Improvements to Session::getDynamicTitle()

Walk over LocalTabTitle just once looking for percent signs, and doing
the appropriate substitution based on the next character.

This not only is slightly more performant, but also avoids trouble if
one of the substitutions happens to contain a percent sign.

src/session/Session.cpp

@@ -1127,37 +1127,86 @@ QString Session::getDynamicTitle()
     QString title = tabTitleFormat(Session::LocalTabTitle);
     // search for and replace known marker
 
+    QString dir = _reportedWorkingUrl.toLocalFile();
+    bool dirOk = true;
+    if (dir.isEmpty()) {
+        // update current directory from process
+        updateWorkingDirectory();
+        // Previous process may have been freed in updateSessionProcessInfo()
+        process = getProcessInfo();
+        dir = process->currentDir(&dirOk);
+    }
+
+    int pos = 0;
+    while ((pos = title.indexOf(QLatin1Char('%'), pos)) != -1) {
+        if (pos >= title.size() - 1) {
+            break;
+        }
+
+        switch (title.at(pos + 1).toLatin1()) {
+        case 'B': {
             int UID = process->userId(&ok);
             if (!ok) {
-        title.replace(QLatin1String("%B"), QStringLiteral("-"));
+                title.replace(pos, 2, QStringLiteral("-"));
+                pos--;
             } else {
                 // title.replace(QLatin1String("%I"), QString::number(UID));
                 if (UID == 0) {
-            title.replace(QLatin1String("%B"), QStringLiteral("#"));
+                    title.replace(pos, 2, QStringLiteral("#"));
+                    pos--;
                 } else {
-            title.replace(QLatin1String("%B"), QStringLiteral("$"));
+                    title.replace(pos, 2, QStringLiteral("$"));
+                    pos--;
+                }
+            }
+        } break;
+        case 'u': {
+            QString replacement = process->userName();
+            title.replace(pos, 2, replacement);
+            pos += replacement.size() - 2;
+        } break;
+        case 'h': {
+            QString replacement = Konsole::ProcessInfo::localHost();
+            title.replace(pos, 2, replacement);
+            pos += replacement.size() - 2;
+        } break;
+        case 'n': {
+            QString replacement = process->name(&ok);
+            title.replace(pos, 2, replacement);
+            pos += replacement.size() - 2;
+        } break;
+        case 'w': {
+            QString replacement = userTitle();
+            title.replace(pos, 2, replacement);
+            pos += replacement.size() - 2;
+        } break;
+        case '#': {
+            QString replacement = QString::number(sessionId());
+            title.replace(pos, 2, replacement);
+            pos += replacement.size() - 2;
+        } break;
+        case 'd':
+            if (!dirOk) {
+                title.replace(pos, 2, QStringLiteral("-"));
+                pos--;
+            } else {
+                // allow for shortname to have the ~ as homeDir
+                const QString homeDir = process->userHomeDir();
+                if (!homeDir.isEmpty()) {
+                    if (dir.startsWith(homeDir)) {
+                        dir.remove(0, homeDir.length());
+                        dir.prepend(QLatin1Char('~'));
                     }
                 }
-
-    title.replace(QLatin1String("%u"), process->userName());
-    title.replace(QLatin1String("%h"), Konsole::ProcessInfo::localHost());
-    title.replace(QLatin1String("%n"), process->name(&ok));
-
-    title.replace(QLatin1String("%w"), userTitle());
-    title.replace(QLatin1String("%#"), QString::number(sessionId()));
-
-    QString dir = _reportedWorkingUrl.toLocalFile();
-    ok = true;
-    if (dir.isEmpty()) {
-        // update current directory from process
-        updateWorkingDirectory();
-        // Previous process may have been freed in updateSessionProcessInfo()
-        process = getProcessInfo();
-        dir = process->currentDir(&ok);
+                const QString replacement = process->formatShortDir(dir);
+                title.replace(pos, 2, replacement);
+                pos += replacement.size() - 2;
             }
-    if (!ok) {
-        title.replace(QLatin1String("%d"), QStringLiteral("-"));
-        title.replace(QLatin1String("%D"), QStringLiteral("-"));
+            break;
+        case 'D':
+            if (!dirOk) {
+                title.replace(pos, 2, QStringLiteral("-"));
+                pos--;
             } else {
                 // allow for shortname to have the ~ as homeDir
                 const QString homeDir = process->userHomeDir();
@@ -1167,8 +1216,11 @@ QString Session::getDynamicTitle()
                         dir.prepend(QLatin1Char('~'));
                     }
                 }
-        title.replace(QLatin1String("%D"), dir);
-        title.replace(QLatin1String("%d"), process->formatShortDir(dir));
+                title.replace(pos, 2, dir);
+                pos += dir.size() - 2;
+            }
+            break;
+        }
     }
 
     return title;