385350 - nsIDownloader truncates large files (33MB) when a save location isn't specified

Status: NEW

(Core :: Networking: HTTP, defect, P5)

Description

[Benjamin Smedberg]

Attachment: XPCShell testcase

I was trying to use nsIDownloader to save a 33MB file and kept discovering corruption issues. Turns out that if the following conditions are true, nsIDownloader will truncate the file size to something smaller (in my case 25599112 bytes):

1) the download is over HTTP (downloading from file: is ok; I haven't tried HTTPs or other transports)
2) nsIDownloader is initialized with "null" as the second parameter indicating that it should pick a default location. It appears that this location is within the HTTP cache
3) the file is large... I'm not quite sure how large

I've attached an xpcshell testcase. Please change the URL to a local server so that you don't kill my webhost, please.

Looking for usage of nsIDownloader in the tree, the only occurence in Firefox is in the JAR code. There are other occurrences in calendar for downloading ICS files.

I thought I would need this for bug 352762, but I've decided to go a slightly different route for a workaround.

Comment 1

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

> 25599112 bytes):

the default cache size is 50 MB; files in the cache can't be larger than half the cache size:
http://lxr.mozilla.org/seamonkey/source/netwerk/cache/src/nsDiskCacheDevice.cpp#692

that's somewhat unfortunate here...

Comment 2

[Firefox Bug Husbandry Bot]

Bulk change to priority: https://bugzilla.mozilla.org/show_bug.cgi?id=1399258