Drop bitcoin-wallet dependency on libevent

Don't require urlDecode function in wallet code since urlDecode implementation
currently uses libevent. Just call urlDecode indirectly though URL_DECODE
function pointer constant if available.

In bitcoind and bitcoin-qt, URL_DECODE is implemented and used to interpret RPC
wallet requests. In bitcoin-wallet, URL_DECODE is null to avoid depending on
libevent.

src/bitcoin-cli.cpp

@@ -15,6 +15,7 @@
 #include <util/strencodings.h>
 #include <util/system.h>
 #include <util/translation.h>
+#include <util/url.h>
 
 #include <functional>
 #include <memory>
@@ -29,6 +30,7 @@
 #include <compat/stdin.h>
 
 const std::function<std::string(const char*)> G_TRANSLATION_FUN = nullptr;
+UrlDecodeFn* const URL_DECODE = urlDecode;
 
 static const char DEFAULT_RPCCONNECT[] = "127.0.0.1";
 static const int DEFAULT_HTTP_CLIENT_TIMEOUT=900;

src/bitcoin-wallet.cpp

@@ -11,11 +11,13 @@
 #include <logging.h>
 #include <util/system.h>
 #include <util/translation.h>
+#include <util/url.h>
 #include <wallet/wallettool.h>
 
 #include <functional>
 
 const std::function<std::string(const char*)> G_TRANSLATION_FUN = nullptr;
+UrlDecodeFn* const URL_DECODE = nullptr;
 
 static void SetupWalletToolArgs()
 {

src/bitcoind.cpp

@@ -20,10 +20,12 @@
 #include <util/system.h>
 #include <util/threadnames.h>
 #include <util/translation.h>
+#include <util/url.h>
 
 #include <functional>
 
 const std::function<std::string(const char*)> G_TRANSLATION_FUN = nullptr;
+UrlDecodeFn* const URL_DECODE = urlDecode;
 
 static void WaitForShutdown(NodeContext& node)
 {

src/qt/main.cpp

@@ -5,6 +5,7 @@
 #include <qt/bitcoin.h>
 
 #include <util/translation.h>
+#include <util/url.h>
 
 #include <QCoreApplication>
 
@@ -15,5 +16,6 @@
 extern const std::function<std::string(const char*)> G_TRANSLATION_FUN = [](const char* psz) {
     return QCoreApplication::translate("bitcoin-core", psz).toStdString();
 };
+UrlDecodeFn* const URL_DECODE = urlDecode;
 
 int main(int argc, char* argv[]) { return GuiMain(argc, argv); }

src/test/util/setup_common.cpp

@@ -27,12 +27,14 @@
 #include <util/string.h>
 #include <util/time.h>
 #include <util/translation.h>
+#include <util/url.h>
 #include <validation.h>
 #include <validationinterface.h>
 
 #include <functional>
 
 const std::function<std::string(const char*)> G_TRANSLATION_FUN = nullptr;
+UrlDecodeFn* const URL_DECODE = nullptr;
 
 FastRandomContext g_insecure_rand_ctx;
 /** Random context to get unique temp data dirs. Separate from g_insecure_rand_ctx, which can be seeded from a const env var */

src/util/url.h

@@ -7,6 +7,8 @@
 
 #include <string>
 
-std::string urlDecode(const std::string &urlEncoded);
+using UrlDecodeFn = std::string(const std::string& url_encoded);
+UrlDecodeFn urlDecode;
+extern UrlDecodeFn* const URL_DECODE;
 
 #endif // BITCOIN_UTIL_URL_H

src/wallet/rpcwallet.cpp

@@ -77,9 +77,9 @@ bool HaveKey(const SigningProvider& wallet, const CKey& key)
 
 bool GetWalletNameFromJSONRPCRequest(const JSONRPCRequest& request, std::string& wallet_name)
 {
-    if (request.URI.substr(0, WALLET_ENDPOINT_BASE.size()) == WALLET_ENDPOINT_BASE) {
+    if (URL_DECODE && request.URI.substr(0, WALLET_ENDPOINT_BASE.size()) == WALLET_ENDPOINT_BASE) {
         // wallet endpoint was used
-        wallet_name = urlDecode(request.URI.substr(WALLET_ENDPOINT_BASE.size()));
+        wallet_name = URL_DECODE(request.URI.substr(WALLET_ENDPOINT_BASE.size()));
         return true;
     }
     return false;