1 files changed, 31 insertions, 2 deletions

diff --git a/src/wallet/db.h b/src/wallet/db.h
index b078edab7b..e453d441d7 100644
--- a/src/wallet/db.h
+++ b/src/wallet/db.h
@@ -11,13 +11,14 @@
 #include <serialize.h>
 #include <streams.h>
 #include <sync.h>
-#include <util.h>
+#include <util/system.h>
 #include <version.h>
 
 #include <atomic>
 #include <map>
 #include <memory>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 #include <db_cxx.h>
@@ -25,6 +26,13 @@
 static const unsigned int DEFAULT_WALLET_DBLOGSIZE = 100;
 static const bool DEFAULT_WALLET_PRIVDB = true;
 
+struct WalletDatabaseFileId {
+    u_int8_t value[DB_FILE_ID_LEN];
+    bool operator==(const WalletDatabaseFileId& rhs) const;
+};
+
+class BerkeleyDatabase;
+
 class BerkeleyEnvironment
 {
 private:
@@ -37,7 +45,9 @@ private:
 public:
     std::unique_ptr<DbEnv> dbenv;
     std::map<std::string, int> mapFileUseCount;
-    std::map<std::string, Db*> mapDb;
+    std::map<std::string, std::reference_wrapper<BerkeleyDatabase>> m_databases;
+    std::unordered_map<std::string, WalletDatabaseFileId> m_fileids;
+    std::condition_variable_any m_db_in_use;
 
     BerkeleyEnvironment(const fs::path& env_directory);
     ~BerkeleyEnvironment();
@@ -46,6 +56,7 @@ public:
     void MakeMock();
     bool IsMock() const { return fMockDb; }
     bool IsInitialized() const { return fDbEnvInit; }
+    bool IsDatabaseLoaded(const std::string& db_filename) const { return m_databases.find(db_filename) != m_databases.end(); }
     fs::path Directory() const { return strPath; }
 
     /**
@@ -75,6 +86,7 @@ public:
     void CheckpointLSN(const std::string& strFile);
 
     void CloseDb(const std::string& strFile);
+    void ReloadDbEnv();
 
     DbTxn* TxnBegin(int flags = DB_TXN_WRITE_NOSYNC)
     {
@@ -86,6 +98,9 @@ public:
     }
 };
 
+/** Return whether a wallet database is currently loaded. */
+bool IsWalletLoaded(const fs::path& wallet_path);
+
 /** Get BerkeleyEnvironment and database filename given a wallet path. */
 BerkeleyEnvironment* GetWalletEnv(const fs::path& wallet_path, std::string& database_filename);
 
@@ -106,6 +121,8 @@ public:
         nUpdateCounter(0), nLastSeen(0), nLastFlushed(0), nLastWalletUpdate(0)
     {
         env = GetWalletEnv(wallet_path, strFile);
+        auto inserted = env->m_databases.emplace(strFile, std::ref(*this));
+        assert(inserted.second);
         if (mock) {
             env->Close();
             env->Reset();
@@ -113,6 +130,13 @@ public:
         }
     }
 
+    ~BerkeleyDatabase() {
+        if (env) {
+            size_t erased = env->m_databases.erase(strFile);
+            assert(erased == 1);
+        }
+    }
+
     /** Return object for accessing database at specified path. */
     static std::unique_ptr<BerkeleyDatabase> Create(const fs::path& path)
     {
@@ -145,11 +169,16 @@ public:
 
     void IncrementUpdateCounter();
 
+    void ReloadDbEnv();
+
     std::atomic<unsigned int> nUpdateCounter;
     unsigned int nLastSeen;
     unsigned int nLastFlushed;
     int64_t nLastWalletUpdate;
 
+    /** Database pointer. This is initialized lazily and reset during flushes, so it can be null. */
+    std::unique_ptr<Db> m_db;
+
 private:
     /** BerkeleyDB specific */
     BerkeleyEnvironment *env;