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Add new constructors for name/number tree helpers

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Add constructors that take a QPDF object so we can issue warnings and
create new indirect objects.
This commit is contained in:
Jay Berkenbilt 2021-01-16 18:35:30 -05:00
parent ba814703fb
commit d61ffb65d0
12 changed files with 169 additions and 29 deletions
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6
ChangeLog
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@ -1,5 +1,11 @@
2021-01-16 Jay Berkenbilt <ejb@ql.org>
* Add new constructors for QPDFNameTreeObjectHelper and
QPDFNumberTreeObjectHelper that take a QPDF object so they can
create indirect objects and issue warnings. The old constructors
are deprecated and will be removed in qpdf 11. Just pass in the
owning QPDF of the object handle used to initialize the helpers.
* Re-implement QPDFNameTreeObjectHelper and
QPDFNumberTreeObjectHelper to be much more efficient and to have
an iterator-based API in addition to the existing one. This makes

5
TODO
View File

@ -84,7 +84,12 @@ ABI Changes
This is a list of changes to make next time there is an ABI change.
Comments appear in the code prefixed by "ABI"
* Search for ABI to find items not listed here.
* Merge two versions of QPDFObjectHandle::makeDirect per comment
* After removing legacy QPDFNameTreeObjectHelper and
QPDFNumberTreeObjectHelper constructors, NNTreeImpl can switch to
having a QPDF reference and assume that the reference is always
valid.
Page splitting/merging
======================

12
include/qpdf/QPDFNameTreeObjectHelper.hh
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@ -42,6 +42,16 @@ class NNTreeDetails;
class QPDFNameTreeObjectHelper: public QPDFObjectHelper
{
public:
// The qpdf object is required so that this class can issue
// warnings, attempt repairs, and add indirect objects.
QPDF_DLL
QPDFNameTreeObjectHelper(QPDFObjectHandle, QPDF&,
bool auto_repair = true);
// ABI: Legacy Constructor will be removed in QPDF 11. A
// QPDFNameTreeObjectHelper constructed in this way can't be
// modified or repaired and will silently ignore problems in the
// structure.
QPDF_DLL
QPDFNameTreeObjectHelper(QPDFObjectHandle);
QPDF_DLL
@ -133,7 +143,7 @@ class QPDFNameTreeObjectHelper: public QPDFObjectHelper
~Members();
private:
Members(QPDFObjectHandle& oh);
Members(QPDFObjectHandle& oh, QPDF*, bool auto_repair);
Members(Members const&) = delete;
std::shared_ptr<NNTreeImpl> impl;

12
include/qpdf/QPDFNumberTreeObjectHelper.hh
View File

@ -39,6 +39,16 @@ class NNTreeDetails;
class QPDFNumberTreeObjectHelper: public QPDFObjectHelper
{
public:
// The qpdf object is required so that this class can issue
// warnings, attempt repairs, and add indirect objects.
QPDF_DLL
QPDFNumberTreeObjectHelper(QPDFObjectHandle, QPDF&,
bool auto_repair = true);
// ABI: Legacy Constructor will be removed in QPDF 11. A
// QPDFNumberTreeObjectHelper constructed in this way can't be
// modified or repaired and will silently ignore problems in the
// structure.
QPDF_DLL
QPDFNumberTreeObjectHelper(QPDFObjectHandle);
QPDF_DLL
@ -154,7 +164,7 @@ class QPDFNumberTreeObjectHelper: public QPDFObjectHelper
~Members();
private:
Members(QPDFObjectHandle& oh);
Members(QPDFObjectHandle& oh, QPDF*, bool auto_repair);
Members(Members const&) = delete;
std::shared_ptr<NNTreeImpl> impl;

86
libqpdf/NNTree.cc
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@ -1,8 +1,49 @@
#include <qpdf/NNTree.hh>
#include <qpdf/QTC.hh>
#include <qpdf/QUtil.hh>
#include <exception>
static std::string
get_description(QPDFObjectHandle& node)
{
std::string result("Name/Number tree node");
if (node.isIndirect())
{
result += " (object " + QUtil::int_to_string(node.getObjectID()) + ")";
}
return result;
}
static void
warn(QPDF* qpdf, QPDFObjectHandle& node, std::string const& msg)
{
// ABI: in qpdf 11, change to a reference.
if (qpdf)
{
qpdf->warn(QPDFExc(
qpdf_e_damaged_pdf,
qpdf->getFilename(), get_description(node), 0, msg));
}
}
static void
error(QPDF* qpdf, QPDFObjectHandle& node, std::string const& msg)
{
// ABI: in qpdf 11, change to a reference.
if (qpdf)
{
throw QPDFExc(qpdf_e_damaged_pdf,
qpdf->getFilename(), get_description(node), 0, msg);
}
else
{
throw std::runtime_error(get_description(node) + ": " + msg);
}
}
NNTreeIterator::PathElement::PathElement(
QPDFObjectHandle const& node, int kid_number) :
node(node),
@ -137,6 +178,13 @@ NNTreeIterator::addPathElement(QPDFObjectHandle const& node,
this->path.push_back(PathElement(node, kid_number));
}
void
NNTreeIterator::reset()
{
this->path.clear();
this->item_number = -1;
}
void
NNTreeIterator::deepen(QPDFObjectHandle node, bool first)
{
@ -148,7 +196,11 @@ NNTreeIterator::deepen(QPDFObjectHandle node, bool first)
auto og = node.getObjGen();
if (seen.count(og))
{
throw std::runtime_error("loop detected");
QTC::TC("qpdf", "NNTree deepen: loop");
warn(qpdf, node,
"loop detected while traversing name/number tree");
reset();
return;
}
seen.insert(og);
}
@ -169,7 +221,11 @@ NNTreeIterator::deepen(QPDFObjectHandle node, bool first)
}
else
{
throw std::runtime_error("node has neither /Kids nor /Names");
QTC::TC("qpdf", "NNTree deepen: invalid node");
warn(qpdf, node,
"name/number tree node has neither /Kids nor /Names");
reset();
return;
}
}
}
@ -179,6 +235,7 @@ NNTreeImpl::NNTreeImpl(NNTreeDetails const& details,
QPDFObjectHandle& oh,
bool auto_repair) :
details(details),
qpdf(qpdf),
oh(oh)
{
}
@ -186,7 +243,7 @@ NNTreeImpl::NNTreeImpl(NNTreeDetails const& details,
NNTreeImpl::iterator
NNTreeImpl::begin()
{
iterator result(details);
iterator result(details, this->qpdf);
result.deepen(this->oh, true);
return result;
}
@ -194,13 +251,13 @@ NNTreeImpl::begin()
NNTreeImpl::iterator
NNTreeImpl::end()
{
return iterator(details);
return iterator(details, this->qpdf);
}
NNTreeImpl::iterator
NNTreeImpl::last()
{
iterator result(details);
iterator result(details, this->qpdf);
result.deepen(this->oh, false);
return result;
}
@ -315,21 +372,22 @@ NNTreeImpl::compareKeyItem(
if (! ((items.isArray() && (items.getArrayNItems() > (2 * idx)) &&
details.keyValid(items.getArrayItem(2 * idx)))))
{
throw std::runtime_error("item at index " +
QUtil::int_to_string(2 * idx) +
error(qpdf, this->oh,
"item at index " + QUtil::int_to_string(2 * idx) +
" is not the right type");
}
return details.compareKeys(key, items.getArrayItem(2 * idx));
}
int
NNTreeImpl::compareKeyKid(QPDFObjectHandle& key, QPDFObjectHandle& kids, int idx)
NNTreeImpl::compareKeyKid(
QPDFObjectHandle& key, QPDFObjectHandle& kids, int idx)
{
if (! (kids.isArray() && (idx < kids.getArrayNItems()) &&
kids.getArrayItem(idx).isDictionary()))
{
throw std::runtime_error("invalid kid at index " +
QUtil::int_to_string(idx));
error(qpdf, this->oh,
"invalid kid at index " + QUtil::int_to_string(idx));
}
return withinLimits(key, kids.getArrayItem(idx));
}
@ -364,14 +422,14 @@ NNTreeImpl::find(QPDFObjectHandle key, bool return_prev_if_not_found)
std::set<QPDFObjGen> seen;
auto node = this->oh;
iterator result(details);
iterator result(details, this->qpdf);
while (true)
{
auto og = node.getObjGen();
if (seen.count(og))
{
throw std::runtime_error("loop detected in find");
error(qpdf, node, "loop detected in find");
}
seen.insert(og);
@ -397,7 +455,7 @@ NNTreeImpl::find(QPDFObjectHandle key, bool return_prev_if_not_found)
&NNTreeImpl::compareKeyKid);
if (idx == -1)
{
throw std::runtime_error(
error(qpdf, node,
"unexpected -1 from binary search of kids;"
" tree may not be sorted");
}
@ -406,7 +464,7 @@ NNTreeImpl::find(QPDFObjectHandle key, bool return_prev_if_not_found)
}
else
{
throw std::runtime_error("bad node during find");
error(qpdf, node, "bad node during find");
}
}

14
libqpdf/QPDFNameTreeObjectHelper.cc
View File

@ -33,14 +33,22 @@ QPDFNameTreeObjectHelper::Members::~Members()
{
}
QPDFNameTreeObjectHelper::Members::Members(QPDFObjectHandle& oh) :
impl(std::make_shared<NNTreeImpl>(name_tree_details, nullptr, oh, false))
QPDFNameTreeObjectHelper::Members::Members(
QPDFObjectHandle& oh, QPDF* q, bool auto_repair) :
impl(std::make_shared<NNTreeImpl>(name_tree_details, q, oh, auto_repair))
{
}
QPDFNameTreeObjectHelper::QPDFNameTreeObjectHelper(
QPDFObjectHandle oh, QPDF& q, bool auto_repair) :
QPDFObjectHelper(oh),
m(new Members(oh, &q, auto_repair))
{
}
QPDFNameTreeObjectHelper::QPDFNameTreeObjectHelper(QPDFObjectHandle oh) :
QPDFObjectHelper(oh),
m(new Members(oh))
m(new Members(oh, nullptr, false))
{
}

14
libqpdf/QPDFNumberTreeObjectHelper.cc
View File

@ -33,14 +33,22 @@ QPDFNumberTreeObjectHelper::Members::~Members()
{
}
QPDFNumberTreeObjectHelper::Members::Members(QPDFObjectHandle& oh) :
impl(std::make_shared<NNTreeImpl>(number_tree_details, nullptr, oh, false))
QPDFNumberTreeObjectHelper::Members::Members(
QPDFObjectHandle& oh, QPDF* q, bool auto_repair) :
impl(std::make_shared<NNTreeImpl>(number_tree_details, q, oh, auto_repair))
{
}
QPDFNumberTreeObjectHelper::QPDFNumberTreeObjectHelper(
QPDFObjectHandle oh, QPDF& q, bool auto_repair) :
QPDFObjectHelper(oh),
m(new Members(oh, &q, auto_repair))
{
}
QPDFNumberTreeObjectHelper::QPDFNumberTreeObjectHelper(QPDFObjectHandle oh) :
QPDFObjectHelper(oh),
m(new Members(oh))
m(new Members(oh, nullptr, false))
{
}

7
libqpdf/qpdf/NNTree.hh
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@ -57,17 +57,21 @@ class NNTreeIterator: public std::iterator<
int kid_number;
};
NNTreeIterator(NNTreeDetails const& details) :
// ABI: for qpdf 11, make qpdf a reference
NNTreeIterator(NNTreeDetails const& details, QPDF* qpdf) :
details(details),
qpdf(qpdf),
item_number(-1)
{
}
void reset();
void deepen(QPDFObjectHandle node, bool first);
void setItemNumber(QPDFObjectHandle const& node, int);
void addPathElement(QPDFObjectHandle const& node, int kid_number);
void increment(bool backward);
NNTreeDetails const& details;
QPDF* qpdf;
std::list<PathElement> path;
QPDFObjectHandle node;
int item_number;
@ -99,6 +103,7 @@ class NNTreeImpl
QPDFObjectHandle& key, QPDFObjectHandle& items, int idx);
NNTreeDetails const& details;
QPDF* qpdf;
QPDFObjectHandle oh;
};

2
qpdf/qpdf.testcov
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@ -522,3 +522,5 @@ qpdf-c called qpdf_oh_unparse_resolved 0
qpdf-c called qpdf_oh_unparse_binary 0
QPDFWriter getFilterOnWrite false 0
QPDFPageObjectHelper::forEachXObject 3
NNTree deepen: invalid node 0
NNTree deepen: loop 0

2
qpdf/qtest/qpdf/number-tree.out
View File

@ -26,4 +26,6 @@
22 twenty-two
23 twenty-three
29 twenty-nine
WARNING: number-tree.pdf (Name/Number tree node (object 14)): name/number tree node has neither /Kids nor /Names
WARNING: number-tree.pdf (Name/Number tree node (object 13)): loop detected while traversing name/number tree
test 46 done

22
qpdf/qtest/qpdf/number-tree.pdf
View File

@ -144,9 +144,22 @@ endobj
>>
endobj
13 0 obj
<<
/Kids [
14 0 R
13 0 R
]
>>
endobj
14 0 obj
<<
>>
endobj
xref
0 13
0 15
0000000000 65535 f
0000000025 00000 n
0000000079 00000 n
@ -160,12 +173,15 @@ xref
0000000791 00000 n
0000000937 00000 n
0000001078 00000 n
0000001214 00000 n
0000001273 00000 n
trailer <<
/Root 1 0 R
/QTest 8 0 R
/Size 13
/Bad1 13 0 R
/Size 15
/ID [<2c3b7a6ec7fc61db8a5db4eebf57f540><2c3b7a6ec7fc61db8a5db4eebf57f540>]
>>
startxref
1215
1296
%%EOF

10
qpdf/test_driver.cc
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@ -1775,6 +1775,16 @@ void runtest(int n, char const* filename1, char const* arg2)
assert(ntoh.findObjectAtOrBelow(8, oh, offset));
assert("six" == oh.getStringValue());
assert(2 == offset);
// Exercise deprecated API until qpdf 11
auto bad1 = QPDFNumberTreeObjectHelper(
pdf.getTrailer().getKey("/Bad1"));
assert(bad1.begin() == bad1.end());
bad1 = QPDFNumberTreeObjectHelper(
pdf.getTrailer().getKey("/Bad1"), pdf);
assert(bad1.begin() == bad1.end());
assert(bad1.last() == bad1.end());
}
else if (n == 47)
{