198694 - Fix nsTime to handle nsInt64 operations better

Status: RESOLVED FIXED

(Core :: XPCOM, defect, P2)

Description

[[e-mail]]

currently, nsTime has limited arithmetic abilities, and doesn't inherit from
nsInt64, so you can't do simple things like

nsTime(foo) / nsTime(bar)

or

nsTime(foo) / nsInt64(bar)

at the moment, these require horrible constructs like |nsInt64(nsTime(foo)) /
nsInt64(nsTime(bar))| if you have two nsTimes.

on a related topic, the types in prtime.h could use some extra helpers (->
wtc?). doing things like

nsTime(foo) / PR_USEC_PER_SEC

doesn't give you expected results, because the nsTime doesn't cast itself to
anything except PRTime, a.k.a PRInt64. so it's most definitely not
!HAS_LONG_LONG safe. since the PR_USEC_PER_SEC (and related) constants are
defined as UL, you need to wrap them with nsInt64() (not nsTime(), because it
can't cast from UL) to do "real" 64-bit ops. further, since they're UL, if
you're compiling on a machine that defines "long" as 64-bit, then you're asking
for a 64-bit unsigned ctor for nsInt64(), which doesn't exist.

so these convenience classes aren't too convenient, when I end up having to do
things like

nsInt64(PR_Now()) / nsInt64(long(PR_USEC_PER_SEC))

so at the very least, can we get some operators added to nsTime(), get a
PRUint64 ctor for nsInt64(), and get some nice nsInt64/nsTime compatible
convenience constants? perhaps we should be making nsTime inherit from nsInt64
instead...

Comment 1

[Doug Turner (:dougt)]

-> alec.

Comment 2

[Alec Flett]

My mozilla 1.4b is already looking cramped.

patches accepted :)

Comment 3

[Christian :Biesinger (don't email me, ping me on IRC)]

Attachment: patch

this should help... makes nsTime inherit from nsInt64

Comment 4

[Doug Turner (:dougt)]

Comment on attachment 151251 [details] [diff] [review]
patch

looks fine.  

Anyone interested in moving this out of XPCOM and into mailnews -- the main
customer of this class?

Comment 5

[Christian :Biesinger (don't email me, ping me on IRC)]

Checking in nsTime.h;
/cvsroot/mozilla/xpcom/ds/nsTime.h,v  <--  nsTime.h
new revision: 3.11; previous revision: 3.10
done

dwitte wants to use this in cookie code afaik, so moving this into mailnews
would be out...