Squashed 'third_party/allwpilib_2017/' content from commit 35ac87d
Change-Id: I7bb6f5556c30d3f5a092e68de0be9c710c60c9f4
git-subtree-dir: third_party/allwpilib_2017
git-subtree-split: 35ac87d6ff8b7f061c4f18c9ea316e5dccd4888a
diff --git a/hal/include/HAL/handles/IndexedHandleResource.h b/hal/include/HAL/handles/IndexedHandleResource.h
new file mode 100644
index 0000000..cfe0668
--- /dev/null
+++ b/hal/include/HAL/handles/IndexedHandleResource.h
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+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2016-2017. All Rights Reserved. */
+/* Open Source Software - may be modified and shared by FRC teams. The code */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project. */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <stdint.h>
+
+#include <array>
+#include <memory>
+
+#include "HAL/Errors.h"
+#include "HAL/Types.h"
+#include "HAL/cpp/make_unique.h"
+#include "HAL/cpp/priority_mutex.h"
+#include "HAL/handles/HandlesInternal.h"
+
+namespace hal {
+
+/**
+ * The IndexedHandleResource class is a way to track handles. This version
+ * allows a limited number of handles that are allocated by index.
+ * Because they are allocated by index, each individual index holds its own
+ * mutex, which reduces contention heavily.]
+ *
+ * @tparam THandle The Handle Type (Must be typedefed from HAL_Handle)
+ * @tparam TStruct The struct type held by this resource
+ * @tparam size The number of resources allowed to be allocated
+ * @tparam enumValue The type value stored in the handle
+ *
+ */
+template <typename THandle, typename TStruct, int16_t size,
+ HAL_HandleEnum enumValue>
+class IndexedHandleResource {
+ friend class IndexedHandleResourceTest;
+
+ public:
+ IndexedHandleResource() = default;
+ IndexedHandleResource(const IndexedHandleResource&) = delete;
+ IndexedHandleResource& operator=(const IndexedHandleResource&) = delete;
+
+ THandle Allocate(int16_t index, int32_t* status);
+ std::shared_ptr<TStruct> Get(THandle handle);
+ void Free(THandle handle);
+
+ private:
+ std::array<std::shared_ptr<TStruct>, size> m_structures;
+ std::array<priority_mutex, size> m_handleMutexes;
+};
+
+template <typename THandle, typename TStruct, int16_t size,
+ HAL_HandleEnum enumValue>
+THandle IndexedHandleResource<THandle, TStruct, size, enumValue>::Allocate(
+ int16_t index, int32_t* status) {
+ // don't aquire the lock if we can fail early.
+ if (index < 0 || index >= size) {
+ *status = RESOURCE_OUT_OF_RANGE;
+ return HAL_kInvalidHandle;
+ }
+ std::lock_guard<priority_mutex> sync(m_handleMutexes[index]);
+ // check for allocation, otherwise allocate and return a valid handle
+ if (m_structures[index] != nullptr) {
+ *status = RESOURCE_IS_ALLOCATED;
+ return HAL_kInvalidHandle;
+ }
+ m_structures[index] = std::make_shared<TStruct>();
+ return static_cast<THandle>(hal::createHandle(index, enumValue));
+}
+
+template <typename THandle, typename TStruct, int16_t size,
+ HAL_HandleEnum enumValue>
+std::shared_ptr<TStruct>
+IndexedHandleResource<THandle, TStruct, size, enumValue>::Get(THandle handle) {
+ // get handle index, and fail early if index out of range or wrong handle
+ int16_t index = getHandleTypedIndex(handle, enumValue);
+ if (index < 0 || index >= size) {
+ return nullptr;
+ }
+ std::lock_guard<priority_mutex> sync(m_handleMutexes[index]);
+ // return structure. Null will propogate correctly, so no need to manually
+ // check.
+ return m_structures[index];
+}
+
+template <typename THandle, typename TStruct, int16_t size,
+ HAL_HandleEnum enumValue>
+void IndexedHandleResource<THandle, TStruct, size, enumValue>::Free(
+ THandle handle) {
+ // get handle index, and fail early if index out of range or wrong handle
+ int16_t index = getHandleTypedIndex(handle, enumValue);
+ if (index < 0 || index >= size) return;
+ // lock and deallocated handle
+ std::lock_guard<priority_mutex> sync(m_handleMutexes[index]);
+ m_structures[index].reset();
+}
+} // namespace hal