"""
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缓存策略和数据结构定义
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"""
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import time
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from enum import Enum
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from typing import Any, Optional
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from dataclasses import dataclass
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class CacheStrategy(Enum):
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"""缓存策略枚举"""
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TTL = "ttl" # 基于时间过期
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LRU = "lru" # 最近最少使用
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FIXED_SIZE = "fixed_size" # 固定大小
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TTL_LRU = "ttl_lru" # TTL + LRU混合策略
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@dataclass
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class CacheEntry:
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"""缓存条目数据结构"""
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value: Any
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timestamp: float
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ttl: Optional[float] = None # 生存时间（秒）
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access_count: int = 0
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last_access: float = None
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def __post_init__(self):
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if self.last_access is None:
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self.last_access = self.timestamp
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def is_expired(self) -> bool:
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"""检查是否过期"""
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if self.ttl is None:
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return False
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return time.time() - self.timestamp > self.ttl
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def touch(self):
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"""更新访问时间和计数"""
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self.last_access = time.time()
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self.access_count += 1
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