Adjust erlang_headers rule to not be platform specific

This simplifies depending on the headers in other rules

Author: HoloRin

private/erlang_build.bzl

@@ -246,59 +246,3 @@ erlang_external = rule(
         "_erlang_version": attr.label(default = Label("//:erlang_version")),
     },
 )
-
-def _erlang_headers_impl(ctx):
-    commands = ["set -euo pipefail", ""]
-
-    otpinfo = ctx.attr.otp[OtpInfo]
-
-    if otpinfo.release_dir != None:
-        otp_root = otpinfo.release_dir.path
-        inputs = [otpinfo.release_dir]
-    else:
-        otp_root = otpinfo.erlang_home
-        inputs = []
-    inputs.append(otpinfo.version_file)
-
-    outs = []
-    for f in ctx.attr.filenames:
-        dest = ctx.actions.declare_file(path_join(ctx.label.name, f))
-        commands.append("cp {otp}/lib/erlang/usr/include/{f} {dest}".format(
-            otp = otp_root,
-            f = f,
-            dest = dest.path,
-        ))
-        outs.append(dest)
-
-    ctx.actions.run_shell(
-        inputs = inputs,
-        outputs = outs,
-        command = "\n".join(commands),
-    )
-
-    return [DefaultInfo(files = depset(outs))]
-
-erlang_headers = rule(
-    implementation = _erlang_headers_impl,
-    attrs = {
-        "otp": attr.label(
-            mandatory = True,
-            providers = [OtpInfo],
-        ),
-        "filenames": attr.string_list(
-            default = [
-                "driver_int.h",
-                "ei.h",
-                "ei_connect.h",
-                "eicode.h",
-                "erl_driver.h",
-                "erl_drv_nif.h",
-                "erl_fixed_size_int_types.h",
-                "erl_int_sizes_config.h",
-                "erl_memory_trace_parser.h",
-                "erl_nif.h",
-                "erl_nif_api_funcs.h",
-            ],
-        ),
-    },
-)

tools/BUILD.bazel

@@ -1,4 +1,11 @@
+load("//tools:erlang_headers.bzl", "erlang_headers")
+
 toolchain_type(
     name = "toolchain_type",
     visibility = ["//visibility:public"],
 )
+
+erlang_headers(
+    name = "erlang_headers",
+    visibility = ["//visibility:public"],
+)

tools/erlang.bzl

@@ -2,6 +2,9 @@ load(
     "//private:erlang_build.bzl",
     "erlang_build",
     "erlang_external",
+)
+load(
+    ":erlang_headers.bzl",
     "erlang_headers",
 )
 load(
@@ -60,12 +63,6 @@ def erlang_toolchain_from_http_archive(
         ],
     )
 
-    erlang_headers(
-        name = "otp_headers{}".format(name_suffix),
-        otp = ":otp{}".format(name_suffix),
-        visibility = ["//visibility:public"],
-    )
-
     erlang_toolchain(
         name = "erlang{}".format(name_suffix),
         otp = ":otp{}".format(name_suffix),

tools/erlang_headers.bzl

@@ -0,0 +1,54 @@
+load("//:util.bzl", "path_join")
+
+def _erlang_headers_impl(ctx):
+    commands = ["set -euo pipefail", ""]
+
+    otpinfo = ctx.toolchains["//tools:toolchain_type"].otpinfo
+
+    if otpinfo.release_dir != None:
+        otp_root = otpinfo.release_dir.path
+        inputs = [otpinfo.release_dir]
+    else:
+        otp_root = otpinfo.erlang_home
+        inputs = []
+    inputs.append(otpinfo.version_file)
+
+    outs = []
+    for f in ctx.attr.filenames:
+        dest = ctx.actions.declare_file(path_join(ctx.label.name, f))
+        commands.append("cp {otp}/lib/erlang/usr/include/{f} {dest}".format(
+            otp = otp_root,
+            f = f,
+            dest = dest.path,
+        ))
+        outs.append(dest)
+
+    ctx.actions.run_shell(
+        inputs = inputs,
+        outputs = outs,
+        command = "\n".join(commands),
+    )
+
+    return [DefaultInfo(files = depset(outs))]
+
+erlang_headers = rule(
+    implementation = _erlang_headers_impl,
+    attrs = {
+        "filenames": attr.string_list(
+            default = [
+                "driver_int.h",
+                "ei.h",
+                "ei_connect.h",
+                "eicode.h",
+                "erl_driver.h",
+                "erl_drv_nif.h",
+                "erl_fixed_size_int_types.h",
+                "erl_int_sizes_config.h",
+                "erl_memory_trace_parser.h",
+                "erl_nif.h",
+                "erl_nif_api_funcs.h",
+            ],
+        ),
+    },
+    toolchains = [":toolchain_type"],
+)