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
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
- Lazily initialize file IO-specific stuff in ExtensionStorage.jsm,
and limit this work to the main process.
- Add local versions of the `storage.local.get` and `storage.local.set`
implementations that perform sanitization (without the change, values
are improperly serialized over IPC).
- Copied the `backgroundScript` test from xpcshell/test_ext_storage.js
to mochitest/test_ext_storage_content.html because they should behave
identical. Before this patch the test failed due to IPC serialization
issues, now the test passes.
Note that the old test also passes with the changes.
MozReview-Commit-ID: 8J8CCdwMACN
