From 9deb4d7904deff765e034c2528dfca93b6cdb714 Mon Sep 17 00:00:00 2001
From: Stefan Boberg <stefan@boberg.org>
Date: Tue, 17 Aug 2021 15:18:37 +0200
Subject: Implemented support for dropping z$ buckets while online

---
 zenserver/cache/structuredcachestore.cpp | 67 ++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

(limited to 'zenserver/cache/structuredcachestore.cpp')

diff --git a/zenserver/cache/structuredcachestore.cpp b/zenserver/cache/structuredcachestore.cpp
index 9ed3cf53e..e6eda05aa 100644
--- a/zenserver/cache/structuredcachestore.cpp
+++ b/zenserver/cache/structuredcachestore.cpp
@@ -81,6 +81,14 @@ ZenCacheStore::Put(std::string_view InBucket, const zen::IoHash& HashKey, const
 	}
 }
 
+bool
+ZenCacheStore::DropBucket(std::string_view Bucket)
+{
+	// TODO: should ensure this is done atomically across all layers
+
+	return m_MemLayer.DropBucket(Bucket) && m_DiskLayer.DropBucket(Bucket);
+}
+
 void
 ZenCacheStore::Flush()
 {
@@ -153,6 +161,16 @@ ZenCacheMemoryLayer::Put(std::string_view InBucket, const zen::IoHash& HashKey,
 	Bucket->Put(HashKey, Value);
 }
 
+bool
+ZenCacheMemoryLayer::DropBucket(std::string_view Bucket)
+{
+	RwLock::ExclusiveLockScope _(m_Lock);
+
+	m_Buckets.erase(std::string(Bucket));
+
+	return true;
+}
+
 bool
 ZenCacheMemoryLayer::CacheBucket::Get(const zen::IoHash& HashKey, ZenCacheValue& OutValue)
 {
@@ -216,9 +234,11 @@ struct ZenCacheDiskLayer::CacheBucket
 	~CacheBucket();
 
 	void OpenOrCreate(std::filesystem::path BucketDir);
+	static bool Delete(std::filesystem::path BucketDir);
 
 	bool Get(const zen::IoHash& HashKey, ZenCacheValue& OutValue);
 	void Put(const zen::IoHash& HashKey, const ZenCacheValue& Value);
+	void Drop();
 	void Flush();
 
 	inline bool IsOk() const { return m_Ok; }
@@ -249,6 +269,19 @@ ZenCacheDiskLayer::CacheBucket::~CacheBucket()
 {
 }
 
+bool
+ZenCacheDiskLayer::CacheBucket::Delete(std::filesystem::path BucketDir)
+{
+	if (std::filesystem::exists(BucketDir))
+	{
+		zen::DeleteDirectories(BucketDir);
+
+		return true;
+	}
+
+	return false;
+}
+
 void
 ZenCacheDiskLayer::CacheBucket::OpenOrCreate(std::filesystem::path BucketDir)
 {
@@ -436,6 +469,16 @@ ZenCacheDiskLayer::CacheBucket::Put(const zen::IoHash& HashKey, const ZenCacheVa
 	}
 }
 
+void
+ZenCacheDiskLayer::CacheBucket::Drop()
+{
+	// TODO: add error handling
+
+	m_SobsFile.Close();
+	m_SlogFile.Close();
+	zen::DeleteDirectories(m_BucketDir);
+}
+
 void
 ZenCacheDiskLayer::CacheBucket::Flush()
 {
@@ -584,6 +627,30 @@ ZenCacheDiskLayer::Put(std::string_view InBucket, const zen::IoHash& HashKey, co
 	}
 }
 
+bool
+ZenCacheDiskLayer::DropBucket(std::string_view InBucket)
+{
+	zen::RwLock::ExclusiveLockScope _(m_Lock);
+
+	auto it = m_Buckets.find(std::string(InBucket));
+
+	if (it != m_Buckets.end())
+	{
+		CacheBucket* Bucket = &it->second;
+
+		Bucket->Drop();
+
+		m_Buckets.erase(it);
+
+		return true;
+	}
+
+	std::filesystem::path BucketPath = m_RootDir;
+	BucketPath /= std::string(InBucket);
+
+	return CacheBucket::Delete(BucketPath);
+}
+
 void
 ZenCacheDiskLayer::Flush()
 {
-- 
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