crashpad/util/misc/initialization_state.h
Mark Mentovai 6278690abe Update copyright boilerplate, 2022 edition (Crashpad)
sed -i '' -E -e 's/Copyright (.+) The Crashpad Authors\. All rights reserved\.$/Copyright \1 The Crashpad Authors/' $(git grep -El 'Copyright (.+) The Crashpad Authors\. All rights reserved\.$')

Bug: chromium:1098010
Change-Id: I8d6138469ddbe3d281a5d83f64cf918ec2491611
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/3878262
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Commit-Queue: Mark Mentovai <mark@chromium.org>
2022-09-06 23:54:07 +00:00

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// Copyright 2014 The Crashpad 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
//
// 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.
#ifndef CRASHPAD_UTIL_MISC_INITIALIZATION_INITIALIZATION_STATE_H_
#define CRASHPAD_UTIL_MISC_INITIALIZATION_INITIALIZATION_STATE_H_
#include <stdint.h>
namespace crashpad {
//! \brief Tracks whether data are initialized.
//!
//! Objects of this type track whether the data theyre guarding are
//! initialized. The three possible states are uninitialized (the initial
//! state), initializing, and valid. As the guarded data are initialized, an
//! InitializationState object will normally transition through these three
//! states. A fourth state corresponds to the destruction of objects of this
//! type, making it less likely that a use-after-free of an InitializationState
//! object will appear in the valid state.
//!
//! If the only purpose for tracking the initialization state of guarded data is
//! to DCHECK when the object is in an unexpected state, use
//! InitializationStateDcheck instead.
class InitializationState {
public:
//! \brief The objects state.
enum State : uint8_t {
//! \brief The object has not yet been initialized.
kStateUninitialized = 0,
//! \brief The object is being initialized.
//!
//! This state protects against attempted reinitializaton of
//! partially-initialized objects whose initial initialization attempt
//! failed. This state is to be used while objects are initializing, but are
//! not yet fully initialized.
kStateInvalid,
//! \brief The object has been initialized.
kStateValid,
//! \brief The object has been destroyed.
kStateDestroyed,
};
InitializationState() : state_(kStateUninitialized) {}
InitializationState(const InitializationState&) = delete;
InitializationState& operator=(const InitializationState&) = delete;
~InitializationState() { state_ = kStateDestroyed; }
//! \brief Returns `true` if the objects state is #kStateUninitialized and it
//! is safe to begin initializing it.
bool is_uninitialized() const { return state_ == kStateUninitialized; }
//! \brief Sets the objects state to #kStateInvalid, marking initialization
//! as being in process.
void set_invalid() { state_ = kStateInvalid; }
//! \brief Sets the objects state to #kStateValid, marking it initialized.
void set_valid() { state_ = kStateValid; }
//! \brief Returns `true` if the the objects state is #kStateValid and it has
//! been fully initialized and may be used.
bool is_valid() const { return state_ == kStateValid; }
protected:
//! \brief Returns the objects state.
//!
//! Consumers of this class should use an is_state_*() method instead.
State state() const { return state_; }
//! \brief Sets the objects state.
//!
//! Consumers of this class should use a set_state_*() method instead.
void set_state(State state) { state_ = state; }
private:
// state_ is volatile to ensure that itll be set by the destructor when it
// runs. Otherwise, optimizations might prevent it from ever being set to
// kStateDestroyed, limiting this class ability to catch use-after-free
// errors.
volatile State state_;
};
} // namespace crashpad
#endif // CRASHPAD_UTIL_MISC_INITIALIZATION_INITIALIZATION_STATE_H_