Flat ODF as the Swiss Army Knife

Transcript

1. Flat ODF
   as the Swiss Army Knife
   Fridrich Štrba
   Software Engineer
   SUSE/Attachmate
   

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2. What is Flat ODF
   

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3. 3
   “Normal” ODF File
   • Package OpenDocument File
   ‒ Chapter 3.1.3 of ODF 1.2 specifications
   ‒ Collection of xml files in a ZIP container
   ‒
   ‒
   ‒
   ‒
   ‒ Images and OLE objects sub-streams in the ZIP container
   ‒ Referenced by xlink:href attribute
   

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4. 4
   “Flat” ODF file
   • Single OpenDocument XML Files
   ‒ Chapter 3.1.2 of the ODF 1.2 specifications
   ‒ Contains the whole document
   ‒ root element
   ‒ office:mimetype and office:version attributes
   ‒ Images and OLE objects inlined
   ‒ [base64 data]
   

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5. 5
   ZIP Storage (1)
   • Main entry point is the Central Directory End
   located at the end of the ZIP file.
   ‒ Scanning for it towards the end of the file
   ‒ Whole file must be present
   • Pointing at the Central Directory containing entries
   ‒ For name access, iterate over them
   ‒ Need to seek back to read the entry
   • Which contains pointer to Local File Header
   ‒ Seek to local file-header offset
   ‒ Need to seek back again
   ‒ The content of the stream comes after the header
   

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6. 6
   ZIP Storage (2)
   FILE
   ENTRY 1
   
   FILE
   ENTRY 2
   
   FILE
   ENTRY 3
   
   FILE
   ENTRY 4
   
   Local header 1
   Local header 2
   Local header 3
   Local header n
   Relative offset 2
   Relative offset 1
   Relative offset 3
   Relative offset n
   File entry 1
   File entry 2
   File entry 3
   n
   CENTRAL
   DIRECTORY
   

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7. Advantages of Flat ODF
   

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8. 8
   No Need for Special tools
   • No need for compression and stream extraction
   tools
   ‒ ODF documents can be generated manually
   ‒ Developer modifying a document
   ‒ XSLT tools
   ‒ Programmatic generation of documents
   ‒ Further processing of documents
   ‒ Easier parsing of document and extraction of relevant information
   

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9. 9
   Sequential Access to File
   • Difference with ZIP file
   ‒ No need to know the end of the file to start to parse it
   • Exchange file-format par excellence
   ‒ Possibility to communicate document as SAX messages
   ‒ Communicate XML to an application sequentially
   ‒ Possibility to stream document over wire
   ‒ Collaboration protocol?
   ‒ Communication with CMS systems?
   

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10. 10
    Storing documents in SCM
    • Package ODF file
    ‒ Stored as binary file
    ‒ Impossibility to see reasonable diff to previous version
    • Simple XML ODF file
    ‒ A text file after all
    ‒ Difference are easily visible between revisions
    ‒ SCMs are designed to handle text files the best
    ‒ Example of LibreOffice templates
    ‒ Stored in git repository
    

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11. Examples of Flat ODF use
    

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12. 12
    LibreOffice UNO Filter API
    • XSLT based filters
    ‒ com.sun.star.comp.Writer.XMLOasisImporter
    ‒ pushes to LibreOffice flat ODT
    ‒ com.sun.star.comp.Calc.XMLOasisExporter
    ‒ receives from LibreOffice flat ODS
    • XML based filters
    ‒ com::sun::star::xml::sax::XDocumentHandler
    ‒ com.sun.star.document.ImportFilter pushes SAX messages to
    com::sun::star::xml::sax::XDocumentHandler
    ‒ com.sun.star.document.ExportFilter is itself a
    com::sun::star::xml::sax::XDocumentHandler and receives SAX
    messages from LibreOffice
    

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13. 13
    File importers
    • Writerperfect ODT generator
    ‒ Libwpd – WordPerfect documents
    ‒ Generates ODT with embedded WPG files as
    elements in flat ODG
    ‒ Libwps – Microsoft Works
    ‒ Generates ODT
    • Writerperfect ODG generator
    ‒ Libwpg – WordPerfect graphics
    ‒ Libvisio – Microsoft Visio diagrams
    ‒ Libcdr – CorelDraw drawings
    ‒ Libmspub – Microsoft Publisher publications
    ‒ Generate ODG documents
    

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14. Thank you.
    14
    Single XML OpenDocument
    representation is an important
    part of the ODF ecosystem
    

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15. Corporate Headquarters
    Maxfeldstrasse 5
    90409 Nuremberg
    Germany
    +49 911 740 53 0 (Worldwide)
    www.suse.com
    Join us on:
    www.opensuse.org
    15
    

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