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Name	Size	Permission
internal	[ DIR ]	drwxr-xr-x
allocation.h	11.61 KB	-rw-r--r--
common.h	643 B	-rw-r--r--
cross-thread-persistent.h	14.81 KB	-rw-r--r--
custom-space.h	2.4 KB	-rw-r--r--
default-platform.h	2.18 KB	-rw-r--r--
ephemeron-pair.h	804 B	-rw-r--r--
explicit-management.h	3.29 KB	-rw-r--r--
garbage-collected.h	3.11 KB	-rw-r--r--
heap-consistency.h	11.74 KB	-rw-r--r--
heap-handle.h	1.26 KB	-rw-r--r--
heap-state.h	2.57 KB	-rw-r--r--
heap-statistics.h	3.89 KB	-rw-r--r--
heap.h	5.7 KB	-rw-r--r--
liveness-broker.h	2.34 KB	-rw-r--r--
macros.h	1.31 KB	-rw-r--r--
member.h	22.75 KB	-rw-r--r--
name-provider.h	1.99 KB	-rw-r--r--
object-size-trait.h	1.6 KB	-rw-r--r--
persistent.h	13.5 KB	-rw-r--r--
platform.h	5.56 KB	-rw-r--r--
prefinalizer.h	2.88 KB	-rw-r--r--
process-heap-statistics.h	1009 B	-rw-r--r--
sentinel-pointer.h	935 B	-rw-r--r--
source-location.h	2.57 KB	-rw-r--r--
testing.h	2.96 KB	-rw-r--r--
trace-trait.h	3.14 KB	-rw-r--r--
type-traits.h	7.78 KB	-rw-r--r--
visitor.h	14.84 KB	-rw-r--r--

Code Editor : explicit-management.h

// Copyright 2021 the V8 project 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 INCLUDE_CPPGC_EXPLICIT_MANAGEMENT_H_
#define INCLUDE_CPPGC_EXPLICIT_MANAGEMENT_H_

#include <cstddef>

#include "cppgc/allocation.h"
#include "cppgc/internal/logging.h"
#include "cppgc/type-traits.h"

namespace cppgc {

class HeapHandle;

namespace subtle {

template <typename T>
void FreeUnreferencedObject(HeapHandle& heap_handle, T& object);
template <typename T>
bool Resize(T& object, AdditionalBytes additional_bytes);

}  // namespace subtle

namespace internal {

class ExplicitManagementImpl final {
 private:
  V8_EXPORT static void FreeUnreferencedObject(HeapHandle&, void*);
  V8_EXPORT static bool Resize(void*, size_t);

template <typename T>
  friend void subtle::FreeUnreferencedObject(HeapHandle&, T&);
  template <typename T>
  friend bool subtle::Resize(T&, AdditionalBytes);
};
}  // namespace internal

namespace subtle {

/**
 * Informs the garbage collector that `object` can be immediately reclaimed. The
 * destructor may not be invoked immediately but only on next garbage
 * collection.
 *
 * It is up to the embedder to guarantee that no other object holds a reference
 * to `object` after calling `FreeUnreferencedObject()`. In case such a
 * reference exists, it's use results in a use-after-free.
 *
 * To aid in using the API, `FreeUnreferencedObject()` may be called from
 * destructors on objects that would be reclaimed in the same garbage collection
 * cycle.
 *
 * \param heap_handle The corresponding heap.
 * \param object Reference to an object that is of type `GarbageCollected` and
 *   should be immediately reclaimed.
 */
template <typename T>
void FreeUnreferencedObject(HeapHandle& heap_handle, T& object) {
  static_assert(IsGarbageCollectedTypeV<T>,
                "Object must be of type GarbageCollected.");
  internal::ExplicitManagementImpl::FreeUnreferencedObject(heap_handle,
                                                           &object);
}

/**
 * Tries to resize `object` of type `T` with additional bytes on top of
 * sizeof(T). Resizing is only useful with trailing inlined storage, see e.g.
 * `MakeGarbageCollected(AllocationHandle&, AdditionalBytes)`.
 *
 * `Resize()` performs growing or shrinking as needed and may skip the operation
 * for internal reasons, see return value.
 *
 * It is up to the embedder to guarantee that in case of shrinking a larger
 * object down, the reclaimed area is not used anymore. Any subsequent use
 * results in a use-after-free.
 *
 * The `object` must be live when calling `Resize()`.
 *
 * \param object Reference to an object that is of type `GarbageCollected` and
 *   should be resized.
 * \param additional_bytes Bytes in addition to sizeof(T) that the object should
 *   provide.
 * \returns true when the operation was successful and the result can be relied
 *   on, and false otherwise.
 */
template <typename T>
bool Resize(T& object, AdditionalBytes additional_bytes) {
  static_assert(IsGarbageCollectedTypeV<T>,
                "Object must be of type GarbageCollected.");
  return internal::ExplicitManagementImpl::Resize(
      &object, sizeof(T) + additional_bytes.value);
}

}  // namespace subtle
}  // namespace cppgc

#endif  // INCLUDE_CPPGC_EXPLICIT_MANAGEMENT_H_

${this.title}

Code Editor : explicit-management.h