| /* |
| * Copyright (C) 2019 The Android Open Source Project |
| * |
| * 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 |
| * |
| * http://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 _UI_INPUT_INPUTDISPATCHER_QUEUE_H |
| #define _UI_INPUT_INPUTDISPATCHER_QUEUE_H |
| |
| namespace android::inputdispatcher { |
| |
| // Generic queue implementation. |
| template <typename T> |
| struct Queue { |
| T* head; |
| T* tail; |
| uint32_t entryCount; |
| |
| inline Queue() : head(nullptr), tail(nullptr), entryCount(0) {} |
| |
| inline bool isEmpty() const { return !head; } |
| |
| inline void enqueueAtTail(T* entry) { |
| entryCount++; |
| entry->prev = tail; |
| if (tail) { |
| tail->next = entry; |
| } else { |
| head = entry; |
| } |
| entry->next = nullptr; |
| tail = entry; |
| } |
| |
| inline void enqueueAtHead(T* entry) { |
| entryCount++; |
| entry->next = head; |
| if (head) { |
| head->prev = entry; |
| } else { |
| tail = entry; |
| } |
| entry->prev = nullptr; |
| head = entry; |
| } |
| |
| inline void dequeue(T* entry) { |
| entryCount--; |
| if (entry->prev) { |
| entry->prev->next = entry->next; |
| } else { |
| head = entry->next; |
| } |
| if (entry->next) { |
| entry->next->prev = entry->prev; |
| } else { |
| tail = entry->prev; |
| } |
| } |
| |
| inline T* dequeueAtHead() { |
| entryCount--; |
| T* entry = head; |
| head = entry->next; |
| if (head) { |
| head->prev = nullptr; |
| } else { |
| tail = nullptr; |
| } |
| return entry; |
| } |
| |
| uint32_t count() const { return entryCount; } |
| }; |
| |
| } // namespace android::inputdispatcher |
| |
| #endif // _UI_INPUT_INPUTDISPATCHER_QUEUE_H |