platform_build_soong/android/env.go

92 lines
2.9 KiB
Go

// Copyright 2015 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 (
"os"
"os/exec"
"strings"
"android/soong/env"
)
// This file supports dependencies on environment variables. During build manifest generation,
// any dependency on an environment variable is added to a list. During the singleton phase
// a JSON file is written containing the current value of all used environment variables.
// The next time the top-level build script is run, it uses the soong_env executable to
// compare the contents of the environment variables, rewriting the file if necessary to cause
// a manifest regeneration.
var originalEnv map[string]string
var SoongDelveListen string
var SoongDelvePath string
func init() {
// Delve support needs to read this environment variable very early, before NewConfig has created a way to
// access originalEnv with dependencies. Store the value where soong_build can find it, it will manually
// ensure the dependencies are created.
SoongDelveListen = os.Getenv("SOONG_DELVE")
SoongDelvePath, _ = exec.LookPath("dlv")
originalEnv = make(map[string]string)
for _, env := range os.Environ() {
idx := strings.IndexRune(env, '=')
if idx != -1 {
originalEnv[env[:idx]] = env[idx+1:]
}
}
// Clear the environment to prevent use of os.Getenv(), which would not provide dependencies on environment
// variable values. The environment is available through ctx.Config().Getenv, ctx.Config().IsEnvTrue, etc.
os.Clearenv()
}
// getenv checks either os.Getenv or originalEnv so that it works before or after the init()
// function above. It doesn't add any dependencies on the environment variable, so it should
// only be used for values that won't change. For values that might change use ctx.Config().Getenv.
func getenv(key string) string {
if originalEnv == nil {
return os.Getenv(key)
} else {
return originalEnv[key]
}
}
func EnvSingleton() Singleton {
return &envSingleton{}
}
type envSingleton struct{}
func (c *envSingleton) GenerateBuildActions(ctx SingletonContext) {
envDeps := ctx.Config().EnvDeps()
envFile := PathForOutput(ctx, ".soong.environment")
if ctx.Failed() {
return
}
data, err := env.EnvFileContents(envDeps)
if err != nil {
ctx.Errorf(err.Error())
}
err = WriteFileToOutputDir(envFile, data, 0666)
if err != nil {
ctx.Errorf(err.Error())
}
ctx.AddNinjaFileDeps(envFile.String())
}