Add a verbosity setting to QDebug.

Add setters for an int verbosity to QDebug. The streaming operators
can check on the setting and output more information accordingly.

[ChangeLog][QtCore][QDebug] How verbose a single debug output should be
can now be fine-tuned by setting a verbosity on the debug stream.

Change-Id: I77001fcf1ef090a580d1a137bb5a667fc1bf1e1b
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

3 files changed, 80 insertions, 6 deletions

diff --git a/src/corelib/io/qdebug.cpp b/src/corelib/io/qdebug.cpp
index 357d63137c..8676fe0259 100644
--- a/src/corelib/io/qdebug.cpp
+++ b/src/corelib/io/qdebug.cpp
@@ -334,6 +334,7 @@ QDebug &QDebug::resetFormat()
     stream->space = true;
     if (stream->context.version > 1)
         stream->flags = 0;
+    stream->setVerbosity(Stream::defaultVerbosity);
     return *this;
 }
 
@@ -424,6 +425,32 @@ QDebug &QDebug::resetFormat()
 */
 
 /*!
+    \fn int QDebug::verbosity() const
+    \since 5.6
+
+    Returns the verbosity of the debug stream.
+
+    Streaming operators can check the value to decide whether
+    verbose output is desired and print more information depending on the
+    level. Higher values indicate that more information is desired.
+
+    The allowed range is from 0 to 7. The default value is 2.
+
+    \sa setVerbosity()
+*/
+
+/*!
+    \fn void QDebug::setVerbosity(int verbosityLevel)
+    \since 5.6
+
+    Sets the verbosity of the stream to \a verbosityLevel.
+
+    The allowed range is from 0 to 7. The default value is 2.
+
+    \sa verbosity()
+*/
+
+/*!
     \fn QDebug &QDebug::operator<<(QChar t)
 
     Writes the character, \a t, to the stream and returns a reference to the
diff --git a/src/corelib/io/qdebug.h b/src/corelib/io/qdebug.h
index 7f1cb82f3a..95f5993e4f 100644
--- a/src/corelib/io/qdebug.h
+++ b/src/corelib/io/qdebug.h
@@ -53,9 +53,14 @@ class Q_CORE_EXPORT QDebug
     friend class QMessageLogger;
     friend class QDebugStateSaverPrivate;
     struct Stream {
-        Stream(QIODevice *device) : ts(device), ref(1), type(QtDebugMsg), space(true), message_output(false), flags(0) {}
-        Stream(QString *string) : ts(string, QIODevice::WriteOnly), ref(1), type(QtDebugMsg), space(true), message_output(false), flags(0) {}
-        Stream(QtMsgType t) : ts(&buffer, QIODevice::WriteOnly), ref(1), type(t), space(true), message_output(true), flags(0) {}
+        enum { defaultVerbosity = 2, verbosityShift = 29, verbosityMask = 0x7 };
+
+        Stream(QIODevice *device) : ts(device), ref(1), type(QtDebugMsg),
+            space(true), message_output(false), flags(defaultVerbosity << verbosityShift) {}
+        Stream(QString *string) : ts(string, QIODevice::WriteOnly), ref(1), type(QtDebugMsg),
+            space(true), message_output(false), flags(defaultVerbosity << verbosityShift) {}
+        Stream(QtMsgType t) : ts(&buffer, QIODevice::WriteOnly), ref(1), type(t),
+            space(true), message_output(true), flags(defaultVerbosity << verbosityShift) {}
         QTextStream ts;
         QString buffer;
         int ref;
@@ -64,7 +69,7 @@ class Q_CORE_EXPORT QDebug
         bool message_output;
         QMessageLogContext context;
 
-        enum FormatFlag {
+        enum FormatFlag { // Note: Bits 29..31 are reserved for the verbose level introduced in 5.6.
             NoQuotes = 0x1
         };
 
@@ -72,7 +77,15 @@ class Q_CORE_EXPORT QDebug
         bool testFlag(FormatFlag flag) const { return (context.version > 1) ? (flags & flag) : false; }
         void setFlag(FormatFlag flag) { if (context.version > 1) { flags |= flag; } }
         void unsetFlag(FormatFlag flag) { if (context.version > 1) { flags &= ~flag; } }
-
+        int verbosity() const
+        { return context.version > 1 ? (flags >> verbosityShift) & verbosityMask : int(Stream::defaultVerbosity); }
+        void setVerbosity(int v)
+        {
+            if (context.version > 1) {
+                flags &= ~(verbosityMask << verbosityShift);
+                flags |= (v & verbosityMask) << verbosityShift;
+            }
+        }
         // added in 5.4
         int flags;
     } *stream;
@@ -96,6 +109,8 @@ public:
     inline QDebug &space() { stream->space = true; stream->ts << ' '; return *this; }
     inline QDebug &nospace() { stream->space = false; return *this; }
     inline QDebug &maybeSpace() { if (stream->space) stream->ts << ' '; return *this; }
+    int verbosity() const { return stream->verbosity(); }
+    void setVerbosity(int verbosityLevel) { stream->setVerbosity(verbosityLevel); }
 
     bool autoInsertSpaces() const { return stream->space; }
     void setAutoInsertSpaces(bool b) { stream->space = b; }
diff --git a/tests/auto/corelib/io/qdebug/tst_qdebug.cpp b/tests/auto/corelib/io/qdebug/tst_qdebug.cpp
index 32344f1e26..1b7d410beb 100644
--- a/tests/auto/corelib/io/qdebug/tst_qdebug.cpp
+++ b/tests/auto/corelib/io/qdebug/tst_qdebug.cpp
@@ -49,6 +49,7 @@ private slots:
     void debugWithBool() const;
     void debugSpaceHandling() const;
     void debugNoQuotes() const;
+    void verbosity() const;
     void stateSaver() const;
     void veryLongWarningMessage() const;
     void qDebugQChar() const;
@@ -192,7 +193,11 @@ public:
 QDebug operator<< (QDebug s, const MyLine& line)
 {
     const QDebugStateSaver saver(s);
-    s.nospace() << "MyLine(" << line.p1 << ", " << line.p2 << ")";
+    s.nospace();
+    s << "MyLine(" << line.p1 << ", "<< line.p2;
+    if (s.verbosity() > 2)
+        s << ", Manhattan length=" << (qAbs(line.p2.v1 - line.p1.v1) + qAbs(line.p2.v2 - line.p1.v2));
+    s << ')';
     return s;
 }
 
@@ -255,6 +260,33 @@ void tst_QDebug::debugNoQuotes() const
     QCOMPARE(s_msg, QString::fromLatin1("'H' \"Hello\" \"Hello\" H Hello Hello"));
 }
 
+void tst_QDebug::verbosity() const
+{
+    MyLine line(MyPoint(10, 11), MyPoint (12, 13));
+    QString output;
+    QDebug d(&output);
+    d.nospace();
+    d << line << '\n';
+    const int oldVerbosity = d.verbosity();
+    d.setVerbosity(0);
+    QCOMPARE(d.verbosity(), 0);
+    d.setVerbosity(7);
+    QCOMPARE(d.verbosity(), 7);
+    const int newVerbosity = oldVerbosity  + 2;
+    d.setVerbosity(newVerbosity);
+    QCOMPARE(d.verbosity(), newVerbosity);
+    d << line << '\n';
+    d.setVerbosity(oldVerbosity );
+    QCOMPARE(d.verbosity(), oldVerbosity );
+    d << line;
+    const QStringList lines = output.split(QLatin1Char('\n'));
+    QCOMPARE(lines.size(), 3);
+    // Verbose should be longer
+    QVERIFY2(lines.at(1).size() > lines.at(0).size(), qPrintable(lines.join(QLatin1Char(','))));
+    // Switching back to brief produces same output
+    QCOMPARE(lines.at(0).size(), lines.at(2).size());
+}
+
 void tst_QDebug::stateSaver() const
 {
     MessageHandlerSetter mhs(myMessageHandler);