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https://github.com/wpilibsuite/allwpilib
synced 2026-06-26 01:51:41 +00:00
3cacc2aba6
As discussed, the old method of was going to have issues, and was not going to help in the case of the structs containing pointers. I think we are just going to have to be careful, as guarenteeing the internal pointers are const is going to be very difficult.
96 lines
3.4 KiB
C++
96 lines
3.4 KiB
C++
/*----------------------------------------------------------------------------*/
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/* Copyright (c) FIRST 2016. All Rights Reserved. */
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/* Open Source Software - may be modified and shared by FRC teams. The code */
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/* must be accompanied by the FIRST BSD license file in the root directory of */
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/* the project. */
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/*----------------------------------------------------------------------------*/
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#pragma once
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#include <stdint.h>
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#include <memory>
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#include <vector>
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#include "HAL/Handles.h"
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#include "HAL/cpp/priority_mutex.h"
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#include "HandlesInternal.h"
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namespace hal {
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/**
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* The LimitedHandleResource class is a way to track handles. This version
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* allows a limited number of handles that are allocated sequentially.
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*
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* @tparam THandle The Handle Type (Must be typedefed from HalHandle)
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* @tparam TStruct The struct type held by this resource
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* @tparam size The number of resources allowed to be allocated
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* @tparam enumValue The type value stored in the handle
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*
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*/
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template <typename THandle, typename TStruct, int16_t size,
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HalHandleEnum enumValue>
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class LimitedHandleResource {
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friend class LimitedHandleResourceTest;
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public:
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LimitedHandleResource(const LimitedHandleResource&) = delete;
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LimitedHandleResource operator=(const LimitedHandleResource&) = delete;
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LimitedHandleResource() = default;
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THandle Allocate();
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std::shared_ptr<TStruct> Get(THandle handle);
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void Free(THandle handle);
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private:
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std::shared_ptr<TStruct> m_structures[size];
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priority_mutex m_handleMutexes[size];
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priority_mutex m_allocateMutex;
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};
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template <typename THandle, typename TStruct, int16_t size,
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HalHandleEnum enumValue>
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THandle LimitedHandleResource<THandle, TStruct, size, enumValue>::Allocate() {
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// globally lock to loop through indices
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std::lock_guard<priority_mutex> sync(m_allocateMutex);
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int16_t i;
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for (i = 0; i < size; i++) {
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if (m_structures[i] == nullptr) {
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// if a false index is found, grab its specific mutex
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// and allocate it.
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std::lock_guard<priority_mutex> sync(m_handleMutexes[i]);
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m_structures[i] = std::make_shared<TStruct>();
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return (THandle)createHandle(i, enumValue);
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}
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}
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return HAL_INVALID_HANDLE;
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}
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template <typename THandle, typename TStruct, int16_t size,
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HalHandleEnum enumValue>
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std::shared_ptr<TStruct>
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LimitedHandleResource<THandle, TStruct, size, enumValue>::Get(THandle handle) {
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// get handle index, and fail early if index out of range or wrong handle
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int16_t index = getHandleTypedIndex(handle, enumValue);
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if (index < 0 || index >= size) {
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return nullptr;
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}
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std::lock_guard<priority_mutex> sync(m_handleMutexes[index]);
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// return structure. Null will propogate correctly, so no need to manually
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// check.
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return m_structures[index];
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}
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template <typename THandle, typename TStruct, int16_t size,
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HalHandleEnum enumValue>
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void LimitedHandleResource<THandle, TStruct, size, enumValue>::Free(
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THandle handle) {
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// get handle index, and fail early if index out of range or wrong handle
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int16_t index = getHandleTypedIndex(handle, enumValue);
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if (index < 0 || index >= size) return;
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// lock and deallocated handle
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std::lock_guard<priority_mutex> sync(m_allocateMutex);
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std::lock_guard<priority_mutex> lock(m_handleMutexes[index]);
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m_structures[index].reset();
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}
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}
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