Add repository rule for Windows SDK.

Due to how the SDK directory is structured (<sdk_root>/include/<version>),
the BUILD file is expanded from a template with version string substituted.

The BUILD file template contains an import target for all SDK libraries
of the selected version.

Bug: 288495471
Change-Id: I4d0c85f42210349f9a81e80b20b6fc09770d0d9d

4 files changed, 105 insertions, 2 deletions

diff --git a/rules/repository_utils.bzl b/rules/repository_utils.bzl
index e614b65e..3c2c297f 100644
--- a/rules/repository_utils.bzl
+++ b/rules/repository_utils.bzl
@@ -60,13 +60,15 @@ def relative_path(path_str, root):
     """

     return path_str.removeprefix(root).lstrip("/\\")

 

-def create_build_file(build_file, repo_ctx):

+def create_build_file(build_file, repo_ctx, substitutions = None):

     """Create a BUILD.bazel file at root of the repository.

 

     Args:

         build_file: A path string to the BUILD file. Relative path is resolved

             relative to the workspace root.

         repo_ctx: The repository context.

+        substitutions: If specified, substitutions to make when expanding

+            build_file as a template.

     """

     repo_ctx.delete("BUILD.bazel")

     build_file = resolve_workspace_path(build_file, repo_ctx)

@@ -78,7 +80,15 @@ def create_build_file(build_file, repo_ctx):
             build_file,

             "is not found.",

         )

-    repo_ctx.symlink(build_file, "BUILD.bazel")

+    if not substitutions:

+        repo_ctx.symlink(build_file, "BUILD.bazel")

+    else:

+        repo_ctx.template(

+            "BUILD.bazel",

+            build_file,

+            substitutions,

+            executable = False,

+        )

 

 def create_workspace_file(workspace_file, repo_ctx, default_content = None):

     """Create a WORKSPACE file at root of the repository. At least one of workspace_file and default_content must be passed.

diff --git a/toolchains/cc/repository_rules.bzl b/toolchains/cc/repository_rules.bzl
index 78120cc5..cf42a547 100644
--- a/toolchains/cc/repository_rules.bzl
+++ b/toolchains/cc/repository_rules.bzl
@@ -134,3 +134,62 @@ msvc_tools_repository = repository_rule(
         ),
     },
 )
+
+def _get_all_win_sdk_versions(sdk_path):
+    sdk_versions = []
+    for versioned_sdk_include in sdk_path.get_child("Include").readdir():
+        if versioned_sdk_include.get_child("um", "winsdkver.h").exists:
+            sdk_versions.append(versioned_sdk_include.basename)
+    return sdk_versions
+
+def _windows_sdk_repository_impl(repo_ctx):
+    """Creates a local repository for a Windows SDK."""
+    sdk_path = repo_ctx.path(repo_ctx.attr.sdk_path)
+    all_versions = {v: None for v in _get_all_win_sdk_versions(sdk_path)}
+    want_versions = repo_ctx.attr.sdk_versions if repo_ctx.attr.sdk_versions else [""]
+    selected_version = _select_version(all_versions, want_versions)
+    if not selected_version:
+        fail(
+            "None of the following Windows SDK versions are found in",
+            str(sdk_path),
+            ":",
+            want_versions,
+            "; available versions are:",
+            all_versions.keys(),
+        )
+    for entry in sdk_path.readdir():
+        repo_ctx.symlink(entry, relative_path(str(entry), str(sdk_path)))
+    create_build_file(
+        repo_ctx.attr.build_file_template,
+        repo_ctx,
+        substitutions = {"%{sdk_version}": selected_version},
+    )
+    create_workspace_file(None, repo_ctx, default_workspace_file_content(
+        repo_ctx.name,
+        "windows_sdk_repository",
+    ))
+
+windows_sdk_repository = repository_rule(
+    implementation = _windows_sdk_repository_impl,
+    local = True,
+    doc = "Creates a local repository for host installed Windows SDK.",
+    attrs = {
+        "build_file_template": attr.string(
+            doc = "A file to be expanded as a BUILD file for this directory, " +
+                  "relative to the main workspace. The template can contain " +
+                  "'%{sdk_version}' tags that will be replaced with exact " +
+                  "SDK version.",
+            mandatory = True,
+        ),
+        "sdk_path": attr.string(
+            doc = "The installation path of Windows SDKs.",
+            mandatory = True,
+        ),
+        "sdk_versions": attr.string_list(
+            doc = "The SDK versions to look for (e.g. 10.0.19041.0). " +
+                  "The first version found will be used. An empty " +
+                  "string can be added at the end for the latest version.",
+            default = [""],
+        ),
+    },
+)
diff --git a/toolchains/cc/windows_clang/sdk.BUILD.tpl b/toolchains/cc/windows_clang/sdk.BUILD.tpl
new file mode 100644
index 00000000..3b528870
--- /dev/null
+++ b/toolchains/cc/windows_clang/sdk.BUILD.tpl
@@ -0,0 +1,27 @@
+"""Exports Windows SDK libraries from the "Windows Kits\\<os major>" directory."""
+
+load("@//build/bazel/toolchains/cc:rules.bzl", "cc_toolchain_import")
+
+package(default_visibility = ["@//build/bazel/toolchains/cc:__subpackages__"])
+
+cc_toolchain_import(
+    name = "sdk_libs_x64",
+    include_paths = [
+        ":include/%{sdk_version}/ucrt",
+        ":include/%{sdk_version}/shared",
+        ":include/%{sdk_version}/um",
+        ":include/%{sdk_version}/winrt",
+        ":include/%{sdk_version}/cppwinrt",
+    ],
+    lib_search_paths = [
+        ":lib/%{sdk_version}/ucrt/x64",
+        ":lib/%{sdk_version}/um/x64",
+    ],
+    support_files = glob(
+        [
+            "include/%{sdk_version}/**",
+            "lib/%{sdk_version}/ucrt/x64/**",
+            "lib/%{sdk_version}/um/x64/**",
+        ],
+    ),
+)
diff --git a/toplevel.WORKSPACE b/toplevel.WORKSPACE
index b04b8ce1..9d87eff0 100644
--- a/toplevel.WORKSPACE
+++ b/toplevel.WORKSPACE
@@ -118,6 +118,7 @@ load(
     "//build/bazel/toolchains/cc:repository_rules.bzl",
     "macos_sdk_repository",
     "msvc_tools_repository",
+    "windows_sdk_repository",
 )
 
 # Repository that provides the clang compilers
@@ -156,6 +157,12 @@ msvc_tools_repository(
     build_file = "build/bazel/toolchains/cc/windows_clang/vctools.BUILD",
 )
 
+windows_sdk_repository(
+    name = "windows_sdk",
+    build_file_template = "build\\bazel\\toolchains\\cc\\windows_clang\\sdk.BUILD.tpl",
+    sdk_path = "C:\\Program Files (x86)\\Windows Kits\\10",
+)
+
 register_toolchains(
     "//build/bazel/toolchains/cc/linux_clang:x64_toolchain",
     "//build/bazel/toolchains/cc/mac_clang:x64_toolchain",