Re: [tdf-discuss] Migrating LibreOffice Build System to Bazel

On 10/14/25 20:18, jijinbei wrote:
> If we could gradually replace some of these with well-maintained 
> external ones, we could reduce maintenance cost and modernize the codebase.
>
> For example:
>
>   * our own smart pointer implementations,

        Hmm; the VclPtr<> stuff started off as a migration to std::shared_ptr - but ... IIRC this 
was stymied at the last minute with the results we see today. The existing code (and there is a lot of 
it) - has the habit of doing a lot of referencing during initialization which creates significant 
aggravation here.

        Find, debug and clean all that up, and we can switch to shared_ptr - although we will 
prolly want to keep dispose() still. Quite probably that is do-able by turning all constructor 
content into some 'initialize()' method with the same parameters as a first step, and then making 
all constructors take no state. Big mechanical change there - hopefully reasonably low risk; and 
can be done incrementally - just make sure all OutputDevice derived constructors chain immediately 
to an initialize() method with those parameters if they do not already - then when done - make the 
cut-over.

        https://git.libreoffice.org/core/+/refs/heads/master/vcl/README.lifecycle.md

        Has details - see "One extra gotcha - an initial reference-count of 1" which is the nub of 
the issue.

        Ultimately the switch to having a hard & reliable lifecycle mechanism to replace the 
nightmare of implicit ownership semantics, combined with some horrible mix of shared_ptrs in some 
places made LibreOffice -much- easier to reason about, debug, and ultimately made things like Collabora 
Online possible (I still have too many scars from debugging the old approach =)

        It was a nightmare change - that was extremely hard to keep working vs. the cutting edge of 
the code since pre the new UI re-work from Caolan it was everywhere. Thanks so much to Noel, Bubli 
and others IIRC for helping me out getting it in, and cleaning up some of the follow-on problems.

        HTH,

                Michael.

--
Michael Meeks <>< CEO Collabora Productivity,
St Johns Innovation Centre, Cowley Road, Cambridge CB4 0DS, UK
Registered in England & Wales no 08644931, (M) +44 7795 666 147


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