| # Copyright (C) 2019-2020 Intel Corporation | |
| # | |
| # SPDX-License-Identifier: MIT | |
| from collections import OrderedDict | |
| _instance = None | |
| DEFAULT_CAPACITY = 2 | |
| class ImageCache: | |
| def get_instance(): | |
| global _instance | |
| if _instance is None: | |
| _instance = ImageCache() | |
| return _instance | |
| def __init__(self, capacity=DEFAULT_CAPACITY): | |
| self.capacity = int(capacity) | |
| self.items = OrderedDict() | |
| def push(self, item_id, image): | |
| if self.capacity <= len(self.items): | |
| self.items.popitem(last=True) | |
| self.items[item_id] = image | |
| def get(self, item_id): | |
| default = object() | |
| item = self.items.get(item_id, default) | |
| if item is default: | |
| return None | |
| self.items.move_to_end(item_id, last=False) # naive splay tree | |
| return item | |
| def size(self): | |
| return len(self.items) | |
| def clear(self): | |
| self.items.clear() |