82 lines
2.5 KiB
C++
82 lines
2.5 KiB
C++
// Copyright 2018 The Chromium 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 BASE_TASK_COMMON_INTRUSIVE_HEAP_H_
|
|
#define BASE_TASK_COMMON_INTRUSIVE_HEAP_H_
|
|
|
|
#include "base/containers/intrusive_heap.h"
|
|
|
|
namespace base {
|
|
namespace internal {
|
|
|
|
using HeapHandle = base::HeapHandle;
|
|
|
|
template <typename T>
|
|
struct IntrusiveHeapImpl {
|
|
struct GreaterUsingLessEqual {
|
|
bool operator()(const T& t1, const T& t2) const { return t2 <= t1; }
|
|
};
|
|
|
|
using type = base::IntrusiveHeap<T, GreaterUsingLessEqual>;
|
|
};
|
|
|
|
// base/task wants a min-heap that uses the <= operator, whereas
|
|
// base::IntrusiveHeap is a max-heap by default. This is a very thin adapter
|
|
// over that class that exposes minimal functionality required by the
|
|
// base/task IntrusiveHeap clients.
|
|
template <typename T>
|
|
class IntrusiveHeap : private IntrusiveHeapImpl<T>::type {
|
|
public:
|
|
using IntrusiveHeapImplType = typename IntrusiveHeapImpl<T>::type;
|
|
|
|
// The majority of sets in the scheduler have 0-3 items in them (a few will
|
|
// have perhaps up to 100), so this means we usually only have to allocate
|
|
// memory once.
|
|
static constexpr size_t kMinimumHeapSize = 4;
|
|
|
|
IntrusiveHeap() { IntrusiveHeapImplType::reserve(kMinimumHeapSize); }
|
|
|
|
~IntrusiveHeap() = default;
|
|
|
|
IntrusiveHeap& operator=(IntrusiveHeap&& other) = default;
|
|
|
|
bool empty() const { return IntrusiveHeapImplType::empty(); }
|
|
size_t size() const { return IntrusiveHeapImplType::size(); }
|
|
|
|
void Clear() {
|
|
IntrusiveHeapImplType::clear();
|
|
IntrusiveHeapImplType::reserve(kMinimumHeapSize);
|
|
}
|
|
|
|
const T& Min() const { return IntrusiveHeapImplType::top(); }
|
|
void Pop() { IntrusiveHeapImplType::pop(); }
|
|
|
|
void insert(T&& element) {
|
|
IntrusiveHeapImplType::insert(std::move(element));
|
|
}
|
|
|
|
void erase(HeapHandle handle) { IntrusiveHeapImplType::erase(handle); }
|
|
|
|
void ReplaceMin(T&& element) {
|
|
IntrusiveHeapImplType::ReplaceTop(std::move(element));
|
|
}
|
|
|
|
void ChangeKey(HeapHandle handle, T&& element) {
|
|
IntrusiveHeapImplType::Replace(handle, std::move(element));
|
|
}
|
|
|
|
const T& at(HeapHandle handle) const {
|
|
return IntrusiveHeapImplType::at(handle);
|
|
}
|
|
|
|
// Caution, mutating the heap invalidates iterators!
|
|
const T* begin() const { return IntrusiveHeapImplType::data(); }
|
|
const T* end() const { return IntrusiveHeapImplType::data() + size(); }
|
|
};
|
|
|
|
} // namespace internal
|
|
} // namespace base
|
|
|
|
#endif // BASE_TASK_COMMON_INTRUSIVE_HEAP_H_
|