Turns out it's currently the fastest among the three currently
implemented (Cache, browser.storage.session, indexedDB). Possibly
because indexedDB can natively persist structure-cloneable data,
something uBO can now benefit with the work on abstracting away
the limitations of various storages being limited to persist only
text or JSON data.
Related issue:
https://github.com/uBlockOrigin/uBlock-issues/issues/2969
In uBO, the "cache storage" is used to save resources which can
be safely discarded, though at the cost of having to fetch or
recompute them again.
Extension storage (browser.storage.local) is now always used as
cache storage backend. This has always been the default for
Chromium-based browsers.
For Firefox-based browsers, IndexedDB was used as backend for
cache storage, with fallback to extension storage when using
Firefox in private mode by default.
Extension storage is reliable since it works in all contexts,
though it may not be the most performant one.
To speed-up loading of resources from extension storage, uBO will
now make use of Cache API storage, which will mirror content of
key assets saved to extension storage. Typically loading resources
from Cache API is faster than loading the same resources from
the extension storage.
Only resources which must be loaded in memory as fast as possible
will make use of the Cache API storage layered on top of the
extension storage.
Compiled filter lists and memory snapshot of filtering engines
(aka "selfies") will be mirrored to the Cache API storage, since
these must be loaded into memory as fast as possible, and reloading
filter lists from their compiled counterpart is a common
operation.
This new design makes it now seamless to work in permanent private
mode for Firefox-based browsers, since extension storage now
always contains cache-related assets.
Support for IndexedDB is removed for the time being, except to
support migration of cached assets the first time uBO runs with
the new cache storage design.
In order to easily support all choices of storage, a new serializer
has been introduced, which is capable of serializing/deserializing
structure-cloneable data to/from a JS string.
Because of this new serializer, JS data structures can be stored
directly from their native representation, and deserialized
directly to their native representation from uBO's point of view,
since the serialization occurs (if needed) only at the storage
interface level.
This new serializer simplifies many code paths where data
structures such as Set, Map, TypedArray, RegExp, etc. had to be
converted in a disparate manner to be able to persist them to
extension storage.
The new serializer supports workers and LZ4 compression. These
can be configured through advanced settings.
With this new layered design, it's possible to introduce more
storage layers if measured as beneficial (i.e. maybe
browser.storage.session)
References:
- https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/storage/local
- https://developer.mozilla.org/en-US/docs/Web/API/Cache
- https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm
Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/1664
The changes are enough to fulfill the related issue.
A new platform has been added in order to allow for building
a NodeJS package. From the root of the project:
./tools/make-nodejs
This will create new uBlock0.nodejs directory in the
./dist/build directory, which is a valid NodeJS package.
From the root of the package, you can try:
node test
This will instantiate a static network filtering engine,
populated by easylist and easyprivacy, which can be used
to match network requests by filling the appropriate
filtering context object.
The test.js file contains code which is typical example
of usage of the package.
Limitations: the NodeJS package can't execute the WASM
versions of the code since the WASM module requires the
use of fetch(), which is not available in NodeJS.
This is a first pass at modularizing the codebase, and
while at it a number of opportunistic small rewrites
have also been made.
This commit requires the minimum supported version for
Chromium and Firefox be raised to 61 and 60 respectively.
Cloud storage is a limited resource, and thus it
makes sense to support data compression before
sending the data to cloud storage.
A new hidden setting allows to toggle on
cloud storage compression:
name: cloudStorageCompression
default: false
By default, this hidden setting is `false`, and a
user must set it to `true` to enable compression
of cloud storage items.
This hidden setting will eventually be toggled
to `true` by default, when there is good confidence
a majority of users are using a version of uBO
which can properly handle compressed cloud storage
items.
A cursory assessment shows that compressed items
are roughly 40-50% smaller in size.
... from platform-independent code.
This should complete the de-chromiumification of
uBO. Next step will be to swap the content of the
`platform/chromium` and `platform/firefox`
folders so as to reflect that Firefox is the
natural platform for uBO.
Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/416
The Chromium version of uBO has declared `unlimitedStorage` since the
extension was first published in 2014. Declaring this permission in
Firefox brings uBO inline with the Chromium version. I suspect some
reported errors could be caused by IndexedDB eviction due to the lack
of `unlimitedStorage` permission.
Additionally, a timeout has been added when uBO tries to access its
indexedDB storage. It's unclear whether this will help with the
mentioned related issue though, the root cause is still to be
identified.
Default behavior is to fall back to an alternative backend
if the uBO-selected one is not available. However there will be
no fall back when the `cacheStorageAPI` is set to one specific
backend by the user.
Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/409
By default `indexedDB` is used in Firefox for purpose of cache storage
backend.
This commit allows to force the use of `browser.storage.local` instead
as cache storage backend. For this to happen, set `cacheStorageAPI` to
`browser.storage.local` in advanced settings.
Additionally, should `indexedDB` not be available for whatever reason,
uBO will automatically fallback to `browser.storage.local`.
The motivation is to address the higher peak memory usage at launch
time with 3rd-gen HNTrie when a selfie was present.
The selfie generation prior to this change was to collect all
filtering data into a single data structure, and then to serialize
that whole structure at once into storage (using JSON.stringify).
However, HNTrie serialization requires that a large UintArray32 be
converted into a plain JS array, which itslef would be indirectly
converted into a JSON string. This was the main reason why peak
memory usage would be higher at launch from selfie, since the JSON
string would need to be wholly unserialized into JS objects, which
themselves would need to be converted into more specialized data
structures (like that Uint32Array one).
The solution to lower peak memory usage at launch is to refactor
selfie generation to allow a more piecemeal approach: each filtering
component is given the ability to serialize itself rather than to be
forced to be embedded in the master selfie. With this approach, the
HNTrie buffer can now serialize to its own storage by converting the
buffer data directly into a string which can be directly sent to
storage. This avoiding expensive intermediate steps such as
converting into a JS array and then to a JSON string.
As part of the refactoring, there was also opportunistic code
upgrade to ES6 and Promise (eventually all of uBO's code will be
proper ES6).
Additionally, the polyfill to bring getBytesInUse() to Firefox has
been revisited to replace the rather expensive previous
implementation with an implementation with virtually no overhead.
Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/399
The advanced setting `cacheStorageAPI` has been added to allow
a user to force the use of IndexedDB as cache storage. Set to
`IndexedDB` to force use of IndexedDB. Default to `unset`.