Currently the transfers aren't actually being used with the "GetOperatorList" message, since the placement of the parameter is wrong; note the method signature: 909a700afa/src/shared/message_handler.js (L219-L229)
This goes back to PR 16588, which added the transfers parameter, and unfortunately we all missed that :-(
Simply fixing the parameter isn't enough however, since that broke printing of Stamp-editors (and possibly others). The solution here is to *not* transfer data during printing, given that a single `PrintAnnotationStorage` instance is being used for all pages.
Change all these cases to use `Map.prototype.getOrInsertComputed()` instead, in combination with a helper function for creating the `Array`s (similar to the previous patch).
With the exception of the first invocation the callback function is unused, which means that a lot of pointless functions may be created.
To avoid this we introduce helper functions for simple cases, such as creating `Map`s and `Objects`s.
Currently we essentially "duplicate" the same code for parsing the `values` and `keys` of the `searchParams`, which seems a little unnecessary.
To be able to parse the `searchParams` from the end, we currently create an Array (from the Iterator) and then reverse it before finally looping through it. Here the latter two steps can be replaced with the `Array.prototype.findLast()` method instead.
*Please note:* I completely understand if this patch is rejected, on account of being less readable than the current code.
There's a number of classes where the constructors can be removed completely by instead using class fields, which help to slightly shorten the code.
It seems that `unicorn/prefer-class-fields` ESLint plugin, see PR 20657, unfortunately isn't able to detect all of these cases.
Rather than assigning it manually in every extending class, we can utilize the fact that the `AnnotationType`-entries are simply the upper-case version of the `/Subtype` (when it exists) in the Annotation dictionary.
This is not only shorter, but (in my opinion) it also simplifies the code.
*Note:* In order to keep the *five* different `BasePDFStreamRangeReader` implementations consistent, we purposely don't re-factor the `PDFWorkerStreamRangeReader` class to support `for await...of` iteration.
This leads to slightly shorter code[1] when initializing classes, and in some cases we can even remove the constructors, which shouldn't hurt; see https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/docs/rules/prefer-class-fields.md
It's probably possible to also change a lot of these class fields to private ones[2], however it's often difficult to tell at a glance if that's safe hence this patch only does this for the `PDFRenderingQueue`.
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[1] This reduces the size of the `gulp mozcentral` output by 999 bytes, for a mostly mechanical code change.
[2] That sort of re-factoring should generally be done separately, on a class-by-class basis, to reduce the risk of regressions.
While we don't dispatch the actual range request after PR 10694 we still parse the returned data, which ends up being an *empty* `ArrayBuffer` and thus cannot affect the `ChunkedStream.prototype._loadedChunks` property.
Given that no actual data arrived, it's thus pointless[1] to invoke the `ChunkedStreamManager.prototype.onReceiveData` method in this case (and it also avoids sending effectively duplicate "DocProgress" messages).
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[1] With the *possible* exception of `disableAutoFetch === false` being set, see f24768d7b4/src/core/chunked_stream.js (L499-L517) however that never happens when streaming is being used; note f24768d7b4/src/core/worker.js (L237-L238)
