update SelectParamsFromCommandLine() handling/order

- move SelectParamsFromCommandLine() from init.cpp to bitcoin.cpp to allow
  to use TestNet() for Bitcoin-Qt instead of GetBoolArg("-testnet", false)
- change order in bitcoind.cpp to match bitcoin.cpp functionality
- hamonize error message strings for missing datadir and failing
  SelectParamsFromCommandLine() in bitcoin.cpp and bitcoind.cpp
- use TestNet() call in splashscreen.cpp

src/bitcoind.cpp

@@ -39,10 +39,15 @@ bool AppInit(int argc, char* argv[])
         ParseParameters(argc, argv);
         if (!boost::filesystem::is_directory(GetDataDir(false)))
         {
-            fprintf(stderr, "Error: Specified directory does not exist\n");
+            fprintf(stderr, "Error: Specified data directory \"%s\" does not exist.\n", mapArgs["-datadir"].c_str());
-            Shutdown();
+            return false;
         }
         ReadConfigFile(mapArgs, mapMultiArgs);
+        // Check for -testnet or -regtest parameter (TestNet() calls are only valid after this clause)
+        if (!SelectParamsFromCommandLine()) {
+            fprintf(stderr, "Error: Invalid combination of -regtest and -testnet.\n");
+            return false;
+        }
 
         if (mapArgs.count("-?") || mapArgs.count("--help"))
         {
@@ -67,10 +72,6 @@ bool AppInit(int argc, char* argv[])
 
         if (fCommandLine)
         {
-            if (!SelectParamsFromCommandLine()) {
-                fprintf(stderr, "Error: invalid combination of -regtest and -testnet.\n");
-                return false;
-            }
             int ret = CommandLineRPC(argc, argv);
             exit(ret);
         }

src/init.cpp

@@ -373,9 +373,6 @@ bool AppInit2(boost::thread_group& threadGroup)
     // ********************************************************* Step 2: parameter interactions
 
     Checkpoints::fEnabled = GetBoolArg("-checkpoints", true);
-    if (!SelectParamsFromCommandLine()) {
-        return InitError("Invalid combination of -testnet and -regtest.");
-    }
 
     if (mapArgs.count("-bind")) {
         // when specifying an explicit binding address, you want to listen on it

src/qt/bitcoin.cpp

@@ -154,10 +154,23 @@ static void initTranslations(QTranslator &qtTranslatorBase, QTranslator &qtTrans
 #ifndef BITCOIN_QT_TEST
 int main(int argc, char *argv[])
 {
+    bool fMissingDatadir = false;
+    bool fSelParFromCLFailed = false;
+
     fHaveGUI = true;
 
     // Command-line options take precedence:
     ParseParameters(argc, argv);
+    // ... then bitcoin.conf:
+    if (!boost::filesystem::is_directory(GetDataDir(false))) {
+        fMissingDatadir = true;
+    } else {
+        ReadConfigFile(mapArgs, mapMultiArgs);
+    }
+    // Check for -testnet or -regtest parameter (TestNet() calls are only valid after this clause)
+    if (!SelectParamsFromCommandLine()) {
+        fSelParFromCLFailed = true;
+    }
 
 #if QT_VERSION < 0x050000
     // Internal string conversion is all UTF-8
@@ -175,7 +188,7 @@ int main(int argc, char *argv[])
     // as it is used to locate QSettings)
     QApplication::setOrganizationName("Bitcoin");
     QApplication::setOrganizationDomain("bitcoin.org");
-    if (GetBoolArg("-testnet", false)) // Separate UI settings for testnet
+    if (TestNet()) // Separate UI settings for testnet
         QApplication::setApplicationName("Bitcoin-Qt-testnet");
     else
         QApplication::setApplicationName("Bitcoin-Qt");
@@ -184,6 +197,17 @@ int main(int argc, char *argv[])
     QTranslator qtTranslatorBase, qtTranslator, translatorBase, translator;
     initTranslations(qtTranslatorBase, qtTranslator, translatorBase, translator);
 
+    // Now that translations are initialized check for errors and allow a translatable error message
+    if (fMissingDatadir) {
+        QMessageBox::critical(0, QObject::tr("Bitcoin"),
+                              QObject::tr("Error: Specified data directory \"%1\" does not exist.").arg(QString::fromStdString(mapArgs["-datadir"])));
+        return 1;
+    }
+    else if (fSelParFromCLFailed) {
+        QMessageBox::critical(0, QObject::tr("Bitcoin"), QObject::tr("Error: Invalid combination of -regtest and -testnet."));
+        return 1;
+    }
+
     // User language is set up: pick a data directory
     Intro::pickDataDirectory();
 
@@ -196,16 +220,7 @@ int main(int argc, char *argv[])
     // Install global event filter that makes sure that long tooltips can be word-wrapped
     app.installEventFilter(new GUIUtil::ToolTipToRichTextFilter(TOOLTIP_WRAP_THRESHOLD, &app));
 
-    // ... then bitcoin.conf:
+    // ... now GUI settings:
-    if (!boost::filesystem::is_directory(GetDataDir(false)))
-    {
-        QMessageBox::critical(0, QObject::tr("Bitcoin"),
-                              QObject::tr("Error: Specified data directory \"%1\" does not exist.").arg(QString::fromStdString(mapArgs["-datadir"])));
-        return 1;
-    }
-    ReadConfigFile(mapArgs, mapMultiArgs);
-
-    // ... then GUI settings:
     OptionsModel optionsModel;
 
     // Subscribe to global signals from core
@@ -245,7 +260,7 @@ int main(int argc, char *argv[])
 
         boost::thread_group threadGroup;
 
-        BitcoinGUI window(GetBoolArg("-testnet", false), 0);
+        BitcoinGUI window(TestNet(), 0);
         guiref = &window;
 
         QTimer* pollShutdownTimer = new QTimer(guiref);

src/qt/splashscreen.cpp

@@ -1,6 +1,7 @@
 #include "splashscreen.h"
 #include "clientversion.h"
 #include "util.h"
+#include "chainparams.h"
 
 #include <QApplication>
 #include <QPainter>
@@ -26,7 +27,7 @@ SplashScreen::SplashScreen(const QPixmap &pixmap, Qt::WindowFlags f) :
 
     // load the bitmap for writing some text over it
     QPixmap newPixmap;
-    if(GetBoolArg("-testnet", false)) {
+    if(TestNet()) {
         newPixmap     = QPixmap(":/images/splash_testnet");
     }
     else {