Add address error location to GUI

src/qt/bitcoinaddressvalidator.cpp

@@ -95,3 +95,8 @@ QValidator::State BitcoinAddressCheckValidator::validate(QString &input, int &po
 
     return QValidator::Invalid;
 }
+
+void BitcoinAddressErrorLocator::locateErrors(const QString& str, std::string& error_message, std::vector<int>* error_locations) const
+{
+    DecodeDestination(str.toStdString(), error_message, error_locations);
+}

src/qt/bitcoinaddressvalidator.h

@@ -32,4 +32,20 @@ class BitcoinAddressCheckValidator : public QValidator
     State validate(QString &input, int &pos) const override;
 };
 
+class ErrorLocator
+{
+public:
+    virtual void locateErrors(const QString& str, std::string& error_message, std::vector<int>* error_locations) const = 0;
+    virtual ~ErrorLocator() {};
+};
+
+/** Bitcoin address error locator.
+ */
+class BitcoinAddressErrorLocator : public ErrorLocator
+{
+public:
+    void locateErrors(const QString& str, std::string& error_message, std::vector<int>* error_locations) const override;
+    ~BitcoinAddressErrorLocator() override {};
+};
+
 #endif // BITCOIN_QT_BITCOINADDRESSVALIDATOR_H

src/qt/guiutil.cpp

@@ -123,6 +123,7 @@ void setupAddressWidget(QValidatedLineEdit *widget, QWidget *parent)
         QString::fromStdString(DummyAddress(Params()))));
     widget->setValidator(new BitcoinAddressEntryValidator(parent));
     widget->setCheckValidator(new BitcoinAddressCheckValidator(parent));
+    widget->setErrorLocator(new BitcoinAddressErrorLocator());
 }
 
 void AddButtonShortcut(QAbstractButton* button, const QKeySequence& shortcut)

src/qt/qvalidatedlineedit.cpp

@@ -7,10 +7,15 @@
 #include <qt/bitcoinaddressvalidator.h>
 #include <qt/guiconstants.h>
 
+#include <QContextMenuEvent>
+#include <QMenu>
+#include <QMessageBox>
+
 QValidatedLineEdit::QValidatedLineEdit(QWidget *parent) :
     QLineEdit(parent),
     valid(true),
-    checkValidator(nullptr)
+    checkValidator(nullptr),
+    errorLocator(nullptr)
 {
     connect(this, &QValidatedLineEdit::textChanged, this, &QValidatedLineEdit::markValid);
 }
@@ -108,6 +113,11 @@ void QValidatedLineEdit::setCheckValidator(const QValidator *v)
     checkValidator = v;
 }
 
+void QValidatedLineEdit::setErrorLocator(const ErrorLocator *e)
+{
+    errorLocator = e;
+}
+
 bool QValidatedLineEdit::isValid()
 {
     // use checkValidator in case the QValidatedLineEdit is disabled
@@ -121,3 +131,52 @@ bool QValidatedLineEdit::isValid()
 
     return valid;
 }
+
+void QValidatedLineEdit::locateErrors()
+{
+    if (!errorLocator) return;
+
+    // Perform error location on the input
+    QString input = text();
+    std::vector<int> error_locations{};
+    std::string error_message;
+    errorLocator->locateErrors(input, error_message, &error_locations);
+
+    if (error_message.empty()) {
+        QMessageBox::information(this, "Error locator", "No errors detected.", QMessageBox::Ok);
+    } else {
+        QString error_text = "Error: " + QString::fromStdString(error_message) + "<br />";
+        if (!error_locations.empty()) {
+            error_text += "<pre>";
+            int prev_loc = 0;
+            for (int loc : error_locations) {
+                error_text += input.mid(prev_loc, loc - prev_loc);
+                error_text +=  QString("<FONT COLOR='#ff0000'>%1</FONT>").arg(input[loc]);
+                prev_loc = loc + 1;
+            }
+            if (prev_loc < input.size()) {
+                error_text += input.right(input.size() - prev_loc);
+            }
+            error_text += "</pre>";
+        }
+        QMessageBox msg = QMessageBox(QMessageBox::Information, "Error locator", error_text, QMessageBox::Ok, parentWidget());
+        msg.exec();
+    }
+}
+
+void QValidatedLineEdit::contextMenuEvent(QContextMenuEvent *event)
+{
+    QMenu *contextMenu = createStandardContextMenu();
+    if (errorLocator) {
+        contextMenu->addAction(tr("Attempt error location"), this, &QValidatedLineEdit::locateErrors);
+    }
+    contextMenu->exec(event->globalPos());
+    delete contextMenu;
+}
+
+QValidatedLineEdit::~QValidatedLineEdit()
+{
+    if (errorLocator) {
+        delete errorLocator;
+    }
+}

src/qt/qvalidatedlineedit.h

@@ -7,6 +7,8 @@
 
 #include <QLineEdit>
 
+class ErrorLocator;
+
 /** Line edit that can be marked as "invalid" to show input validation feedback. When marked as invalid,
    it will get a red background until it is focused.
  */
@@ -16,17 +18,21 @@ class QValidatedLineEdit : public QLineEdit
 
 public:
     explicit QValidatedLineEdit(QWidget *parent);
+    ~QValidatedLineEdit();
     void clear();
     void setCheckValidator(const QValidator *v);
+    void setErrorLocator(const ErrorLocator *e);
     bool isValid();
 
 protected:
     void focusInEvent(QFocusEvent *evt) override;
     void focusOutEvent(QFocusEvent *evt) override;
+    void contextMenuEvent(QContextMenuEvent *event) override;
 
 private:
     bool valid;
     const QValidator *checkValidator;
+    const ErrorLocator *errorLocator;
 
 public Q_SLOTS:
     void setValid(bool valid);
@@ -38,6 +44,7 @@ public Q_SLOTS:
 private Q_SLOTS:
     void markValid();
     void checkValidity();
+    void locateErrors();
 };
 
 #endif // BITCOIN_QT_QVALIDATEDLINEEDIT_H