Improve progress reporting in ChunkedStreamManager, and prevent unnecessary data copy in ChunkedStream.prototype.onReceiveData#20627
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timvandermeij merged 2 commits intomozilla:masterfrom Feb 5, 2026
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Currently there's two small bugs, which have existed around a decade, in the `loaded` property that's sent via the "DocProgress" message from the `ChunkedStreamManager.prototype.onReceiveData` method. - When the entire PDF has loaded the `loaded` property can become larger than the `total` property, which obviously doesn't make sense. This happens whenever the size of the PDF is *not* a multiple of the `rangeChunkSize` API-option, which is a very common situation. - When streaming is being used, the `loaded` property can become smaller than the actually loaded amount of data. This happens whenever the size of a streamed chunk is *not* a multiple of the `rangeChunkSize` API-option, which is a common situation.
This method is only invoked via `ChunkedStreamManager.prototype.sendRequest`, which currently returns data in `Uint8Array` format (since it potentially combines multiple `ArrayBuffer`s). Hence we end up doing a short-lived, but still completely unnecessary, data copy[1] in `ChunkedStream.prototype.onReceiveData` when handling range requests. In practice this is unlikely to be a big problem by default, given that streaming is used and the (low) value of the `rangeChunkSize` API-option. (However, in custom PDF.js deployments it might affect things more.) Given that no data copy is better than a short lived one, let's fix this small oversight and add non-production `assert`s to keep it working as intended. This way we also improve consistency, since all other streaming and range request methods (see e.g. `BasePDFStream` and related code) only return `ArrayBuffer` data. --- [1] Remember that `new Uint8Array(arrayBuffer)` only creates a view of the underlying `arrayBuffer`, whereas `new Uint8Array(typedArray)` actually creates a copy of the `typedArray`.
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/botio test |
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From: Bot.io (Linux m4)ReceivedCommand cmd_test from @Snuffleupagus received. Current queue size: 0 Live output at: http://54.241.84.105:8877/37df1e548c97eaf/output.txt |
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From: Bot.io (Windows)ReceivedCommand cmd_test from @Snuffleupagus received. Current queue size: 0 Live output at: http://54.193.163.58:8877/ed825c8b327ec66/output.txt |
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From: Bot.io (Linux m4)FailedFull output at http://54.241.84.105:8877/37df1e548c97eaf/output.txt Total script time: 42.01 mins
Image differences available at: http://54.241.84.105:8877/37df1e548c97eaf/reftest-analyzer.html#web=eq.log |
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From: Bot.io (Windows)FailedFull output at http://54.193.163.58:8877/ed825c8b327ec66/output.txt Total script time: 83.76 mins
Image differences available at: http://54.193.163.58:8877/ed825c8b327ec66/reftest-analyzer.html#web=eq.log |
timvandermeij
approved these changes
Feb 5, 2026
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Thanks! |
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