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Attempt to further reduce re-parsing for globally cached images (PR 11912, 16108 follow-up) #17428

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merged 3 commits into from
Dec 22, 2023
Merged

Attempt to further reduce re-parsing for globally cached images (PR 11912, 16108 follow-up) #17428

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b09f238
Add iteration support in the `PDFObjects` class
Snuffleupagus Dec 14, 2023
e547b19
Compute the length of the final image-bitmap/data on the worker-thread
Snuffleupagus Dec 14, 2023
9f02cc3
Attempt to further reduce re-parsing for globally cached images (PR 1…
Snuffleupagus Dec 14, 2023
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54 changes: 43 additions & 11 deletions src/core/evaluator.js
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Original file line number Diff line number Diff line change
Expand Up @@ -546,6 +546,12 @@ class PartialEvaluator {
}

_sendImgData(objId, imgData, cacheGlobally = false) {
if (
(typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) &&
imgData
) {
assert(Number.isInteger(imgData.dataLen), "Expected dataLen to be set.");
}
const transfers = imgData ? [imgData.bitmap || imgData.data.buffer] : null;

if (this.parsingType3Font || cacheGlobally) {
Expand Down Expand Up @@ -690,6 +696,10 @@ class PartialEvaluator {

const objId = `mask_${this.idFactory.createObjId()}`;
operatorList.addDependency(objId);

imgData.dataLen = imgData.bitmap
? imgData.width * imgData.height * 4
: imgData.data.length;
this._sendImgData(objId, imgData);

args = [
Expand Down Expand Up @@ -761,20 +771,46 @@ class PartialEvaluator {

if (this.parsingType3Font) {
objId = `${this.idFactory.getDocId()}_type3_${objId}`;
} else if (imageRef) {
} else if (cacheKey && imageRef) {
cacheGlobally = this.globalImageCache.shouldCache(
imageRef,
this.pageIndex
);

if (cacheGlobally) {
assert(!isInline, "Cannot cache an inline image globally.");

objId = `${this.idFactory.getDocId()}_${objId}`;
}
}

// Ensure that the dependency is added before the image is decoded.
operatorList.addDependency(objId);
args = [objId, w, h];
operatorList.addImageOps(OPS.paintImageXObject, args, optionalContent);

// For large images, at least 500x500 in size, that we'll cache globally
// check if the image is still cached locally on the main-thread to avoid
// having to re-parse the image (since that can be slow).
if (cacheGlobally && w * h > 250000) {
const localLength = await this.handler.sendWithPromise("commonobj", [
objId,
"CopyLocalImage",
{ imageRef },
]);

if (localLength) {
this.globalImageCache.setData(imageRef, {
objId,
fn: OPS.paintImageXObject,
args,
optionalContent,
byteSize: 0, // Temporary entry, to avoid `setData` returning early.
});
this.globalImageCache.addByteSize(imageRef, localLength);
return;
}
}

PDFImage.buildImage({
xref: this.xref,
Expand All @@ -790,14 +826,14 @@ class PartialEvaluator {
/* isOffscreenCanvasSupported = */ this.options
.isOffscreenCanvasSupported
);
imgData.dataLen = imgData.bitmap
? imgData.width * imgData.height * 4
: imgData.data.length;
imgData.ref = imageRef;

if (cacheKey && imageRef && cacheGlobally) {
const length = imgData.bitmap
? imgData.width * imgData.height * 4
: imgData.data.length;
this.globalImageCache.addByteSize(imageRef, length);
if (cacheGlobally) {
this.globalImageCache.addByteSize(imageRef, imgData.dataLen);
}

return this._sendImgData(objId, imgData, cacheGlobally);
})
.catch(reason => {
Expand All @@ -806,8 +842,6 @@ class PartialEvaluator {
return this._sendImgData(objId, /* imgData = */ null, cacheGlobally);
});

operatorList.addImageOps(OPS.paintImageXObject, args, optionalContent);

if (cacheKey) {
const cacheData = {
fn: OPS.paintImageXObject,
Expand All @@ -820,8 +854,6 @@ class PartialEvaluator {
this._regionalImageCache.set(/* name = */ null, imageRef, cacheData);

if (cacheGlobally) {
assert(!isInline, "Cannot cache an inline image globally.");

this.globalImageCache.setData(imageRef, {
objId,
fn: OPS.paintImageXObject,
Expand Down
59 changes: 44 additions & 15 deletions src/display/api.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2704,11 +2704,11 @@ class WorkerTransport {

messageHandler.on("commonobj", ([id, type, exportedData]) => {
if (this.destroyed) {
return; // Ignore any pending requests if the worker was terminated.
return null; // Ignore any pending requests if the worker was terminated.
}

if (this.commonObjs.has(id)) {
return;
return null;
}

switch (type) {
Expand Down Expand Up @@ -2750,6 +2750,23 @@ class WorkerTransport {
this.commonObjs.resolve(id, font);
});
break;
case "CopyLocalImage":
const { imageRef } = exportedData;
assert(imageRef, "The imageRef must be defined.");

for (const pageProxy of this.#pageCache.values()) {
for (const [, data] of pageProxy.objs) {
if (data.ref !== imageRef) {
continue;
}
if (!data.dataLen) {
return null;
}
this.commonObjs.resolve(id, structuredClone(data));
return data.dataLen;
}
}
break;
case "FontPath":
case "Image":
case "Pattern":
Expand All @@ -2758,6 +2775,8 @@ class WorkerTransport {
default:
throw new Error(`Got unknown common object type ${type}`);
}

return null;
});

messageHandler.on("obj", ([id, pageIndex, type, imageData]) => {
Expand All @@ -2781,18 +2800,8 @@ class WorkerTransport {
pageProxy.objs.resolve(id, imageData);

// Heuristic that will allow us not to store large data.
if (imageData) {
let length;
if (imageData.bitmap) {
const { width, height } = imageData;
length = width * height * 4;
} else {
length = imageData.data?.length || 0;
}

if (length > MAX_IMAGE_SIZE_TO_CACHE) {
pageProxy._maybeCleanupAfterRender = true;
}
if (imageData?.dataLen > MAX_IMAGE_SIZE_TO_CACHE) {
pageProxy._maybeCleanupAfterRender = true;
}
break;
case "Pattern":
Expand Down Expand Up @@ -3125,7 +3134,7 @@ class PDFObjects {
*/
has(objId) {
const obj = this.#objs[objId];
return obj?.capability.settled || false;
return obj?.capability.settled ?? false;
}

/**
Expand All @@ -3147,6 +3156,17 @@ class PDFObjects {
}
this.#objs = Object.create(null);
}

*[Symbol.iterator]() {
for (const objId in this.#objs) {
const { capability, data } = this.#objs[objId];

if (!capability.settled) {
continue;
}
yield [objId, data];
}
}
}

/**
Expand All @@ -3165,6 +3185,15 @@ class RenderTask {
* @type {function}
*/
this.onContinue = null;

if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
// For testing purposes.
Object.defineProperty(this, "getOperatorList", {
value: () => {
return this.#internalRenderTask.operatorList;
},
});
}
}

/**
Expand Down
38 changes: 36 additions & 2 deletions test/unit/api_spec.js
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Original file line number Diff line number Diff line change
Expand Up @@ -3811,14 +3811,36 @@ Caron Broadcasting, Inc., an Ohio corporation (“Lessee”).`)
const loadingTask = getDocument(
buildGetDocumentParams("issue11878.pdf", {
isOffscreenCanvasSupported: false,
pdfBug: true,
})
);
const pdfDoc = await loadingTask.promise;
let firstImgData = null;
let checkedCopyLocalImage = false,
firstImgData = null,
firstStatsOverall = null;

for (let i = 1; i <= pdfDoc.numPages; i++) {
const pdfPage = await pdfDoc.getPage(i);
const opList = await pdfPage.getOperatorList();
const viewport = pdfPage.getViewport({ scale: 1 });

const canvasAndCtx = CanvasFactory.create(
viewport.width,
viewport.height
);
const renderTask = pdfPage.render({
canvasContext: canvasAndCtx.context,
viewport,
});

await renderTask.promise;
const opList = renderTask.getOperatorList();
// The canvas is no longer necessary, since we only care about
// the image-data below.
CanvasFactory.destroy(canvasAndCtx);

const [statsOverall] = pdfPage.stats.times
.filter(time => time.name === "Overall")
.map(time => time.end - time.start);

const { commonObjs, objs } = pdfPage;
const imgIndex = opList.fnArray.indexOf(OPS.paintImageXObject);
Expand All @@ -3843,6 +3865,7 @@ Caron Broadcasting, Inc., an Ohio corporation (“Lessee”).`)
// Ensure that the actual image data is identical for all pages.
if (i === 1) {
firstImgData = objs.get(objId);
firstStatsOverall = statsOverall;

expect(firstImgData.width).toEqual(EXPECTED_WIDTH);
expect(firstImgData.height).toEqual(EXPECTED_HEIGHT);
Expand All @@ -3854,6 +3877,8 @@ Caron Broadcasting, Inc., an Ohio corporation (“Lessee”).`)
const objsPool = i >= NUM_PAGES_THRESHOLD ? commonObjs : objs;
const currentImgData = objsPool.get(objId);

expect(currentImgData).not.toBe(firstImgData);

expect(currentImgData.width).toEqual(firstImgData.width);
expect(currentImgData.height).toEqual(firstImgData.height);

Expand All @@ -3866,11 +3891,20 @@ Caron Broadcasting, Inc., an Ohio corporation (“Lessee”).`)
return value === firstImgData.data[index];
})
).toEqual(true);

if (i === NUM_PAGES_THRESHOLD) {
checkedCopyLocalImage = true;
// Ensure that the image was copied in the main-thread, rather
// than being re-parsed in the worker-thread (which is slower).
expect(statsOverall).toBeLessThan(firstStatsOverall / 5);
}
}
}
expect(checkedCopyLocalImage).toBeTruthy();

await loadingTask.destroy();
firstImgData = null;
firstStatsOverall = null;
});

it("render for printing, with `printAnnotationStorage` set", async function () {
Expand Down