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c71dc6888c
If we are unable to filter a page's content streams, don't attempt to remove objects from the page's resource dictionary. Also provide a command line option to suppress resource removal in case we ever need this as a workaround for some bug or broken PDF files.
170 lines
4.2 KiB
C++
170 lines
4.2 KiB
C++
#include <qpdf/QPDFPageObjectHelper.hh>
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#include <qpdf/QTC.hh>
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QPDFPageObjectHelper::Members::~Members()
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{
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}
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QPDFPageObjectHelper::Members::Members()
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{
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}
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QPDFPageObjectHelper::QPDFPageObjectHelper(QPDFObjectHandle oh) :
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QPDFObjectHelper(oh)
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{
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}
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std::map<std::string, QPDFObjectHandle>
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QPDFPageObjectHelper::getPageImages()
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{
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return this->oh.getPageImages();
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}
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std::vector<QPDFAnnotationObjectHelper>
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QPDFPageObjectHelper::getAnnotations(std::string const& only_subtype)
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{
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std::vector<QPDFAnnotationObjectHelper> result;
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QPDFObjectHandle annots = this->oh.getKey("/Annots");
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if (annots.isArray())
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{
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size_t nannots = annots.getArrayNItems();
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for (size_t i = 0; i < nannots; ++i)
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{
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QPDFObjectHandle annot = annots.getArrayItem(i);
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if (only_subtype.empty() ||
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(annot.isDictionary() &&
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annot.getKey("/Subtype").isName() &&
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(only_subtype == annot.getKey("/Subtype").getName())))
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{
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result.push_back(QPDFAnnotationObjectHelper(annot));
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}
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}
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}
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return result;
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}
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std::vector<QPDFObjectHandle>
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QPDFPageObjectHelper::getPageContents()
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{
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return this->oh.getPageContents();
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}
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void
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QPDFPageObjectHelper::addPageContents(QPDFObjectHandle contents, bool first)
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{
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this->oh.addPageContents(contents, first);
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}
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void
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QPDFPageObjectHelper::rotatePage(int angle, bool relative)
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{
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this->oh.rotatePage(angle, relative);
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}
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void
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QPDFPageObjectHelper::coalesceContentStreams()
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{
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this->oh.coalesceContentStreams();
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}
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void
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QPDFPageObjectHelper::parsePageContents(
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QPDFObjectHandle::ParserCallbacks* callbacks)
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{
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this->oh.parsePageContents(callbacks);
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}
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void
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QPDFPageObjectHelper::filterPageContents(
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QPDFObjectHandle::TokenFilter* filter,
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Pipeline* next)
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{
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this->oh.filterPageContents(filter, next);
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}
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void
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QPDFPageObjectHelper::pipePageContents(Pipeline* p)
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{
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this->oh.pipePageContents(p);
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}
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void
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QPDFPageObjectHelper::addContentTokenFilter(
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PointerHolder<QPDFObjectHandle::TokenFilter> token_filter)
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{
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this->oh.addContentTokenFilter(token_filter);
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}
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class NameWatcher: public QPDFObjectHandle::TokenFilter
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{
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public:
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virtual ~NameWatcher()
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{
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}
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virtual void handleToken(QPDFTokenizer::Token const&);
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std::set<std::string> names;
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};
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void
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NameWatcher::handleToken(QPDFTokenizer::Token const& token)
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{
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if (token.getType() == QPDFTokenizer::tt_name)
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{
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// Create a name object and get its name. This canonicalizes
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// the representation of the name
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this->names.insert(
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QPDFObjectHandle::newName(token.getValue()).getName());
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}
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writeToken(token);
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}
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void
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QPDFPageObjectHelper::removeUnreferencedResources()
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{
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NameWatcher nw;
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try
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{
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filterPageContents(&nw);
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}
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catch (std::exception& e)
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{
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this->oh.warnIfPossible(
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std::string("Unable to parse content stream: ") + e.what() +
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"; not attempting to remove unreferenced objects from this page");
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return;
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}
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// Walk through /Font and /XObject dictionaries, removing any
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// resources that are not referenced. We must make copies of
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// resource dictionaries down into the dictionaries are mutating
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// to prevent mutating one dictionary from having the side effect
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// of mutating the one it was copied from.
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std::vector<std::string> to_filter;
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to_filter.push_back("/Font");
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to_filter.push_back("/XObject");
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QPDFObjectHandle resources = this->oh.getKey("/Resources");
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if (resources.isDictionary())
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{
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resources = resources.shallowCopy();
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this->oh.replaceKey("/Resources", resources);
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}
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for (std::vector<std::string>::iterator d_iter = to_filter.begin();
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d_iter != to_filter.end(); ++d_iter)
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{
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QPDFObjectHandle dict = resources.getKey(*d_iter);
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if (! dict.isDictionary())
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{
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continue;
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}
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resources.replaceKey(*d_iter, dict);
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std::set<std::string> keys = dict.getKeys();
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for (std::set<std::string>::iterator k_iter = keys.begin();
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k_iter != keys.end(); ++k_iter)
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{
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if (! nw.names.count(*k_iter))
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{
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dict.removeKey(*k_iter);
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}
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}
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}
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}
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