[FOP-1610] Thread-safety issue rendering SVG

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 2.5
• Component/s: renderer/svg
• Environment: Operating System: All; Platform: All; URL: http://markmail.org/message/2dk2ib4e5t6vfsrl
• External issue ID: 46360
• Assignee: fop-dev
• Reporter: Jeremias Maerki
• Created: 07/Dec/08 05:55
• Updated: 02/Sep/10 07:52
• Resolved: 28/Mar/12 08:38

Description

FOP reuses/caches SVG documents to improve performance. But as we had to learn, this approach is not thread-safe as Batik attaches some facilities (like the CSS engine) to the DOM which are not thread-safe. The detailed discussion of the issue can be found here:
http://markmail.org/message/2dk2ib4e5t6vfsrl

The safest approach is to clone the SVG DOM prior to passing it to Batik.

Obviously that will cost a bit of performance and increase memory usage a bit. If we're careful and have the resources to implement that we can improve performance by caching Batik's GVT tree. Ideas can also be found in the thread indicated above.