ee6b5643b5
Add a variable reflecting the current_state to all DISK_* macros, in order to
check if the original variable in struct preferences is changed.
Only save to disk if actually changed
[Dirk Hohndel: merged Jan's commit and renamed the variable and adjusted the
commit message... but fundamentally the commit is still what Jan
wrote, so he should get the credit]
Signed-off-by: Jan Iversen <jani@apache.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
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|---|---|---|
| .. | ||
| qPref.cpp | ||
| qPref.h | ||
| qPrefCloudStorage.cpp | ||
| qPrefCloudStorage.h | ||
| qPrefDisplay.cpp | ||
| qPrefDisplay.h | ||
| qPrefDiveComputer.cpp | ||
| qPrefDiveComputer.h | ||
| qPrefDivePlanner.cpp | ||
| qPrefDivePlanner.h | ||
| qPrefFacebook.cpp | ||
| qPrefFacebook.h | ||
| qPrefGeneral.cpp | ||
| qPrefGeneral.h | ||
| qPrefGeocoding.cpp | ||
| qPrefGeocoding.h | ||
| qPrefLanguage.cpp | ||
| qPrefLanguage.h | ||
| qPrefLocationService.cpp | ||
| qPrefLocationService.h | ||
| qPrefPartialPressureGas.cpp | ||
| qPrefPartialPressureGas.h | ||
| qPrefPrivate.cpp | ||
| qPrefPrivate.h | ||
| qPrefProxy.cpp | ||
| qPrefProxy.h | ||
| qPrefTechnicalDetails.cpp | ||
| qPrefTechnicalDetails.h | ||
| qPrefUnit.cpp | ||
| qPrefUnit.h | ||
| qPrefUpdateManager.cpp | ||
| qPrefUpdateManager.h | ||
| README.md | ||
Short explanation of how qPref works
System startup:
core/qt-init.cpp init_qt_late()
does
qPref::load();
to load all properties from all qPref* classes
System shutdown:
subsurface-mobile-main.cpp and subsurface-desktop-main.cpp main()
calls
call qPref::sync()
to save all changes to disk, this is needed because part of the program modifies struct preferences instead of calling the set method.
EXCEPTION:
Variables not present in struct preferences (local static variables in the class are not written, see later.
System startup/shutdown common handling:
qPref::load() calls qPref::doSync(false)
qPref::sync() calls qPref::doSync(true)
qPrefDoSync()
qPref::doSync() calls qPref::doSync() for all qPref* classes Meaning qPref knows which classes exist, but not which variables
qPref*::doSync() calls
disk_<variable name>() for each variable
EXCEPTION:
some variables are not in struct preferences, but local static variables which can only be accessed through the set/get functions, therefore there are no need to sync them
if (!doSync) // meaining load
load_<variable_name>()
qPref*::disk_*()
qPref*::disk_*() calls qPrefPrivate::propSetValue to save a property, and qPrefPrivate::propValue() to read a property. The function also keeps struct preferences in sync.
qPrefPrivate::propSetValue()
qPrefPrivate::propSetValue() is static and calls QSettings to write property
qPrefPrivate::propValue()
qPrefPrivate::propValue() is static and calls QSettings to read property
macros
the macros are defined in qPrefPrivate.h
the macros are used in qPref*cpp
Reading properties
Reading a property is done through an inline function, and thus no more expensive than accessing the variable directly.
qPref*::<variable_name>()
Setting properties
Setting a property is done through a dedicated set function which are static to simplify the call:
qPref<class>::set_<variable_name>(value)
like:
qPrefDisplay::animation_speed(500);
the set function updates struct preferences (if not a local variable), and saves the property to disk, however save is only done if the variable is changed.
Updating struct preferences
When a program part updates struct preferences directly, changes are NOT saved to disk if the programm crashes, otherwise all variables are saved to disk with the program exists.