Bug 104302

Summary: JPEGImageDecoder should use SharedBuffer::getSomeData() instead of data()
Product: WebKit Reporter: Hin-Chung Lam <hclam>
Component: ImagesAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: enne, jamesr, nduca, noel.gordon, pkasting, qinmin, senorblanco
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   

Description Hin-Chung Lam 2012-12-06 14:15:38 PST 
JPEGImageDecoder calls data() to consolidate the entire buffer into one piece. This involves memcpys and can possibly avoided by using getSomeData().
Comment 1 noel gordon 2013-04-15 08:04:47 PDT 
Noticed in the animated webp patch bug 113124, that a member variable m_demux (a webp demux object needed for decoding) is used to read the SharedBuffer::data(). 
The m_demux object internally maintains pointers into that data().

That's probably ok for a single pass through decode(). However, for progessive decoding of large webp images, decode() is called multiple times.  Any new calls SharedBuffer::data() in any decode() might cause that data() to be consolidated if I'm reading this bug correctly?