Armin Le Grand (allotropia)
ae7807c889
The issue is that the flag RegisteredAtPool at the SfxPoolItem is Pool-dependent: It marks that the Item is registeres at *one* Pool/Model. This makes it Pool-dependent. Due to this there is no way to share Items that need to be registered globally/ in multiple Pools/Models what is one of the goals for optimal sharing. We can also not live without having access to all Items associated with the Pool, due to mechanisms in place like the Surrogate stuff. This again is used for two purposes: (1) Access all Items associated with one Pool/Model, at least that is the assumption. This is not valid since it gets corrupted with a single ItemSet/Holder used that does not host model data, e.g. an open Dialog or the Sidebar (or...). But works in principle. (2) Access extra-Items that are held nowhere and are created using DirectPutItemInPool, e.g. infos for a Dialog. These would need a instance/place to host them, the Pool is (ab)used for that. Both are 'compromizes' (to not use a more bad word) and should not exist. (1) should iterate over the Model and do actions. There are even places that use (1) to *change* Items, by casting them to non-const, even RefCounted ones, so having no control over what all might be changed doing so. Since we talk about ca. 100+ places there is no way to get away from this - I can imagine how this happened: The 'poolable' attr traditionally needed for the old binary format was one day 'used' to not need to iterate over the Model, an API was added to access and this usage was copied. Sigh.. It is even used when ODF is loaded: E.g. the FillStyle is imported from XML, interpreted, and put into an ItemSet. Then it gets set at the XShape using UNO API and a *name* -> that name and the Surrogate mechanism is used to find and set the FillStyle at the Model Object. The FillStyle could probably just be set using UNO API and the data directly. The association between Model/Pool and Item is created by the object hosting the Item, these are ItemSets and ItemHolders. Thus it is possible to register these at the Pool. This allows to iterate and collect the Items associated with the Pool and keep the Surrogate mechanism alive. This is the main change done here. It limits the registrations to Items for which (at the Pool) the NeedsPoolRegistration is set, also Item-independent. Speed is okay, I saw no big changes in my tests here. The registration is just pointers, no ownership or RefCounting needed here. The advantage is that Items get closer to be shared office-wide, they can be referenced by multiple ItemSets (RefCnt) associated with different Pools/Models. NOTE: This is not true for SfxSetItems, these are and will stay Pool-dependent due to their need to a Pool in the contained ItemSet. Note that we have ca. six deivations of SfxSetItem, but ca. 500+ Item derivations, so not too bad. For the usages of Surrogates to change existing, RefCounted Items: These can now at least be changed - if they show up to be problematic - to iterate over the registered ItemSets and change Items there the correct way: Set a changed one at the ItemSet. That also allows Objects to *react* on ItemChanges, there is no way to do that with the existing 'compromize'... UnitTests show that this already works well for SC and SD, but SW has still some issues. I will put this to gerrit now, but there will be additional work. A involved problem is the current DefaultItem handling and the state the Pool implementation is in. E.g. StaticDefaults are not really static, Pools hard-delete the DefaultItems (forcing the RefCnt to zero to not have the destructor complain) and other quirks. Looking at that right now, hoping to get this change done without having to change that too much. I thought about adapting PoolItemTest to this, but it is only related to DirectPutItemInPool which is mostly gone and hopefully completely soon. Nonetheless I adapted that mechanism to use a list of SfxPoolItemHolder at the Pool. That makes it safe and abandons the need for indirect garbage collection removal at the Pool. Change-Id: Ib47f21dafa989202930919eace5f7e9c5632ce96 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/161896 Tested-by: Jenkins Reviewed-by: Armin Le Grand <Armin.Le.Grand@me.com>
LibreOffice
LibreOffice is an integrated office suite based on copyleft licenses and compatible with most document formats and standards. Libreoffice is backed by The Document Foundation, which represents a large independent community of enterprises, developers and other volunteers moved by the common goal of bringing to the market the best software for personal productivity. LibreOffice is open source, and free to download, use and distribute.
A quick overview of the LibreOffice code structure.
Overview
You can develop for LibreOffice in one of two ways, one recommended and one much less so. First the somewhat less recommended way: it is possible to use the SDK to develop an extension, for which you can read the API docs and Developers Guide. This re-uses the (extremely generic) UNO APIs that are also used by macro scripting in StarBasic.
The best way to add a generally useful feature to LibreOffice is to work on the code base however. Overall this way makes it easier to compile and build your code, it avoids any arbitrary limitations of our scripting APIs, and in general is far more simple and intuitive - if you are a reasonably able C++ programmer.
The Build Chain and Runtime Baselines
These are the current minimal operating system and compiler versions to run and compile LibreOffice, also used by the TDF builds:
- Windows:
- Runtime: Windows 7
- Build: Cygwin + Visual Studio 2019 version 16.10
- macOS:
- Runtime: 10.15
- Build: 12 (13 for aarch64) + Xcode 14
- Linux:
- Runtime: RHEL 8 or CentOS 8 and comparable
- Build: either GCC 12; or Clang 12 with libstdc++ 8.5
- iOS (only for LibreOfficeKit):
- Runtime: 11.4 (only support for newer i devices == 64 bit)
- Build: Xcode 9.3 and iPhone SDK 11.4
- Android:
- Build: NDK r23 and SDK 30.0.3
- Emscripten / WASM:
- Runtime: a browser with SharedMemory support (threads + atomics)
- Build: Qt 5.15 with Qt supported Emscripten 1.39.8
- See README.wasm
Java is required for building many parts of LibreOffice. In TDF Wiki article Development/Java, the exact modules that depend on Java are listed.
The baseline for Java is Java Development Kit (JDK) Version 17 or later.
If you want to use Clang with the LibreOffice compiler plugins, the minimal version of Clang is 12.0.1. Since Xcode doesn't provide the compiler plugin headers, you have to compile your own Clang to use them on macOS.
You can find the TDF configure switches in the distro-configs/ directory.
To setup your initial build environment on Windows and macOS, we provide the LibreOffice Development Environment (LODE) scripts.
For more information see the build instructions for your platform in the TDF wiki.
The Important Bits of Code
Each module should have a README.md file inside it which has some
degree of documentation for that module; patches are most welcome to
improve those. We have those turned into a web page here:
However, there are two hundred modules, many of them of only peripheral interest for a specialist audience. So - where is the good stuff, the code that is most useful. Here is a quick overview of the most important ones:
| Module | Description |
|---|---|
| sal/ | this provides a simple System Abstraction Layer |
| tools/ | this provides basic internal types: Rectangle, Color etc. |
| vcl/ | this is the widget toolkit library and one rendering abstraction |
| framework/ | UNO framework, responsible for building toolbars, menus, status bars, and the chrome around the document using widgets from VCL, and XML descriptions from /uiconfig/ files |
| sfx2/ | legacy core framework used by Writer/Calc/Draw: document model / load/save / signals for actions etc. |
| svx/ | drawing model related helper code, including much of Draw/Impress |
Then applications
| Module | Description |
|---|---|
| desktop/ | this is where the main() for the application lives, init / bootstrap. the name dates back to an ancient StarOffice that also drew a desktop |
| sw/ | Writer |
| sc/ | Calc |
| sd/ | Draw / Impress |
There are several other libraries that are helpful from a graphical perspective:
| Module | Description |
|---|---|
| basegfx/ | algorithms and data-types for graphics as used in the canvas |
| canvas/ | new (UNO) canvas rendering model with various backends |
| cppcanvas/ | C++ helper classes for using the UNO canvas |
| drawinglayer/ | View code to render drawable objects and break them down into primitives we can render more easily. |
Rules for #include Directives (C/C++)
Use the "..." form if and only if the included file is found next to the
including file. Otherwise, use the <...> form. (For further details, see the
mail Re: C[++]: Normalizing include syntax ("" vs
<>).)
The UNO API include files should consistently use double quotes, for the benefit of external users of this API.
loplugin:includeform (compilerplugins/clang/includeform.cxx) enforces these rules.
Finding Out More
Beyond this, you can read the README.md files, send us patches, ask
on the mailing list libreoffice@lists.freedesktop.org (no subscription
required) or poke people on IRC #libreoffice-dev on irc.libera.chat -
we're a friendly and generally helpful mob. We know the code can be
hard to get into at first, and so there are no silly questions.