1// Copyright 2015 Google Inc. All rights reserved. 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15package android 16 17import ( 18 "os" 19 "os/exec" 20 "strings" 21 22 "android/soong/env" 23) 24 25// This file supports dependencies on environment variables. During build manifest generation, 26// any dependency on an environment variable is added to a list. During the singleton phase 27// a JSON file is written containing the current value of all used environment variables. 28// The next time the top-level build script is run, it uses the soong_env executable to 29// compare the contents of the environment variables, rewriting the file if necessary to cause 30// a manifest regeneration. 31 32var originalEnv map[string]string 33var SoongDelveListen string 34var SoongDelvePath string 35 36func init() { 37 // Delve support needs to read this environment variable very early, before NewConfig has created a way to 38 // access originalEnv with dependencies. Store the value where soong_build can find it, it will manually 39 // ensure the dependencies are created. 40 SoongDelveListen = os.Getenv("SOONG_DELVE") 41 SoongDelvePath, _ = exec.LookPath("dlv") 42 43 originalEnv = make(map[string]string) 44 for _, env := range os.Environ() { 45 idx := strings.IndexRune(env, '=') 46 if idx != -1 { 47 originalEnv[env[:idx]] = env[idx+1:] 48 } 49 } 50 // Clear the environment to prevent use of os.Getenv(), which would not provide dependencies on environment 51 // variable values. The environment is available through ctx.Config().Getenv, ctx.Config().IsEnvTrue, etc. 52 os.Clearenv() 53} 54 55// getenv checks either os.Getenv or originalEnv so that it works before or after the init() 56// function above. It doesn't add any dependencies on the environment variable, so it should 57// only be used for values that won't change. For values that might change use ctx.Config().Getenv. 58func getenv(key string) string { 59 if originalEnv == nil { 60 return os.Getenv(key) 61 } else { 62 return originalEnv[key] 63 } 64} 65 66func EnvSingleton() Singleton { 67 return &envSingleton{} 68} 69 70type envSingleton struct{} 71 72func (c *envSingleton) GenerateBuildActions(ctx SingletonContext) { 73 envDeps := ctx.Config().EnvDeps() 74 75 envFile := PathForOutput(ctx, ".soong.environment") 76 if ctx.Failed() { 77 return 78 } 79 80 data, err := env.EnvFileContents(envDeps) 81 if err != nil { 82 ctx.Errorf(err.Error()) 83 } 84 85 err = WriteFileToOutputDir(envFile, data, 0666) 86 if err != nil { 87 ctx.Errorf(err.Error()) 88 } 89 90 ctx.AddNinjaFileDeps(envFile.String()) 91} 92