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Always check all Kids nodes, in Catalog.getPageDict, to avoid getting stuck in an empty node further down in the Pages tree (issue 8088)

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As discussed on IRC, we need to check all nodes at the *bottom* of the tree to ensure that we find the correct `Page` dict.
Furthermore, this patch also gets rid of the caching present in a previous version, since it's not clear if that really helps.

Note that this patch purposely adds an `eq` test, using a reduced test-case, so that we can be sure that the algorithm actually finds the correct `Page` dict for each `pageIndex`.

Fixes 8088.
This commit is contained in:
Jonas Jenwald 2017-02-23 13:28:50 +01:00
parent cada411af4
commit 1ce295541c
4 changed files with 182 additions and 25 deletions
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30
src/core/obj.js
View File

@ -452,7 +452,6 @@ var Catalog = (function CatalogClosure() {
var nodesToVisit = [this.catDict.getRaw('Pages')];
var currentPageIndex = 0;
var xref = this.xref;
var checkAllKids = false;
function next() {
while (nodesToVisit.length) {
@ -476,16 +475,10 @@ var Catalog = (function CatalogClosure() {
}
// Must be a child page dictionary.
assert(
isDict(currentNode),
'page dictionary kid reference points to wrong type of object'
);
assert(isDict(currentNode),
'page dictionary kid reference points to wrong type of object');
var count = currentNode.get('Count');
// If the current node doesn't have any children, avoid getting stuck
// in an empty node further down in the tree (see issue5644.pdf).
if (count === 0) {
checkAllKids = true;
}
// Skip nodes where the page can't be.
if (currentPageIndex + count <= pageIndex) {
currentPageIndex += count;
@ -494,23 +487,14 @@ var Catalog = (function CatalogClosure() {
var kids = currentNode.get('Kids');
assert(isArray(kids), 'page dictionary kids object is not an array');
if (!checkAllKids && count === kids.length) {
// Nodes that don't have the page have been skipped and this is the
// bottom of the tree which means the page requested must be a
// descendant of this pages node. Ideally we would just resolve the
// promise with the page ref here, but there is the case where more
// pages nodes could link to single a page (see issue 3666 pdf). To
// handle this push it back on the queue so if it is a pages node it
// will be descended into.
nodesToVisit = [kids[pageIndex - currentPageIndex]];
currentPageIndex = pageIndex;
continue;
} else {
// Always check all `Kids` nodes, to avoid getting stuck in an empty
// node further down in the tree (see issue5644.pdf, issue8088.pdf),
// and to ensure that we actually find the correct `Page` dict.
for (var last = kids.length - 1; last >= 0; last--) {
nodesToVisit.push(kids[last]);
}
}
}
capability.reject('Page index ' + pageIndex + ' not found.');
}
next();

1
test/pdfs/.gitignore vendored
View File

@ -46,6 +46,7 @@
!issue7872.pdf
!issue7901.pdf
!issue8061.pdf
!issue8088.pdf
!bad-PageLabels.pdf
!filled-background.pdf
!ArabicCIDTrueType.pdf

163
test/pdfs/issue8088.pdf Normal file
View File

@ -0,0 +1,163 @@
%PDF-1.7
%âãÏÓ
1 0 obj
<<
/Parent 2 0 R
/Resources
<<
/Font
<<
/F1 3 0 R
>>
>>
/MediaBox [0 0 200 50]
/Type /Page
/Contents 4 0 R
>>
endobj
4 0 obj
<<
/Length 50
>>
stream
BT
10 20 TD
/F1 20 Tf
(Issue 8088 - Page 2) Tj
ET
endstream
endobj
5 0 obj
<<
/Parent 6 0 R
/Resources
<<
/Font
<<
/F1 3 0 R
>>
>>
/MediaBox [0 0 200 50]
/Type /Page
/Contents 7 0 R
>>
endobj
7 0 obj
<<
/Length 50
>>
stream
BT
10 20 TD
/F1 20 Tf
(Issue 8088 - Page 3) Tj
ET
endstream
endobj
8 0 obj
<<
/Parent 9 0 R
/Kids []
/Type /Pages
/Count 0
>>
endobj
2 0 obj
<<
/Parent 9 0 R
/Kids [10 0 R 1 0 R]
/Type /Pages
/Count 2
>>
endobj
9 0 obj
<<
/Parent 11 0 R
/Kids [8 0 R 2 0 R]
/Type /Pages
/Count 2
>>
endobj
6 0 obj
<<
/Parent 11 0 R
/Kids [5 0 R]
/Type /Pages
/Count 1
>>
endobj
11 0 obj
<<
/Kids [9 0 R 6 0 R]
/Type /Pages
/Count 3
>>
endobj
12 0 obj
<<
/Pages 11 0 R
/Type /Catalog
>>
endobj
10 0 obj
<<
/Parent 2 0 R
/Resources
<<
/Font
<<
/F1 3 0 R
>>
>>
/MediaBox [0 0 200 50]
/Type /Page
/Contents 13 0 R
>>
endobj
13 0 obj
<<
/Length 50
>>
stream
BT
10 20 TD
/F1 20 Tf
(Issue 8088 - Page 1) Tj
ET
endstream
endobj
3 0 obj
<<
/BaseFont /Times-Roman
/Subtype /Type1
/Encoding /WinAnsiEncoding
/Type /Font
>>
endobj xref
0 14
0000000000 65535 f
0000000015 00000 n
0000000547 00000 n
0000001135 00000 n
0000000144 00000 n
0000000247 00000 n
0000000707 00000 n
0000000376 00000 n
0000000479 00000 n
0000000627 00000 n
0000000900 00000 n
0000000781 00000 n
0000000847 00000 n
0000001031 00000 n
trailer
<<
/Root 12 0 R
/Size 14
>>
startxref
1235
%%EOF

9
test/test_manifest.json
View File

@ -1318,6 +1318,15 @@
"lastPage": 6,
"type": "eq"
},
{ "id": "issue8088",
"file": "pdfs/issue8088.pdf",
"md5": "5bbc33c7433799487518eb0d8094348c",
"rounds": 1,
"link": false,
"firstPage": 1,
"lastPage": 3,
"type": "eq"
},
{ "id": "bug866395",
"file": "pdfs/bug866395.pdf",
"md5": "f03bc77e84637241980b09a0a220f575",