wallet: Reduce references to global bitdb environment

src/wallet/db.cpp

@@ -364,6 +364,7 @@ CDB::CDB(CWalletDBWrapper& dbw, const char* pszMode, bool fFlushOnCloseIn) : pdb
     int ret;
     fReadOnly = (!strchr(pszMode, '+') && !strchr(pszMode, 'w'));
     fFlushOnClose = fFlushOnCloseIn;
+    env = dbw.env;
     if (dbw.IsDummy()) {
         return;
     }
@@ -375,17 +376,17 @@ CDB::CDB(CWalletDBWrapper& dbw, const char* pszMode, bool fFlushOnCloseIn) : pdb
         nFlags |= DB_CREATE;
 
     {
-        LOCK(bitdb.cs_db);
-        if (!bitdb.Open(GetDataDir()))
+        LOCK(env->cs_db);
+        if (!env->Open(GetDataDir()))
             throw std::runtime_error("CDB: Failed to open database environment.");
 
         strFile = strFilename;
-        ++bitdb.mapFileUseCount[strFile];
-        pdb = bitdb.mapDb[strFile];
+        ++env->mapFileUseCount[strFile];
+        pdb = env->mapDb[strFile];
         if (pdb == NULL) {
-            pdb = new Db(bitdb.dbenv, 0);
+            pdb = new Db(env->dbenv, 0);
 
-            bool fMockDb = bitdb.IsMock();
+            bool fMockDb = env->IsMock();
             if (fMockDb) {
                 DbMpoolFile* mpf = pdb->get_mpf();
                 ret = mpf->set_flags(DB_MPOOL_NOFILE, 1);
@@ -403,7 +404,7 @@ CDB::CDB(CWalletDBWrapper& dbw, const char* pszMode, bool fFlushOnCloseIn) : pdb
             if (ret != 0) {
                 delete pdb;
                 pdb = NULL;
-                --bitdb.mapFileUseCount[strFile];
+                --env->mapFileUseCount[strFile];
                 strFile = "";
                 throw std::runtime_error(strprintf("CDB: Error %d, can't open database %s", ret, strFilename));
             }
@@ -415,7 +416,7 @@ CDB::CDB(CWalletDBWrapper& dbw, const char* pszMode, bool fFlushOnCloseIn) : pdb
                 fReadOnly = fTmp;
             }
 
-            bitdb.mapDb[strFile] = pdb;
+            env->mapDb[strFile] = pdb;
         }
     }
 }
@@ -430,7 +431,7 @@ void CDB::Flush()
     if (fReadOnly)
         nMinutes = 1;
 
-    bitdb.dbenv->txn_checkpoint(nMinutes ? GetArg("-dblogsize", DEFAULT_WALLET_DBLOGSIZE) * 1024 : 0, nMinutes, 0);
+    env->dbenv->txn_checkpoint(nMinutes ? GetArg("-dblogsize", DEFAULT_WALLET_DBLOGSIZE) * 1024 : 0, nMinutes, 0);
 }
 
 void CDB::Close()
@@ -446,8 +447,8 @@ void CDB::Close()
         Flush();
 
     {
-        LOCK(bitdb.cs_db);
-        --bitdb.mapFileUseCount[strFile];
+        LOCK(env->cs_db);
+        --env->mapFileUseCount[strFile];
     }
 }
 
@@ -479,22 +480,23 @@ bool CDB::Rewrite(CWalletDBWrapper& dbw, const char* pszSkip)
     if (dbw.IsDummy()) {
         return true;
     }
+    CDBEnv *env = dbw.env;
     const std::string& strFile = dbw.strFile;
     while (true) {
         {
-            LOCK(bitdb.cs_db);
-            if (!bitdb.mapFileUseCount.count(strFile) || bitdb.mapFileUseCount[strFile] == 0) {
+            LOCK(env->cs_db);
+            if (!env->mapFileUseCount.count(strFile) || env->mapFileUseCount[strFile] == 0) {
                 // Flush log data to the dat file
-                bitdb.CloseDb(strFile);
-                bitdb.CheckpointLSN(strFile);
-                bitdb.mapFileUseCount.erase(strFile);
+                env->CloseDb(strFile);
+                env->CheckpointLSN(strFile);
+                env->mapFileUseCount.erase(strFile);
 
                 bool fSuccess = true;
                 LogPrintf("CDB::Rewrite: Rewriting %s...\n", strFile);
                 std::string strFileRes = strFile + ".rewrite";
                 { // surround usage of db with extra {}
                     CDB db(dbw, "r");
-                    Db* pdbCopy = new Db(bitdb.dbenv, 0);
+                    Db* pdbCopy = new Db(env->dbenv, 0);
 
                     int ret = pdbCopy->open(NULL,               // Txn pointer
                                             strFileRes.c_str(), // Filename
@@ -537,17 +539,17 @@ bool CDB::Rewrite(CWalletDBWrapper& dbw, const char* pszSkip)
                         }
                     if (fSuccess) {
                         db.Close();
-                        bitdb.CloseDb(strFile);
+                        env->CloseDb(strFile);
                         if (pdbCopy->close(0))
                             fSuccess = false;
                         delete pdbCopy;
                     }
                 }
                 if (fSuccess) {
-                    Db dbA(bitdb.dbenv, 0);
+                    Db dbA(env->dbenv, 0);
                     if (dbA.remove(strFile.c_str(), NULL, 0))
                         fSuccess = false;
-                    Db dbB(bitdb.dbenv, 0);
+                    Db dbB(env->dbenv, 0);
                     if (dbB.rename(strFileRes.c_str(), NULL, strFile.c_str(), 0))
                         fSuccess = false;
                 }
@@ -608,14 +610,15 @@ bool CDB::PeriodicFlush(CWalletDBWrapper& dbw)
         return true;
     }
     bool ret = false;
+    CDBEnv *env = dbw.env;
     const std::string& strFile = dbw.strFile;
     TRY_LOCK(bitdb.cs_db,lockDb);
     if (lockDb)
     {
         // Don't do this if any databases are in use
         int nRefCount = 0;
-        std::map<std::string, int>::iterator mit = bitdb.mapFileUseCount.begin();
-        while (mit != bitdb.mapFileUseCount.end())
+        std::map<std::string, int>::iterator mit = env->mapFileUseCount.begin();
+        while (mit != env->mapFileUseCount.end())
         {
             nRefCount += (*mit).second;
             mit++;
@@ -624,17 +627,17 @@ bool CDB::PeriodicFlush(CWalletDBWrapper& dbw)
         if (nRefCount == 0)
         {
             boost::this_thread::interruption_point();
-            std::map<std::string, int>::iterator mi = bitdb.mapFileUseCount.find(strFile);
-            if (mi != bitdb.mapFileUseCount.end())
+            std::map<std::string, int>::iterator mi = env->mapFileUseCount.find(strFile);
+            if (mi != env->mapFileUseCount.end())
             {
                 LogPrint(BCLog::DB, "Flushing %s\n", strFile);
                 int64_t nStart = GetTimeMillis();
 
                 // Flush wallet file so it's self contained
-                bitdb.CloseDb(strFile);
-                bitdb.CheckpointLSN(strFile);
+                env->CloseDb(strFile);
+                env->CheckpointLSN(strFile);
 
-                bitdb.mapFileUseCount.erase(mi++);
+                env->mapFileUseCount.erase(mi++);
                 LogPrint(BCLog::DB, "Flushed %s %dms\n", strFile, GetTimeMillis() - nStart);
                 ret = true;
             }
@@ -657,13 +660,13 @@ bool CWalletDBWrapper::Backup(const std::string& strDest)
     while (true)
     {
         {
-            LOCK(bitdb.cs_db);
-            if (!bitdb.mapFileUseCount.count(strFile) || bitdb.mapFileUseCount[strFile] == 0)
+            LOCK(env->cs_db);
+            if (!env->mapFileUseCount.count(strFile) || env->mapFileUseCount[strFile] == 0)
             {
                 // Flush log data to the dat file
-                bitdb.CloseDb(strFile);
-                bitdb.CheckpointLSN(strFile);
-                bitdb.mapFileUseCount.erase(strFile);
+                env->CloseDb(strFile);
+                env->CheckpointLSN(strFile);
+                env->mapFileUseCount.erase(strFile);
 
                 // Copy wallet file
                 fs::path pathSrc = GetDataDir() / strFile;
@@ -685,3 +688,10 @@ bool CWalletDBWrapper::Backup(const std::string& strDest)
     }
     return false;
 }
+
+void CWalletDBWrapper::Flush(bool shutdown)
+{
+    if (!IsDummy()) {
+        env->Flush(shutdown);
+    }
+}

src/wallet/db.h

@@ -116,6 +116,10 @@ public:
      */
     std::string GetName() const { return strFile; }
 
+    /** Make sure all changes are flushed to disk.
+     */
+    void Flush(bool shutdown);
+
     /** Return whether this database handle is a dummy for testing.
      * Only to be used at a low level, application should ideally not care
      * about this.
@@ -138,6 +142,7 @@ protected:
     DbTxn* activeTxn;
     bool fReadOnly;
     bool fFlushOnClose;
+    CDBEnv *env;
 
     explicit CDB(CWalletDBWrapper& dbw, const char* pszMode = "r+", bool fFlushOnCloseIn=true);
     ~CDB() { Close(); }

src/wallet/wallet.cpp

@@ -431,7 +431,7 @@ bool CWallet::HasWalletSpend(const uint256& txid) const
 
 void CWallet::Flush(bool shutdown)
 {
-    bitdb.Flush(shutdown);
+    dbw->Flush(shutdown);
 }
 
 bool CWallet::Verify()