This commit changes a lot of how IDs are handled internally, especially the unlinking/freeing
processes. So far, this was very fuzy, to summarize cleanly deleting or replacing a datablock
was pretty much impossible, except for a few special cases.
Also, unlinking was handled by each datatype, in a rather messy and prone-to-errors way (quite
a few ID usages were missed or wrongly handled that way).
One of the main goal of id-remap branch was to cleanup this, and fatorize ID links handling
by using library_query utils to allow generic handling of those, which is now the case
(now, generic ID links handling is only "knwon" from readfile.c and library_query.c).
This commit also adds backends to allow live replacement and deletion of datablocks in Blender
(so-called 'remapping' process, where we replace all usages of a given ID pointer by a new one,
or NULL one in case of unlinking).
This will allow nice new features, like ability to easily reload or relocate libraries, real immediate
deletion of datablocks in blender, replacement of one datablock by another, etc.
Some of those are for next commits.
A word of warning: this commit is highly risky, because it affects potentially a lot in Blender core.
Though it was tested rather deeply, being totally impossible to check all possible ID usage cases,
it's likely there are some remaining issues and bugs in new code... Please report them! ;)
Review task: D2027 (https://developer.blender.org/D2027).
Reviewed by campbellbarton, thanks a bunch.
Some area were still not in sync with readfile.c, now should be better.
Note that readfile.c has been used as référence here re us refcounting,
not sure how accurate it is, time will say :|
This commit:
* Fixes bad handling of 'stop iteration' (by adding a status flag, so that we can actually
stop in helper functions too, and jumping to a finalize label instead of raw return, to
allow propper clean up).
* Adds optional recursion into 'ID tree' - callback can also decide to exclude current id_pp
from recursion. Note that this implies 'readonly', modifying IDs while recursing is not
something we want to support!
* Changes callback signature/expected behavior: return behavior is now handled through flags,
and 'parent' ID of id_pp is also passed (since it may not always be root id anymore).
Reviewers: sergey, campbellbarton
Differential Revision: https://developer.blender.org/D1869
This mainly adds bpy.data.user_map() method, which goes over the whole Main database
to build a mapping (dict) {ID: {users_of_that_ID}}.
Very handy to check and debug ID usages, but could also be really valuable for py addons
creating temporary scenes, or some exporters, etc.
Note: current code in master's libquery misses some IDs (and reports some it should not,
like nodetrees), this is fixed in id-remap but still needs serious review before going to master.
This basically means that current bpy.data.user_map() **will not** report a complete and exhaustive
state of dependencies between IDs. Should work OK in most cases though.
Original work/idea comes from id-remap branch, was heavily reworked by @campbellbarton
and myself for master.
Reviewers: campbellbarton, sergey
Differential Revision: https://developer.blender.org/D1678
Looping twice on same ID pointer may not be an issue in master currently, but with work done in id-remap
branch this should be avoided as much as possible, so for now assuming we do not need this here.
Note: if we really need this and have to add it back, then please at least use IDWALK_USER, and not
IDWALK_NOP flag!
As we can see in (original) read code, ob pointer in groupobject is actually a 'USER_ONE' case.
This was not done in 'add object to group' code, probably because we can assume objects always
have at least one user in that case? Made it explicit now. Also fixed foreach_ID_link looper.
In general we have waaayyyyyy too much 'own handling' of ID->us count in code currently,
will clean up that...
Duplicate wasn't updating links,
so duplicatinvg a objects would still point to the originals for curve-taper, texmesh, drivers.
Use generic id-looper to handle replacing data.
This func is long enough, there's no real need to make it even longer with
verbose local varnames and multi-line for loops...
Also, avoid mono-leters names as well for data pointers.
Root of the issues comes to the fact that it's possible to produce
a situation when library object data uses local object. This is
actually forbidden and not supported by .blend IO.
Made it so Make Local wouldn't produce such an unsupported states.
Reviewers: brecht
Differential Revision: https://developer.blender.org/D372
