From 45922b47ece3f1010aa7ddc6092ac06d8fde1da4 Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Wed, 26 Jan 2022 00:41:53 +0100
Subject: [PATCH] lmdb: Allow configuring cache limit

---
 libpkg/data/config.cpp       |  5 +++++
 libpkg/data/config.h         |  1 +
 libpkg/data/storage.cpp      | 15 +++++++++++++++
 libpkg/data/storageprivate.h |  8 ++++++++
 librepomgr/serversetup.cpp   |  4 ++++
 librepomgr/serversetup.h     |  1 +
 6 files changed, 34 insertions(+)

diff --git a/libpkg/data/config.cpp b/libpkg/data/config.cpp
index f5f9def..98a928a 100644
--- a/libpkg/data/config.cpp
+++ b/libpkg/data/config.cpp
@@ -62,6 +62,11 @@ void Config::initStorage(const char *path, std::uint32_t maxDbs)
     aur.initStorage(*m_storage);
 }
 
+void Config::setPackageCacheLimit(std::size_t limit)
+{
+    m_storage->packageCache().setLimit(limit);
+}
+
 static std::string addDatabaseDependencies(
     Config &config, Database &database, std::vector<Database *> &result, std::unordered_map<Database *, bool> &visited, bool addSelf)
 {
diff --git a/libpkg/data/config.h b/libpkg/data/config.h
index a72755f..751ad04 100644
--- a/libpkg/data/config.h
+++ b/libpkg/data/config.h
@@ -115,6 +115,7 @@ struct LIBPKG_EXPORT Config : public Lockable, public ReflectiveRapidJSON::Binar
 
     // storage and caching
     void initStorage(const char *path = "libpkg.db", std::uint32_t maxDbs = 0);
+    void setPackageCacheLimit(std::size_t limit);
     std::unique_ptr<StorageDistribution> &storage();
     std::uint64_t restoreFromCache();
     std::uint64_t dumpCacheFile();
diff --git a/libpkg/data/storage.cpp b/libpkg/data/storage.cpp
index cc466e0..8e4d8b0 100644
--- a/libpkg/data/storage.cpp
+++ b/libpkg/data/storage.cpp
@@ -43,6 +43,14 @@ template <typename StorageEntryType> std::size_t StorageCacheEntries<StorageEntr
     return count;
 }
 
+template <typename StorageEntryType> void StorageCacheEntries<StorageEntryType>::setLimit(std::size_t limit)
+{
+    m_limit = limit;
+    while (m_entries.size() > limit) {
+        m_entries.pop_back();
+    }
+}
+
 template <typename StorageEntriesType, typename StorageType, typename SpecType>
 auto StorageCache<StorageEntriesType, StorageType, SpecType>::retrieve(Storage &storage, ROTxn *txn, StorageID storageID) -> SpecType
 {
@@ -234,6 +242,13 @@ void StorageCache<StorageEntriesType, StorageType, SpecType>::clearCacheOnly(Sto
     m_entries.clear(storage);
 }
 
+template <typename StorageEntriesType, typename StorageType, typename SpecType>
+void StorageCache<StorageEntriesType, StorageType, SpecType>::setLimit(std::size_t limit)
+{
+    const auto lock = std::unique_lock(m_mutex);
+    m_entries.setLimit(limit);
+}
+
 template struct StorageCacheRef<DatabaseStorage, Package>;
 template struct StorageCacheEntry<PackageCacheRef, Package>;
 template class StorageCacheEntries<PackageCacheEntry>;
diff --git a/libpkg/data/storageprivate.h b/libpkg/data/storageprivate.h
index 29ac416..f731c0a 100644
--- a/libpkg/data/storageprivate.h
+++ b/libpkg/data/storageprivate.h
@@ -104,6 +104,7 @@ public:
     std::size_t clear(const Storage &storage);
     iterator begin();
     iterator end();
+    void setLimit(std::size_t limit);
 
 private:
     EntryList m_entries;
@@ -156,6 +157,7 @@ template <typename StorageEntriesType, typename StorageType, typename SpecType>
     bool invalidate(Storage &storage, const std::string &entryName);
     void clear(Storage &storage);
     void clearCacheOnly(Storage &storage);
+    void setLimit(std::size_t limit);
 
 private:
     Entries m_entries;
@@ -181,6 +183,7 @@ struct StorageDistribution {
     explicit StorageDistribution(const char *path, std::uint32_t maxDbs);
 
     std::unique_ptr<DatabaseStorage> forDatabase(std::string_view uniqueDatabaseName);
+    PackageCache &packageCache();
 
 private:
     std::shared_ptr<LMDBSafe::MDBEnv> m_env;
@@ -192,6 +195,11 @@ inline std::unique_ptr<DatabaseStorage> StorageDistribution::forDatabase(std::st
     return std::make_unique<DatabaseStorage>(m_env, m_packageCache, uniqueDatabaseName);
 }
 
+inline PackageCache &StorageDistribution::packageCache()
+{
+    return m_packageCache;
+}
+
 struct DatabaseStorage {
     explicit DatabaseStorage(const std::shared_ptr<LMDBSafe::MDBEnv> &env, PackageCache &packageCache, std::string_view uniqueDatabaseName);
     PackageCache &packageCache;
diff --git a/librepomgr/serversetup.cpp b/librepomgr/serversetup.cpp
index c6c26f3..f597523 100644
--- a/librepomgr/serversetup.cpp
+++ b/librepomgr/serversetup.cpp
@@ -235,6 +235,7 @@ void ServiceSetup::loadConfigFiles(bool doFirstTimeSetup)
                 convertValue(iniEntry.second, "pacman_config_file_path", pacmanConfigFilePath);
                 convertValue(iniEntry.second, "working_directory", workingDirectory);
                 convertValue(iniEntry.second, "max_dbs", maxDbs);
+                convertValue(iniEntry.second, "package_cache_limit", packageCacheLimit);
             }
         }
         // apply working directory
@@ -288,6 +289,8 @@ void ServiceSetup::loadConfigFiles(bool doFirstTimeSetup)
     // restore state/cache and discard databases if not done yet
     if (doFirstTimeSetup) {
         initStorage();
+    } else {
+        config.setPackageCacheLimit(packageCacheLimit);
     }
 
     // read pacman config
@@ -509,6 +512,7 @@ std::size_t ServiceSetup::restoreState()
     // open LMDB storage
     cout << Phrases::InfoMessage << "Opening LMDB file: " << dbPath << " (max DBs: " << maxDbs << ')' << Phrases::EndFlush;
     config.initStorage(dbPath.data(), maxDbs);
+    config.setPackageCacheLimit(packageCacheLimit);
 
     // restore build actions from JSON file
     if (!hasBuildActions) {
diff --git a/librepomgr/serversetup.h b/librepomgr/serversetup.h
index c0fa37f..5274c61 100644
--- a/librepomgr/serversetup.h
+++ b/librepomgr/serversetup.h
@@ -44,6 +44,7 @@ struct LIBREPOMGR_EXPORT ServiceSetup : public LibPkg::Lockable {
     std::string workingDirectory = "workingdir";
     std::string dbPath = "libpkg.db";
     std::uint32_t maxDbs = 512;
+    std::size_t packageCacheLimit = 1000;
 
     // variables relevant for the web server; only changed when (re)loading config
     struct LIBREPOMGR_EXPORT WebServerSetup {