ea5641baee
Previously, all of the README files have been renamed to README.md and now, the contents of these files were changed to use Markdown format. Other than format inconsistency, some README.md files lacked information about modules, or were out of date. By using LibreOffice / OpenOffice wiki and other documentation websites, these files were updated. Now every README.md file has a title, and some description. The top-level README.md file is changed to add links to the modules. The result of processing the Markdown format README.md files can be seen at: https://docs.libreoffice.org/ Change-Id: Ic3b0c3c064a2498d6a435253b041df010cd7797a Reviewed-on: https://gerrit.libreoffice.org/c/core/+/113424 Tested-by: Jenkins Reviewed-by: Michael Stahl <michael.stahl@allotropia.de> Reviewed-by: Adolfo Jayme Barrientos <fitojb@ubuntu.com>
51 lines
2.1 KiB
Markdown
51 lines
2.1 KiB
Markdown
# Non-Graphical Helper Code (svtools light)
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Contains non-graphical helper code for office applications.
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Specifically this module does not depend on or use includes from module
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vcl. Originally all code in svtools that did not depend on vcl was split
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off into this svl ("svtools light") module.
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In particular the `SfxItemSet` is a property-bag like container that
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stores arbitrary sets of properties for everything from text run
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formats, to Chart regression line properties.
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There are lots of other useful helpers in here for various office
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tasks; much of this code was originally moved from `svx/sfx2`.
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## Items, Pools and Sets
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### SfxPoolItem
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A small reference counted piece of data. Many subclasses, each with a
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unique integer to identify its type (`WhichId`). Can be compared for equality
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(`operator==`), `Clone()`d, and converted to/from `uno::Any` (`QueryValue/PutValue`).
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A pool item may have value semantics ("poolable"), meaning that
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there will generally be only one instance that compares equal per item pool,
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or not, in which case the item will be `Clone()`d quite a bit.
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### SfxItemPool
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Usually there is one item pool per document, with a range of valid `WhichId`s
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that is specific to the type of document.
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The item pool owns all instances of `SfxPoolItem` or its subclasses that have
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ever been added to an item set. It also contains a default item for
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every WhichId, which will be (depending on parameters) returned from item
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sets if the set does not contain an item at this `WhichId`.
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### SfxItemSet
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The item set can be created with a user-supplied range of `WhichId`s; it
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will accept `SfxPoolItems` with matching `WhichId`s and ignore attempts to
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insert items with non-matching `WhichId`s.
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Items that are successfully inserted into the set will be stored in the
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set's `SfxItemPool`, and for poolable items only a single instance that
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compares equal under the predicate `operator==` will be stored in the pool,
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regardless of how many sets contain it, thus conserving memory.
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There are members `m_pWhichRanges` for the valid ranges (as pairs of `WhichId`s),
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`m_nCount` for the number of items contained, and `m_pItems` for the pointers to
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the actual items.
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