Like in case of bug 1506534, this telemetry is sampled periodically every time 2GB of data is written to the cache, i.e. when the cache was used for some time and there is a chance that its content has changed significantly.
Differential Revision: https://phabricator.services.mozilla.com/D29678
Whenever a cache entry is accessed during a document load, eTLD+1 of the top level document is added to the entry's metadata. Number of accessing sites is also stored in cache index. So we know how many copies of each entry would we have if we did a first party isolation without data deduplication. The telemetry is sent every time we write 2GB to the cache and then the data is reset. Telemetry report ID is an identifier of the telemetry cycle and it's used to invalidate eTLD+1 hashes in all cache entries.
Differential Revision: https://phabricator.services.mozilla.com/D26425
This patch changes all size limits in CacheObserver to kilobytes. The same unit is used at most places when checking these limits. This avoids uint32_t overflow when converting to bytes and back.
We can hit the limit very easily when writing javascript bytecode as alternative data to the cache entry because all data is written at once but CacheFileOutputStream splits it into chunks which are then written on a backgound thread. 40MB was chosen because bytecode is usually 4x-10x larger than the original data, so it can occupy most of the cache entry which is limited to 50MB.
The bulk of this commit was generated with a script, executed at the top
level of a typical source code checkout. The only non-machine-generated
part was modifying MFBT's moz.build to reflect the new naming.
CLOSED TREE makes big refactorings like this a piece of cake.
# The main substitution.
find . -name '*.cpp' -o -name '*.cc' -o -name '*.h' -o -name '*.mm' -o -name '*.idl'| \
xargs perl -p -i -e '
s/nsRefPtr\.h/RefPtr\.h/g; # handle includes
s/nsRefPtr ?</RefPtr</g; # handle declarations and variables
'
# Handle a special friend declaration in gfx/layers/AtomicRefCountedWithFinalize.h.
perl -p -i -e 's/::nsRefPtr;/::RefPtr;/' gfx/layers/AtomicRefCountedWithFinalize.h
# Handle nsRefPtr.h itself, a couple places that define constructors
# from nsRefPtr, and code generators specially. We do this here, rather
# than indiscriminantly s/nsRefPtr/RefPtr/, because that would rename
# things like nsRefPtrHashtable.
perl -p -i -e 's/nsRefPtr/RefPtr/g' \
mfbt/nsRefPtr.h \
xpcom/glue/nsCOMPtr.h \
xpcom/base/OwningNonNull.h \
ipc/ipdl/ipdl/lower.py \
ipc/ipdl/ipdl/builtin.py \
dom/bindings/Codegen.py \
python/lldbutils/lldbutils/utils.py
# In our indiscriminate substitution above, we renamed
# nsRefPtrGetterAddRefs, the class behind getter_AddRefs. Fix that up.
find . -name '*.cpp' -o -name '*.h' -o -name '*.idl' | \
xargs perl -p -i -e 's/nsRefPtrGetterAddRefs/RefPtrGetterAddRefs/g'
if [ -d .git ]; then
git mv mfbt/nsRefPtr.h mfbt/RefPtr.h
else
hg mv mfbt/nsRefPtr.h mfbt/RefPtr.h
fi
The bulk of this commit was generated by running:
run-clang-tidy.py \
-checks='-*,llvm-namespace-comment' \
-header-filter=^/.../mozilla-central/.* \
-fix
