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Update include/base headers for C++11/14 (see issue #3140)

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See the issue for update guidelines.
This commit is contained in:
Marshall Greenblatt
2021-06-17 15:40:57 -04:00
parent 6d80ec69d7
commit 43f9baa23a
57 changed files with 5466 additions and 11523 deletions
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238
include/base/cef_weak_ptr.h
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@ -29,7 +29,7 @@
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Weak pointers are pointers to an object that do not affect its lifetime,
// and which may be invalidated (i.e. reset to NULL) by the object, or its
// and which may be invalidated (i.e. reset to nullptr) by the object, or its
// owner, at any time, most commonly when the object is about to be deleted.
// Weak pointers are useful when an object needs to be accessed safely by one
@ -42,25 +42,24 @@
//
// class Controller {
// public:
// Controller() : weak_factory_(this) {}
// void SpawnWorker() { Worker::StartNew(weak_factory_.GetWeakPtr()); }
// void WorkComplete(const Result& result) { ... }
// private:
// // Member variables should appear before the WeakPtrFactory, to ensure
// // that any WeakPtrs to Controller are invalidated before its members
// // variable's destructors are executed, rendering them invalid.
// WeakPtrFactory<Controller> weak_factory_;
// WeakPtrFactory<Controller> weak_factory_{this};
// };
//
// class Worker {
// public:
// static void StartNew(const WeakPtr<Controller>& controller) {
// Worker* worker = new Worker(controller);
// static void StartNew(WeakPtr<Controller> controller) {
// Worker* worker = new Worker(std::move(controller));
// // Kick off asynchronous processing...
// }
// private:
// Worker(const WeakPtr<Controller>& controller)
// : controller_(controller) {}
// Worker(WeakPtr<Controller> controller)
// : controller_(std::move(controller)) {}
// void DidCompleteAsynchronousProcessing(const Result& result) {
// if (controller_)
// controller_->WorkComplete(result);
@ -75,18 +74,19 @@
// ------------------------- IMPORTANT: Thread-safety -------------------------
// Weak pointers may be passed safely between threads, but must always be
// dereferenced and invalidated on the same thread otherwise checking the
// pointer would be racey.
// dereferenced and invalidated on the same ThreaddTaskRunner otherwise
// checking the pointer would be racey.
//
// To ensure correct use, the first time a WeakPtr issued by a WeakPtrFactory
// is dereferenced, the factory and its WeakPtrs become bound to the calling
// thread, and cannot be dereferenced or invalidated on any other thread. Bound
// WeakPtrs can still be handed off to other threads, e.g. to use to post tasks
// back to object on the bound thread.
// thread or current ThreaddWorkerPool token, and cannot be dereferenced or
// invalidated on any other task runner. Bound WeakPtrs can still be handed
// off to other task runners, e.g. to use to post tasks back to object on the
// bound thread.
//
// If all WeakPtr objects are destroyed or invalidated then the factory is
// unbound from the SequencedTaskRunner/Thread. The WeakPtrFactory may then be
// destroyed, or new WeakPtr objects may be used, from a different sequence.
// unbound from the ThreaddTaskRunner/Thread. The WeakPtrFactory may then be
// destroyed, or new WeakPtr objects may be used, from a different thread.
//
// Thus, at least one WeakPtr object must exist and have been dereferenced on
// the correct thread to enforce that other WeakPtr objects will enforce they
@ -96,12 +96,7 @@
#define CEF_INCLUDE_BASE_CEF_WEAK_PTR_H_
#pragma once
#if defined(BASE_MEMORY_WEAK_PTR_H_)
// Do nothing if the Chromium header has already been included.
// This can happen in cases where Chromium code is used directly by the
// client application. When using Chromium code directly always include
// the Chromium header first to avoid type conflicts.
#elif defined(USING_CHROMIUM_INCLUDES)
#if defined(USING_CHROMIUM_INCLUDES)
// When building CEF include the Chromium header directly.
#include "base/memory/weak_ptr.h"
#else // !USING_CHROMIUM_INCLUDES
@ -109,10 +104,13 @@
// If the Chromium implementation diverges the below implementation should be
// updated to match.
#include "include/base/cef_basictypes.h"
#include <cstddef>
#include <type_traits>
#include "include/base/cef_atomic_flag.h"
#include "include/base/cef_logging.h"
#include "include/base/cef_macros.h"
#include "include/base/cef_ref_counted.h"
#include "include/base/cef_template_util.h"
#include "include/base/cef_thread_checker.h"
namespace base {
@ -122,14 +120,14 @@ class SupportsWeakPtr;
template <typename T>
class WeakPtr;
namespace cef_internal {
namespace internal {
// These classes are part of the WeakPtr implementation.
// DO NOT USE THESE CLASSES DIRECTLY YOURSELF.
class WeakReference {
public:
// Although Flag is bound to a specific thread, it may be deleted from another
// via base::WeakPtr::~WeakPtr().
// Although Flag is bound to a specific ThreaddTaskRunner, it may be
// deleted from another via base::WeakPtr::~WeakPtr().
class Flag : public RefCountedThreadSafe<Flag> {
public:
Flag();
@ -137,23 +135,30 @@ class WeakReference {
void Invalidate();
bool IsValid() const;
bool MaybeValid() const;
void DetachFromThread();
private:
friend class base::RefCountedThreadSafe<Flag>;
~Flag();
// The current Chromium implementation uses SequenceChecker instead of
// ThreadChecker to support SequencedWorkerPools. CEF does not yet expose
// the concept of SequencedWorkerPools.
ThreadChecker thread_checker_;
bool is_valid_;
base::ThreadChecker thread_checker_;
AtomicFlag invalidated_;
};
WeakReference();
explicit WeakReference(const Flag* flag);
explicit WeakReference(const scoped_refptr<Flag>& flag);
~WeakReference();
bool is_valid() const;
WeakReference(WeakReference&& other) noexcept;
WeakReference(const WeakReference& other);
WeakReference& operator=(WeakReference&& other) noexcept = default;
WeakReference& operator=(const WeakReference& other) = default;
bool IsValid() const;
bool MaybeValid() const;
private:
scoped_refptr<const Flag> flag_;
@ -166,12 +171,12 @@ class WeakReferenceOwner {
WeakReference GetRef() const;
bool HasRefs() const { return flag_.get() && !flag_->HasOneRef(); }
bool HasRefs() const { return !flag_->HasOneRef(); }
void Invalidate();
private:
mutable scoped_refptr<WeakReference::Flag> flag_;
scoped_refptr<WeakReference::Flag> flag_;
};
// This class simplifies the implementation of WeakPtr's type conversion
@ -183,10 +188,24 @@ class WeakPtrBase {
WeakPtrBase();
~WeakPtrBase();
WeakPtrBase(const WeakPtrBase& other) = default;
WeakPtrBase(WeakPtrBase&& other) noexcept = default;
WeakPtrBase& operator=(const WeakPtrBase& other) = default;
WeakPtrBase& operator=(WeakPtrBase&& other) noexcept = default;
void reset() {
ref_ = internal::WeakReference();
ptr_ = 0;
}
protected:
explicit WeakPtrBase(const WeakReference& ref);
WeakPtrBase(const WeakReference& ref, uintptr_t ptr);
WeakReference ref_;
// This pointer is only valid when ref_.is_valid() is true. Otherwise, its
// value is undefined (as opposed to nullptr).
uintptr_t ptr_;
};
// This class provides a common implementation of common functions that would
@ -198,13 +217,14 @@ class SupportsWeakPtrBase {
// conversion will only compile if there is exists a Base which inherits
// from SupportsWeakPtr<Base>. See base::AsWeakPtr() below for a helper
// function that makes calling this easier.
//
// Precondition: t != nullptr
template <typename Derived>
static WeakPtr<Derived> StaticAsWeakPtr(Derived* t) {
typedef is_convertible<Derived, cef_internal::SupportsWeakPtrBase&>
convertible;
COMPILE_ASSERT(convertible::value,
AsWeakPtr_argument_inherits_from_SupportsWeakPtr);
return AsWeakPtrImpl<Derived>(t, *t);
static_assert(
std::is_base_of<internal::SupportsWeakPtrBase, Derived>::value,
"AsWeakPtr argument must inherit from SupportsWeakPtr");
return AsWeakPtrImpl<Derived>(t);
}
private:
@ -212,14 +232,14 @@ class SupportsWeakPtrBase {
// which is an instance of SupportsWeakPtr<Base>. We can then safely
// static_cast the Base* to a Derived*.
template <typename Derived, typename Base>
static WeakPtr<Derived> AsWeakPtrImpl(Derived* t,
const SupportsWeakPtr<Base>&) {
WeakPtr<Base> ptr = t->Base::AsWeakPtr();
return WeakPtr<Derived>(ptr.ref_, static_cast<Derived*>(ptr.ptr_));
static WeakPtr<Derived> AsWeakPtrImpl(SupportsWeakPtr<Base>* t) {
WeakPtr<Base> ptr = t->AsWeakPtr();
return WeakPtr<Derived>(
ptr.ref_, static_cast<Derived*>(reinterpret_cast<Base*>(ptr.ptr_)));
}
};
} // namespace cef_internal
} // namespace internal
template <typename T>
class WeakPtrFactory;
@ -238,81 +258,113 @@ class WeakPtrFactory;
// foo->method();
//
template <typename T>
class WeakPtr : public cef_internal::WeakPtrBase {
class WeakPtr : public internal::WeakPtrBase {
public:
WeakPtr() : ptr_(NULL) {}
WeakPtr() = default;
WeakPtr(std::nullptr_t) {}
// Allow conversion from U to T provided U "is a" T. Note that this
// is separate from the (implicit) copy constructor.
// is separate from the (implicit) copy and move constructors.
template <typename U>
WeakPtr(const WeakPtr<U>& other) : WeakPtrBase(other), ptr_(other.ptr_) {}
WeakPtr(const WeakPtr<U>& other) : WeakPtrBase(other) {
// Need to cast from U* to T* to do pointer adjustment in case of multiple
// inheritance. This also enforces the "U is a T" rule.
T* t = reinterpret_cast<U*>(other.ptr_);
ptr_ = reinterpret_cast<uintptr_t>(t);
}
template <typename U>
WeakPtr(WeakPtr<U>&& other) noexcept : WeakPtrBase(std::move(other)) {
// Need to cast from U* to T* to do pointer adjustment in case of multiple
// inheritance. This also enforces the "U is a T" rule.
T* t = reinterpret_cast<U*>(other.ptr_);
ptr_ = reinterpret_cast<uintptr_t>(t);
}
T* get() const { return ref_.is_valid() ? ptr_ : NULL; }
T* get() const {
return ref_.IsValid() ? reinterpret_cast<T*>(ptr_) : nullptr;
}
T& operator*() const {
CHECK(ref_.is_valid());
CHECK(ref_.IsValid());
return *get();
}
T* operator->() const {
CHECK(ref_.is_valid());
CHECK(ref_.IsValid());
return get();
}
// Allow WeakPtr<element_type> to be used in boolean expressions, but not
// implicitly convertible to a real bool (which is dangerous).
// Allow conditionals to test validity, e.g. if (weak_ptr) {...};
explicit operator bool() const { return get() != nullptr; }
// Returns false if the WeakPtr is confirmed to be invalid. This call is safe
// to make from any thread, e.g. to optimize away unnecessary work, but
// operator bool() must always be called, on the correct thread, before
// actually using the pointer.
//
// Note that this trick is only safe when the == and != operators
// are declared explicitly, as otherwise "weak_ptr1 == weak_ptr2"
// will compile but do the wrong thing (i.e., convert to Testable
// and then do the comparison).
private:
typedef T* WeakPtr::*Testable;
// Warning: as with any object, this call is only thread-safe if the WeakPtr
// instance isn't being re-assigned or reset() racily with this call.
bool MaybeValid() const { return ref_.MaybeValid(); }
public:
operator Testable() const { return get() ? &WeakPtr::ptr_ : NULL; }
void reset() {
ref_ = cef_internal::WeakReference();
ptr_ = NULL;
}
// Returns whether the object |this| points to has been invalidated. This can
// be used to distinguish a WeakPtr to a destroyed object from one that has
// been explicitly set to null.
bool WasInvalidated() const { return ptr_ && !ref_.IsValid(); }
private:
// Explicitly declare comparison operators as required by the bool
// trick, but keep them private.
template <class U>
bool operator==(WeakPtr<U> const&) const;
template <class U>
bool operator!=(WeakPtr<U> const&) const;
friend class cef_internal::SupportsWeakPtrBase;
friend class internal::SupportsWeakPtrBase;
template <typename U>
friend class WeakPtr;
friend class SupportsWeakPtr<T>;
friend class WeakPtrFactory<T>;
WeakPtr(const cef_internal::WeakReference& ref, T* ptr)
: WeakPtrBase(ref), ptr_(ptr) {}
// This pointer is only valid when ref_.is_valid() is true. Otherwise, its
// value is undefined (as opposed to NULL).
T* ptr_;
WeakPtr(const internal::WeakReference& ref, T* ptr)
: WeakPtrBase(ref, reinterpret_cast<uintptr_t>(ptr)) {}
};
// Allow callers to compare WeakPtrs against nullptr to test validity.
template <class T>
bool operator!=(const WeakPtr<T>& weak_ptr, std::nullptr_t) {
return !(weak_ptr == nullptr);
}
template <class T>
bool operator!=(std::nullptr_t, const WeakPtr<T>& weak_ptr) {
return weak_ptr != nullptr;
}
template <class T>
bool operator==(const WeakPtr<T>& weak_ptr, std::nullptr_t) {
return weak_ptr.get() == nullptr;
}
template <class T>
bool operator==(std::nullptr_t, const WeakPtr<T>& weak_ptr) {
return weak_ptr == nullptr;
}
namespace internal {
class WeakPtrFactoryBase {
protected:
WeakPtrFactoryBase(uintptr_t ptr);
~WeakPtrFactoryBase();
internal::WeakReferenceOwner weak_reference_owner_;
uintptr_t ptr_;
};
} // namespace internal
// A class may be composed of a WeakPtrFactory and thereby
// control how it exposes weak pointers to itself. This is helpful if you only
// need weak pointers within the implementation of a class. This class is also
// useful when working with primitive types. For example, you could have a
// WeakPtrFactory<bool> that is used to pass around a weak reference to a bool.
template <class T>
class WeakPtrFactory {
class WeakPtrFactory : public internal::WeakPtrFactoryBase {
public:
explicit WeakPtrFactory(T* ptr) : ptr_(ptr) {}
explicit WeakPtrFactory(T* ptr)
: WeakPtrFactoryBase(reinterpret_cast<uintptr_t>(ptr)) {}
~WeakPtrFactory() { ptr_ = NULL; }
~WeakPtrFactory() = default;
WeakPtr<T> GetWeakPtr() {
DCHECK(ptr_);
return WeakPtr<T>(weak_reference_owner_.GetRef(), ptr_);
WeakPtr<T> GetWeakPtr() const {
return WeakPtr<T>(weak_reference_owner_.GetRef(),
reinterpret_cast<T*>(ptr_));
}
// Call this method to invalidate all existing weak pointers.
@ -328,8 +380,6 @@ class WeakPtrFactory {
}
private:
cef_internal::WeakReferenceOwner weak_reference_owner_;
T* ptr_;
DISALLOW_IMPLICIT_CONSTRUCTORS(WeakPtrFactory);
};
@ -339,19 +389,19 @@ class WeakPtrFactory {
// weak pointers to the class until after the derived class' members have been
// destroyed, its use can lead to subtle use-after-destroy issues.
template <class T>
class SupportsWeakPtr : public cef_internal::SupportsWeakPtrBase {
class SupportsWeakPtr : public internal::SupportsWeakPtrBase {
public:
SupportsWeakPtr() {}
SupportsWeakPtr() = default;
WeakPtr<T> AsWeakPtr() {
return WeakPtr<T>(weak_reference_owner_.GetRef(), static_cast<T*>(this));
}
protected:
~SupportsWeakPtr() {}
~SupportsWeakPtr() = default;
private:
cef_internal::WeakReferenceOwner weak_reference_owner_;
internal::WeakReferenceOwner weak_reference_owner_;
DISALLOW_COPY_AND_ASSIGN(SupportsWeakPtr);
};
@ -375,7 +425,7 @@ class SupportsWeakPtr : public cef_internal::SupportsWeakPtrBase {
template <typename Derived>
WeakPtr<Derived> AsWeakPtr(Derived* t) {
return cef_internal::SupportsWeakPtrBase::StaticAsWeakPtr<Derived>(t);
return internal::SupportsWeakPtrBase::StaticAsWeakPtr<Derived>(t);
}
} // namespace base