Core: Improve handling of long output chunks

Single chunks exceeding the limit were truncated and then shown
in a single line, potentially resulting in only a few chars if there
was a newline close to the cut-off point.

Now, don't restrict to a single line in that csae.

Additionally elide in the middle, assuming this is a better compromise
than truncating at either end.

Also, make the truncation more obvious, and mention the amount of
elided characters.

Change-Id: I850e2833e7f1f8be0f584d8e4439dd1a64f851d0
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/coreplugin/outputwindow.cpp

@@ -408,10 +408,14 @@ void OutputWindow::handleOutputChunk(const QString &output, OutputFormat format)
 {
     QString out = output;
     if (out.size() > d->maxCharCount) {
-        // Current line alone exceeds limit, we need to cut it.
-        out.truncate(d->maxCharCount);
-        out.append("[...]");
-        setMaximumBlockCount(1);
+        // Current chunk alone exceeds limit, we need to cut it.
+        const int elided = out.size() - d->maxCharCount;
+        out = out.left(d->maxCharCount / 2)
+                + "[[[... "
+                + tr("Elided %1 characters due to Application Output settings").arg(elided)
+                + " ...]]]"
+                + out.right(d->maxCharCount / 2);
+        setMaximumBlockCount(out.count('\n') + 1);
     } else {
         int plannedChars = document()->characterCount() + out.size();
         if (plannedChars > d->maxCharCount) {