highlight error URLs in logwindow

tools/lammps-gui/TODO.md

@@ -2,6 +2,7 @@ LAMMPS-GUI TODO list:
 
 # Short term goals (v1.x)
 
+- open highlighted errorURL in web browser when clicking on it in the logfile viewer.
 - add a "Colors" menu to the image viewer to adjust color settings for the
   current image (unlike the defaults in the perferences) including assigning
   colors to individual atom types.

tools/lammps-gui/flagwarnings.cpp

@@ -28,13 +28,16 @@ const QColor Red = QColor::fromRgb(0xff, 0x00, 0x00);
 #endif
 
 FlagWarnings::FlagWarnings(QLabel *label, QTextDocument *parent) :
-    QSyntaxHighlighter(parent), isWarning(QStringLiteral("^(ERROR|WARNING).*$")), summary(label),
+    QSyntaxHighlighter(parent), isWarning(QStringLiteral("^(ERROR|WARNING).*$")),
+    isURL(QStringLiteral("^.*(https://docs.lammps.org/err[0-9]+).*$")), summary(label),
     document(parent)
 {
     nwarnings = nlines = 0;
 
     formatWarning.setForeground(QColorConstants::Red);
     formatWarning.setFontWeight(QFont::Bold);
+    formatURL.setForeground(QColorConstants::Blue);
+    formatURL.setFontWeight(QFont::Bold);
 }
 
 void FlagWarnings::highlightBlock(const QString &text)
@@ -42,11 +45,20 @@ void FlagWarnings::highlightBlock(const QString &text)
     // nothing to do for empty lines
     if (text.isEmpty()) return;
 
+    // highlight errors or warnings
     auto match = isWarning.match(text);
     if (match.hasMatch()) {
         ++nwarnings;
         setFormat(match.capturedStart(0), match.capturedLength(0), formatWarning);
     }
+
+    // highlight ErrorURL links
+    match = isURL.match(text);
+    if (match.hasMatch()) {
+        setFormat(match.capturedStart(1), match.capturedLength(1), formatURL);
+    }
+
+    // update error summary label
     if (document && summary) {
         summary->setText(
             QString("%1 Warnings / Errors - %2 Lines").arg(nwarnings).arg(document->lineCount()));

tools/lammps-gui/flagwarnings.h

@@ -32,8 +32,15 @@ protected:
     void highlightBlock(const QString &text) override;
 
 private:
+#if QT_VERSION < QT_VERSION_CHECK(5, 15, 0)
+    QRegExp isWarning;
+    QRegExp isURL;
+#else
     QRegularExpression isWarning;
+    QRegularExpression isURL;
+#endif
     QTextCharFormat formatWarning;
+    QTextCharFormat formatURL;
     QLabel *summary;
     QTextDocument *document;
     int nwarnings, nlines;