1berry/qtbase
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

qhighdpiscaling: de-pessimize qEnvironmentVariableOptional*() functions

Browse Source 
Don't call qEnvironmentVariableIsSet(), since it locks the environment
mutex. Since qgetenv() and qEnvironmentVariable() both report whether
the value was set (returning non-isNull()), we can avoid the extra
mutex lock (and envvar lookup) by just calling those and then checking
for isNull().

In qEnvironmentVariableOptionalReal(), in addition, use qgetenv()
instead of qEnvironmentVariable(). While on Windows, that may convert
encoding, QString::toDouble() first converts to Latin-1, and only then
converts to double, so we avoid one encoding conversion, even on
Windows; on Unix we avoid two.

Amends 4d1f13f3549a73f5ca4e64dac9137e83138080fa.

Pick-to: 6.8 6.5
Change-Id: I6803e2277b324c2568726765245681bcbf517362
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
(cherry picked from commit 8669bc97ff6811bae304a8bb2a0e3af2bb78cfe0)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Marc Mutz 2025-02-10 10:30:46 +01:00 committed by Qt Cherry-pick Bot
parent 03fc43b5e9
commit a639174daa
1 changed files with 7 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
src/gui/kernel/qhighdpiscaling.cpp
View File

@ -30,18 +30,14 @@ static const char usePhysicalDpiEnvVar[] = "QT_USE_PHYSICAL_DPI";
static std::optional<QString> qEnvironmentVariableOptionalString(const char *name)
{
if (!qEnvironmentVariableIsSet(name))
return std::nullopt;
return std::optional(qEnvironmentVariable(name));
QString value = qEnvironmentVariable(name);
return value.isNull() ? std::nullopt : std::optional(std::move(value));
}
static std::optional<QByteArray> qEnvironmentVariableOptionalByteArray(const char *name)
{
if (!qEnvironmentVariableIsSet(name))
return std::nullopt;
return std::optional(qgetenv(name));
QByteArray value = qgetenv(name);
return value.isNull() ? std::nullopt : std::optional(std::move(value));
}
static std::optional<int> qEnvironmentVariableOptionalInt(const char *name)
@ -54,11 +50,12 @@ static std::optional<int> qEnvironmentVariableOptionalInt(const char *name)
static std::optional<qreal> qEnvironmentVariableOptionalReal(const char *name)
{
if (!qEnvironmentVariableIsSet(name))
const QByteArray val = qgetenv(name);
if (val.isNull())
return std::nullopt;
bool ok = false;
const qreal value = qEnvironmentVariable(name).toDouble(&ok);
const qreal value = val.toDouble(&ok);
return ok ? std::optional(value) : std::nullopt;
}