Ceph

h1. CommonFormatter - make it streamable

h3. Task Name: 

make Formatter streamable

h3. Size:

S

h3. Skill:

intermediate

h3. Mentor(s):

"Sage Weil":mailto:sage@inktank.com

h3. Components:

common/Formatter

optionally adjust users

h3. Description:

The current Formatter interface accumulates everything in an in-memory buffer (or buffers, even), which makes it unusable in cases where we are dumping/formatter large amounts of memory (e.g., a significant portion of the allocate memory).  We should make an alternative interface that lets you specify an ostream for the Formatter and emits output as it goes (instead of appending to the buffer).

h3. External Documentation:

Edit section

 http://stackoverflow.com/questions/524641/how-do-i-create-my-own-ostream-streambuf

there is also an ostream stream_buf in tree; see https://github.com/ceph/ceph/blob/master/src/common/PrebufferedStreambuf.h