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Change the _pagePromises cache, in the worker, from an Array to a Map #14313

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Merged
merged 2 commits into from
Nov 27, 2021
Merged

Change the _pagePromises cache, in the worker, from an Array to a Map #14313

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080996a
Change the `_pagePromises` cache, in the worker, from an Array to a Map
Snuffleupagus Nov 26, 2021
4c56214
Convert `PDFDocument._getLinearizationPage` to an async method
Snuffleupagus Nov 26, 2021
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91 changes: 38 additions & 53 deletions src/core/document.js
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Original file line number Diff line number Diff line change
Expand Up @@ -655,7 +655,7 @@ class PDFDocument {
this.pdfManager = pdfManager;
this.stream = stream;
this.xref = new XRef(stream, pdfManager);
this._pagePromises = [];
this._pagePromises = new Map();
this._version = null;

const idCounters = {
Expand Down Expand Up @@ -1261,7 +1261,7 @@ class PDFDocument {
]);
}

_getLinearizationPage(pageIndex) {
async _getLinearizationPage(pageIndex) {
const { catalog, linearization } = this;
if (
typeof PDFJSDev === "undefined" ||
Expand All @@ -1274,61 +1274,43 @@ class PDFDocument {
}

const ref = Ref.get(linearization.objectNumberFirst, 0);
return this.xref
.fetchAsync(ref)
.then(obj => {
// Ensure that the object that was found is actually a Page dictionary.
if (
isDict(obj, "Page") ||
(isDict(obj) && !obj.has("Type") && obj.has("Contents"))
) {
if (ref && !catalog.pageKidsCountCache.has(ref)) {
catalog.pageKidsCountCache.put(ref, 1); // Cache the Page reference.
}
return [obj, ref];
try {
const obj = await this.xref.fetchAsync(ref);
// Ensure that the object that was found is actually a Page dictionary.
if (
isDict(obj, "Page") ||
(isDict(obj) && !obj.has("Type") && obj.has("Contents"))
) {
if (ref && !catalog.pageKidsCountCache.has(ref)) {
catalog.pageKidsCountCache.put(ref, 1); // Cache the Page reference.
}
throw new FormatError(
"The Linearization dictionary doesn't point " +
"to a valid Page dictionary."
);
})
.catch(reason => {
info(reason);
return catalog.getPageDict(pageIndex);
});
return [obj, ref];
}
throw new FormatError(
"The Linearization dictionary doesn't point to a valid Page dictionary."
);
} catch (reason) {
info(reason);
return catalog.getPageDict(pageIndex);
}
}

getPage(pageIndex) {
if (this._pagePromises[pageIndex] !== undefined) {
return this._pagePromises[pageIndex];
const cachedPromise = this._pagePromises.get(pageIndex);
if (cachedPromise) {
return cachedPromise;
}
const { catalog, linearization } = this;
const { catalog, linearization, xfaFactory } = this;

if (this.xfaFactory) {
return Promise.resolve(
new Page({
pdfManager: this.pdfManager,
xref: this.xref,
pageIndex,
pageDict: Dict.empty,
ref: null,
globalIdFactory: this._globalIdFactory,
fontCache: catalog.fontCache,
builtInCMapCache: catalog.builtInCMapCache,
standardFontDataCache: catalog.standardFontDataCache,
globalImageCache: catalog.globalImageCache,
nonBlendModesSet: catalog.nonBlendModesSet,
xfaFactory: this.xfaFactory,
})
);
let promise;
if (xfaFactory) {
promise = Promise.resolve([Dict.empty, null]);
} else if (linearization && linearization.pageFirst === pageIndex) {
promise = this._getLinearizationPage(pageIndex);
} else {
promise = catalog.getPageDict(pageIndex);
}

const promise =
linearization && linearization.pageFirst === pageIndex
? this._getLinearizationPage(pageIndex)
: catalog.getPageDict(pageIndex);

return (this._pagePromises[pageIndex] = promise.then(([pageDict, ref]) => {
promise = promise.then(([pageDict, ref]) => {
return new Page({
pdfManager: this.pdfManager,
xref: this.xref,
Expand All @@ -1341,9 +1323,12 @@ class PDFDocument {
standardFontDataCache: catalog.standardFontDataCache,
globalImageCache: catalog.globalImageCache,
nonBlendModesSet: catalog.nonBlendModesSet,
xfaFactory: null,
xfaFactory,
});
}));
});

this._pagePromises.set(pageIndex, promise);
return promise;
}

checkFirstPage() {
Expand All @@ -1352,7 +1337,7 @@ class PDFDocument {
// Clear out the various caches to ensure that we haven't stored any
// inconsistent and/or incorrect state, since that could easily break
// subsequent `this.getPage` calls.
this._pagePromises.length = 0;
this._pagePromises.clear();
await this.cleanup();

throw new XRefParseException();
Expand Down