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Code Issues Releases Wiki Activity

Refactor removal of unreferenced resources

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Refactor in preparation for resolving unresolved resources in form
xobjects from page.
This commit is contained in:
Jay Berkenbilt 2021-02-02 16:34:06 -05:00
parent 5fdf37b1ba
commit 81025e4998
2 changed files with 31 additions and 33 deletions
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2
include/qpdf/QPDFPageObjectHelper.hh
View File

@ -319,7 +319,7 @@ class QPDFPageObjectHelper: public QPDFObjectHelper
private:
static void
removeUnreferencedResourcesHelper(
QPDFPageObjectHelper ph, std::set<QPDFObjGen>& seen);
QPDFPageObjectHelper ph);
class Members
{

62
libqpdf/QPDFPageObjectHelper.cc
View File

@ -703,13 +703,8 @@ NameWatcher::handleToken(QPDFTokenizer::Token const& token)
void
QPDFPageObjectHelper::removeUnreferencedResourcesHelper(
QPDFPageObjectHelper ph, std::set<QPDFObjGen>& seen)
QPDFPageObjectHelper ph)
{
if (seen.count(ph.oh.getObjGen()))
{
return;
}
seen.insert(ph.oh.getObjGen());
NameWatcher nw;
try
{
@ -730,39 +725,35 @@ QPDFPageObjectHelper::removeUnreferencedResourcesHelper(
"not attempting to remove unreferenced objects from this page");
return;
}
// Walk through /Font and /XObject dictionaries, removing any
// resources that are not referenced. We must make copies of
// We will walk through /Font and /XObject dictionaries, removing
// any resources that are not referenced. We must make copies of
// resource dictionaries down into the dictionaries are mutating
// to prevent mutating one dictionary from having the side effect
// of mutating the one it was copied from.
std::vector<std::string> to_filter;
to_filter.push_back("/Font");
to_filter.push_back("/XObject");
QPDFObjectHandle resources = ph.getAttribute("/Resources", true);
for (std::vector<std::string>::iterator d_iter = to_filter.begin();
d_iter != to_filter.end(); ++d_iter)
std::vector<QPDFObjectHandle> rdicts;
if (resources.isDictionary())
{
QPDFObjectHandle dict = resources.getKey(*d_iter);
if (! dict.isDictionary())
std::vector<std::string> to_filter = {"/Font", "/XObject"};
for (auto const& iter: to_filter)
{
continue;
}
dict = dict.shallowCopy();
resources.replaceKey(*d_iter, dict);
std::set<std::string> keys = dict.getKeys();
for (std::set<std::string>::iterator k_iter = keys.begin();
k_iter != keys.end(); ++k_iter)
{
if (! nw.names.count(*k_iter))
QPDFObjectHandle dict = resources.getKey(iter);
if (dict.isDictionary())
{
dict.removeKey(*k_iter);
dict = dict.shallowCopy();
resources.replaceKey(iter, dict);
rdicts.push_back(dict);
}
QPDFObjectHandle resource = dict.getKey(*k_iter);
if (resource.isFormXObject())
}
}
for (auto& dict: rdicts)
{
for (auto const& key: dict.getKeys())
{
if (! nw.names.count(key))
{
QTC::TC("qpdf", "QPDFPageObjectHelper filter form xobject");
removeUnreferencedResourcesHelper(
QPDFPageObjectHelper(resource), seen);
dict.removeKey(key);
}
}
}
@ -771,8 +762,15 @@ QPDFPageObjectHelper::removeUnreferencedResourcesHelper(
void
QPDFPageObjectHelper::removeUnreferencedResources()
{
std::set<QPDFObjGen> seen;
removeUnreferencedResourcesHelper(*this, seen);
forEachFormXObject(
true,
[](
QPDFObjectHandle& obj, QPDFObjectHandle&, std::string const&)
{
QTC::TC("qpdf", "QPDFPageObjectHelper filter form xobject");
removeUnreferencedResourcesHelper(QPDFPageObjectHelper(obj));
});
removeUnreferencedResourcesHelper(*this);
}
QPDFPageObjectHelper