Reading the extension permissions DB at startup takes several hundred
milliseconds, largely from the overhead of initializing OS.File. We can avoid
that somewhat by using the stream APIs to read the files, and beginning the
read very early. But the eager initialization gets complicated, and we still
add extra IO to startup.
After this change, the permissions JSON file still remains the primary source
of truth, but the state as of the last session is cached in the volatile
extension startup cache to decrease the overhead of reading it at startup.
MozReview-Commit-ID: HGDt5kSsdzX
For unpacked extensions, loading the locales list adds an appreciable delay to
startup time. For packed extension, the overhead is much lower, but still best
avoided.
MozReview-Commit-ID: 6kicOU78fpZ
This gives us performance wins in sevaral areas:
- Creating a structured clone blob of storage data directly from the source
compartment allows us to avoid X-ray and JSON serialization overhead when
storing new values.
- Storing the intermediate StructuredCloneBlob, rather than JSON values,
in-memory saves us additional JSON and structured clone overhead when
passing the values to listeners and API callers, and saves us a fair amount
of memory to boot.
- Serializing storage values before sending them over a message manager allows
us to deserialize them directly into an extension scope on the other side,
saving us a lot of additional structured clone overhead and intermediate
garbage generation.
- Using JSONFile.jsm for storage lets us consolidate multiple storage file
write operations, rather than performing a separate JSON serialization for
each individual storage write.
- Additionally, this paves the way for us to transition to IndexedDB as a
storage backend, with full support for arbitrary structured-clone-compatible
data structures.
MozReview-Commit-ID: JiRE7EFMYxn
Also removes some dead code.
A lot of the code in ExtensionUtils.jsm is not needed in all processes, and a
lot of the rest isn't needed until extension code runs. Most of it winds up
being loaded into all processes way earlier than necessary.
MozReview-Commit-ID: CMRjCPOjRF2
This replaces the JS policy service stubs with a pure C++ version which
directly makes policy decisions based on active WebExtensionPolicy objects.
This is the first step in a larger refactoring, which will remove the
ExtensionManagement module entirely, and replace the current add-on policy
service with direct, non-virtual access to native WebExtensionPolicy objects.
It will also be followed by related changes to migrate the content script and
extension page matching to native code, based on the existing MatchPattern and
WebExtensionPolicy bindings.
MozReview-Commit-ID: 2MpbmXZGiPZ
This is the second step to migrating the policy service to pure native code,
with similar impacts and reasoning to the previous patch.
MozReview-Commit-ID: L5XdPzWNZXM
This is the first step toward migrating the web-accessible URL policy to
purely native code. It should have a noticeable performance improvement on its
own, but the main improvement comes from being able to pass the pattern
objects to the pure C++ policy service.
MozReview-Commit-ID: DHoGLVr8yJ9
