Config variables reader

Fixes: 182330871
Test: go test config_variables_test.go
Change-Id: I89240fb0f1900172cb4d62057c86907bb9a1f58f

mk2rbc/config_variables.go

@@ -0,0 +1,67 @@
+// Copyright 2021 Google LLC
+//
+// 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.
+
+package mk2rbc
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	mkparser "android/soong/androidmk/parser"
+)
+
+// Extracts the list of product config variables from a file, calling
+// given registrar for each variable.
+func FindConfigVariables(mkFile string, vr variableRegistrar) error {
+	mkContents, err := ioutil.ReadFile(mkFile)
+	if err != nil {
+		return err
+	}
+	parser := mkparser.NewParser(mkFile, bytes.NewBuffer(mkContents))
+	nodes, errs := parser.Parse()
+	if len(errs) > 0 {
+		for _, e := range errs {
+			fmt.Fprintln(os.Stderr, "ERROR:", e)
+		}
+		return fmt.Errorf("cannot parse %s", mkFile)
+	}
+	for _, node := range nodes {
+		asgn, ok := node.(*mkparser.Assignment)
+		if !ok {
+			continue
+		}
+		// We are looking for a variable called '_product_list_vars'
+		// or '_product_single_value_vars'.
+		if !asgn.Name.Const() {
+			continue
+		}
+		varName := asgn.Name.Strings[0]
+		var starType starlarkType
+		if varName == "_product_list_vars" {
+			starType = starlarkTypeList
+		} else if varName == "_product_single_value_vars" {
+			starType = starlarkTypeUnknown
+		} else {
+			continue
+		}
+		for _, name := range strings.Fields(asgn.Value.Dump()) {
+			vr.NewVariable(name, VarClassConfig, starType)
+		}
+
+	}
+	return nil
+}

mk2rbc/config_variables_test.go

@@ -0,0 +1,60 @@
+// Copyright 2021 Google LLC
+//
+// 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.
+
+package mk2rbc
+
+import (
+	"path/filepath"
+	"reflect"
+	"runtime"
+	"testing"
+)
+
+type testVar struct {
+	name string
+	cl   varClass
+	ty   starlarkType
+}
+
+type testVariables struct {
+	v []testVar
+}
+
+func (v *testVariables) NewVariable(name string, varClass varClass, valueType starlarkType) {
+	v.v = append(v.v, testVar{name, varClass, valueType})
+}
+
+// getTestDirectory returns the test directory, which should be the test/ subdirectory
+func getTestDirectory() string {
+	_, myFile, _, _ := runtime.Caller(1)
+	return filepath.Join(filepath.Dir(myFile), "test")
+}
+
+func TestConfigVariables(t *testing.T) {
+	testFile := filepath.Join(getTestDirectory(), "config_variables.mk.test")
+	var actual testVariables
+	if err := FindConfigVariables(testFile, &actual); err != nil {
+		t.Fatal(err)
+	}
+	expected := testVariables{[]testVar{
+		{"PRODUCT_NAME", VarClassConfig, starlarkTypeUnknown},
+		{"PRODUCT_MODEL", VarClassConfig, starlarkTypeUnknown},
+		{"PRODUCT_LOCALES", VarClassConfig, starlarkTypeList},
+		{"PRODUCT_AAPT_CONFIG", VarClassConfig, starlarkTypeList},
+		{"PRODUCT_AAPT_PREF_CONFIG", VarClassConfig, starlarkTypeUnknown},
+	}}
+	if !reflect.DeepEqual(expected, actual) {
+		t.Errorf("\nExpected: %v\n  Actual: %v", expected, actual)
+	}
+}

mk2rbc/test/config_variables.mk.test

@@ -0,0 +1,12 @@
+_product_single_value_vars :=
+
+# Variables that are lists of values.
+_product_list_vars :=
+
+_product_single_value_vars += PRODUCT_NAME
+_product_single_value_vars += PRODUCT_MODEL
+
+# The resoure configuration options to use for this product.
+_product_list_vars += PRODUCT_LOCALES
+_product_list_vars += PRODUCT_AAPT_CONFIG
+_product_single_value_vars += PRODUCT_AAPT_PREF_CONFIG

mk2rbc/types.go

@@ -0,0 +1,55 @@
+// Copyright 2021 Google LLC
+//
+// 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.
+
+package mk2rbc
+
+// Starlark expression types we use
+type starlarkType int
+
+const (
+	starlarkTypeUnknown starlarkType = iota
+	starlarkTypeList    starlarkType = iota
+	starlarkTypeString  starlarkType = iota
+	starlarkTypeInt     starlarkType = iota
+	starlarkTypeBool    starlarkType = iota
+	starlarkTypeVoid    starlarkType = iota
+)
+
+type varClass int
+
+const (
+	VarClassConfig varClass = iota
+	VarClassSoong  varClass = iota
+	VarClassLocal  varClass = iota
+)
+
+type variableRegistrar interface {
+	NewVariable(name string, varClass varClass, valueType starlarkType)
+}
+
+// ScopeBase is a dummy implementation of the mkparser.Scope.
+// All our scopes are read-only and resolve only simple variables.
+type ScopeBase struct{}
+
+func (s ScopeBase) Set(_, _ string) {
+	panic("implement me")
+}
+
+func (s ScopeBase) Call(_ string, _ []string) []string {
+	panic("implement me")
+}
+
+func (s ScopeBase) SetFunc(_ string, _ func([]string) []string) {
+	panic("implement me")
+}