4 files changed, 179 insertions, 4 deletions

diff --git a/src/db.cpp b/src/db.cpp
index 7cfb7c5..c4ea81e 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -124,6 +124,13 @@ void WalletSQLiteRuntimeClose()
 {
     if (pWalletSQLiteRuntime)
     {
+        // Fold the write-ahead log into the main file on the way out. WAL +
+        // synchronous=FULL already makes every committed write durable across a
+        // kill, so this is housekeeping, not the thing that protects the data:
+        // if it fails, or the node is killed before it runs, the wallet is
+        // still whole. Best effort, never throws.
+        string strCheckpointError;
+        pWalletSQLiteRuntime->Checkpoint(strCheckpointError);
         delete pWalletSQLiteRuntime;
         pWalletSQLiteRuntime = NULL;
     }
@@ -1426,6 +1433,90 @@ bool LoadWalletFromSQLite(const string& strPath)
     return FinishLoadedWallet(visitor.vchDefaultKey, false);
 }
 
+// Open a SQLite wallet read-write and keep it open as the active runtime
+// backend, then load its records into memory the same way LoadWalletFromSQLite
+// does. Unlike the read-only staging path, this leaves pWalletSQLiteRuntime set
+// so every later CWalletDB read/write/erase routes to this file for the life of
+// the process. The Berkeley DB wallet.dat is never opened.
+bool LoadWalletFromSQLiteRuntime(const string& strPath)
+{
+    strWalletLoadError.clear();
+
+    if (!FileExists(strPath.c_str()))
+    {
+        strWalletLoadError = strprintf("SQLite wallet does not exist: %s",
+                                       strPath.c_str());
+        printf("LoadWallet: %s\n", strWalletLoadError.c_str());
+        return false;
+    }
+
+    string strError;
+    if (!WalletSQLiteRuntimeOpen(strPath, strError))
+    {
+        strWalletLoadError = strError;
+        printf("LoadWallet: cannot open SQLite wallet backend: %s\n",
+               strError.c_str());
+        return false;
+    }
+
+    CSQLiteWalletRuntimeLoadVisitor visitor;
+    try
+    {
+        CRITICAL_BLOCK(cs_mapKeys)
+        CRITICAL_BLOCK(cs_mapWallet)
+        {
+            if (!pWalletSQLiteRuntime->ScanRecords(visitor, strError))
+            {
+                WalletSQLiteRuntimeClose();
+                if (strWalletLoadError.empty())
+                    strWalletLoadError = strError;
+                printf("LoadWallet: SQLite wallet backend could not be read. "
+                       "Failed while handling a '%s' record: %s\n",
+                       visitor.strLastType.c_str(), strError.c_str());
+                return false;
+            }
+        }
+    }
+    catch (const std::exception& e)
+    {
+        WalletSQLiteRuntimeClose();
+        strWalletLoadError = strprintf(
+            "SQLite wallet backend could not be read while handling a '%s' record: %s",
+            visitor.strLastType.c_str(), e.what());
+        printf("LoadWallet: %s\n", strWalletLoadError.c_str());
+        return false;
+    }
+    catch (...)
+    {
+        WalletSQLiteRuntimeClose();
+        strWalletLoadError = strprintf(
+            "SQLite wallet backend could not be read while handling a '%s' record",
+            visitor.strLastType.c_str());
+        printf("LoadWallet: %s\n", strWalletLoadError.c_str());
+        return false;
+    }
+
+    if (!ReconcileLoadedWalletMetadata(visitor.fHaveStoredMineMode,
+                                       visitor.fHaveStoredHDCoinType))
+    {
+        WalletSQLiteRuntimeClose();
+        if (strWalletLoadError.empty())
+            strWalletLoadError = "SQLite wallet metadata is not supported by this build";
+        return false;
+    }
+
+    // Never fabricate a default key: an export always carries one, and a file
+    // that does not is refused with the wallet left open to no writes rather
+    // than quietly minted into a new identity.
+    if (!FinishLoadedWallet(visitor.vchDefaultKey, false))
+    {
+        WalletSQLiteRuntimeClose();
+        return false;
+    }
+
+    return true;
+}
+
 
 // Write a copy of wallet.dat that can be opened anywhere.
 //
diff --git a/src/db.h b/src/db.h
index 8fa4ea8..fee5a82 100644
--- a/src/db.h
+++ b/src/db.h
@@ -624,6 +624,7 @@ bool ScanWalletRecords(CWalletRecordVisitor& visitor, string& strErrorRet);
 
 bool LoadWallet();
 bool LoadWalletFromSQLite(const string& strPath);
+bool LoadWalletFromSQLiteRuntime(const string& strPath);
 
 // Writes a wallet.dat that opens on its own, anywhere -- see the definition in
 // db.cpp for why a plain file copy does not. Still a point-in-time snapshot:
diff --git a/src/main_gui.cpp b/src/main_gui.cpp
index ee875c7..4d77533 100644
--- a/src/main_gui.cpp
+++ b/src/main_gui.cpp
@@ -190,6 +190,8 @@ static void PrintUsage()
     printf("  /walletsqliteloadcheck=FILE\n");
     printf("                              (parse a SQLite export like the wallet loader)\n");
     printf("  /walletsqlite=FILE         (stage-load a SQLite wallet export, then exit)\n");
+    printf("  /walletbackend=sqlite      (opt-in: run the node on <datadir>/wallet.sqlite\n");
+    printf("                              instead of wallet.dat; export one first)\n");
     printf("  /rescan                    (walk the chain for coins this wallet owns\n");
     printf("                              but never recorded, then exit)\n");
     printf("\n");
@@ -618,9 +620,59 @@ int main(int argc, char* argv[])
     printf("Loading wallet...\n");
     try
     {
+        string strWalletBackend =
+            argval2(argc, argv, "/walletbackend", "-walletbackend");
         string strWalletSQLite =
             argval2(argc, argv, "/walletsqlite", "-walletsqlite");
-        if (!strWalletSQLite.empty())
+
+        if (strWalletBackend == "sqlite")
+        {
+            // Opt-in, experimental. The node runs on <datadir>/wallet.sqlite and
+            // never opens wallet.dat, but the user has to have exported one
+            // first -- there is no silent migration, and wallet.dat is left
+            // exactly where it is so a plain restart goes back to it.
+            AttachTerminal();
+            string strSQLitePath = GetAppDir() + "/wallet.sqlite";
+            if (!FileExists(strSQLitePath.c_str()))
+            {
+                string strGuide = strprintf(
+                    "No SQLite wallet was found at\n"
+                    "  %s\n\n"
+                    "The SQLite wallet backend is opt-in and needs an exported\n"
+                    "wallet first. Your Berkeley DB wallet.dat is not touched by\n"
+                    "any of this.\n\n"
+                    "  Step 1  Export your existing wallet to SQLite:\n"
+                    "            bitflash -walletsqliteexport=\"%s\"\n"
+                    "  Step 2  Start again with the SQLite backend:\n"
+                    "            bitflash -walletbackend=sqlite\n\n"
+                    "To go back to Berkeley DB at any time, just start without\n"
+                    "-walletbackend=sqlite. wallet.dat is still your wallet.",
+                    strSQLitePath.c_str(), strSQLitePath.c_str());
+                FatalStartupError(fHeadlessStartup,
+                                  "The SQLite wallet backend needs an exported wallet first.",
+                                  strGuide);
+                return 1;
+            }
+
+            if (!LoadWalletFromSQLiteRuntime(strSQLitePath))
+            {
+                FatalStartupError(fHeadlessStartup,
+                                  "Cannot open the SQLite wallet backend.",
+                                  strWalletLoadError);
+                return 1;
+            }
+
+            fprintf(stderr,
+                    "Wallet backend: SQLite (experimental)\n"
+                    "  %s\n"
+                    "Your Berkeley DB wallet.dat is left untouched. Restart without\n"
+                    "-walletbackend=sqlite to go back to it.\n",
+                    strSQLitePath.c_str());
+            fflush(stderr);
+            // Fall through and run the node normally: every CWalletDB read,
+            // write, and erase now routes to this SQLite file.
+        }
+        else if (!strWalletSQLite.empty())
         {
             AttachTerminal();
             if (!LoadWalletFromSQLite(strWalletSQLite))
@@ -638,8 +690,7 @@ int main(int argc, char* argv[])
             DBFlush(true);
             return 0;
         }
-
-        if (!LoadWallet())
+        else if (!LoadWallet())
         {
             // LoadWallet() explains itself into strWalletLoadError when it
             // knows why -- an unsupported wallet format, for one, which is the
@@ -650,7 +701,9 @@ int main(int argc, char* argv[])
         }
 
         // After the block index, so there is a chain to compare the wallet
-        // against, and before anything reports a balance.
+        // against, and before anything reports a balance. Works on either
+        // backend: RescanSpentFlags writes corrected flags through CWalletDB,
+        // which routes to SQLite when that backend is active.
         RescanSpentFlags();
     }
     catch (const std::exception& e)
@@ -894,6 +947,10 @@ int main(int argc, char* argv[])
         // called here, which is why a wallet.dat copied elsewhere would not
         // open -- issue #40. Not optional.
         DBFlush(true);
+        // Checkpoint and close the SQLite wallet backend if one is active. A
+        // no-op on the Berkeley DB path. Safe to kill before this runs: WAL +
+        // synchronous=FULL already made every committed write durable.
+        WalletSQLiteRuntimeClose();
 #ifdef _WIN32
         // wallet.dat is safely flushed and closed now; let a pending console
         // control handler (CLOSE/LOGOFF/SHUTDOWN) return so the OS can finish.
@@ -910,6 +967,7 @@ int main(int argc, char* argv[])
     StopNode();
     BtfStopManagedTor();
     DBFlush(true);
+    WalletSQLiteRuntimeClose();
     return ret;
 #endif
 }
diff --git a/src/selftest.cpp b/src/selftest.cpp
index 9fa0938..098eed6 100644
--- a/src/selftest.cpp
+++ b/src/selftest.cpp
@@ -1230,6 +1230,31 @@ static int RunWalletSQLiteSelfTest()
 
                 nFail += Check(!FileExists((strRuntimeDir + "/wallet.dat").c_str()),
                                "active SQLite runtime does not create wallet.dat") ? 0 : 1;
+
+                // Durability: close the backend (checkpoints the WAL), reopen
+                // the same file, and confirm what CWalletDB wrote is still
+                // there. This is the write-survives-a-restart property the real
+                // -walletbackend=sqlite node depends on.
+                WalletSQLiteRuntimeClose();
+                bool fReopened =
+                    WalletSQLiteRuntimeOpen(strRuntimePath, strError);
+                nFail += Check(fReopened,
+                               "SQLite runtime wallet reopens after close") ? 0 : 1;
+                if (fReopened)
+                {
+                    int64 nPersisted = 0;
+                    CPrivKey vchPersistedPrivKey;
+                    vector<unsigned char> vchPersistedDefaultKey;
+                    nFail += Check(CWalletDB("r").ReadSetting("runtime-sqlite-setting",
+                                                              nPersisted) &&
+                                   nPersisted == 909090 &&
+                                   CWalletDB("r").ReadDefaultKey(vchPersistedDefaultKey) &&
+                                   vchPersistedDefaultKey == vchRuntimePubKey &&
+                                   CWalletDB("r").ReadKey(vchRuntimePubKey,
+                                                          vchPersistedPrivKey) &&
+                                   vchPersistedPrivKey == vchRuntimePrivKey,
+                                   "SQLite runtime writes persist across a close and reopen") ? 0 : 1;
+                }
             }
 
             WalletSQLiteRuntimeClose();