From 715ae29080906fe5fcabaea7667b4fa591c85c70 Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Tue, 7 Jan 2025 23:43:55 -0300
Subject: [PATCH] QMessagePattern: replace Q{Elapsed,Deadline}Timer with
 std::chrono

There's nothing wrong with those two, but we don't need the middle men
to the monotonic clock. This also reduces the sizeof QMessagePattern by
one quint64 (QElapsedTimer is 16 bytes in Qt 6).

Change-Id: I0eb171f03ee8f3a7148bfffd5534a7f3daba3a01
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
(cherry picked from commit 9dc294143d8fab498268f88c176b1af16de9b2ee)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/corelib/global/qlogging.cpp | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/src/corelib/global/qlogging.cpp b/src/corelib/global/qlogging.cpp
index e2a547f47e4..87077d865fb 100644
--- a/src/corelib/global/qlogging.cpp
+++ b/src/corelib/global/qlogging.cpp
@@ -16,8 +16,6 @@
 #include <QtCore/private/qlocking_p.h>
 #include "qloggingcategory.h"
 #ifndef QT_BOOTSTRAPPED
-#include "qelapsedtimer.h"
-#include "qdeadlinetimer.h"
 #include "qdatetime.h"
 #include "qcoreapplication.h"
 #include "qthread.h"
@@ -121,6 +119,7 @@ static QT_PREPEND_NAMESPACE(qint64) qt_gettid()
 
 #include <cstdlib>
 #include <algorithm>
+#include <chrono>
 #include <memory>
 #include <vector>
 
@@ -1165,7 +1164,7 @@ struct QMessagePattern
     std::unique_ptr<const char *[]> tokens;
     QList<QString> timeArgs; // timeFormats in sequence of %{time
 #ifndef QT_BOOTSTRAPPED
-    QElapsedTimer timer;
+    std::chrono::steady_clock::time_point appStartTime = std::chrono::steady_clock::now();
 #endif
 #ifdef QLOGGING_HAVE_BACKTRACE
     struct BacktraceParams
@@ -1200,9 +1199,6 @@ Q_CONSTINIT QBasicMutex QMessagePattern::mutex;
 
 QMessagePattern::QMessagePattern()
 {
-#ifndef QT_BOOTSTRAPPED
-    timer.start();
-#endif
     const QString envPattern = qEnvironmentVariable("QT_MESSAGE_PATTERN");
     if (envPattern.isEmpty()) {
         setDefaultPattern();
@@ -1690,15 +1686,17 @@ static QString formatLogMessage(QtMsgType type, const QMessageLogContext &contex
             message.append(formatBacktraceForLogMessage(backtraceParams, context));
 #endif
         } else if (token == timeTokenC) {
+            using namespace std::chrono;
             QString timeFormat = pattern->timeArgs.at(timeArgsIdx);
             timeArgsIdx++;
             if (timeFormat == "process"_L1) {
-                quint64 ms = pattern->timer.elapsed();
+                auto elapsed = steady_clock::now() - pattern->appStartTime;
+                quint64 ms = duration_cast<milliseconds>(elapsed).count();
                 message.append(QString::asprintf("%6d.%03d", uint(ms / 1000), uint(ms % 1000)));
             } else if (timeFormat == "boot"_L1) {
                 // just print the milliseconds since the elapsed timer reference
                 // like the Linux kernel does
-                qint64 ms = QDeadlineTimer::current().deadline();
+                qint64 ms = duration_cast<milliseconds>(steady_clock::now().time_since_epoch()).count();
                 message.append(QString::asprintf("%6d.%03d", uint(ms / 1000), uint(ms % 1000)));
 #if QT_CONFIG(datestring)
             } else if (timeFormat.isEmpty()) {