123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122 |
- /*
- * Copyright 2017-present Facebook, Inc.
- *
- * 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.
- */
- #pragma once
- #include <map>
- #include <string>
- #include <unordered_map>
- #include <vector>
- #include <folly/CPortability.h>
- #include <folly/Memory.h>
- namespace folly {
- namespace experimental {
- // Class to model the process environment in idiomatic C++
- //
- // Changes to the modeled environment do not change the process environment
- // unless `setAsCurrentEnvironment()` is called.
- struct EnvironmentState {
- using EnvType = std::unordered_map<std::string, std::string>;
- // Returns an EnvironmentState containing a copy of the current process
- // environment. Subsequent changes to the process environment do not
- // alter the stored model. If the process environment is altered during the
- // execution of this method the results are not defined.
- //
- // Throws MalformedEnvironment if the process environment cannot be modeled.
- static EnvironmentState fromCurrentEnvironment();
- // Returns an empty EnvironmentState
- static EnvironmentState empty() {
- return {};
- }
- explicit EnvironmentState(EnvType const& env) : env_(env) {}
- explicit EnvironmentState(EnvType&& env) : env_(std::move(env)) {}
- // Get the model environment for querying.
- EnvType const& operator*() const {
- return env_;
- }
- EnvType const* operator->() const {
- return &env_;
- }
- // Get the model environment for mutation or querying.
- EnvType& operator*() {
- return env_;
- }
- EnvType* operator->() {
- return &env_;
- }
- // Update the process environment with the one in the stored model.
- // Subsequent changes to the model do not alter the process environment. The
- // state of the process environment during execution of this method is not
- // defined. If the process environment is altered by another thread during the
- // execution of this method the results are not defined.
- void setAsCurrentEnvironment();
- // Get a copy of the model environment in the form used by `folly::Subprocess`
- std::vector<std::string> toVector() const;
- // Get a copy of the model environment in the form commonly used by C routines
- // such as execve, execle, etc. Example usage:
- //
- // EnvironmentState forChild{};
- // ... manipulate `forChild` as needed ...
- // execve("/bin/program",pArgs,forChild.toPointerArray().get());
- std::unique_ptr<char*, void (*)(char**)> toPointerArray() const;
- private:
- EnvironmentState() {}
- EnvType env_;
- };
- struct FOLLY_EXPORT MalformedEnvironment : std::runtime_error {
- using std::runtime_error::runtime_error;
- };
- } // namespace experimental
- namespace test {
- // RAII class allowing scoped changes to the process environment. The
- // environment state at the time of its construction is restored at the time
- // of its destruction.
- struct EnvVarSaver {
- EnvVarSaver()
- : state_(std::make_unique<experimental::EnvironmentState>(
- experimental::EnvironmentState::fromCurrentEnvironment())) {}
- EnvVarSaver(EnvVarSaver&& other) noexcept : state_(std::move(other.state_)) {}
- EnvVarSaver& operator=(EnvVarSaver&& other) noexcept {
- state_ = std::move(other.state_);
- return *this;
- }
- ~EnvVarSaver() {
- if (state_) {
- state_->setAsCurrentEnvironment();
- }
- }
- private:
- std::unique_ptr<experimental::EnvironmentState> state_;
- };
- } // namespace test
- } // namespace folly
|