68f55102da
Ninja can't depend on environment variables, so modifying build behavior based on environment variables requires coordinating between the soong script that invokes ninja and the soong_build manifest generator. Allow any module to call Config.Getenv to get the contents of an environment variable while registering a dependency on it. After all modules have been processed write out the state of all used environment variables to a JSON file called .soong.environment. During the next build the soong script will use the soong_env tool to compare the contents of .soong.environment to the current environment, and force a build manifest regeneration by deleting the .soong.environment file if any variables have changed. Change-Id: Id0d81933a857bc2fc1cd7a393a3c6cec73dc4824
47 lines
1.5 KiB
Go
47 lines
1.5 KiB
Go
// Copyright 2015 Google Inc. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package common
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import (
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"android/soong/env"
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"github.com/google/blueprint"
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)
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// This file supports dependencies on environment variables. During build manifest generation,
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// any dependency on an environment variable is added to a list. During the singleton phase
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// a JSON file is written containing the current value of all used environment variables.
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// The next time the top-level build script is run, it uses the soong_env executable to
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// compare the contents of the environment variables, rewriting the file if necessary to cause
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// a manifest regeneration.
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func EnvSingleton() blueprint.Singleton {
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return &envSingleton{}
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}
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type envSingleton struct{}
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func (c *envSingleton) GenerateBuildActions(ctx blueprint.SingletonContext) {
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envDeps := ctx.Config().(Config).EnvDeps()
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envFile := ".soong.environment"
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err := env.WriteEnvFile(envFile, envDeps)
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if err != nil {
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ctx.Errorf(err.Error())
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}
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ctx.AddNinjaFileDeps(envFile)
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}
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