1 files changed, 53 insertions, 29 deletions

diff --git a/src/wallet/db.cpp b/src/wallet/db.cpp
index a7bf89c572..98e2abbd18 100644
--- a/src/wallet/db.cpp
+++ b/src/wallet/db.cpp
@@ -8,7 +8,7 @@
 #include <addrman.h>
 #include <hash.h>
 #include <protocol.h>
-#include <utilstrencodings.h>
+#include <util/strencodings.h>
 #include <wallet/walletutil.h>
 
 #include <stdint.h>
@@ -20,6 +20,7 @@
 #include <boost/thread.hpp>
 
 namespace {
+
 //! Make sure database has a unique fileid within the environment. If it
 //! doesn't, throw an error. BDB caches do not work properly when more than one
 //! open database has the same fileid (values written to one database may show
@@ -29,25 +30,19 @@ namespace {
 //! (https://docs.oracle.com/cd/E17275_01/html/programmer_reference/program_copy.html),
 //! so bitcoin should never create different databases with the same fileid, but
 //! this error can be triggered if users manually copy database files.
-void CheckUniqueFileid(const BerkeleyEnvironment& env, const std::string& filename, Db& db)
+void CheckUniqueFileid(const BerkeleyEnvironment& env, const std::string& filename, Db& db, WalletDatabaseFileId& fileid)
 {
     if (env.IsMock()) return;
 
-    u_int8_t fileid[DB_FILE_ID_LEN];
-    int ret = db.get_mpf()->get_fileid(fileid);
+    int ret = db.get_mpf()->get_fileid(fileid.value);
     if (ret != 0) {
         throw std::runtime_error(strprintf("BerkeleyBatch: Can't open database %s (get_fileid failed with %d)", filename, ret));
     }
 
-    for (const auto& item : env.mapDb) {
-        u_int8_t item_fileid[DB_FILE_ID_LEN];
-        if (item.second && item.second->get_mpf()->get_fileid(item_fileid) == 0 &&
-            memcmp(fileid, item_fileid, sizeof(fileid)) == 0) {
-            const char* item_filename = nullptr;
-            item.second->get_dbname(&item_filename, nullptr);
+    for (const auto& item : env.m_fileids) {
+        if (fileid == item.second && &fileid != &item.second) {
             throw std::runtime_error(strprintf("BerkeleyBatch: Can't open database %s (duplicates fileid %s from %s)", filename,
-                HexStr(std::begin(item_fileid), std::end(item_fileid)),
-                item_filename ? item_filename : "(unknown database)"));
+                HexStr(std::begin(item.second.value), std::end(item.second.value)), item.first));
         }
     }
 }
@@ -56,9 +51,13 @@ CCriticalSection cs_db;
 std::map<std::string, BerkeleyEnvironment> g_dbenvs GUARDED_BY(cs_db); //!< Map from directory name to open db environment.
 } // namespace
 
-BerkeleyEnvironment* GetWalletEnv(const fs::path& wallet_path, std::string& database_filename)
+bool WalletDatabaseFileId::operator==(const WalletDatabaseFileId& rhs) const
+{
+    return memcmp(value, &rhs.value, sizeof(value)) == 0;
+}
+
+static void SplitWalletPath(const fs::path& wallet_path, fs::path& env_directory, std::string& database_filename)
 {
-    fs::path env_directory;
     if (fs::is_regular_file(wallet_path)) {
         // Special case for backwards compatibility: if wallet path points to an
         // existing file, treat it as the path to a BDB data file in a parent
@@ -71,6 +70,23 @@ BerkeleyEnvironment* GetWalletEnv(const fs::path& wallet_path, std::string& data
         env_directory = wallet_path;
         database_filename = "wallet.dat";
     }
+}
+
+bool IsWalletLoaded(const fs::path& wallet_path)
+{
+    fs::path env_directory;
+    std::string database_filename;
+    SplitWalletPath(wallet_path, env_directory, database_filename);
+    LOCK(cs_db);
+    auto env = g_dbenvs.find(env_directory.string());
+    if (env == g_dbenvs.end()) return false;
+    return env->second.IsDatabaseLoaded(database_filename);
+}
+
+BerkeleyEnvironment* GetWalletEnv(const fs::path& wallet_path, std::string& database_filename)
+{
+    fs::path env_directory;
+    SplitWalletPath(wallet_path, env_directory, database_filename);
     LOCK(cs_db);
     // Note: An unused temporary BerkeleyEnvironment object may be created inside the
     // emplace function if the key already exists. This is a little inefficient,
@@ -90,13 +106,13 @@ void BerkeleyEnvironment::Close()
 
     fDbEnvInit = false;
 
-    for (auto& db : mapDb) {
+    for (auto& db : m_databases) {
         auto count = mapFileUseCount.find(db.first);
         assert(count == mapFileUseCount.end() || count->second == 0);
-        if (db.second) {
-            db.second->close(0);
-            delete db.second;
-            db.second = nullptr;
+        BerkeleyDatabase& database = db.second.get();
+        if (database.m_db) {
+            database.m_db->close(0);
+            database.m_db.reset();
         }
     }
 
@@ -463,7 +479,7 @@ BerkeleyBatch::BerkeleyBatch(BerkeleyDatabase& database, const char* pszMode, bo
         if (!env->Open(false /* retry */))
             throw std::runtime_error("BerkeleyBatch: Failed to open database environment.");
 
-        pdb = env->mapDb[strFilename];
+        pdb = database.m_db.get();
         if (pdb == nullptr) {
             int ret;
             std::unique_ptr<Db> pdb_temp = MakeUnique<Db>(env->dbenv.get(), 0);
@@ -504,11 +520,11 @@ BerkeleyBatch::BerkeleyBatch(BerkeleyDatabase& database, const char* pszMode, bo
             // versions of BDB have an set_lk_exclusive method for this
             // purpose, but the older version we use does not.)
             for (const auto& env : g_dbenvs) {
-                CheckUniqueFileid(env.second, strFilename, *pdb_temp);
+                CheckUniqueFileid(env.second, strFilename, *pdb_temp, this->env->m_fileids[strFilename]);
             }
 
             pdb = pdb_temp.release();
-            env->mapDb[strFilename] = pdb;
+            database.m_db.reset(pdb);
 
             if (fCreate && !Exists(std::string("version"))) {
                 bool fTmp = fReadOnly;
@@ -563,12 +579,13 @@ void BerkeleyEnvironment::CloseDb(const std::string& strFile)
 {
     {
         LOCK(cs_db);
-        if (mapDb[strFile] != nullptr) {
+        auto it = m_databases.find(strFile);
+        assert(it != m_databases.end());
+        BerkeleyDatabase& database = it->second.get();
+        if (database.m_db) {
             // Close the database handle
-            Db* pdb = mapDb[strFile];
-            pdb->close(0);
-            delete pdb;
-            mapDb[strFile] = nullptr;
+            database.m_db->close(0);
+            database.m_db.reset();
         }
     }
 }
@@ -586,7 +603,7 @@ void BerkeleyEnvironment::ReloadDbEnv()
     });
 
     std::vector<std::string> filenames;
-    for (auto it : mapDb) {
+    for (auto it : m_databases) {
         filenames.push_back(it.first);
     }
     // Close the individual Db's
@@ -692,7 +709,7 @@ void BerkeleyEnvironment::Flush(bool fShutdown)
 {
     int64_t nStart = GetTimeMillis();
     // Flush log data to the actual data file on all files that are not in use
-    LogPrint(BCLog::DB, "BerkeleyEnvironment::Flush: Flush(%s)%s\n", fShutdown ? "true" : "false", fDbEnvInit ? "" : " database not started");
+    LogPrint(BCLog::DB, "BerkeleyEnvironment::Flush: [%s] Flush(%s)%s\n", strPath, fShutdown ? "true" : "false", fDbEnvInit ? "" : " database not started");
     if (!fDbEnvInit)
         return;
     {
@@ -826,6 +843,13 @@ void BerkeleyDatabase::Flush(bool shutdown)
             LOCK(cs_db);
             g_dbenvs.erase(env->Directory().string());
             env = nullptr;
+        } else {
+            // TODO: To avoid g_dbenvs.erase erasing the environment prematurely after the
+            // first database shutdown when multiple databases are open in the same
+            // environment, should replace raw database `env` pointers with shared or weak
+            // pointers, or else separate the database and environment shutdowns so
+            // environments can be shut down after databases.
+            env->m_fileids.erase(strFile);
         }
     }
 }