From 612c345108dca3e6c67e75bcf08912641f3f6f13 Mon Sep 17 00:00:00 2001
From: Edward Welbourne <edward.welbourne@qt.io>
Date: Tue, 23 Aug 2022 19:11:09 +0200
Subject: [PATCH] Reverse toLocalTime()'s and toUTC()'s delegation to
 toTimeSpec()
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The implementations of toLocalTime() and toUTC() get marginally more
efficient and toTimeSpec() now manifestly does what its documentation
declares it does. Previously, passing TimeZone would have produced a
warning about passing it to toTimeSpec(), which was less than helpful;
it now gives a more appropriate warning.

Rationalize the \sa lines between these functions and their close
relatives in the process.

Change-Id: Ie94c63cbea8ef3d1d14c2f1febdc10f0e53023c0
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/time/qdatetime.cpp | 52 +++++++++++++++++++++++-----------
 src/corelib/time/qdatetime.h   |  4 +--
 2 files changed, 37 insertions(+), 19 deletions(-)

diff --git a/src/corelib/time/qdatetime.cpp b/src/corelib/time/qdatetime.cpp
index f96aa5d3fd..611eb6bd8c 100644
--- a/src/corelib/time/qdatetime.cpp
+++ b/src/corelib/time/qdatetime.cpp
@@ -4386,21 +4386,14 @@ qint64 QDateTime::msecsTo(const QDateTime &other) const
     Example:
     \snippet code/src_corelib_time_qdatetime.cpp 16
 
-    \sa timeSpec(), toTimeZone(), toOffsetFromUtc()
+    \sa timeSpec(), toUTC(), toLocalTime(), toOffsetFromUtc(), toTimeZone()
 */
 
 QDateTime QDateTime::toTimeSpec(Qt::TimeSpec spec) const
 {
-    if (getSpec(d) == spec && (spec == Qt::UTC || spec == Qt::LocalTime))
-        return *this;
-
-    if (!isValid()) {
-        QDateTime ret = *this;
-        ret.setTimeSpec(spec);
-        return ret;
-    }
-
-    return fromMSecsSinceEpoch(toMSecsSinceEpoch(), spec, 0);
+    if (spec == Qt::TimeZone) // No zone supplied, so treating as LocalTime.
+        qWarning("Use toTimeZone() rather than toTimeSpec(Qt::TimeZone)");
+    return spec == Qt::UTC || spec == Qt::OffsetFromUTC ? toUTC() : toLocalTime();
 }
 
 /*!
@@ -4413,13 +4406,12 @@ QDateTime QDateTime::toTimeSpec(Qt::TimeSpec spec) const
 
     If the \a offsetSeconds equals 0 then a UTC datetime will be returned
 
-    \sa setOffsetFromUtc(), offsetFromUtc(), toTimeSpec()
+    \sa setOffsetFromUtc(), offsetFromUtc(), toUTC(), toLocalTime(), toTimeZone(), toTimeSpec()
 */
 
 QDateTime QDateTime::toOffsetFromUtc(int offsetSeconds) const
 {
-    if (getSpec(d) == Qt::OffsetFromUTC
-            && d->m_offsetFromUtc == offsetSeconds)
+    if (getSpec(d) == Qt::OffsetFromUTC && d->m_offsetFromUtc == offsetSeconds)
         return *this;
 
     if (!isValid()) {
@@ -4437,7 +4429,7 @@ QDateTime QDateTime::toOffsetFromUtc(int offsetSeconds) const
 
     Returns a copy of this datetime converted to the given \a timeZone
 
-    \sa timeZone(), toTimeSpec()
+    \sa timeZone(), toUTC(), toLocalTime(), toOffsetFromUtc(), toTimeSpec()
 */
 
 QDateTime QDateTime::toTimeZone(const QTimeZone &timeZone) const
@@ -5138,8 +5130,21 @@ QDateTime QDateTime::fromString(const QString &string, QStringView format, QCale
 
     \snippet code/src_corelib_time_qdatetime.cpp 17
 
-    \sa toTimeSpec()
+    \sa toUTC(), toOffsetFromUtc(), toTimeZone(), toTimeSpec()
 */
+QDateTime QDateTime::toLocalTime() const
+{
+    if (getSpec(d) == Qt::LocalTime)
+        return *this;
+
+    if (!isValid()) {
+        QDateTime ret = *this;
+        ret.setTimeSpec(Qt::LocalTime);
+        return ret;
+    }
+
+    return fromMSecsSinceEpoch(toMSecsSinceEpoch());
+}
 
 /*!
     \fn QDateTime QDateTime::toUTC() const
@@ -5151,8 +5156,21 @@ QDateTime QDateTime::fromString(const QString &string, QStringView format, QCale
 
     \snippet code/src_corelib_time_qdatetime.cpp 18
 
-    \sa toTimeSpec()
+    \sa toLocalTime(), toOffsetFromUtc(), toTimeZone(), toTimeSpec()
 */
+QDateTime QDateTime::toUTC() const
+{
+    if (getSpec(d) == Qt::UTC)
+        return *this;
+
+    if (!isValid()) {
+        QDateTime ret = *this;
+        ret.setTimeSpec(Qt::UTC);
+        return ret;
+    }
+
+    return fromMSecsSinceEpoch(toMSecsSinceEpoch(), Qt::UTC);
+}
 
 /*****************************************************************************
   Date/time stream functions
diff --git a/src/corelib/time/qdatetime.h b/src/corelib/time/qdatetime.h
index 58dff850db..a2f6198d08 100644
--- a/src/corelib/time/qdatetime.h
+++ b/src/corelib/time/qdatetime.h
@@ -355,8 +355,8 @@ public:
     }
 
     QDateTime toTimeSpec(Qt::TimeSpec spec) const;
-    inline QDateTime toLocalTime() const { return toTimeSpec(Qt::LocalTime); }
-    inline QDateTime toUTC() const { return toTimeSpec(Qt::UTC); }
+    QDateTime toLocalTime() const;
+    QDateTime toUTC() const;
     QDateTime toOffsetFromUtc(int offsetSeconds) const;
 #if QT_CONFIG(timezone)
     QDateTime toTimeZone(const QTimeZone &toZone) const;