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, 13 insertions, 2 deletions

diff --git a/src/wallet/db.cpp b/src/wallet/db.cpp
index 0ef3b7e926..ebe7b48da0 100644
--- a/src/wallet/db.cpp
+++ b/src/wallet/db.cpp
@@ -59,8 +59,19 @@ std::map<std::string, CDBEnv> g_dbenvs; //!< Map from directory name to open db
 
 CDBEnv* GetWalletEnv(const fs::path& wallet_path, std::string& database_filename)
 {
-    fs::path env_directory = wallet_path.parent_path();
-    database_filename = wallet_path.filename().string();
+    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
+        // directory that also contains BDB log files.
+        env_directory = wallet_path.parent_path();
+        database_filename = wallet_path.filename().string();
+    } else {
+        // Normal case: Interpret wallet path as a directory path containing
+        // data and log files.
+        env_directory = wallet_path;
+        database_filename = "wallet.dat";
+    }
     LOCK(cs_db);
     // Note: An ununsed temporary CDBEnv object may be created inside the
     // emplace function if the key already exists. This is a little inefficient,