Share version settings with product config makefile.

Generate version settings from build/make/core/version_defaults.mk.
The generated settings are then loaded into the launcher code and passed
to the environment setup code.

Bug: 198995713
Test: internal
Change-Id: I66131d2c5b232784a9ff0bba9fbd5db62302aaba

mk2rbc/version_defaults.go

@@ -0,0 +1,109 @@
+// 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 (
+	mkparser "android/soong/androidmk/parser"
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+const codenamePrefix = "PLATFORM_VERSION_CODENAME."
+
+// ParseVersionDefaults extracts version settings from the given file
+// and returns the map.
+func ParseVersionDefaults(path string) (map[string]string, error) {
+	contents, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	parser := mkparser.NewParser(path, bytes.NewBuffer(contents))
+	nodes, errs := parser.Parse()
+	if len(errs) > 0 {
+		for _, e := range errs {
+			fmt.Fprintln(os.Stderr, "ERROR:", e)
+		}
+		return nil, fmt.Errorf("cannot parse %s", path)
+	}
+
+	result := map[string]string{
+		"DEFAULT_PLATFORM_VERSION":            "",
+		"MAX_PLATFORM_VERSION":                "",
+		"MIN_PLATFORM_VERSION":                "A",
+		"PLATFORM_BASE_SDK_EXTENSION_VERSION": "",
+		"PLATFORM_SDK_EXTENSION_VERSION":      "",
+		"PLATFORM_SDK_VERSION":                "",
+		"PLATFORM_SECURITY_PATCH":             "",
+		"PLATFORM_VERSION_LAST_STABLE":        "",
+	}
+	for _, node := range nodes {
+		asgn, ok := node.(*mkparser.Assignment)
+		if !(ok && asgn.Name.Const()) {
+			continue
+		}
+		s := asgn.Name.Strings[0]
+		_, ok = result[s]
+		if !ok {
+			ok = strings.HasPrefix(s, codenamePrefix)
+		}
+		if !ok {
+			continue
+		}
+		v := asgn.Value
+		if !v.Const() {
+			return nil, fmt.Errorf("the value of %s should be constant", s)
+		}
+		result[s] = strings.TrimSpace(v.Strings[0])
+	}
+	return result, nil
+}
+
+func genericValue(s string) interface{} {
+	if ival, err := strconv.ParseInt(s, 0, 0); err == nil {
+		return ival
+	}
+	return s
+}
+
+// VersionDefaults generates the contents of the version_defaults.rbc file
+func VersionDefaults(values map[string]string) string {
+	var sink bytes.Buffer
+	var lines []string
+	var codenames []string
+	for name, value := range values {
+		if strings.HasPrefix(name, codenamePrefix) {
+			codenames = append(codenames,
+				fmt.Sprintf("%q: %q", strings.TrimPrefix(name, codenamePrefix), value))
+		} else {
+			// Print numbers as such
+			lines = append(lines, fmt.Sprintf("    %s = %#v,\n",
+				strings.ToLower(name), genericValue(value)))
+		}
+	}
+	sort.Strings(lines)
+	sink.WriteString("version_defaults = struct(\n")
+	for _, l := range lines {
+		sink.WriteString(l)
+	}
+	sink.WriteString("    codenames = { ")
+	sink.WriteString(strings.Join(codenames, ", "))
+	sink.WriteString(" }\n)\n")
+	return sink.String()
+}