shared/src/main/java/com/android/tools/analytics/Environment.kt

/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * 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 com.android.tools.analytics

/**
 * Helper class to create indirection reading environment variables and system properties. This
 * allows providing custom logic for reading these values. E.g. because Java doesn't allow
 * overwriting environment variables for the current process, in tests this is used to provide the
 * environment variables. Also, build system may implement this in a way that is using build system
 * specific APIs to access system properties and environment variables.
 */
abstract class Environment {

  abstract fun getVariable(name: String): String?

  open fun getSystemProperty(name: String): String? {
    return System.getProperty(name)
  }

  companion object {
    @JvmStatic
    val SYSTEM: Environment = object : Environment() {
      override fun getVariable(name: String): String? {
        return System.getenv(name)
      }
    }

    @JvmStatic
    var instance: Environment = SYSTEM
  }
}