Lumiera
The new emerging NLE for GNU/Linux

State

Dropped

Date

Fr 22 Apr 2011 10:46:50 CEST

Proposed by

Christian Thaeter <ct@pipapo.org>
Abstract

liblumiera contains a lot of useful and re-useable code which is already in use by other projects

Description

Over the time we’ve put some efforts into the liblumiera. I have added some from my code which predates the Lumiera project and which I am using on many other projects. This means that I would have to maintain these sources in different unrelated projects and have to cross merge and update several copies of the same code when I do updates and fixes somewhere. I think its time to factor the re-useable parts out into a independent library (similar to what Glib does for GTK). In fact, I had this plan long ago.

What parts are eligible for a standalone library

Anything which is something tool alike and useful for other projects and not tied to Lumiera only. This are the algorithms/datastructures, allocators, tool macros. Additionally some of the src/common things should be moved into the library. I give some lists below.

How to name it

Long time ago my plan was to name it ‘ctlib’ or ‘cehlib’ but meanwhile there is enough code done by others. So I’d propose a more neutral name, still ‘lumieralib’ or ‘lulib’ would be appropriate. The only thing we have to account for is that some parts which are too specific for Lumiera and should not be integrated into this spinoff need either to stay in a lumiera-internal lib (src/lib/) as currently or being moved to the respective subsystems using them (src/backend, src/proc, src/common, …), so the names should not clash.

C, C++ …

For myself I need the C parts, while there is C++ code which interfaces to the C implementations and also a lot code which does nice C++ things on its own. This possibly means that we should in fact make 2 packages out of this, one C and one C++ library (where the C++ part is more than just the wrappers, but also the tools and tricks which are currently in src/lib/ and reusable).

Who maintains it

Despite of being a spin-off I think we don’t want to change anything from our current practice and maintain it by the Lumiera developers. In part I feel responsible for it, while it is really a part of the Lumiera codebase, despite of being independently usable.

How to maintain it

We need to decide about build system and documentation system. As build system we may right start using SCons. For documentation the situation is somewhat different since some of my code uses pipadoc/asciidoc and other uses doxygen.

What not to do

Some of the code is currently quite specific to Lumiera while it could be made more generic. This is NOT subject of this RfC — we may or may not do such a refactoring but this RfC and any work resulting from this should be restricted to simple things like necessary namespace and variable renaming and integration in the build system.

C Parts

Library

What belongs to the library

Containers

  • cuckoo hashing (cuckoo.c|h)

  • linked lists (llist.h)

  • cache lists (mrucache.c|h)

  • splay trees (psplay.c|h)

  • priority queues (not done yet)

Runtime tools

  • error handling (error.h error.c) used by the other facilities too

  • clib convenience wrappers (safeclib.c|h) needs better name, maybe refactor into new facilities

Multithreading

  • locking, condition variables etc. (condition.c|h (rec)mutex.c|h, rwlock …)

Memory management

  • Memory pools (mpool.c|h)

  • Temporary buffers (tmpbuf.c|h)

Metaprogramming

  • preprocessor tools (ppmpl.h) move common preprocessor macros here

  • polymorphic call helper for C (vcall.h)

Interface system and module loader

except for some hardcoded references to ‘lumiera_org’ and ‘.lum’ plugin names this is quite generic, possibly moving this over could be postponed, but might eventually be done.

From src/common

interface.c interfacedescriptor.h interface.h interfaceproxy.cpp
interfaceregistry.c interfaceregistry.h plugin.c plugin_dynlib.c plugin.h

The “config system” could become a candidate too if it ever gets finished and proves itself useful, but for the time being it’s better kept in Lumiera.

Not Library

Tied specifically to Lumiera:

luid.c luid.h time.h

C++ Parts

For most of the C++ parts I am not sure, ichthyo should decide upon these (please edit this here)

Library

These look generic or wrap the C parts:

singleton-factory.hpp singleton.hpp singleton-policies.hpp
singleton-preconfigure.hpp singleton-ref.hpp singleton-subclass.hpp
sync-classlock.hpp sync.cpp sync.hpp thread-local.hpp
typed-allocation-manager.hpp typed-counter.hpp util.cpp util-foreach.hpp
util.hpp variant.hpp

Not Sure

access-casted.hpp advice advice.hpp allocation-cluster.cpp
allocation-cluster.hpp bool-checkable.hpp cmdline.cpp cmdline.hpp del-stash.hpp
diagnostic-context.hpp element-tracker.hpp error.hpp (currently too
lumiera specific) exception.cpp (as before) factory.hpp format.hpp
frameid.hpp functor-util.hpp handle.hpp hash-indexed.hpp iter-adapter.hpp
iter-adapter-stl.hpp iter-source.hpp itertools.hpp iter-type-binding.hpp
lifecycle.cpp lifecycleregistry.hpp lumitime-fmt.hpp lumitime.hpp
multifact-arg.hpp multifact.hpp meta/* null-value.hpp observable-list.hpp
opaque-holder.hpp optional-ref.hpp p.hpp query.cpp query.hpp ref-array.hpp
ref-array-impl.hpp result.hpp scoped-holder.hpp scoped-holder-transfer.hpp
scoped-ptrvect.hpp searchpath.cpp searchpath.hpp sub-id.hpp symbol.hpp
symbol-impl.cpp visitor-dispatcher.hpp visitor.hpp visitor-policies.hpp
wrapper.hpp wrapperptr.hpp appstate.cpp appstate.hpp basic-setup.cpp
basic-setup.hpp DIR_INFO external guifacade.cpp instancehandle.hpp option.cpp
option.hpp query subsys.cpp subsys.hpp subsystem-runner.hpp

Not Library

logging.cpp nobug-init.cpp nobug-init.hpp streamtype.cpp streamtype.hpp test/*
time/* time.cpp tree.hpp

Tasks

  • decide on name, namespaces WIP

  • create git repository, setup boilerplate (build system, legalise) WIP

  • move all code over into the git repos, refactor (namespace renames) () WIP

  • make Lumiera use the new lib WIP

Discussion

Pros

  • I am already reuse much of its code, making it independent makes maintaining it less burden

Cons

  • new packages, new dependencies for Lumiera instead batteries included

Alternatives

Do nothing and handle fixes on a case by case base.

Comments

State → Dropped

Ongoing development over the following years (after 2011) helped to clarify the situation regarding the support library in Lumiera. The improved language standards, most notably C++14, obsoleted most of the ad-hoc solutions in our library, since many aspects of system integration are now handled by language and STL facilities in a satisfactory way. On the other hand, by using the heightened capabilities of the language, some solution patterns very specific to Lumiera could be established, gradually turning the support library into some kind of an application framework.

It is quite common in the field of software development to put great hopes into code reuse — yet it is this very tendency towards a framework which prevents that ideal from playing out as anticipated, in practice. What seems to work best is to look at some well-made piece of software, understand how it works, and then to copy and extract parts in order to transform it into your own solution.

Ichthyostega

2025-09-16

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