From 698c285cb3ef6c016bbb08970a518cc36180bdac Mon Sep 17 00:00:00 2001
From: Sonullx Liu <Sonullx.Liu@gmail.com>
Date: Mon, 14 Sep 2020 18:11:49 +0800
Subject: [PATCH] Fix bugs in branch windows (#47)

* fix: Fix the bug that LRUCache cannot work well when it is full

* fix: Avoid possible division by zero crash
---
 src/manager/UpstreamManager.cc | 11 +++++++----
 src/util/LRUCache.h            | 25 ++++++++++---------------
 2 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/src/manager/UpstreamManager.cc b/src/manager/UpstreamManager.cc
index afce47e9..78d425d5 100644
--- a/src/manager/UpstreamManager.cc
+++ b/src/manager/UpstreamManager.cc
@@ -467,11 +467,13 @@ static inline bool __is_alive_or_group_alive(const UpstreamAddress *ua)
 
 const UpstreamAddress *Upstream::weighted_random_try_another() const
 {
-	if (available_weight_ == 0)
+	int temp_weight = available_weight_;
+
+	if (temp_weight == 0)
 		return NULL;
 
 	const UpstreamAddress *ua = NULL;
-	int x = rand() % available_weight_;
+	int x = rand() % temp_weight;
 	int s = 0;
 
 	for (const auto *master : masters_)
@@ -604,9 +606,10 @@ const UpstreamAddress *Upstream::get(const ParsedURI& uri)
 		{
 			int x = 0;
 			int s = 0;
+			int temp_weight = total_weight_;
 
-			if (total_weight_ > 0)
-				x = rand() % total_weight_;
+			if (temp_weight > 0)
+				x = rand() % temp_weight;
 
 			for (idx = 0; idx < n; idx++)
 			{
diff --git a/src/util/LRUCache.h b/src/util/LRUCache.h
index bedc9a12..a665e10e 100644
--- a/src/util/LRUCache.h
+++ b/src/util/LRUCache.h
@@ -185,23 +185,18 @@ public:
 		e->ref = 1;
 		std::lock_guard<std::mutex> lock(mutex_);
 
-		if (max_size_ == 0 || size_ < max_size_)
+		size_++;
+		e->in_cache = true;
+		e->ref++;
+		list_append(&in_use_, e);
+		MapIterator it = cache_map_.find(key);
+		if (it != cache_map_.end())
 		{
-			size_++;
-			e->in_cache = true;
-			e->ref++;
-			list_append(&in_use_, e);
-			MapIterator it = cache_map_.find(key);
-			if (it != cache_map_.end())
-			{
-				erase_node(it->second);
-				it->second = e;
-			}
-			else
-				cache_map_[key] = e;
+			erase_node(it->second);
+			it->second = e;
 		}
-		else//do not cache
-			e->next = NULL;
+		else
+			cache_map_[key] = e;
 
 		if (max_size_ > 0)
 		{