SpreadsheetML

SpreadsheetML is the XML format used by Microsoft Excel 2007 and that is part of the Office Open XML specification.

SpreadsheetML Basics

workbook

A SpreadsheetML document is described at the top level by a workbook part ( /xl/workbook.xml ). The type of the work book type is

 http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument

The workbook part contains document's metadata and one or more sheets. Each sheet can be a worksheet, a chart sheet, or a dialog sheet.

Both strings and formulas are stored in shared tables to avoid redundant storage and speed file I/O's.

Sample Files

Convenient locations to download sample files are here

• Gnumeric repository
• OpenOffice.org repository
• ooo-build repository

Implementation Strategy

Eventually, the code handling SpreadsheetML import will merge with the existing Excel binary filter. As such, the new code needs to be designed with this in mind. It's always desirable to understand how the existing binary filter works when implementing the XML filter to make the future merging work less painful.

Code Organization

Source files for handling the SpreadsheetML format are located in inc/oox/xls and source/xls under module oox. A good place to start tracing the code would be ExcelFilter::Import and follow the calls it makes.

A substream in the XML package is called "fragment", and each fragment has an associated *fragment.hxx header file. For instance, the code for loading of the workbook.xml fragment is found in workbookfragment.hxx, and so on.

A nested element is called "context", and, like the fragments, each context has an associated *context.hxx. For instance, the code for parsing the <sheetData> element is found in sheetdatacontext.hxx.

The term workbook in this context refers to an entire document which includes worksheets and other document metadata, whereas the term worksheet refers to each individual sheet in the workbook.

The existing binary Excel filter is located in sc/source/filter/(inc|excel)/xi(page|view).(c|h)xx. The XclImpTabViewSettings class handles importing sheet's view settings, which corresponds to worksheet/sheetViews context in the XML format.

The UNO interface code is found in sc/source/ui/uno.

Handling Fragment

WorkbookFragment (class)

Handles loading of workbook.xml fragment. It loads the associated relationship file (xl/_rels/workbook.xml.rels) in the constructor.

Handling Context

In most cases the fragment handler will handle all nested contexts by itself to increase performance. For this, some helper classes have been implemented that do all needed work to deal with nested contexts (ContextHelper, FragmentBase, and ContextBase respectively in contexthelper.hxx, excelfragmentbase.hxx, and excelcontextbase.hxx). In general, for implementing a new fragment or context handler, the interface of the ContextHelper class from contexthelper.hxx has to be implemented. The classes FragmentBase (excelfragmentbase.hxx) and ContextBase (excelcontextbase.hxx) already provide default implementations of all virtual functions, but a derived class is free to implement them as well.

Relation (class)

Holds three string data for ID, Type and Target (need more info).

AddressConverter (class)

converts strings to addresses and ranges, and tracks invalid addresses (e.g. a not-importable cell at address ZZZ1000000). Later, this information will be used to generate a "Imported document contains data outside of sheet limits" warning box after loading. Header: addressconverter.hxx

UnitConverter (class)

provides basic unit conversion, including font dependent stuff such as calculating column width from a specific number of characters. Header: unitconverter.hxx

Development

Feature	Developer	OOo 3.0	OOo 3.2	OOo 3.3	OOo 3.4	Comments/Missing
Framework, fragment handling	cl/dr	yes
Password, decryption	cmc/dr		yes			For all filters: Word, Excel, Powerpoint
Workbook, worksheet fragment, sheet names	tbe/dr	yes
Simple cell contents (values, strings)	dr	yes				missing Calc feature: error cells
Shared strings	dr	yes
Simple cell formatting (alignment, protection, borders, fill)	dr	yes
Builtin number formats	dr	yes
Font handling for cells	tbe/dr	yes
Cell styles (names, formatting)	dr	yes
Column settings (format, width, outlines)	tbe/dr/kohei	yes				missing Calc feature: outline symbol position
Row settings (format, height, outlines)	tbe/dr/kohei	yes				missing Calc feature: outline symbol position
Rich text in cells	dr	yes
Scheme fragment, scheme colors	dr	yes
Cell formulas, array formulas, shared formulas	dr	yes
Conditional formatting	dr	yes
External references/links	dr/er	partly	yes
Print ranges, builtin defined names	dr	yes
Page/print settings	dr	yes
Page header/footer	kohei/dr	yes
Column/row breaks	kohei	yes
Sheet/document view settings	dr	yes
Cell hyperlinks	dr/kohei	yes				because a cell hyperlink is a in-cell text field object in Calc, as opposed to a cell property in Excel, a hyperlink will not get imported when the cell is a value cell.
Label ranges [reference]						MS Office 2007 has dropped support for this feature.
Data validation	dr	yes
Web queries	kohei	partly			yes
Pivot tables	dr	partly	yes			The geometry of Calc's data pilot and Excel's pivot table objects are different, so some overlapping problems are expected.
Auto filter, user filter	kohei	partly			yes	Some incompatible bits present, so we have to be creative in importing Excel's autofilter items.
Tables	dr	yes
Table filters	dr				yes
Scenarios	dr		yes
Drawing objects	sj/dr	yes
Charts - chart types	dr	yes				Supported types: bar/column 2D/3D clustered/stacked/percent, line 2D/3D standard/stacked/percent, area 2D/3D, stock (4 types), line radar, pie 2D/3D, doughnut, scatter, bubble (OOo 3.2), filled radar (OOo 3.2). Missing: surface (mapped to 3D bars).
Charts - titles/legend	dr	yes
Charts - series settings	dr	yes				Including: sheet source links, primary/secondary axes, error bars, trendlines.
Charts - formatting	dr	yes				Including: manual formatting, chart styles.
Charts - titles/legend/plot area position	iha/dr			yes
Charts - embedded drawing objects	iha/tbe/dr			yes
OLE objects, ActiveX controls	sj/hbrinkm/dr		yes
Drawing controls	dr				yes
Cell notes	dr		partly			Includes import of VML shape formatting usable for all filters. Missing: Rich text formatting.
Change tracking	dr
VBA project	dr			yes

External References

• xl/workbook.xml contains externalReference tags that references relationship items in xl/_rels/workbook.xml.rels by rID.
• xl/_rels/workbook.xml.rels contains path(s) to external link fragments, that are usually xl/externalLinks/externalLink*.xml.
• xl/externalLinks/externalLink*.xml contains summary content information of the external book being referenced. It should provide enough information to display external cell's content. It also contains reference to the path to the external file by rID.
• xl/externalLinks/_rels/externalLink*.xml.rels contains the path to the external file, stored by rID.

Inside a cell that contains an external cell reference, the format is given

 <f>[1]Sheet1!A1</f>

as formula.

Data Validations

The UNO API for data validation is here.

ScConditionEntry needs new methods to allow setting pFormula1 and pFormula2 that are of type ScTokenArray. ScValidationData is an immediate child class of ScConditionEntry, and it represents the data validation attribute of a cell.

ScTableValidationObj implements UNO wrapper for ScValidationData, and this class needs to implement the css::sheet::XFormulaTokens interface so that the client code can pass formula tokens to this class, and that formula token set needs to eventually find its way into ScValidationData as ScTokenArray.

Web Queries

There are 5 relevant sections to touch.

• /xl/worksheets/_rels/sheet?.xml.rels - contains the paths to query table properties fragments.
• /xl/queryTables/queryTable?.xml - contains query table properties, especially their name and associated connection IDs.
• /xl/_rels/workbook.xml.rels - contains the path to connections properties fragment.
• /xl/connections.xml - contains connections properties, such as URL.
• /xl/workbook.xml - defined names are used to associate a cell range to a query table by name.

The import strategy is to:

1. Store the query table properties into query table container, with name as a key.
2. Store the connections properties into connection container, with connection ID as a key.
3. Parse a defined name and see if a query table for the same name exists.
4. If yes, get the connection ID from the query table list.
5. Get the connection properties by that ID from the connection list.
6. Connect to the URL for data retrieval.

Pivot Table

• /xl/workbook.xml - contains the IDs of pivot table caches and their relation IDs.
• /xl/_rels/workbook.xml.rels - contains paths to pivot table cache fragments and their IDs.
• /xl/worksheets/_rels/sheet?.xml.rels - contains path to pivot table xml fragment(s). Note that the source sheet fragment does not contain the relation ID to such pivot table fragment.
• /xl/pivotTables/pivotTable?.xml - contains the pivot table definitions.
• /xl/pivotTables/_rels/pivotTable?.xml.rels - contains the path to pivot table cache.
• /xl/pivotCache/pivotCacheDefinition?.xml - pivot cache definitions.
• /xl/pivotCache/_rels/pivotCacheDefinition?.xml.rels - contains the path to pivot cache records.
• /xl/pirovtCache/pivotCacheRecords?.xml - pivot cache records.

Related

• [[How to import Pivot Table in oox module]]

See Also

• sc module page for the implementation of Calc core.