Attempts to create a new schema source corresponding to the contents of the given directory.
This function is not required for normal uses of Settings but it may be useful to authors of plugin management systems.
The directory should contain a file called `gschemas.compiled` as produced by the glib-compile-schemas tool.
If trusted is true then `gschemas.compiled` is trusted not to be corrupted.
This assumption has a performance advantage, but can result in crashes or inconsistent behaviour in the case of a corrupted file.
Generally, you should set trusted to true for files installed by the system and
to false for files in the home directory.
If parent is non-null then there are two effects.
First, if lookup is called with the recursive flag set to
true and the schema can not be found in the source, the lookup will recurse to the parent.
Second, any references to other schemas specified within this source (ie: `child` or `extends`) references may be resolved from the
parent.
For this second reason, except in very unusual situations, the parent should probably be given as the default schema source,
as returned by get_default.
| directory |
the filename of a directory |
| parent |
a SettingsSchemaSource, or null |
| trusted |
true, if the directory is trusted |