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// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/check.h"
#include "base/compiler_specific.h"
#if CHECK_WILL_STREAM()
#include "base/logging.h"
#endif // CHECK_WILL_STREAM()
#ifndef BASE_CHECK_DEREF_H_
#define BASE_CHECK_DEREF_H_
namespace logging {
// Returns a reference to pointee of `ptr` if `ptr` is not null, or dies if
// `ptr` is null.
//
// It is useful in initializers and direct assignments, where a direct `CHECK`
// call can't be used:
//
// MyType& type_ref = CHECK_DEREF(MethodReturningAPointer());
//
// If your raw pointer is stored in a wrapped type like `unique_ptr` or
// `raw_ptr`, you should use their `.get()` methods to get the raw pointer
// before calling `CHECK_DEREF()`:
//
// MyType& type_ref = CHECK_DEREF(your_wrapped_pointer.get());
//
#define CHECK_DEREF(ptr) ::logging::CheckDeref(ptr, #ptr " != nullptr")
template <typename T>
[[nodiscard]] T& CheckDeref(
T* ptr,
const char* message,
const base::Location& location = base::Location::Current()) {
// Note: we can't just call `CHECK_NE(ptr, nullptr)` here, as that would
// cause the error to be reported from this header, and we want the error
// to be reported at the file and line of the caller.
if (ptr == nullptr) [[unlikely]] {
#if CHECK_WILL_STREAM()
// `CheckNoreturnError` will die with a fatal error in its destructor.
CheckNoreturnError::Check(message, location);
#else
CheckFailure();
#endif // !CHECK_WILL_STREAM()
}
return *ptr;
}
} // namespace logging
#endif // BASE_CHECK_DEREF_H_
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