From: Scott Kostyshak <skostysh@lyx.org>
Date: Mon, 16 Mar 2020 00:32:16 +0000 (-0400)
Subject: Fix Qt deprecation warns for QTime
X-Git-Tag: lyx-2.4.0dev-acb2ca7b~1103
X-Git-Url: https://git.lyx.org/gitweb/?a=commitdiff_plain;h=24e0bd3afea847218c0f590561cf172b3799432f;p=features.git

Fix Qt deprecation warns for QTime

This commit fixes a couple of warnings from Qt 5.14 like the
following one:

  error: ‘int QTime::restart()’ is deprecated: Use QElapsedTimer instead [-Werror=deprecated-declarations]

This commit changes two uses of QTime to QElapsedTimer, one used
only when the "files" debug flag is set, and the other for timing
whether a script (e.g., knitr) takes longer than a certain amount of
time to run.

QElapsedTimer is superior for these two use cases in that it uses a
monotonic clock if possible, and is thus more robust to certain
changes (e.g., daylight savings changes) [1]. Similarly, the commit
in Qt Base that makes this deprecation [2] mentions the following in
the commit message:

  QElapsedTimer does the job better and without the DST kludges.

Note that QElapsedTimer class was introduced in Qt 4.7, so no
conditioning on Qt version is necessary.

Not all methods of QTime are deprecated and we still use some of
the non-deprecated methods in our code (e.g., to get the current
wall clock time in GuiProgress::currentTime()).

[1] https://doc.qt.io/qt-5/qelapsedtimer.html
[2] https://code.qt.io/cgit/qt/qtbase.git/commit/?id=ed99a591a83a399458f12341d0a1c0b3152f247a
---

diff --git a/src/support/FileName.cpp b/src/support/FileName.cpp
index 505b485d7f..179fef46ee 100644
--- a/src/support/FileName.cpp
+++ b/src/support/FileName.cpp
@@ -28,7 +28,7 @@
 #include <QFileInfo>
 #include <QList>
 #include <QTemporaryFile>
-#include <QTime>
+#include <QElapsedTimer>
 
 #ifdef _WIN32
 #include <QThread>
@@ -563,7 +563,7 @@ unsigned long FileName::checksum() const
 	}
 
 	// This is used in the debug output at the end of the method.
-	static QTime t;
+	static QElapsedTimer t;
 	if (lyxerr.debugging(Debug::FILES))
 		t.restart();
 
diff --git a/src/support/Systemcall.cpp b/src/support/Systemcall.cpp
index f5b6c27a50..d0ff9ae993 100644
--- a/src/support/Systemcall.cpp
+++ b/src/support/Systemcall.cpp
@@ -29,7 +29,7 @@
 #include <iostream>
 
 #include <QProcess>
-#include <QTime>
+#include <QElapsedTimer>
 #include <QThread>
 #include <QCoreApplication>
 #include <QDebug>
@@ -467,7 +467,7 @@ bool SystemcallPrivate::waitWhile(State waitwhile, bool process_events, int time
 	}
 
 	// process events while waiting with timeout
-	QTime timer;
+	QElapsedTimer timer;
 	timer.start();
 	while (state == waitwhile && state != Error && !timedout) {
 		// check for cancellation of background process