Writer application code.

Exact history was lost before Sept. 18th, 2000, but old source code
comments show that Writer core dates back until at least November
1990.

== Module contents ==
 * inc: headers available to all source files inside the module
 * qa: unit, slow and subsequent tests
 * sdi
 * source: see below
 * uiconfig: user interface configuration
 * util: UNO passive registration config

== Source contents ==
 * core: Writer core (document model, layout, UNO API implementation)
 * filter: Writer internal filters
   * ascii: plan text filter
   * basflt
   * html: HTML filter
   * inc: include files for filters
   * rtf: thin copy&paste helper around the UNO RTF import filter (in writerfilter)
   * writer
   * ww1
   * ww8: DOC import, DOC/DOCX/RTF export
   * xml: ODF import/export, subclassed from xmloff (where most of the work is done)
 * uibase: user interface (those parts that are linked into sw & always loaded)
 * ui: user interface (optional parts that are loaded on demand (swui))

== Core ==

There is a good overview documentation of basic architecture of Writer core
in the OOo wiki:

http://wiki.openoffice.org/wiki/Writer/Core_And_Layout
http://wiki.openoffice.org/wiki/Writer/Text_Formatting

Writer specific WhichIds are defined in sw/inc/hintids.hxx.

The details below are mainly about details missing from the Wiki pages.

=== SwDoc ===

The central class for a document is SwDoc, which represents a document.

This is a huge class with hundreds of methods; there are some efforts
to split up the class into many smaller classes that implement more
specific interfaces but this is not fully implemented yet; see the various
IDocument* classes.

=== SwNodes ===

Basically a (fancy) array of SwNode pointers.  There are special subclasses of
SwNode (SwStartNode and SwEndNode) which are used to encode a nested tree
structure into the flat array; the range of nodes from SwStartNode to its
corresponding SwEndNode is sometimes called a "section" (but is not necessarily
what the high-level document model calls a "Section"; that is just one of the
possibilities).

The SwNodes contains the following top-level sections:

1. Empty
2. Footnote content
3. Frame / Header / Footer content
4. Deleted Change Tracking content
5. Body content

=== Undo ===

The Undo/Redo information is stored in a sw::UndoManager member of SwDoc,
which implements the IDocumentUndoRedo interface.
Its members include a SwNodes array containing the document content that
is currently not in the actual document but required for Undo/Redo, and
a stack of SwUndo actions, each of which represents one user-visible
Undo/Redo step.

There are also ListActions which internally contain several individual SwUndo
actions; these are created by the StartUndo/EndUndo wrapper methods.

=== Text Attributes ===

The sub-structure of paragraphs is stored in the SwpHintsArray member
SwTxtNode::m_pSwpHints.  There is a base class SwTxtAttr with numerous
subclasses; the SwTxtAttr has a start and end index and a SfxPoolItem
to store the actual formatting attribute.

There are several sub-categories of SwTxtAttr:

- formatting attributes: Character Styles (SwTxtCharFmt, RES_TXTATR_CHARFMT)
  and Automatic Styles (no special class, RES_TXTATR_AUTOFMT):
  these are handled by SwpHintsArray::BuildPortions and MergePortions,
  which create non-overlapping portions of formatting attributes.

- nesting attributes: Hyperlinks (SwTxtINetFmt, RES_TXTATR_INETFMT),
  Ruby (SwTxtRuby, RES_TXTATR_CJK_RUBY) and Meta/MetaField (SwTxtMeta,
  RES_TXTATR_META/RES_TXTATR_METAFIELD):
  these maintain a properly nested tree structure.
  The Meta/Metafield are "special" because they have both start/end
  and a dummy character at the start.

- misc. attributes: Reference Marks, ToX Marks

- attributes without end: Fields, Footnotes, Flys (AS_CHAR)
  These all have a corresponding dummy character in the paragraph text, which
  is a placeholder for the "expansion" of the attribute, e.g. field content.