Bazel: code reorganization

WORKSPACE.bazel

@@ -27,6 +27,6 @@ http_archive(
     ],
 )
 
-load("@ql//:defs.bzl", "ql_utils")
+load("@ql//misc/bazel:workspace.bzl", "ql_workspace")
 
-ql_utils(name = "utils")
+ql_workspace()

defs.bzl

@@ -3,17 +3,3 @@ codeql_platform = select({
     "@platforms//os:macos": "osx64",
     "@platforms//os:windows": "win64",
 })
-
-_paths_bzl = """
-def source_dir():
-    return '%s/' + native.package_name()
-"""
-
-def _ql_utils_impl(repository_ctx):
-    root = repository_ctx.path(Label("@ql//:WORKSPACE.bazel")).realpath.dirname
-    repository_ctx.file("BUILD.bazel")
-    repository_ctx.file("paths.bzl", content = _paths_bzl % root)
-
-ql_utils = repository_rule(
-    implementation = _ql_utils_impl,
-)

misc/bazel/source_dir.bzl.tpl

@@ -0,0 +1,11 @@
+def root_source_dir():
+    """ get absolute path to the root source directory
+
+        This can break hermeticity if used in a build step"""
+    return '{root}'
+
+def current_source_dir():
+    """ get absolute path to the source directory of this bazel package
+
+        This can break hermeticity if used in a build step"""
+    return root_source_dir() + '/' + native.package_name()

misc/bazel/workspace.bzl

@@ -0,0 +1,15 @@
+def _ql_utils_impl(repository_ctx):
+    root = repository_ctx.path(Label("//:WORKSPACE.bazel")).realpath.dirname
+    repository_ctx.file("BUILD.bazel")
+    repository_ctx.template(
+        "source_dir.bzl",
+        Label("@ql//misc/bazel:source_dir.bzl.tpl"),
+        substitutions = {"{root}": str(root)},
+    )
+
+_ql_utils = repository_rule(
+    implementation = _ql_utils_impl,
+)
+
+def ql_workspace():
+    _ql_utils(name = "utils")

swift/install/BUILD.bazel

@@ -1,4 +1,4 @@
-load("@utils//:paths.bzl", "source_dir")
+load("@utils//:source_dir.bzl", "current_source_dir")
 load("@rules_pkg//:install.bzl", "pkg_install")
 
 pkg_install(
@@ -6,6 +6,6 @@ pkg_install(
     srcs = ["//swift:extractor-pack"],
     args = [
         "--destdir",
-        source_dir() + "/../extractor_pack",
+        current_source_dir() + "/../extractor_pack",
     ],
 )