mirror of
https://github.com/subsurface/subsurface.git
synced 2024-11-28 13:10:19 +00:00
92 lines
2.4 KiB
Markdown
92 lines
2.4 KiB
Markdown
|
# 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<xyz>::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.
|
||
|
|
|