Generate file to map codenames to API levels.

The NDK stub library generator needs to know what unreleased API
levels exist and what the ordering is between them. This singleton
will later be expanded to generate api-level.h to cut down on
duplication.

Test: make out/soong/api_levels.json && cat out/soong/api_levels.json
Bug: None
Change-Id: I53126dd2cacb67c331c44f7d7c77c98b176b93cd

Android.bp

@@ -47,6 +47,7 @@ bootstrap_go_package {
     ],
     srcs: [
         "android/androidmk.go",
+        "android/api_levels.go",
         "android/arch.go",
         "android/config.go",
         "android/defaults.go",

android/api_levels.go

@@ -0,0 +1,63 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// 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 android
+
+import (
+	"encoding/json"
+
+	"github.com/google/blueprint"
+)
+
+func init() {
+	RegisterSingletonType("api_levels", ApiLevelsSingleton)
+}
+
+func ApiLevelsSingleton() blueprint.Singleton {
+	return &apiLevelsSingleton{}
+}
+
+type apiLevelsSingleton struct{}
+
+func createApiLevelsJson(ctx blueprint.SingletonContext, file string,
+	apiLevelsMap map[string]int) {
+
+	jsonStr, err := json.Marshal(apiLevelsMap)
+	if err != nil {
+		ctx.Errorf(err.Error())
+	}
+
+	ctx.Build(pctx, blueprint.BuildParams{
+		Rule:    WriteFile,
+		Outputs: []string{file},
+		Args: map[string]string{
+			"content": string(jsonStr[:]),
+		},
+	})
+}
+
+func GetApiLevelsJson(ctx PathContext) Path {
+	return PathForOutput(ctx, "api_levels.json")
+}
+
+func (a *apiLevelsSingleton) GenerateBuildActions(ctx blueprint.SingletonContext) {
+	baseApiLevel := 9000
+	apiLevelsMap := map[string]int{}
+	for i, codename := range ctx.Config().(Config).PlatformVersionAllCodenames() {
+		apiLevelsMap[codename] = baseApiLevel + i
+	}
+
+	apiLevelsJson := GetApiLevelsJson(ctx)
+	createApiLevelsJson(ctx, apiLevelsJson.String(), apiLevelsMap)
+}

android/config.go

@@ -353,6 +353,10 @@ func (c *config) PlatformSdkVersion() string {
 	return strconv.Itoa(c.PlatformSdkVersionInt())
 }
 
+func (c *config) PlatformVersionAllCodenames() []string {
+	return c.ProductVariables.Platform_version_all_codenames
+}
+
 func (c *config) BuildNumber() string {
 	return "000000"
 }

android/defs.go

@@ -80,6 +80,13 @@ var (
 			Description: "concatenate licenses $out",
 		})
 
+	WriteFile = pctx.AndroidStaticRule("WriteFile",
+		blueprint.RuleParams{
+			Command:     "echo '$content' > $out",
+			Description: "writing file $out",
+		},
+		"content")
+
 	// Used only when USE_GOMA=true is set, to restrict non-goma jobs to the local parallelism value
 	localPool = blueprint.NewBuiltinPool("local_pool")
 )

android/variable.go

@@ -82,7 +82,8 @@ type productVariables struct {
 	// Suffix to add to generated Makefiles
 	Make_suffix *string `json:",omitempty"`
 
-	Platform_sdk_version *int `json:",omitempty"`
+	Platform_sdk_version           *int     `json:",omitempty"`
+	Platform_version_all_codenames []string `json:",omitempty"`
 
 	DeviceName        *string   `json:",omitempty"`
 	DeviceArch        *string   `json:",omitempty"`