74668 - [rfe] Provide a way to determine what cache device a given nsICacheEntryDescriptor is talking about

Status: VERIFIED FIXED

(Core :: Networking: Cache, enhancement)

Description

[Daniel Brooks [:db48x]]

The old cache had a property that was a reference back to the actual cache
object. Dunno yet how that translates over to the new cache architecture, but
similar I need similar functionalilty. I'm using this information for the page
info window, where it is desireable it be able to tell if whether a given
document is cached, where it's cached and where it's stored (path to a file for
the disk cache, for example). I could get this information by getting an
nsICacheVisitor and iterating through all the cached objects looking for the one
in question, but that seems a tad bit inefficient.

Comment 1

[gordon]

I'm not so sure we want to maintain this functionality in precisely the same way.  
I think reporting the storage policy that the entry is stored with will less 
problematic.

Entries in the disk cache may not be stored in a separate file soon, unless they 
are explicitly requested (reducing performance).  Also in the future, we would 
like to be able to migrate entries, or duplicate entries between disk and memory 
caches.

We also may be moving to a model where all objects for the current page are 
cached, so it may not make any sense to report that a page is cached (http:// 
will be cached, file:// won't be).

Darin?  Patrick?  Other comments?

Comment 2

[Daniel Brooks [:db48x]]

Agreed. There isn't much point in rewriting something if you're going to keep
doing everything the same old way. At minimum I'd like to be able to show which
cache an object is in (currently a choice between Disk and Memory, it looks
like). That should be easy enough to show by just mentioning which storage
policy was acutally used, as you say. The other stuff is just there because it's
shown in ns4.7x and IE, so surely we must do the same thing. Sounds like a plan
to me.

Comment 3

[gordon]

Actually, the storage policy indicates which caches COULD be used, not 
necessarily which cache is currently used.  It may be important to a user to know 
that a particular entry won't be allowed in the disk cache, for example.

If we REALLY NEED to learn the device from the descriptor, we could add a read-
only attribute.

Comment 4

[gordon]

Okay, Darin convinced me.  We will add deviceID as a read-only attribute on 
nsICacheEntryInfo.

Comment 5

[gordon]

Attachment: patch to add DeviceID attribute to nsICacheDescriptor

Comment 6

[Darin Fisher]

looks good r/sr=darin

Comment 7

[Patrick C. Beard]

r=beard

Comment 8

[gordon]

Changes checked in.

Comment 9

[Brant Gurganus]

[RFE] is deprecated in favor of severity: enhancement.  They have the same meaning.

Comment 10

[benc]

http://bonsai.mozilla.org/cvslog.cgi?file=mozilla/netwerk/cache/public/nsICacheVisitor.idl
change for 1.9