Merge pull request #10696 from Snuffleupagus/makeSubStream-ensureByte

Update `ChunkedStream.makeSubStream` to actually check if (some) data exists when the `length` parameter is undefined
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Tim van der Meij 2019-04-13 17:12:20 +02:00 committed by GitHub
commit 2d0c38d626
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@ -98,6 +98,10 @@ class ChunkedStream {
}
ensureByte(pos) {
if (pos < this.progressiveDataLength) {
return;
}
const chunk = Math.floor(pos / this.chunkSize);
if (chunk === this.lastSuccessfulEnsureByteChunk) {
return;
@ -234,7 +238,20 @@ class ChunkedStream {
}
makeSubStream(start, length, dict) {
this.ensureRange(start, start + length);
if (length) {
this.ensureRange(start, start + length);
} else {
// When the `length` is undefined you do *not*, under any circumstances,
// want to fallback on calling `this.ensureRange(start, this.end)` since
// that would force the *entire* PDF file to be loaded, thus completely
// breaking the whole purpose of using streaming and/or range requests.
//
// However, not doing any checking here could very easily lead to wasted
// time/resources during e.g. parsing, since `MissingDataException`s will
// require data to be re-parsed, which we attempt to minimize by at least
// checking that the *beginning* of the data is available here.
this.ensureByte(start);
}
function ChunkedStreamSubstream() {}
ChunkedStreamSubstream.prototype = Object.create(this);