File size: 3,813 Bytes
39eec6f | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 | // Copyright 2020 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_INTERNAL_POINTER_POLICIES_H_
#define INCLUDE_CPPGC_INTERNAL_POINTER_POLICIES_H_
#include <cstdint>
#include <type_traits>
#include "cppgc/source-location.h"
#include "v8config.h" // NOLINT(build/include_directory)
namespace cppgc {
namespace internal {
class PersistentRegion;
// Tags to distinguish between strong and weak member types.
class StrongMemberTag;
class WeakMemberTag;
class UntracedMemberTag;
struct DijkstraWriteBarrierPolicy {
static void InitializingBarrier(const void*, const void*) {
// Since in initializing writes the source object is always white, having no
// barrier doesn't break the tri-color invariant.
}
static void AssigningBarrier(const void*, const void*) {
// TODO(chromium:1056170): Add actual implementation.
}
};
struct NoWriteBarrierPolicy {
static void InitializingBarrier(const void*, const void*) {}
static void AssigningBarrier(const void*, const void*) {}
};
class V8_EXPORT EnabledCheckingPolicy {
protected:
EnabledCheckingPolicy();
void CheckPointer(const void* ptr);
private:
void* impl_;
};
class DisabledCheckingPolicy {
protected:
void CheckPointer(const void* raw) {}
};
#if V8_ENABLE_CHECKS
using DefaultCheckingPolicy = EnabledCheckingPolicy;
#else
using DefaultCheckingPolicy = DisabledCheckingPolicy;
#endif
class KeepLocationPolicy {
public:
constexpr const SourceLocation& Location() const { return location_; }
protected:
constexpr explicit KeepLocationPolicy(const SourceLocation& location)
: location_(location) {}
// KeepLocationPolicy must not copy underlying source locations.
KeepLocationPolicy(const KeepLocationPolicy&) = delete;
KeepLocationPolicy& operator=(const KeepLocationPolicy&) = delete;
// Location of the original moved from object should be preserved.
KeepLocationPolicy(KeepLocationPolicy&&) = default;
KeepLocationPolicy& operator=(KeepLocationPolicy&&) = default;
private:
SourceLocation location_;
};
class IgnoreLocationPolicy {
public:
constexpr SourceLocation Location() const { return {}; }
protected:
constexpr explicit IgnoreLocationPolicy(const SourceLocation&) {}
};
#if CPPGC_SUPPORTS_OBJECT_NAMES
using DefaultLocationPolicy = KeepLocationPolicy;
#else
using DefaultLocationPolicy = IgnoreLocationPolicy;
#endif
struct StrongPersistentPolicy {
using IsStrongPersistent = std::true_type;
static V8_EXPORT PersistentRegion& GetPersistentRegion(void* object);
};
struct WeakPersistentPolicy {
using IsStrongPersistent = std::false_type;
static V8_EXPORT PersistentRegion& GetPersistentRegion(void* object);
};
// Persistent/Member forward declarations.
template <typename T, typename WeaknessPolicy,
typename LocationPolicy = DefaultLocationPolicy,
typename CheckingPolicy = DefaultCheckingPolicy>
class BasicPersistent;
template <typename T, typename WeaknessTag, typename WriteBarrierPolicy,
typename CheckingPolicy = DefaultCheckingPolicy>
class BasicMember;
// Special tag type used to denote some sentinel member. The semantics of the
// sentinel is defined by the embedder.
struct SentinelPointer {
template <typename T>
operator T*() const { // NOLINT
static constexpr intptr_t kSentinelValue = -1;
return reinterpret_cast<T*>(kSentinelValue);
}
// Hidden friends.
friend bool operator==(SentinelPointer, SentinelPointer) { return true; }
friend bool operator!=(SentinelPointer, SentinelPointer) { return false; }
};
} // namespace internal
constexpr internal::SentinelPointer kSentinelPointer;
} // namespace cppgc
#endif // INCLUDE_CPPGC_INTERNAL_POINTER_POLICIES_H_
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