The existing mix of UniquePtr and raw pointers is confusing when
trying to figure out the exact lifetime of these objects.
MozReview-Commit-ID: Br4S7BXEFKs
I tried to make TableUpdateArray point to const TableUpdate objects
everywhere but there were two problems:
- HashStore::ApplyUpdate() triggers a few Merge() calls which include
sorting the underlying TableUpdate object first.
- LookupCacheV4::ApplyUpdate() calls TableUpdateV4::NewChecksum() when the
checksum is missing and that sets mChecksum.
MozReview-Commit-ID: LIhJcoxo7e7
Manually keeping tabs on the lifetime of these objects is a pain
and is the likely source of some of our crashes. I suspect we might
also be leaking memory.
This change creates an explicit copy of the main array into the
update thread to avoid using a non-thread-safe shared data
structure. This is a shallow copy. Only the pointers to the
TableUpdates are copied, which means one pointer per list (e.g. 5
in total for google4 in a new profile).
MozReview-Commit-ID: 221d6GkKt0M
Disk corruption can lead to the stored length of a value to be
unreasonably large and trigger an OOM.
Since values are all currently <= 32 bytes, we can safely enforce
a 256-byte upper bound.
MozReview-Commit-ID: XygReOpEK3
In this patch, we will make Safebrowsing V2 caching use the same algorithm as V4.
So we remove "mMissCache" for negative caching and TableFresness check for
positive caching.
But Safebrowsing V2 doesn't contain negative/positive cache duration information in
gethash response. So we hard-code a fixed value, 15 minutes, as cache duration.
In this way, we can sync the mechanism we handle caching for V2 and V4.
An extra effort for V2 here is that we need to manually record prefixes misses
because we won't get any response for those prefixes(implemented in
nsUrlClassifierLookupCallback::CacheMisses).
LookupCacheV4::Has implements safebrowsing v4 caching logic.
1. Check if fullhash match any prefix in local database:
- If not, the URL is safe.
2. Check if prefix is in the cache(prefix is always the first 4-byte of
the fullhash, Bug 1323953):
- If not, send fullhash request
3. Check if fullhash is in the positive cache:
- If fullhash is found and it is not expired, the URL is not safe.
- If fullhash is found and it is expired, send fullhash request.
4. If fullhash is not found, check negative cache expired time:
- If negative cache time is not expired, the URL is safe.
- If negative cache time is expired, send fullhash request.
MozReview-Commit-ID: GRX7CP8ig49
LookupCacheV4::Has implements safebrowsing v4 caching logic.
1. Check if fullhash match any prefix in local database:
- If not, the URL is safe.
2. Check if prefix is in the cache(prefix is always the first 4-byte of
the fullhash, Bug 1323953):
- If not, send fullhash request
3. Check if fullhash is in the positive cache:
- If fullhash is found and it is not expired, the URL is not safe.
- If fullhash is found and it is expired, send fullhash request.
4. If fullhash is not found, check negative cache expired time:
- If negative cache time is not expired, the URL is safe.
- If negative cache time is expired, send fullhash request.
MozReview-Commit-ID: GRX7CP8ig49
