This patch adds support of recomputation with external linked object,
as well as external document auto loading and partial loading.
Application:
* Modified new/openDocument()/signalNewDocument to choose whether to
signal GUI for creating a view for the document. This makes it possible
to suppress view creation when opening external documents.
* New API openDocuments() which does the actual job of loading the
document together with any external dependencies. There are afew
extra arguments to allow setting FileName property differently from
the actual file path, which are required when auto loading
dependencies during document recovery (with future patch to
Gui::DocumentRecovery)
* openDocumentPrivate() is an internal helper for opening individual
document.
* New signalStart/FinishOpenDocument to be signaled before and after
opening a document. There may be multiple depending documents actually
opened in between these two signals.
* New signalBeforeRecomputeDocument signaled before recompute a
document.
* New API addPendingDocument() for use by external capable link
properties' to queue up external documents.
* isRestoring/isClosingAll(), for convenience status reporting.
Document:
* signalFinishImport/RestoreObjects, new signal triggered after imported
or restored all input objects
* signalBeforeRecompute, signaled before start recomputing this document
* Modified signalRecomputed with additional recomputed objects, this is
to make it more efficient for Gui::TreeWidget to check recomputation
result.
* signalSkipRecompute, signal to inform which objects are skipped
during recomputation because of their owner document SkipRecompute
setting.
* restore/save/read/writeObjects() modified to suport partial
loading. See [here](https://git.io/fj6PY) for more information.
* afterRestore(), internal function called to finish restore. The
function is separated from restore() because there is quite a few
critical steps needed to fully restore a document with external
linking. See [here](https://git.io/fj6P4) for more information.
* DocumentP::_RecomputeLog is modified to store more accurate object
recomputation error, including those happened during restore/import.
* isExporting(), new API for checking if an object is exporting.
External linking properties will use this function to decide how to
export.
* copyObject(), modified to support external linking objects, and
accepts multiple input objects.
* moveObject(), modified to support arbitary object moves. The original
implementation may cause crash if undo/redo is enabled. Furthermore,
because the original information fakes the object's deletion to break
its dependency, it does not work for objects that may auto delete their
children when being deleted. The new implementation copy the object,
and than paste it to the other document. It then deletes the input
objects from the original document. In case of recursive move, it only
deletes the depending object if it has an empty in list.
* importLinks(), new API to import any external object linked by the
input objects into this document. It will auto correct all link
references after importing.
* getDependencyList/_rebuildDependencyList(), these two APIs are unified
and implemented by an internal function _buildDependencyList() with a
new algorithm to handle external objects. The returned dependency list
will now include objects from external documents. In case of cyclic
dependencies, getDpendencyList() will report the actual objects
involved in dependency loops.
* mustExecute(), new API to check if there are any object requires
recomputation. This function will call _buildDependencyList() and
check for external objects as well.
* addRecomputeObject(), new API for marking changes during document
restore. It only marks the object but does not actually recompute
them for performance reason. One use case is for geo feature to
request for recomputation to generate geometry topological names.
* recompute(), support partial, external, and inverse dependency
recomputation. Improve error handling during recomputation.
See [here](https://git.io/fj6PO) for more information.
* _recomputeFeature(), suppoert user abort.
* getDependentDocuments/getInList(), new API to obtain an optional
dependency sorted list of depending documents.
DocumentObject:
* Add various ObjectStatus flags
* isExporting/getExportName(), return a safe name for exporting, in the
form of <ObjName>@<DocName>, which is guarrenteed to be unique.
Various link property will save linked object using this name if the
the linked object is exported together with the owner object, see
[PropertyLinkBase::restoreLabelReference()](https://git.io/fj6XO)
for more information.
* recomputeFeature(), add option to recompute this object together with
all its dependent objects.
* canLoadPartial(), new API for [partial document loading](https://git.io/fj6PY).
MergeDocuments:
* Move object name mapping logic to various link properties. See
Base::Sequencer:
* Add new API checkAbort() for checking user abort.
