open_database avoids creating a wallet dir if...

...not necessary

This is useful for the wasm integration, where we want to call the
`open_database` function directly, without wanting it to create any
directories.
Note that when using bdk-cli normally, it won't create a db directory
if it's useless, but it will still create a base directory (even if
empty). This is suboptimal, but fixing it would require a quite big
refactor to the code.

src/utils.rs

@@ -163,6 +163,11 @@ pub(crate) fn prepare_home_dir(home_path: Option<PathBuf>) -> Result<PathBuf, Er
 }
 
 /// prepare bdk_cli wallet directory
+#[cfg(any(
+ feature = "key-value-db",
+ feature = "sqlite-db",
+ feature = "compact_filters"
+))]
 fn prepare_wallet_dir(wallet_name: &str, home_path: &Path) -> Result<PathBuf, Error> {
  let mut dir = home_path.to_owned();
 
@@ -177,6 +182,7 @@ fn prepare_wallet_dir(wallet_name: &str, home_path: &Path) -> Result<PathBuf, Er
 }
 
 /// Prepare wallet database directory
+#[cfg(any(feature = "key-value-db", feature = "sqlite-db",))]
 fn prepare_wallet_db_dir(wallet_name: &str, home_path: &Path) -> Result<PathBuf, Error> {
  let mut db_dir = prepare_wallet_dir(wallet_name, home_path)?;
 
@@ -252,7 +258,9 @@ pub(crate) fn open_database(
  wallet_opts: &WalletOpts,
  home_path: &Path,
 ) -> Result<AnyDatabase, Error> {
+ #![allow(unused_variables)]
  let wallet_name = wallet_opts.wallet.as_ref().expect("wallet name");
+ #[cfg(any(feature = "key-value-db", feature = "sqlite-db",))]
  let database_path = prepare_wallet_db_dir(wallet_name, home_path)?;
 
  #[cfg(feature = "key-value-db")]