[wallet] Add CWallet::Verify function

This allows a single wallet to be verified. Prior to this commit, all
wallets were verified together by the WalletInit::Verify() function at
start-up.

Individual wallet verification will be done when loading wallets
dynamically at runtime.

src/wallet/wallet.cpp

@@ -27,6 +27,7 @@
 #include <txmempool.h>
 #include <utilmoneystr.h>
 #include <wallet/fees.h>
+#include <wallet/walletutil.h>
 
 #include <algorithm>
 #include <assert.h>
@@ -3989,6 +3990,61 @@ void CWallet::MarkPreSplitKeys()
     }
 }
 
+bool CWallet::Verify(std::string wallet_file, bool salvage_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.
+    LOCK(cs_wallets);
+    fs::path wallet_path = fs::absolute(wallet_file, GetWalletDir());
+    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(wallet_file).filename() == wallet_file))) {
+        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)"),
+            wallet_file, GetWalletDir()));
+    }
+
+    // Make sure that the wallet path doesn't clash with an existing wallet path
+    for (auto wallet : GetWallets()) {
+        if (fs::absolute(wallet->GetName(), GetWalletDir()) == wallet_path) {
+            return InitError(strprintf(_("Error loading wallet %s. Duplicate -wallet filename specified."), wallet_file));
+        }
+    }
+
+    std::string strError;
+    if (!WalletBatch::VerifyEnvironment(wallet_path, strError)) {
+        return InitError(strError);
+    }
+
+    if (salvage_wallet) {
+        // Recover readable keypairs:
+        CWallet dummyWallet("dummy", WalletDatabase::CreateDummy());
+        std::string backup_filename;
+        if (!WalletBatch::Recover(wallet_path, (void *)&dummyWallet, WalletBatch::RecoverKeysOnlyFilter, backup_filename)) {
+            return false;
+        }
+    }
+
+    std::string strWarning;
+    bool dbV = WalletBatch::VerifyDatabaseFile(wallet_path, strWarning, strError);
+    if (!strWarning.empty()) {
+        InitWarning(strWarning);
+    }
+    if (!dbV) {
+        InitError(strError);
+        return false;
+    }
+
+    return true;
+}
+
 CWallet* CWallet::CreateWalletFromFile(const std::string& name, const fs::path& path)
 {
     const std::string& walletFile = name;