TestUtil.h

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/*
 * Copyright 2012-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 <folly/Range.h>
#include <folly/ScopeGuard.h>
#include <folly/experimental/io/FsUtil.h>

namespace folly {
namespace test {

class TemporaryFile {
 public:
  enum class Scope {
    PERMANENT,
    UNLINK_IMMEDIATELY,
    UNLINK_ON_DESTRUCTION,
  };
  explicit TemporaryFile(
      StringPiece namePrefix = StringPiece(),
      fs::path dir = fs::path(),
      Scope scope = Scope::UNLINK_ON_DESTRUCTION,
      bool closeOnDestruction = true);
  ~TemporaryFile();

  // Movable, but not copyable
  TemporaryFile(TemporaryFile&& other) noexcept {
    assign(other);
  }

  TemporaryFile& operator=(TemporaryFile&& other) {
    if (this != &other) {
      reset();
      assign(other);
    }
    return *this;
  }

  void close();
  int fd() const {
    return fd_;
  }
  const fs::path& path() const;
  void reset();

 private:
  Scope scope_;
  bool closeOnDestruction_;
  int fd_;
  fs::path path_;

  void assign(TemporaryFile& other) {
    scope_ = other.scope_;
    closeOnDestruction_ = other.closeOnDestruction_;
    fd_ = std::exchange(other.fd_, -1);
    path_ = other.path_;
  }
};

class TemporaryDirectory {
 public:
  enum class Scope {
    PERMANENT,
    DELETE_ON_DESTRUCTION,
  };
  explicit TemporaryDirectory(
      StringPiece namePrefix = StringPiece(),
      fs::path dir = fs::path(),
      Scope scope = Scope::DELETE_ON_DESTRUCTION);
  ~TemporaryDirectory();

  // Movable, but not copiable
  TemporaryDirectory(TemporaryDirectory&&) = default;
  TemporaryDirectory& operator=(TemporaryDirectory&&) = default;

  const fs::path& path() const {
    return *path_;
  }

 private:
  Scope scope_;
  std::unique_ptr<fs::path> path_;
};

class ChangeToTempDir {
 public:
  ChangeToTempDir();
  ~ChangeToTempDir();

  // Movable, but not copiable
  ChangeToTempDir(ChangeToTempDir&&) = default;
  ChangeToTempDir& operator=(ChangeToTempDir&&) = default;

  const fs::path& path() const {
    return dir_.path();
  }

 private:
  TemporaryDirectory dir_;
  fs::path orig_;
};

namespace detail {
struct SavedState {
  void* previousThreadLocalHandler;
  int previousCrtReportMode;
};
SavedState disableInvalidParameters();
void enableInvalidParameters(SavedState state);
} // namespace detail

// Ok, so fun fact: The CRT on windows will actually abort
// on certain failed parameter validation checks in debug
// mode rather than simply returning -1 as it does in release
// mode. We can however, ensure consistent behavior by
// registering our own thread-local invalid parameter handler
// for the duration of the call, and just have that handler
// immediately return. We also have to disable CRT asertion
// alerts for the duration of the call, otherwise we get
// the abort-retry-ignore window.
template <typename Func>
auto msvcSuppressAbortOnInvalidParams(Func func) -> decltype(func()) {
  auto savedState = detail::disableInvalidParameters();
  SCOPE_EXIT {
    detail::enableInvalidParameters(savedState);
  };
  return func();
}

#define EXPECT_PCRE_MATCH(pattern_stringpiece, target_stringpiece) \
  EXPECT_PRED2(                                                    \
      ::folly::test::detail::hasPCREPatternMatch,                  \
      pattern_stringpiece,                                         \
      target_stringpiece)
#define EXPECT_NO_PCRE_MATCH(pattern_stringpiece, target_stringpiece) \
  EXPECT_PRED2(                                                       \
      ::folly::test::detail::hasNoPCREPatternMatch,                   \
      pattern_stringpiece,                                            \
      target_stringpiece)

namespace detail {
bool hasPCREPatternMatch(StringPiece pattern, StringPiece target);
bool hasNoPCREPatternMatch(StringPiece pattern, StringPiece target);
} // namespace detail

inline std::string glogErrorPattern() {
  return ".*(^|\n)E[0-9].*";
}
inline std::string glogWarningPattern() {
  return ".*(^|\n)W[0-9].*";
}
// Error OR warning
inline std::string glogErrOrWarnPattern() {
  return ".*(^|\n)[EW][0-9].*";
}

class CaptureFD {
 private:
  struct NoOpChunkCob {
    void operator()(StringPiece) {}
  };

 public:
  using ChunkCob = std::function<void(folly::StringPiece)>;

  explicit CaptureFD(int fd, ChunkCob chunk_cob = NoOpChunkCob());
  ~CaptureFD();

  void release();

  std::string read() const;

  std::string readIncremental();

 private:
  ChunkCob chunkCob_;
  TemporaryFile file_;

  int fd_;
  int oldFDCopy_; // equal to fd_ after restore()

  off_t readOffset_; // for incremental reading
};

} // namespace test
} // namespace folly