OutputFormatter: Fix visual glitch

When inserting a line into an output window, we have to delay appending
the line feed character. Otherwise strange visual effects appear under
certain circumstances.
I have no idea why.

Fixes: QTCREATORBUG-24411
Change-Id: If8842ae4d9db36d514996b1f34dcca0432fafbfc
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/libs/utils/outputformatter.cpp

@@ -216,6 +216,7 @@ public:
     PostPrintAction postPrintAction;
     bool boldFontEnabled = true;
     bool prependCarriageReturn = false;
+    bool prependLineFeed = false;
 };
 
 OutputFormatter::OutputFormatter() : d(new Private) { }
@@ -436,6 +437,7 @@ void OutputFormatter::append(const QString &text, const QTextCharFormat &format)
         d->cursor.movePosition(QTextCursor::StartOfBlock, QTextCursor::KeepAnchor);
         startPos = crPos + 1;
     }
+    flushTrailingNewline();
     if (startPos < text.count())
         d->cursor.insertText(text.mid(startPos), format);
 }
@@ -495,6 +497,14 @@ void OutputFormatter::flushIncompleteLine()
     d->incompleteLine.first.clear();
 }
 
+void Utils::OutputFormatter::flushTrailingNewline()
+{
+    if (d->prependLineFeed) {
+        d->cursor.insertText("\n");
+        d->prependLineFeed = false;
+    }
+}
+
 void OutputFormatter::dumpIncompleteLine(const QString &line, OutputFormat format)
 {
     if (line.isEmpty())
@@ -560,6 +570,7 @@ void OutputFormatter::flush()
 {
     if (!d->incompleteLine.first.isEmpty())
         flushIncompleteLine();
+    flushTrailingNewline();
     d->escapeCodeHandler.endFormatScope();
     for (OutputLineParser * const p : qAsConst(d->lineParsers))
         p->flush();
@@ -641,7 +652,8 @@ void OutputFormatter::appendMessage(const QString &text, OutputFormat format)
             dumpIncompleteLine(out.mid(startPos), format);
             break;
         }
-        doAppendMessage(out.mid(startPos, eolPos - startPos + 1), format);
+        doAppendMessage(out.mid(startPos, eolPos - startPos), format);
+        d->prependLineFeed = true;
         startPos = eolPos + 1;
     }
 }

src/libs/utils/outputformatter.h

@@ -83,8 +83,8 @@ public:
     void setDemoteErrorsToWarnings(bool demote);
     bool demoteErrorsToWarnings() const;
 
-    // line contains at most one line feed character, and if it does occur, it's the last character.
-    // Either way, the input is to be considered "complete" for parsing purposes.
+    // Represents a single line, without a trailing line feed character.
+    // The input is to be considered "complete" for parsing purposes.
     virtual Result handleLine(const QString &line, OutputFormat format) = 0;
 
     virtual bool handleLink(const QString &href) { Q_UNUSED(href); return false; }
@@ -183,6 +183,7 @@ private:
     void append(const QString &text, const QTextCharFormat &format);
     void initFormats();
     void flushIncompleteLine();
+    void flushTrailingNewline();
     void dumpIncompleteLine(const QString &line, OutputFormat format);
     void clearLastLine();
     QList<FormattedText> parseAnsi(const QString &text, const QTextCharFormat &format);

src/plugins/projectexplorer/linuxiccparser.cpp

@@ -57,7 +57,7 @@ LinuxIccParser::LinuxIccParser() :
 
     // ".pch/Qt5Core.pchi.cpp": creating precompiled header file ".pch/Qt5Core.pchi"
     // "animation/qabstractanimation.cpp": using precompiled header file ".pch/Qt5Core.pchi"
-    m_pchInfoLine.setPattern(QLatin1String("^\".*?\": (creating|using) precompiled header file \".*?\"\n$"));
+    m_pchInfoLine.setPattern(QLatin1String("^\".*?\": (creating|using) precompiled header file \".*?\"$"));
     QTC_CHECK(m_pchInfoLine.isValid());
 }
 

src/plugins/projectexplorer/outputparser_test.cpp

@@ -111,11 +111,10 @@ TestTerminator::TestTerminator(OutputParserTester *t) :
 
 Utils::OutputLineParser::Result TestTerminator::handleLine(const QString &line, Utils::OutputFormat type)
 {
-    QTC_CHECK(line.endsWith('\n'));
     if (type == Utils::StdOutFormat)
-        m_tester->m_receivedStdOutChildLine.append(line);
+        m_tester->m_receivedStdOutChildLine.append(line + '\n');
     else
-        m_tester->m_receivedStdErrChildLine.append(line);
+        m_tester->m_receivedStdErrChildLine.append(line + '\n');
     return Status::Done;
 }
 

src/plugins/qtsupport/qtoutputformatter.cpp

@@ -511,6 +511,7 @@ void QtSupportPlugin::testQtOutputFormatter_appendMixedAssertAndAnsi()
                 "Blue\n";
 
     formatter.appendMessage(inputText, StdOutFormat);
+    formatter.flush();
 
     QCOMPARE(edit.toPlainText(), outputText);