check_op.h | Explore in Territory

// Copyright 2022 The Abseil Authors.
//
// 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
//
//      https://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.
//
// -----------------------------------------------------------------------------
// File: log/internal/check_op.h
// -----------------------------------------------------------------------------
//
// This file declares helpers routines and macros used to implement `CHECK`
// macros.

#ifndef ABSL_LOG_INTERNAL_CHECK_OP_H_
#define ABSL_LOG_INTERNAL_CHECK_OP_H_

#include <stdint.h>

#include <cstddef>
#include <ostream>
#include <sstream>
#include <string>
#include <type_traits>
#include <utility>

#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/nullability.h"
#include "absl/base/optimization.h"
#include "absl/log/internal/nullguard.h"
#include "absl/log/internal/nullstream.h"
#include "absl/log/internal/strip.h"
#include "absl/strings/has_absl_stringify.h"
#include "absl/strings/string_view.h"

// `ABSL_LOG_INTERNAL_STRIP_STRING_LITERAL` wraps string literals that
// should be stripped when `ABSL_MIN_LOG_LEVEL` exceeds `kFatal`.
#ifdef ABSL_MIN_LOG_LEVEL
#define ABSL_LOG_INTERNAL_STRIP_STRING_LITERAL …
#else
#define ABSL_LOG_INTERNAL_STRIP_STRING_LITERAL(literal) …
#endif

#ifdef NDEBUG
// `NDEBUG` is defined, so `DCHECK_EQ(x, y)` and so on do nothing.  However, we
// still want the compiler to parse `x` and `y`, because we don't want to lose
// potentially useful errors and warnings.
#define ABSL_LOG_INTERNAL_DCHECK_NOP …
#endif

#define ABSL_LOG_INTERNAL_CHECK_OP(name, op, val1, val1_text, val2, val2_text) …
#define ABSL_LOG_INTERNAL_QCHECK_OP(name, op, val1, val1_text, val2, \
                                    val2_text) …
#define ABSL_LOG_INTERNAL_CHECK_STROP(func, op, expected, s1, s1_text, s2,     \
                                      s2_text) …
#define ABSL_LOG_INTERNAL_QCHECK_STROP(func, op, expected, s1, s1_text, s2,    \
                                       s2_text) …
// This one is tricky:
// * We must evaluate `val` exactly once, yet we need to do two things with it:
//   evaluate `.ok()` and (sometimes) `.ToString()`.
// * `val` might be an `absl::Status` or some `absl::StatusOr<T>`.
// * `val` might be e.g. `ATemporary().GetStatus()`, which may return a
//   reference to a member of `ATemporary` that is only valid until the end of
//   the full expression.
// * We don't want this file to depend on `absl::Status` `#include`s or linkage,
//   nor do we want to move the definition to status and introduce a dependency
//   in the other direction.  We can be assured that callers must already have a
//   `Status` and the necessary `#include`s and linkage.
// * Callsites should be small and fast (at least when `val.ok()`): one branch,
//   minimal stack footprint.
//   * In particular, the string concat stuff should be out-of-line and emitted
//     in only one TU to save linker input size
// * We want the `val.ok()` check inline so static analyzers and optimizers can
//   see it.
// * As usual, no braces so we can stream into the expansion with `operator<<`.
// * Also as usual, it must expand to a single (partial) statement with no
//   ambiguous-else problems.
// * When stripped by `ABSL_MIN_LOG_LEVEL`, we must discard the `<expr> is OK`
//   string literal and abort without doing any streaming.  We don't need to
//   strip the call to stringify the non-ok `Status` as long as we don't log it;
//   dropping the `Status`'s message text is out of scope.
#define ABSL_LOG_INTERNAL_CHECK_OK(val, val_text) …
#define ABSL_LOG_INTERNAL_QCHECK_OK(val, val_text) …

namespace absl {
ABSL_NAMESPACE_BEGIN

class Status;
template <typename T>
class StatusOr;

namespace status_internal {
ABSL_ATTRIBUTE_PURE_FUNCTION absl::Nonnull<std::string*> MakeCheckFailString(
    absl::Nonnull<const absl::Status*> status,
    absl::Nonnull<const char*> prefix);
}  // namespace status_internal

log_internal  // namespace log_internal
ABSL_NAMESPACE_END
}  // namespace absl

#endif  // ABSL_LOG_INTERNAL_CHECK_OP_H_
chromium/third_party/abseil-cpp/absl/log/internal/check_op.h
