refactor: Delay translation of _() literals

This is required for a future commit that requires _() to be consteval
for format literals.

Co-Authored-By: Ryan Ofsky <ryan@ofsky.org>

src/banman.cpp

@@ -30,7 +30,7 @@ void BanMan::LoadBanlist()
 {
     LOCK(m_banned_mutex);
 
-    if (m_client_interface) m_client_interface->InitMessage(_("Loading banlist…").translated);
+    if (m_client_interface) m_client_interface->InitMessage(_("Loading banlist…"));
 
     const auto start{SteadyClock::now()};
     if (m_ban_db.Read(m_banned)) {

src/clientversion.cpp

@@ -95,7 +95,7 @@ std::string LicenseInfo()
            strprintf(_("The source code is available from %s."), URL_SOURCE_CODE).translated +
            "\n" +
            "\n" +
-           _("This is experimental software.").translated + "\n" +
+           _("This is experimental software.") + "\n" +
            strprintf(_("Distributed under the MIT software license, see the accompanying file %s or %s"), "COPYING", "<https://opensource.org/licenses/MIT>").translated +
            "\n";
 }

src/init.cpp

@@ -1244,8 +1244,8 @@ static ChainstateLoadResult InitAndLoadChainstate(
             _("Error reading from database, shutting down."),
             "", CClientUIInterface::MSG_ERROR);
     };
-    uiInterface.InitMessage(_("Loading block index…").translated);
-    auto catch_exceptions = [](auto&& f) {
+    uiInterface.InitMessage(_("Loading block index…"));
+    auto catch_exceptions = [](auto&& f) -> ChainstateLoadResult {
         try {
             return f();
         } catch (const std::exception& e) {
@@ -1255,7 +1255,7 @@ static ChainstateLoadResult InitAndLoadChainstate(
     };
     auto [status, error] = catch_exceptions([&] { return LoadChainstate(chainman, cache_sizes, options); });
     if (status == node::ChainstateLoadStatus::SUCCESS) {
-        uiInterface.InitMessage(_("Verifying blocks…").translated);
+        uiInterface.InitMessage(_("Verifying blocks…"));
         if (chainman.m_blockman.m_have_pruned && options.check_blocks > MIN_BLOCKS_TO_KEEP) {
             LogWarning("pruned datadir may not have more than %d blocks; only checking available blocks\n",
                        MIN_BLOCKS_TO_KEEP);
@@ -1418,7 +1418,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
 
         // Initialize addrman
         assert(!node.addrman);
-        uiInterface.InitMessage(_("Loading P2P addresses…").translated);
+        uiInterface.InitMessage(_("Loading P2P addresses…"));
         auto addrman{LoadAddrman(*node.netgroupman, args)};
         if (!addrman) return InitError(util::ErrorString(addrman));
         node.addrman = std::move(*addrman);
@@ -1703,7 +1703,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
         if (chainman.m_blockman.m_blockfiles_indexed) {
             LOCK(cs_main);
             for (Chainstate* chainstate : chainman.GetAll()) {
-                uiInterface.InitMessage(_("Pruning blockstore…").translated);
+                uiInterface.InitMessage(_("Pruning blockstore…"));
                 chainstate->PruneAndFlush();
             }
         }
@@ -1999,7 +1999,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     // ChainstateManager's active tip.
     SetRPCWarmupFinished();
 
-    uiInterface.InitMessage(_("Done loading").translated);
+    uiInterface.InitMessage(_("Done loading"));
 
     for (const auto& client : node.chain_clients) {
         client->start(scheduler);

src/net.cpp

@@ -3296,7 +3296,7 @@ bool CConnman::Start(CScheduler& scheduler, const Options& connOptions)
     }
 
     if (m_client_interface) {
-        m_client_interface->InitMessage(_("Starting network threads…").translated);
+        m_client_interface->InitMessage(_("Starting network threads…"));
     }
 
     fAddressesInitialized = true;

src/util/translation.h

@@ -6,12 +6,15 @@
 #define BITCOIN_UTIL_TRANSLATION_H
 
 #include <tinyformat.h>
+#include <util/string.h>
 
+#include <cassert>
 #include <functional>
 #include <string>
 
 /** Translate a message to the native language of the user. */
-const extern std::function<std::string(const char*)> G_TRANSLATION_FUN;
+using TranslateFn = std::function<std::string(const char*)>;
+const extern TranslateFn G_TRANSLATION_FUN;
 
 /**
  * Bilingual messages:
@@ -47,6 +50,27 @@ inline bilingual_str operator+(bilingual_str lhs, const bilingual_str& rhs)
     return lhs;
 }
 
+namespace util {
+//! Compile-time literal string that can be translated with an optional translation function.
+struct TranslatedLiteral {
+    const char* const original;
+    const TranslateFn* translate_fn;
+
+    consteval TranslatedLiteral(const char* str, const TranslateFn* fn = &G_TRANSLATION_FUN) : original{str}, translate_fn{fn} { assert(original); }
+    operator std::string() const { return translate_fn && *translate_fn ? (*translate_fn)(original) : original; }
+    operator bilingual_str() const { return {original, std::string{*this}}; }
+};
+
+// TranslatedLiteral operators for formatting and adding to strings.
+inline std::ostream& operator<<(std::ostream& os, const TranslatedLiteral& lit) { return os << std::string{lit}; }
+template<typename T>
+T operator+(const T& lhs, const TranslatedLiteral& rhs) { return lhs + static_cast<T>(rhs); }
+template<typename T>
+T operator+(const TranslatedLiteral& lhs, const T& rhs) { return static_cast<T>(lhs) + rhs; }
+} // namespace util
+
+consteval auto _(util::TranslatedLiteral str) { return str; }
+
 /** Mark a bilingual_str as untranslated */
 inline bilingual_str Untranslated(std::string original) { return {original, original}; }
 
@@ -67,19 +91,4 @@ bilingual_str format(const bilingual_str& fmt, const Args&... args)
 }
 } // namespace tinyformat
 
-struct ConstevalStringLiteral {
-    const char* const lit;
-    consteval ConstevalStringLiteral(const char* str) : lit{str} {}
-    consteval ConstevalStringLiteral(std::nullptr_t) = delete;
-};
-
-/**
- * Translation function.
- * If no translation function is set, simply return the input.
- */
-inline bilingual_str _(ConstevalStringLiteral str)
-{
-    return bilingual_str{str.lit, G_TRANSLATION_FUN ? (G_TRANSLATION_FUN)(str.lit) : str.lit};
-}
-
 #endif // BITCOIN_UTIL_TRANSLATION_H

src/wallet/load.cpp

@@ -52,7 +52,7 @@ bool VerifyWallets(WalletContext& context)
 
     LogPrintf("Using wallet directory %s\n", fs::PathToString(GetWalletDir()));
 
-    chain.initMessage(_("Verifying wallet(s)…").translated);
+    chain.initMessage(_("Verifying wallet(s)…"));
 
     // For backwards compatibility if an unnamed top level wallet exists in the
     // wallets directory, include it in the default list of wallets to load.
@@ -135,7 +135,7 @@ bool LoadWallets(WalletContext& context)
             if (!database && status == DatabaseStatus::FAILED_NOT_FOUND) {
                 continue;
             }
-            chain.initMessage(_("Loading wallet…").translated);
+            chain.initMessage(_("Loading wallet…"));
             std::shared_ptr<CWallet> pwallet = database ? CWallet::Create(context, name, std::move(database), options.create_flags, error, warnings) : nullptr;
             if (!warnings.empty()) chain.initWarning(Join(warnings, Untranslated("\n")));
             if (!pwallet) {

src/wallet/rpc/backup.cpp

@@ -534,7 +534,7 @@ RPCHelpMan importwallet()
 
         // Use uiInterface.ShowProgress instead of pwallet.ShowProgress because pwallet.ShowProgress has a cancel button tied to AbortRescan which
         // we don't want for this progress bar showing the import progress. uiInterface.ShowProgress does not have a cancel button.
-        pwallet->chain().showProgress(strprintf("%s %s", pwallet->GetDisplayName(), _("Importing…").translated), 0, false); // show progress dialog in GUI
+        pwallet->chain().showProgress(strprintf("%s %s", pwallet->GetDisplayName(), _("Importing…")), 0, false); // show progress dialog in GUI
         std::vector<std::tuple<CKey, int64_t, bool, std::string>> keys;
         std::vector<std::pair<CScript, int64_t>> scripts;
         while (file.good()) {

src/wallet/wallet.cpp

@@ -280,7 +280,7 @@ std::shared_ptr<CWallet> LoadWalletInternal(WalletContext& context, const std::s
             return nullptr;
         }
 
-        context.chain->initMessage(_("Loading wallet…").translated);
+        context.chain->initMessage(_("Loading wallet…"));
         std::shared_ptr<CWallet> wallet = CWallet::Create(context, name, std::move(database), options.create_flags, error, warnings);
         if (!wallet) {
             error = Untranslated("Wallet loading failed.") + Untranslated(" ") + error;
@@ -430,7 +430,7 @@ std::shared_ptr<CWallet> CreateWallet(WalletContext& context, const std::string&
     }
 
     // Make the wallet
-    context.chain->initMessage(_("Loading wallet…").translated);
+    context.chain->initMessage(_("Loading wallet…"));
     std::shared_ptr<CWallet> wallet = CWallet::Create(context, name, std::move(database), wallet_creation_flags, error, warnings);
     if (!wallet) {
         error = Untranslated("Wallet creation failed.") + Untranslated(" ") + error;
@@ -1903,7 +1903,7 @@ CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_bloc
                     fast_rescan_filter ? "fast variant using block filters" : "slow variant inspecting all blocks");
 
     fAbortRescan = false;
-    ShowProgress(strprintf("%s %s", GetDisplayName(), _("Rescanning…").translated), 0); // show rescan progress in GUI as dialog or on splashscreen, if rescan required on startup (e.g. due to corruption)
+    ShowProgress(strprintf("%s %s", GetDisplayName(), _("Rescanning…")), 0); // show rescan progress in GUI as dialog or on splashscreen, if rescan required on startup (e.g. due to corruption)
     uint256 tip_hash = WITH_LOCK(cs_wallet, return GetLastBlockHash());
     uint256 end_hash = tip_hash;
     if (max_height) chain().findAncestorByHeight(tip_hash, *max_height, FoundBlock().hash(end_hash));
@@ -1918,7 +1918,7 @@ CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_bloc
             m_scanning_progress = 0;
         }
         if (block_height % 100 == 0 && progress_end - progress_begin > 0.0) {
-            ShowProgress(strprintf("%s %s", GetDisplayName(), _("Rescanning…").translated), std::max(1, std::min(99, (int)(m_scanning_progress * 100))));
+            ShowProgress(strprintf("%s %s", GetDisplayName(), _("Rescanning…")), std::max(1, std::min(99, (int)(m_scanning_progress * 100))));
         }
 
         bool next_interval = reserver.now() >= current_time + INTERVAL_TIME;
@@ -2015,7 +2015,7 @@ CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_bloc
         WalletLogPrintf("Scanning current mempool transactions.\n");
         WITH_LOCK(cs_wallet, chain().requestMempoolTransactions(*this));
     }
-    ShowProgress(strprintf("%s %s", GetDisplayName(), _("Rescanning…").translated), 100); // hide progress dialog in GUI
+    ShowProgress(strprintf("%s %s", GetDisplayName(), _("Rescanning…")), 100); // hide progress dialog in GUI
     if (block_height && fAbortRescan) {
         WalletLogPrintf("Rescan aborted at block %d. Progress=%f\n", block_height, progress_current);
         result.status = ScanResult::USER_ABORT;
@@ -3353,7 +3353,7 @@ bool CWallet::AttachChain(const std::shared_ptr<CWallet>& walletInstance, interf
             }
         }
 
-        chain.initMessage(_("Rescanning…").translated);
+        chain.initMessage(_("Rescanning…"));
         walletInstance->WalletLogPrintf("Rescanning last %i blocks (from block %i)...\n", *tip_height - rescan_height, rescan_height);
 
         {