From d8b1c8d9ef3802c5b72297bf7b627faded9372b6 Mon Sep 17 00:00:00 2001
From: yupix <yupi0982@outlook.jp>
Date: Sun, 18 Aug 2024 17:33:57 +0900
Subject: [PATCH] =?UTF-8?q?feat:=20=E3=82=AD=E3=83=A3=E3=83=83=E3=82=B7?=
 =?UTF-8?q?=E3=83=A5=E3=82=B7=E3=82=B9=E3=83=86=E3=83=A0=E3=82=92FIFO?=
 =?UTF-8?q?=E3=81=8B=E3=82=89LRU=E3=81=AB=E5=A4=89=E6=9B=B4=20close=20#145?=
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fix #144, #146
---
 mipac/utils/cache.py | 110 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 88 insertions(+), 22 deletions(-)

diff --git a/mipac/utils/cache.py b/mipac/utils/cache.py
index 5386e23..db85693 100644
--- a/mipac/utils/cache.py
+++ b/mipac/utils/cache.py
@@ -1,30 +1,88 @@
+from __future__ import annotations
+
 from functools import lru_cache, wraps
 from typing import Any
 
-DEFAULT_CACHE: dict[str, list[str]] = {}
-DEFAULT_CACHE_VALUE: dict[str, Any] = {}
+DEFAULT_CACHE: dict[str, "LRUCache"] = {}
 
 
-def set_cache(group: str, key: str, value: Any) -> None:
-    """キャッシュを設定します
+class Node:
+    """キャッシュのノード
 
-    Parameters
+    Attributes
     ----------
-    group : str
-        キャッシュのグループ名
     key : str
-        一意のキー
+        キャッシュのキー
     value : Any
-        設定する値
+        キャッシュの値
+    next : ListNode
+        次のノード
+    prev : ListNode
+        前のノード
     """
-    if len(DEFAULT_CACHE.get(group, [])) > 50:
-        del DEFAULT_CACHE[group][-1]
-        del DEFAULT_CACHE_VALUE[key]
 
-    if DEFAULT_CACHE.get(group) is None:
-        DEFAULT_CACHE[group] = []
-    DEFAULT_CACHE[group].append(key)
-    DEFAULT_CACHE_VALUE[key] = value
+    def __init__(self, key: str, value: Any) -> None:
+        self.key: str = key
+        self.value: Any = value
+        self.next: Node | None = None
+        self.prev: Node | None = None
+
+
+class LRUCache:
+    def __init__(self, capacity: int = 100) -> None:
+        self.items: dict[str, Node] = {}
+        # headとtailはダミーノード、この間にノードを追加していく
+        self.head_node = Node("", 0)
+        self.tail_node = Node("", 0)
+        self.head_node.next = self.tail_node  # 先頭 => 末尾
+        self.tail_node.prev = self.head_node  # 先頭 <= 末尾
+        self.capacity = capacity
+
+    def _remove_node(self, node: Node):
+        if node.prev:  # 削除対象の前にいるnodeのnextを削除対象の次のnodeに変更
+            node.prev.next = node.next
+
+        if node.next:  # 削除対象の次のnodeのprevを削除対象の前のnodeに変更
+            node.next.prev = node.prev
+
+        del self.items[node.key]
+
+    def _add(self, node: Node):
+        prev_node = self.tail_node.prev
+        next_node = self.tail_node
+
+        if prev_node:
+            prev_node.next = node
+            node.prev = prev_node
+
+        if next_node:
+            next_node.prev = node
+            node.next = next_node
+
+        self.items[node.key] = node
+
+    def get(self, key: str) -> Any:
+        if key not in self.items:
+            raise KeyError
+
+        node = self.items[key]
+
+        # 一度削除して追加しなおすことで最新のノードとして更新する
+        self._remove_node(node)
+        self._add(node)
+
+        return node.value
+
+    def put(self, key: str, value: Any):
+        if key in self.items:  # 既に同一のキーが存在する場合は再登録するために一度消す
+            del self.items[key]
+
+        node = Node(key, value)
+        self._add(node)
+
+        if len(self.items) > self.capacity:
+            if self.head_node.next:  # 基本存在するはずだけど型的に一応やっとく
+                self._remove_node(self.head_node.next)
 
 
 def cache(group: str = "default", override: bool = False):
@@ -34,12 +92,20 @@ def cache(group: str = "default", override: bool = False):
         @wraps(func)
         async def wrapper(self, *args, **kwargs):
             key = cache_key_builder(func, self, *args, **kwargs)
-            hit_item = DEFAULT_CACHE_VALUE.get(key)
-            if hit_item and override is False and kwargs.get("cache_override") is None:
-                return hit_item
-            res = await func(self, *args, **kwargs)
-            set_cache(group, key, res)
-            return res
+            target_cache = DEFAULT_CACHE.get(group)
+
+            if target_cache is None:
+                target_cache = LRUCache()
+                DEFAULT_CACHE[group] = target_cache
+
+            try:
+                hit_item = target_cache.get(key)
+                if hit_item and override is False and kwargs.get("cache_override") is None:
+                    return hit_item
+            except KeyError:
+                res = await func(self, *args, **kwargs)
+                target_cache.put(key, res)
+                return res
 
         return wrapper