {
+        "_windows_constraint": attr.label(default = "@platforms//os:windows"),
+    },
+)
+
+IS_EXEC_PLATFORM_WINDOWS_ATTRS = {
+    "_is_platform_windows_exec": attr.label(
+        default = "@aspect_bazel_lib//lib/private:is_platform_windows_exec",
+        executable = True,
+        cfg = "exec",
+    ),
+}
+
+def is_windows_exec(ctx):
+    """Utility function for checking if the action run on windows.
+
+    TODO: explain
+
+    Args:
+        ctx: rule context
+    """
+
+    outputgroupinfo = ctx.attr._is_platform_windows_exec[OutputGroupInfo]
+    return hasattr("windows", outputgroupinfo)

lib/windows_utils.bzl

@@ -14,97 +14,13 @@
 
 "Helpers for rules running on windows"
 
-load("//lib/private:paths.bzl", "paths")
-
-# cmd.exe function for looking up runfiles.
-# Equivalent of the BASH_RLOCATION_FUNCTION in paths.bzl.
-# Use this to write actions that don't require bash.
-# Originally by @meteorcloudy in
-# https://github.com/bazelbuild/rules_nodejs/commit/f06553a
-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
+load(
+    "//lib/private:windows_utils.bzl",
+    _IS_EXEC_PLATFORM_WINDOWS_ATTRS = "IS_EXEC_PLATFORM_WINDOWS_ATTRS",
+    _create_windows_native_launcher_script = "create_windows_native_launcher_script",
+    _is_exec_platform_windows = "is_exec_platform_windows",
 )
-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 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.
-
-    Args:
-        ctx: Rule context
-        shell_script: The bash launcher script
-
-    Returns:
-        A windows launcher script
-    """
-    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 = paths.to_rlocation_path(ctx, shell_script),
-            rlocation_function = BATCH_RLOCATION_FUNCTION,
-        ),
-        is_executable = True,
-    )
-    return win_launcher
+IS_EXEC_PLATFORM_WINDOWS_ATTRS = _IS_EXEC_PLATFORM_WINDOWS_ATTRS
+is_exec_platform_windows = _is_exec_platform_windows
+create_windows_native_launcher_script = _create_windows_native_launcher_script