From f1e76092a0183d3d8e1226b4671a725434771d2b Mon Sep 17 00:00:00 2001
From: LamGC <lam827@lamgc.net>
Date: Mon, 11 Jan 2021 16:24:55 +0800
Subject: [PATCH] =?UTF-8?q?[Fix]=20CacheStore-Redis=20=E4=BF=AE=E5=A4=8D?=
 =?UTF-8?q?=20RemoveElementByIndex=20=E8=84=9A=E6=9C=AC=E4=B8=AD=E5=AF=B9?=
 =?UTF-8?q?=E6=97=A0=E6=95=88=E9=A1=B9=E5=88=A4=E6=96=AD=E7=9A=84=E9=94=99?=
 =?UTF-8?q?=E8=AF=AF;?=
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[Fix] RemoveElementByIndex.lua 修复范围溢出, 不存在键检查失效的问题;
---
 .../src/main/lua/RemoveElementByIndex.lua     | 23 +++++++++++--------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/ContentGrabbingJi-CacheStore-redis/src/main/lua/RemoveElementByIndex.lua b/ContentGrabbingJi-CacheStore-redis/src/main/lua/RemoveElementByIndex.lua
index d16a416..1949646 100644
--- a/ContentGrabbingJi-CacheStore-redis/src/main/lua/RemoveElementByIndex.lua
+++ b/ContentGrabbingJi-CacheStore-redis/src/main/lua/RemoveElementByIndex.lua
@@ -1,10 +1,3 @@
-local key = tostring(KEYS[1])
-local index = tonumber(ARGV[1])
-
-if (key == nil) or (index == nil) then
-    return 0
-end
-
 local function getRandom(n)
     local t = {
         "0","1","2","3","4","5","6","7","8","9",
@@ -16,13 +9,23 @@ local function getRandom(n)
         s = s .. t[math.random(#t)]
     end;
     return s
-end;
+end
 
-local flag = getRandom(24)
+local key = tostring(KEYS[1])
+local index = tonumber(ARGV[1])
 
-if (redis.call("llen", key) <= index) or redis.call("lIndex", key, index) == nil then
+if (key == nil) or (index == nil) or (redis.call("exists", key) == false) then
+    return 0
+end
+
+local listLength = redis.call("llen", key)
+if listLength == 0 then
+    return 0
+end
+if (index < 0) or (index >= listLength) or redis.call("lIndex", key, index) == nil then
     return 0
 else
+    local flag = getRandom(24)
     redis.call("lSet", key, index, flag);
     return redis.call("lRem", key, 0, flag);
 end