validation.h

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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#ifndef FLUTTER_IMPELLER_BASE_VALIDATION_H_
#define FLUTTER_IMPELLER_BASE_VALIDATION_H_
 
#include <functional>
#include <sstream>
 
namespace impeller {
 
class ValidationLog {
 public:
  ValidationLog(const char* file, int line);
 
  ~ValidationLog();
 
  std::ostream& GetStream();
 
 private:
  const char* file_ = nullptr;
  int line_ = 0;
  std::ostringstream stream_;
 
  ValidationLog(const ValidationLog&) = delete;
 
  ValidationLog(ValidationLog&&) = delete;
 
  ValidationLog& operator=(const ValidationLog&) = delete;
 
  ValidationLog& operator=(ValidationLog&&) = delete;
};
 
void ImpellerValidationBreak(const char* message, const char* file, int line);
 
void ImpellerValidationErrorsSetFatal(bool fatal);
 
bool ImpellerValidationErrorsAreFatal();
 
using ValidationFailureCallback =
    std::function<bool(const char* message, const char* file, int line)>;
 
//------------------------------------------------------------------------------
/// @brief      Sets a callback that callers (usually tests) can set to
///             intercept validation failures.
///
///             Returning true from the callback indicates that Impeller can
///             continue and avoid any default behavior on tripping validation
///             (which could include process termination).
///
/// @param[in]  callback  The callback
///
void ImpellerValidationErrorsSetCallback(ValidationFailureCallback callback);
 
struct ScopedValidationDisable {
  ScopedValidationDisable();
 
  ~ScopedValidationDisable();
 
  ScopedValidationDisable(const ScopedValidationDisable&) = delete;
 
  ScopedValidationDisable& operator=(const ScopedValidationDisable&) = delete;
};
 
struct ScopedValidationFatal {
  ScopedValidationFatal();
 
  ~ScopedValidationFatal();
 
  ScopedValidationFatal(const ScopedValidationFatal&) = delete;
 
  ScopedValidationFatal& operator=(const ScopedValidationFatal&) = delete;
};
 
}  // namespace impeller
 
//------------------------------------------------------------------------------
/// Get a stream to the log Impeller uses for all validation errors. The
/// behavior of these logs is as follows:
///
/// * Validation error are completely ignored in the Flutter release
///   runtime-mode.
/// * In non-release runtime-modes, validation logs are redirected to the
///   Flutter `INFO` log. These logs typically show up when verbose logging is
///   enabled.
/// * If `ImpellerValidationErrorsSetFatal` is set to `true`, validation logs
///   are fatal. The runtime-mode restriction still applies. This usually
///   happens in test environments.
///
#define VALIDATION_LOG ::impeller::ValidationLog{__FILE__, __LINE__}.GetStream()
 
#endif  // FLUTTER_IMPELLER_BASE_VALIDATION_H_