QCommandLineParser: add support for hiding options from --help.

[ChangeLog][QtCore][QCommandLineParser] Added support for hiding options
from the --help output, with QCommandLineOption::setHidden(true).

Task-number: QTBUG-44298
Change-Id: I62cc2a55428365c0bcc79d2e47c72c0c92104e74
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

src/corelib/tools/qcommandlineoption.cpp

@@ -42,6 +42,7 @@ class QCommandLineOptionPrivate : public QSharedData
 {
 public:
     inline QCommandLineOptionPrivate()
+        : hidden(false)
     { }
 
     void setNames(const QStringList &nameList);
@@ -58,6 +59,9 @@ public:
 
     //! The list of default values used for this option.
     QStringList defaultValues;
+
+    //! Show or hide in --help
+    bool hidden;
 };
 
 /*!
@@ -362,4 +366,30 @@ QStringList QCommandLineOption::defaultValues() const
     return d->defaultValues;
 }
 
+/*!
+    Sets whether to hide this option in the user-visible help output.
+
+    All options are visible by default. Setting \a hidden to true for
+    a particular option makes it internal, i.e. not listed in the help output.
+
+    \since 5.5
+    \sa isHidden
+ */
+void QCommandLineOption::setHidden(bool hide)
+{
+    d->hidden = hide;
+}
+
+/*!
+    Returns true if this option is omitted from the help output,
+    false if the option is listed.
+
+    \since 5.5
+    \sa setHidden()
+ */
+bool QCommandLineOption::isHidden() const
+{
+    return d->hidden;
+}
+
 QT_END_NAMESPACE

src/corelib/tools/qcommandlineoption.h

@@ -77,6 +77,9 @@ public:
     void setDefaultValues(const QStringList &defaultValues);
     QStringList defaultValues() const;
 
+    void setHidden(bool hidden);
+    bool isHidden() const;
+
 private:
     QSharedDataPointer<QCommandLineOptionPrivate> d;
 };

src/corelib/tools/qcommandlineparser.cpp

@@ -1062,6 +1062,8 @@ QString QCommandLineParserPrivate::helpText() const
     ++longestOptionNameString;
     for (int i = 0; i < commandLineOptionList.count(); ++i) {
         const QCommandLineOption &option = commandLineOptionList.at(i);
+        if (option.isHidden())
+            continue;
         text += wrapText(optionNameList.at(i), longestOptionNameString, option.description());
     }
     if (!positionalArgumentDefinitions.isEmpty()) {

tests/auto/corelib/tools/qcommandlineparser/testhelper/qcommandlineparser_test_helper.cpp

@@ -73,6 +73,12 @@ int main(int argc, char *argv[])
                 "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz"));
     parser.addOption(newlineOption);
 
+    // A hidden option
+    QCommandLineOption hiddenOption(QStringList() << QStringLiteral("hidden"));
+    hiddenOption.setDescription(QStringLiteral("THIS SHOULD NEVER APPEAR"));
+    hiddenOption.setHidden(true);
+    parser.addOption(hiddenOption);
+
     // This program supports different options depending on the "command" (first argument).
     // Call parse() to find out the positional arguments.
     parser.parse(QCoreApplication::arguments());