Merge bitcoin-core/gui#620: Replace `QRegExp` with `QRegularExpression`

67364ebe4c499eb8effe8dac11a5e3648f30c6c7 test, qt: Add tests for `GUIUtil::extractFirstSuffixFromFilter` (w0xlt)
ace9af5688662a56d855bd26f36bc5c145b909e3 qt: Replace `QRegExp` with `QRegularExpression` (w0xlt)
c378535e28e0c54353fde9c4a66cb3134a3ee742 qt: Add a function that extracts the suffix from a filter (w0xlt)

Pull request description:

  Picking up https://github.com/bitcoin-core/gui/pull/606 (labeled "Up for grabs") and applying https://github.com/bitcoin-core/gui/pull/606#pullrequestreview-984607067 and https://github.com/bitcoin-core/gui/pull/606#issuecomment-1137149907.

  Replaces occurrences of `QRegExp` usage with `QRegularExpression` as part of the roadmap for Qt6 integration.

  Fixes https://github.com/bitcoin-core/gui/issues/578

ACKs for top commit:
  laanwj:
    Code review and lightly tested ACK 67364ebe4c499eb8effe8dac11a5e3648f30c6c7
  hebasto:
    ACK 67364ebe4c499eb8effe8dac11a5e3648f30c6c7

Tree-SHA512: 4a17d83e557bc635cbd1a15776856e9edb7162b23a369ccbd2ac59c68b8a1ea663baaa7d5ad98e419dc03b91ef3315c768eeadc01c0b29162de109493161e814

1 files changed, 15 insertions, 15 deletions

diff --git a/src/qt/guiutil.cpp b/src/qt/guiutil.cpp
index 186ed4f644..2551be0af3 100644
--- a/src/qt/guiutil.cpp
+++ b/src/qt/guiutil.cpp
@@ -53,6 +53,7 @@
 #include <QMouseEvent>
 #include <QPluginLoader>
 #include <QProgressDialog>
+#include <QRegularExpression>
 #include <QScreen>
 #include <QSettings>
 #include <QShortcut>
@@ -289,6 +290,17 @@ QString getDefaultDataDirectory()
     return PathToQString(GetDefaultDataDir());
 }
 
+QString ExtractFirstSuffixFromFilter(const QString& filter)
+{
+    QRegularExpression filter_re(QStringLiteral(".* \\(\\*\\.(.*)[ \\)]"), QRegularExpression::InvertedGreedinessOption);
+    QString suffix;
+    QRegularExpressionMatch m = filter_re.match(filter);
+    if (m.hasMatch()) {
+        suffix = m.captured(1);
+    }
+    return suffix;
+}
+
 QString getSaveFileName(QWidget *parent, const QString &caption, const QString &dir,
     const QString &filter,
     QString *selectedSuffixOut)
@@ -306,13 +318,7 @@ QString getSaveFileName(QWidget *parent, const QString &caption, const QString &
     /* Directly convert path to native OS path separators */
     QString result = QDir::toNativeSeparators(QFileDialog::getSaveFileName(parent, caption, myDir, filter, &selectedFilter));
 
-    /* Extract first suffix from filter pattern "Description (*.foo)" or "Description (*.foo *.bar ...) */
-    QRegExp filter_re(".* \\(\\*\\.(.*)[ \\)]");
-    QString selectedSuffix;
-    if(filter_re.exactMatch(selectedFilter))
-    {
-        selectedSuffix = filter_re.cap(1);
-    }
+    QString selectedSuffix = ExtractFirstSuffixFromFilter(selectedFilter);
 
     /* Add suffix if needed */
     QFileInfo info(result);
@@ -354,14 +360,8 @@ QString getOpenFileName(QWidget *parent, const QString &caption, const QString &
 
     if(selectedSuffixOut)
     {
-        /* Extract first suffix from filter pattern "Description (*.foo)" or "Description (*.foo *.bar ...) */
-        QRegExp filter_re(".* \\(\\*\\.(.*)[ \\)]");
-        QString selectedSuffix;
-        if(filter_re.exactMatch(selectedFilter))
-        {
-            selectedSuffix = filter_re.cap(1);
-        }
-        *selectedSuffixOut = selectedSuffix;
+        *selectedSuffixOut = ExtractFirstSuffixFromFilter(selectedFilter);
+        ;
     }
     return result;
 }