Fix race condition related to the measurement of PdfView#1
Merged
WoLewicki merged 2 commits intoWoLewicki:@wolewicki/add-fabricfrom Dec 9, 2022
Merged
Fix race condition related to the measurement of PdfView#1WoLewicki merged 2 commits intoWoLewicki:@wolewicki/add-fabricfrom
PdfView#1WoLewicki merged 2 commits intoWoLewicki:@wolewicki/add-fabricfrom
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WoLewicki
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Dec 9, 2022
| // | ||
| // I'm not sure whether the second condition is necessary, but without it, it would be impossible | ||
| // to set the dimensions to zero after first measurement. | ||
| private int oldW = 0, oldH = 0; |
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I'd move it up to the rest of private variables, also, can't we use oldw and oldh from the method?
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Sure, I can move them.
Since we're not calling super method every time, using oldw and oldh could result in inconsistencies: i.e.:
onSizeChangedgets called withw: 1080, h: 0, oldw: 0, oldh: 0- since
h === 0,super.onSizeChangeddoesn't get called onSizeChangedgets called withw: 1080, h: 1600, oldw: 1080, oldh: 0super.onSizeChangedgets called - if we were to use values from the arguments we would call it witholdw: 1080where it wasn't called withw: 1080
I haven't looked that deep to see whether it's actually used anywhere, but since those params are there I guess they are used somewhere.
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It seems like in some cases, Yoga (I think) will measure the view only along one axis first, resulting in
onSizeChangedbeing called with either w or h set to zero. This in turn starts the rendering of the pdf under the hood with one dimension being set to zero and the follow-up call toonSizeChangedwith the correct dimensions doesn't have any effect on the already started process.The offending class is DecodingAsyncTask, which tries to get width and height of the
PdfViewin the constructor, and is created as soon as the measurement is complete (relevant lines here and here), which in some cases may be incomplete as described above.By delaying calling
super.onSizeChangeduntil the size in both dimensions is correct we are able to prevent this from happening.