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authorVincent Ambo <tazjin@google.com>2020-05-20T01·32+0100
committerVincent Ambo <tazjin@google.com>2020-05-20T01·32+0100
commitfc8dc48020ac5b52731d0828a96ea4d2526c77ba (patch)
tree353204eea3268095a9ad3f5345720f32c2615c69 /third_party/abseil_cpp/absl/base/internal/hide_ptr.h
parentffb2ae54beb5796cd408fbe15d2d2da09ff37adf (diff)
parent768eb2ca2857342673fcd462792ce04b8bac3fa3 (diff)
Add 'third_party/abseil_cpp/' from commit '768eb2ca2857342673fcd462792ce04b8bac3fa3' r/781
git-subtree-dir: third_party/abseil_cpp
git-subtree-mainline: ffb2ae54beb5796cd408fbe15d2d2da09ff37adf
git-subtree-split: 768eb2ca2857342673fcd462792ce04b8bac3fa3
Diffstat (limited to 'third_party/abseil_cpp/absl/base/internal/hide_ptr.h')
-rw-r--r--third_party/abseil_cpp/absl/base/internal/hide_ptr.h51
1 files changed, 51 insertions, 0 deletions
diff --git a/third_party/abseil_cpp/absl/base/internal/hide_ptr.h b/third_party/abseil_cpp/absl/base/internal/hide_ptr.h
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+++ b/third_party/abseil_cpp/absl/base/internal/hide_ptr.h
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+// Copyright 2018 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.
+
+#ifndef ABSL_BASE_INTERNAL_HIDE_PTR_H_
+#define ABSL_BASE_INTERNAL_HIDE_PTR_H_
+
+#include <cstdint>
+
+#include "absl/base/config.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace base_internal {
+
+// Arbitrary value with high bits set. Xor'ing with it is unlikely
+// to map one valid pointer to another valid pointer.
+constexpr uintptr_t HideMask() {
+  return (uintptr_t{0xF03A5F7BU} << (sizeof(uintptr_t) - 4) * 8) | 0xF03A5F7BU;
+}
+
+// Hide a pointer from the leak checker. For internal use only.
+// Differs from absl::IgnoreLeak(ptr) in that absl::IgnoreLeak(ptr) causes ptr
+// and all objects reachable from ptr to be ignored by the leak checker.
+template <class T>
+inline uintptr_t HidePtr(T* ptr) {
+  return reinterpret_cast<uintptr_t>(ptr) ^ HideMask();
+}
+
+// Return a pointer that has been hidden from the leak checker.
+// For internal use only.
+template <class T>
+inline T* UnhidePtr(uintptr_t hidden) {
+  return reinterpret_cast<T*>(hidden ^ HideMask());
+}
+
+}  // namespace base_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_BASE_INTERNAL_HIDE_PTR_H_