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Remove some assertions that are not necessarily true (fixes #514)

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Operations that add the same object to multiple places in the pages
tree are throwing exceptions and then later causing assertion
failures. The assert calls shouldn't be there.
This commit is contained in:
Jay Berkenbilt 2021-03-21 19:29:26 -04:00
parent 3f05429cc5
commit a77f58142d
2 changed files with 27 additions and 4 deletions
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27
TODO
View File

@ -1,6 +1,12 @@
Document-level work
===================
* Implement the tree helper described in the ABI section and provide
the getPagesTree method so QPDF::getAllPages can be deprecated in
10.4 and people have time to transition before qpdf 11. Maybe I
should have a qpdf 11 branch so I can make sure I have the
interfaces the way I want them before releasing 10.4.
* QPDFPageCopier -- object for moving pages around within files or
between files and performing various transformations
@ -182,6 +188,25 @@ Comments appear in the code prefixed by "ABI"
before copying, though maybe we don't because it could cause
multiple copies to be made...usually it's better to handle that
explicitly.
* (Also API) Create a helper class for tree structures like the pages
tree that have /Kids and /Count. It would be great to be able to
eliminate flattenPagesTree and all the page object to page caching,
and to get rid of getAllPages() that returns a reference to an
internal data structure. The tree helper object can have
bidirectional iterator and const_iterator, implement at and
operator[], and have reasonable insertion and deletion semantics.
Then a new getAllPages, perhaps getPagesTree, can return that and
make it easy to change existing code even if it assumes the result
of getAllPages() is mutating automatically as the pages tree is
manipulated. This will free us up to finally get rid of the
troublesome pages cache and its exposure by getAllPages. See also
note below with "balance the pages tree". Maybe we can get rid of
pageobj_to_pages_pos as well or convert it into something that is
merely advisory and not so heavily trusted. We should either make
the code not care if the same object appears more than once in the
pages tree or detect it and shallow copy, though the latter would
cause a significant performance penalty when manipulating pages if
we get rid of the cache.
Page splitting/merging
======================
@ -334,6 +359,8 @@ directory or that are otherwise not publicly accessible. This includes
things sent to me by email that are specifically not public. Even so,
I find it useful to make reference to them in this list.
* Get rid of remaining assert() calls from non-test code.
* Consider updating the fuzzer with code that exercises
copyAnnotations, file attachments, and name and number trees. Check
fuzzer coverage.

4
libqpdf/QPDF_pages.cc
View File

@ -255,13 +255,11 @@ QPDF::insertPage(QPDFObjectHandle newpage, int pos)
int npages = kids.getArrayNItems();
pages.replaceKey("/Count", QPDFObjectHandle::newInteger(npages));
this->m->all_pages.insert(this->m->all_pages.begin() + pos, newpage);
assert(this->m->all_pages.size() == QIntC::to_size(npages));
for (int i = pos + 1; i < npages; ++i)
{
insertPageobjToPage(this->m->all_pages.at(toS(i)), i, false);
}
insertPageobjToPage(newpage, pos, true);
assert(this->m->pageobj_to_pages_pos.size() == QIntC::to_size(npages));
}
void
@ -280,9 +278,7 @@ QPDF::removePage(QPDFObjectHandle page)
int npages = kids.getArrayNItems();
pages.replaceKey("/Count", QPDFObjectHandle::newInteger(npages));
this->m->all_pages.erase(this->m->all_pages.begin() + pos);
assert(this->m->all_pages.size() == QIntC::to_size(npages));
this->m->pageobj_to_pages_pos.erase(page.getObjGen());
assert(this->m->pageobj_to_pages_pos.size() == QIntC::to_size(npages));
for (int i = pos; i < npages; ++i)
{
insertPageobjToPage(this->m->all_pages.at(toS(i)), i, false);