Create new wallet databases as directories rather than files

This change should make it easier for users to make complete backups of wallets
because they can now just back up the specified `-wallet=<path>` path directly,
instead of having to back up the specified path as well as the transaction log
directory (for incompletely flushed wallets).

Another advantage of this change is that if two wallets are located in the same
directory, they will now use their own BerkeleyDB environments instead using a
shared environment. Using a shared environment makes it difficult to manage and
back up wallets separately because transaction log files will contain a mix of
data from all wallets in the environment.

1 files changed, 17 insertions, 5 deletions

diff --git a/src/wallet/init.cpp b/src/wallet/init.cpp
index 11fd067b4b..e028cf4210 100644
--- a/src/wallet/init.cpp
+++ b/src/wallet/init.cpp
@@ -35,7 +35,7 @@ std::string GetWalletHelpString(bool showDebug)
     strUsage += HelpMessageOpt("-spendzeroconfchange", strprintf(_("Spend unconfirmed change when sending transactions (default: %u)"), DEFAULT_SPEND_ZEROCONF_CHANGE));
     strUsage += HelpMessageOpt("-txconfirmtarget=<n>", strprintf(_("If paytxfee is not set, include enough fee so transactions begin confirmation on average within n blocks (default: %u)"), DEFAULT_TX_CONFIRM_TARGET));
     strUsage += HelpMessageOpt("-upgradewallet", _("Upgrade wallet to latest format on startup"));
-    strUsage += HelpMessageOpt("-wallet=<path>", _("Specify wallet database path. Can be specified multiple times to load multiple wallets. Path is interpreted relative to <walletdir> if it is not absolute, and will be created if it does not exist.") + " " + strprintf(_("(default: %s)"), DEFAULT_WALLET_DAT));
+    strUsage += HelpMessageOpt("-wallet=<path>", _("Specify wallet database path. Can be specified multiple times to load multiple wallets. Path is interpreted relative to <walletdir> if it is not absolute, and will be created if it does not exist (as a directory containing a wallet.dat file and log files). For backwards compatibility this will also accept names of existing data files in <walletdir>.)"));
     strUsage += HelpMessageOpt("-walletbroadcast", _("Make the wallet broadcast transactions") + " " + strprintf(_("(default: %u)"), DEFAULT_WALLETBROADCAST));
     strUsage += HelpMessageOpt("-walletdir=<dir>", _("Specify directory to hold wallets (default: <datadir>/wallets if it exists, otherwise <datadir>)"));
     strUsage += HelpMessageOpt("-walletnotify=<cmd>", _("Execute command when a wallet transaction changes (%s in cmd is replaced by TxID)"));
@@ -66,7 +66,7 @@ bool WalletParameterInteraction()
         return true;
     }
 
-    gArgs.SoftSetArg("-wallet", DEFAULT_WALLET_DAT);
+    gArgs.SoftSetArg("-wallet", "");
     const bool is_multiwallet = gArgs.GetArgs("-wallet").size() > 1;
 
     if (gArgs.GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY) && gArgs.SoftSetBoolArg("-walletbroadcast", false)) {
@@ -230,10 +230,22 @@ bool VerifyWallets()
     std::set<fs::path> wallet_paths;
 
     for (const std::string& walletFile : gArgs.GetArgs("-wallet")) {
+        // Do some checking on wallet path. It should be either a:
+        //
+        // 1. Path where a directory can be created.
+        // 2. Path to an existing directory.
+        // 3. Path to a symlink to a directory.
+        // 4. For backwards compatibility, the name of a data file in -walletdir.
         fs::path wallet_path = fs::absolute(walletFile, GetWalletDir());
-
-        if (fs::exists(wallet_path) && (!fs::is_regular_file(wallet_path) || fs::is_symlink(wallet_path))) {
-            return InitError(strprintf(_("Error loading wallet %s. -wallet filename must be a regular file."), walletFile));
+        fs::file_type path_type = fs::symlink_status(wallet_path).type();
+        if (!(path_type == fs::file_not_found || path_type == fs::directory_file ||
+              (path_type == fs::symlink_file && fs::is_directory(wallet_path)) ||
+              (path_type == fs::regular_file && fs::path(walletFile).filename() == walletFile))) {
+            return InitError(strprintf(
+                _("Invalid -wallet path '%s'. -wallet path should point to a directory where wallet.dat and "
+                  "database/log.?????????? files can be stored, a location where such a directory could be created, "
+                  "or (for backwards compatibility) the name of an existing data file in -walletdir (%s)"),
+                walletFile, GetWalletDir()));
         }
 
         if (!wallet_paths.insert(wallet_path).second) {