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qpdf/libqpdf/QPDFAcroFormDocumentHelper.cc

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#include <qpdf/QPDFAcroFormDocumentHelper.hh>
#include <qpdf/Pl_Buffer.hh>
#include <qpdf/QPDFPageDocumentHelper.hh>
#include <qpdf/QTC.hh>
#include <qpdf/QUtil.hh>
#include <qpdf/ResourceFinder.hh>
QPDFAcroFormDocumentHelper::Members::Members() :
cache_valid(false)
{
}
QPDFAcroFormDocumentHelper::QPDFAcroFormDocumentHelper(QPDF& qpdf) :
QPDFDocumentHelper(qpdf),
m(new Members())
{
// We have to analyze up front. Otherwise, when we are adding annotations and fields, we are in
// a temporarily unstable configuration where some widget annotations are not reachable.
analyze();
}
void
QPDFAcroFormDocumentHelper::invalidateCache()
{
m->cache_valid = false;
m->field_to_annotations.clear();
m->annotation_to_field.clear();
}
bool
QPDFAcroFormDocumentHelper::hasAcroForm()
{
return this->qpdf.getRoot().hasKey("/AcroForm");
}
QPDFObjectHandle
QPDFAcroFormDocumentHelper::getOrCreateAcroForm()
{
auto acroform = this->qpdf.getRoot().getKey("/AcroForm");
if (!acroform.isDictionary()) {
acroform = this->qpdf.getRoot().replaceKeyAndGetNew(
"/AcroForm", this->qpdf.makeIndirectObject(QPDFObjectHandle::newDictionary()));
}
return acroform;
}
void
QPDFAcroFormDocumentHelper::addFormField(QPDFFormFieldObjectHelper ff)
{
auto acroform = getOrCreateAcroForm();
auto fields = acroform.getKey("/Fields");
if (!fields.isArray()) {
fields = acroform.replaceKeyAndGetNew("/Fields", QPDFObjectHandle::newArray());
}
fields.appendItem(ff.getObjectHandle());
QPDFObjGen::set visited;
traverseField(ff.getObjectHandle(), QPDFObjectHandle::newNull(), 0, visited);
}
void
QPDFAcroFormDocumentHelper::addAndRenameFormFields(std::vector<QPDFObjectHandle> fields)
{
analyze();
std::map<std::string, std::string> renames;
QPDFObjGen::set seen;
for (std::list<QPDFObjectHandle> queue{fields.begin(), fields.end()}; !queue.empty();
queue.pop_front()) {
auto& obj = queue.front();
if (seen.add(obj)) {
auto kids = obj.getKey("/Kids");
if (kids.isArray()) {
for (auto const& kid: kids.aitems()) {
queue.push_back(kid);
}
}
if (obj.hasKey("/T")) {
// Find something we can append to the partial name that makes the fully qualified
// name unique. When we find something, reuse the same suffix for all fields in this
// group with the same name. We can only change the name of fields that have /T, and
// this field's /T is always at the end of the fully qualified name, appending to /T
// has the effect of appending the same thing to the fully qualified name.
std::string old_name = QPDFFormFieldObjectHelper(obj).getFullyQualifiedName();
if (renames.count(old_name) == 0) {
std::string new_name = old_name;
int suffix = 0;
std::string append;
while (!getFieldsWithQualifiedName(new_name).empty()) {
++suffix;
append = "+" + std::to_string(suffix);
new_name = old_name + append;
}
renames[old_name] = append;
}
std::string append = renames[old_name];
if (!append.empty()) {
obj.replaceKey(
"/T",
QPDFObjectHandle::newUnicodeString(
obj.getKey("/T").getUTF8Value() + append));
}
}
}
}
for (auto const& i: fields) {
addFormField(i);
}
}
void
QPDFAcroFormDocumentHelper::removeFormFields(std::set<QPDFObjGen> const& to_remove)
{
auto acroform = this->qpdf.getRoot().getKey("/AcroForm");
if (!acroform.isDictionary()) {
return;
}
auto fields = acroform.getKey("/Fields");
if (!fields.isArray()) {
return;
}
for (auto const& og: to_remove) {
auto annotations = m->field_to_annotations.find(og);
if (annotations != m->field_to_annotations.end()) {
for (auto aoh: annotations->second) {
m->annotation_to_field.erase(aoh.getObjectHandle().getObjGen());
}
m->field_to_annotations.erase(og);
}
auto name = m->field_to_name.find(og);
if (name != m->field_to_name.end()) {
m->name_to_fields[name->second].erase(og);
if (m->name_to_fields[name->second].empty()) {
m->name_to_fields.erase(name->second);
}
m->field_to_name.erase(og);
}
}
int i = 0;
while (i < fields.getArrayNItems()) {
auto field = fields.getArrayItem(i);
if (to_remove.count(field.getObjGen())) {
fields.eraseItem(i);
} else {
++i;
}
}
}
void
QPDFAcroFormDocumentHelper::setFormFieldName(QPDFFormFieldObjectHelper ff, std::string const& name)
{
ff.setFieldAttribute("/T", name);
QPDFObjGen::set visited;
auto ff_oh = ff.getObjectHandle();
traverseField(ff_oh, ff_oh.getKey("/Parent"), 0, visited);
}
std::vector<QPDFFormFieldObjectHelper>
QPDFAcroFormDocumentHelper::getFormFields()
{
analyze();
std::vector<QPDFFormFieldObjectHelper> result;
for (auto const& iter: m->field_to_annotations) {
result.emplace_back(this->qpdf.getObject(iter.first));
}
return result;
}
std::set<QPDFObjGen>
QPDFAcroFormDocumentHelper::getFieldsWithQualifiedName(std::string const& name)
{
analyze();
// Keep from creating an empty entry
auto iter = m->name_to_fields.find(name);
if (iter != m->name_to_fields.end()) {
return iter->second;
}
return {};
}
std::vector<QPDFAnnotationObjectHelper>
QPDFAcroFormDocumentHelper::getAnnotationsForField(QPDFFormFieldObjectHelper h)
{
analyze();
std::vector<QPDFAnnotationObjectHelper> result;
QPDFObjGen og(h.getObjectHandle().getObjGen());
if (m->field_to_annotations.count(og)) {
result = m->field_to_annotations[og];
}
return result;
}
std::vector<QPDFAnnotationObjectHelper>
QPDFAcroFormDocumentHelper::getWidgetAnnotationsForPage(QPDFPageObjectHelper h)
{
return h.getAnnotations("/Widget");
}
std::vector<QPDFFormFieldObjectHelper>
QPDFAcroFormDocumentHelper::getFormFieldsForPage(QPDFPageObjectHelper ph)
{
analyze();
QPDFObjGen::set todo;
std::vector<QPDFFormFieldObjectHelper> result;
for (auto& annot: getWidgetAnnotationsForPage(ph)) {
auto field = getFieldForAnnotation(annot).getTopLevelField();
if (todo.add(field) && field.getObjectHandle().isDictionary()) {
result.push_back(field);
}
}
return result;
}
QPDFFormFieldObjectHelper
QPDFAcroFormDocumentHelper::getFieldForAnnotation(QPDFAnnotationObjectHelper h)
{
QPDFObjectHandle oh = h.getObjectHandle();
QPDFFormFieldObjectHelper result(QPDFObjectHandle::newNull());
if (!oh.isDictionaryOfType("", "/Widget")) {
return result;
}
analyze();
QPDFObjGen og(oh.getObjGen());
if (m->annotation_to_field.count(og)) {
result = m->annotation_to_field[og];
}
return result;
}
void
QPDFAcroFormDocumentHelper::analyze()
{
if (m->cache_valid) {
return;
}
m->cache_valid = true;
QPDFObjectHandle acroform = this->qpdf.getRoot().getKey("/AcroForm");
if (!(acroform.isDictionary() && acroform.hasKey("/Fields"))) {
return;
}
QPDFObjectHandle fields = acroform.getKey("/Fields");
if (!fields.isArray()) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper fields not array");
acroform.warnIfPossible("/Fields key of /AcroForm dictionary is not an array; ignoring");
fields = QPDFObjectHandle::newArray();
}
// Traverse /AcroForm to find annotations and map them bidirectionally to fields.
QPDFObjGen::set visited;
int nfields = fields.getArrayNItems();
QPDFObjectHandle null(QPDFObjectHandle::newNull());
for (int i = 0; i < nfields; ++i) {
traverseField(fields.getArrayItem(i), null, 0, visited);
}
// All Widget annotations should have been encountered by traversing /AcroForm, but in case any
// weren't, find them by walking through pages, and treat any widget annotation that is not
// associated with a field as its own field. This just ensures that requesting the field for any
// annotation we find through a page's /Annots list will have some associated field. Note that
// a file that contains this kind of error will probably not
// actually work with most viewers.
for (auto const& ph: QPDFPageDocumentHelper(this->qpdf).getAllPages()) {
for (auto const& iter: getWidgetAnnotationsForPage(ph)) {
QPDFObjectHandle annot(iter.getObjectHandle());
QPDFObjGen og(annot.getObjGen());
if (m->annotation_to_field.count(og) == 0) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper orphaned widget");
// This is not supposed to happen, but it's easy enough for us to handle this case.
// Treat the annotation as its own field. This could allow qpdf to sensibly handle a
// case such as a PDF creator adding a self-contained annotation (merged with the
// field dictionary) to the page's /Annots array and forgetting to also put it in
// /AcroForm.
annot.warnIfPossible("this widget annotation is not"
" reachable from /AcroForm in the document catalog");
m->annotation_to_field[og] = QPDFFormFieldObjectHelper(annot);
m->field_to_annotations[og].emplace_back(annot);
}
}
}
}
void
QPDFAcroFormDocumentHelper::traverseField(
QPDFObjectHandle field, QPDFObjectHandle parent, int depth, QPDFObjGen::set& visited)
{
if (depth > 100) {
// Arbitrarily cut off recursion at a fixed depth to avoid specially crafted files that
// could cause stack overflow.
return;
}
if (!field.isIndirect()) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper direct field");
field.warnIfPossible("encountered a direct object as a field or annotation while "
"traversing /AcroForm; ignoring field or annotation");
return;
}
if (!field.isDictionary()) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper non-dictionary field");
field.warnIfPossible("encountered a non-dictionary as a field or annotation while"
" traversing /AcroForm; ignoring field or annotation");
return;
}
QPDFObjGen og(field.getObjGen());
if (!visited.add(og)) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper loop");
field.warnIfPossible("loop detected while traversing /AcroForm");
return;
}
// A dictionary encountered while traversing the /AcroForm field may be a form field, an
// annotation, or the merger of the two. A field that has no fields below it is a terminal. If a
// terminal field looks like an annotation, it is an annotation because annotation dictionary
// fields can be merged with terminal field dictionaries. Otherwise, the annotation fields might
// be there to be inherited by annotations below it.
bool is_annotation = false;
bool is_field = (0 == depth);
QPDFObjectHandle kids = field.getKey("/Kids");
if (kids.isArray()) {
is_field = true;
int nkids = kids.getArrayNItems();
for (int k = 0; k < nkids; ++k) {
traverseField(kids.getArrayItem(k), field, 1 + depth, visited);
}
} else {
if (field.hasKey("/Parent")) {
is_field = true;
}
if (field.hasKey("/Subtype") || field.hasKey("/Rect") || field.hasKey("/AP")) {
is_annotation = true;
}
}
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper field found", (depth == 0) ? 0 : 1);
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper annotation found", (is_field ? 0 : 1));
if (is_annotation) {
QPDFObjectHandle our_field = (is_field ? field : parent);
m->field_to_annotations[our_field.getObjGen()].emplace_back(field);
m->annotation_to_field[og] = QPDFFormFieldObjectHelper(our_field);
}
if (is_field && (field.hasKey("/T"))) {
QPDFFormFieldObjectHelper foh(field);
auto f_og = field.getObjGen();
std::string name = foh.getFullyQualifiedName();
auto old = m->field_to_name.find(f_og);
if (old != m->field_to_name.end()) {
// We might be updating after a name change, so remove any old information
std::string old_name = old->second;
m->name_to_fields[old_name].erase(f_og);
}
m->field_to_name[f_og] = name;
m->name_to_fields[name].insert(f_og);
}
}
bool
QPDFAcroFormDocumentHelper::getNeedAppearances()
{
bool result = false;
QPDFObjectHandle acroform = this->qpdf.getRoot().getKey("/AcroForm");
if (acroform.isDictionary() && acroform.getKey("/NeedAppearances").isBool()) {
result = acroform.getKey("/NeedAppearances").getBoolValue();
}
return result;
}
void
QPDFAcroFormDocumentHelper::setNeedAppearances(bool val)
{
QPDFObjectHandle acroform = this->qpdf.getRoot().getKey("/AcroForm");
if (!acroform.isDictionary()) {
this->qpdf.getRoot().warnIfPossible(
"ignoring call to QPDFAcroFormDocumentHelper::setNeedAppearances"
" on a file that lacks an /AcroForm dictionary");
return;
}
if (val) {
acroform.replaceKey("/NeedAppearances", QPDFObjectHandle::newBool(true));
} else {
acroform.removeKey("/NeedAppearances");
}
}
void
QPDFAcroFormDocumentHelper::generateAppearancesIfNeeded()
{
if (!getNeedAppearances()) {
return;
}
for (auto const& page: QPDFPageDocumentHelper(this->qpdf).getAllPages()) {
for (auto& aoh: getWidgetAnnotationsForPage(page)) {
QPDFFormFieldObjectHelper ffh = getFieldForAnnotation(aoh);
if (ffh.getFieldType() == "/Btn") {
// Rather than generating appearances for button fields, rely on what's already
// there. Just make sure /AS is consistent with /V, which we can do by resetting the
// value of the field back to itself. This code is referenced in a comment in
// QPDFFormFieldObjectHelper::generateAppearance.
if (ffh.isRadioButton() || ffh.isCheckbox()) {
ffh.setV(ffh.getValue());
}
} else {
ffh.generateAppearance(aoh);
}
}
}
setNeedAppearances(false);
}
void
QPDFAcroFormDocumentHelper::disableDigitalSignatures()
{
qpdf.removeSecurityRestrictions();
std::set<QPDFObjGen> to_remove;
auto fields = getFormFields();
for (auto& f: fields) {
auto ft = f.getFieldType();
if (ft == "/Sig") {
auto oh = f.getObjectHandle();
to_remove.insert(oh.getObjGen());
// Make this no longer a form field. If it's also an annotation, the annotation will
// survive. If it's only a field and is no longer referenced, it will disappear.
oh.removeKey("/FT");
// Remove fields that are specific to signature fields.
oh.removeKey("/V");
oh.removeKey("/SV");
oh.removeKey("/Lock");
}
}
removeFormFields(to_remove);
}
void
QPDFAcroFormDocumentHelper::adjustInheritedFields(
QPDFObjectHandle obj,
bool override_da,
std::string const& from_default_da,
bool override_q,
int from_default_q)
{
// Override /Q or /DA if needed. If this object has a field type, directly or inherited, it is a
// field and not just an annotation. In that case, we need to override if we are getting a value
// from the document that is different from the value we would have gotten from the old
// document. We must take care not to override an explicit value. It's possible that /FT may be
// inherited by lower fields that may explicitly set /DA or /Q or that this is a field whose
// type does not require /DA or /Q and we may be put a value on the field that is unused. This
// is harmless, so it's not worth trying to work around.
auto has_explicit = [](QPDFFormFieldObjectHelper& field, std::string const& key) {
if (field.getObjectHandle().hasKey(key)) {
return true;
}
auto oh = field.getInheritableFieldValue(key);
if (!oh.isNull()) {
return true;
}
return false;
};
if (override_da || override_q) {
QPDFFormFieldObjectHelper cur_field(obj);
if (override_da && (!has_explicit(cur_field, "/DA"))) {
std::string da = cur_field.getDefaultAppearance();
if (da != from_default_da) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper override da");
obj.replaceKey("/DA", QPDFObjectHandle::newUnicodeString(from_default_da));
}
}
if (override_q && (!has_explicit(cur_field, "/Q"))) {
int q = cur_field.getQuadding();
if (q != from_default_q) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper override q");
obj.replaceKey("/Q", QPDFObjectHandle::newInteger(from_default_q));
}
}
}
}
namespace
{
class ResourceReplacer: public QPDFObjectHandle::TokenFilter
{
public:
ResourceReplacer(
std::map<std::string, std::map<std::string, std::string>> const& dr_map,
std::map<std::string, std::map<std::string, std::set<size_t>>> const& rnames);
~ResourceReplacer() override = default;
void handleToken(QPDFTokenizer::Token const&) override;
private:
size_t offset{0};
std::map<std::string, std::map<size_t, std::string>> to_replace;
};
} // namespace
ResourceReplacer::ResourceReplacer(
std::map<std::string, std::map<std::string, std::string>> const& dr_map,
std::map<std::string, std::map<std::string, std::set<size_t>>> const& rnames)
{
// We have:
// * dr_map[resource_type][key] == new_key
// * rnames[resource_type][key] == set of offsets
//
// We want:
// * to_replace[key][offset] = new_key
for (auto const& rn_iter: rnames) {
std::string const& rtype = rn_iter.first;
auto dr_map_rtype = dr_map.find(rtype);
if (dr_map_rtype == dr_map.end()) {
continue;
}
auto const& key_offsets = rn_iter.second;
for (auto const& ko_iter: key_offsets) {
std::string const& old_key = ko_iter.first;
auto dr_map_rtype_old = dr_map_rtype->second.find(old_key);
if (dr_map_rtype_old == dr_map_rtype->second.end()) {
continue;
}
auto const& offsets = ko_iter.second;
for (auto const& o_iter: offsets) {
to_replace[old_key][o_iter] = dr_map_rtype_old->second;
}
}
}
}
void
ResourceReplacer::handleToken(QPDFTokenizer::Token const& token)
{
bool wrote = false;
if (token.getType() == QPDFTokenizer::tt_name) {
std::string name = QPDFObjectHandle::newName(token.getValue()).getName();
if (to_replace.count(name) && to_replace[name].count(offset)) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper replaced DA token");
write(to_replace[name][offset]);
wrote = true;
}
}
this->offset += token.getRawValue().length();
if (!wrote) {
writeToken(token);
}
}
void
QPDFAcroFormDocumentHelper::adjustDefaultAppearances(
QPDFObjectHandle obj, std::map<std::string, std::map<std::string, std::string>> const& dr_map)
{
// This method is called on a field that has been copied from another file but whose /DA still
// refers to resources in the original file's /DR.
// When appearance streams are generated for variable text fields (see ISO 32000 PDF spec
// section 12.7.3.3), the field's /DA is used to generate content of the appearance stream. /DA
// contains references to resources that may be resolved in the document's /DR dictionary, which
// appears in the document's /AcroForm dictionary. For fields that we copied from other
// documents, we need to ensure that resources are mapped correctly in the case of conflicting
// names. For example, if a.pdf's /DR has /F1 pointing to one font and b.pdf's /DR also has /F1
// but it points elsewhere, we need to make sure appearance streams of fields copied from b.pdf
// into a.pdf use whatever font /F1 meant in b.pdf, not whatever it means in a.pdf. This method
// takes care of that. It is only called on fields copied from foreign files.
// A few notes:
//
// * If the from document's /DR and the current document's /DR have conflicting keys, we have
// already resolved the conflicts before calling this method. The dr_map parameter contains
// the mapping from old keys to new keys.
//
// * /DA may be inherited from the document's /AcroForm dictionary. By the time this method has
// been called, we have already copied any document-level values into the fields to avoid
// having them inherit from the new document. This was done in adjustInheritedFields.
auto DA = obj.getKey("/DA");
if (!DA.isString()) {
return;
}
// Find names in /DA. /DA is a string that contains content stream-like code, so we create a
// stream out of the string and then filter it. We don't attach the stream to anything, so it
// will get discarded.
ResourceFinder rf;
auto da_stream = QPDFObjectHandle::newStream(&this->qpdf, DA.getUTF8Value());
try {
auto nwarnings = this->qpdf.numWarnings();
da_stream.parseAsContents(&rf);
if (this->qpdf.numWarnings() > nwarnings) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper /DA parse error");
}
} catch (std::exception& e) {
// No way to reproduce in test suite right now since error conditions are converted to
// warnings.
obj.warnIfPossible(
std::string("Unable to parse /DA: ") + e.what() +
"; this form field may not update properly");
return;
}
// Regenerate /DA by filtering its tokens.
ResourceReplacer rr(dr_map, rf.getNamesByResourceType());
Pl_Buffer buf_pl("filtered DA");
da_stream.filterAsContents(&rr, &buf_pl);
std::string new_da = buf_pl.getString();
obj.replaceKey("/DA", QPDFObjectHandle::newString(new_da));
}
void
QPDFAcroFormDocumentHelper::adjustAppearanceStream(
QPDFObjectHandle stream, std::map<std::string, std::map<std::string, std::string>> dr_map)
{
// We don't have to modify appearance streams or their resource dictionaries for them to display
// properly, but we need to do so to make them save to regenerate. Suppose an appearance stream
// as a font /F1 that is different from /F1 in /DR, and that when we copy the field, /F1 is
// remapped to /F1_1. When the field is regenerated, /F1_1 won't appear in the stream's resource
// dictionary, so the regenerated appearance stream will revert to the /F1_1 in /DR. If we
// adjust existing appearance streams, we are protected from this problem.
auto dict = stream.getDict();
auto resources = dict.getKey("/Resources");
// Make sure this stream has its own private resource dictionary.
bool was_indirect = resources.isIndirect();
resources = resources.shallowCopy();
if (was_indirect) {
resources = this->qpdf.makeIndirectObject(resources);
}
dict.replaceKey("/Resources", resources);
// Create a dictionary with top-level keys so we can use mergeResources to force them to be
// unshared. We will also use this to resolve conflicts that may already be in the resource
// dictionary.
auto merge_with = QPDFObjectHandle::newDictionary();
for (auto const& top_key: dr_map) {
merge_with.replaceKey(top_key.first, QPDFObjectHandle::newDictionary());
}
resources.mergeResources(merge_with);
// Rename any keys in the resource dictionary that we remapped.
for (auto const& i1: dr_map) {
std::string const& top_key = i1.first;
auto subdict = resources.getKey(top_key);
if (!subdict.isDictionary()) {
continue;
}
for (auto const& i2: i1.second) {
std::string const& old_key = i2.first;
std::string const& new_key = i2.second;
auto existing_new = subdict.getKey(new_key);
if (!existing_new.isNull()) {
// The resource dictionary already has a key in it matching what we remapped an old
// key to, so we'll have to move it out of the way. Stick it in merge_with, which we
// will re-merge with the dictionary when we're done. We know merge_with already has
// dictionaries for all the top keys.
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper ap conflict");
merge_with.getKey(top_key).replaceKey(new_key, existing_new);
}
auto existing_old = subdict.getKey(old_key);
if (!existing_old.isNull()) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper ap rename");
subdict.replaceKey(new_key, existing_old);
subdict.removeKey(old_key);
}
}
}
// Deal with any any conflicts by re-merging with merge_with and updating our local copy of
// dr_map, which we will use to modify the stream contents.
resources.mergeResources(merge_with, &dr_map);
// Remove empty subdictionaries
for (auto iter: resources.ditems()) {
if (iter.second.isDictionary() && (iter.second.getKeys().size() == 0)) {
resources.removeKey(iter.first);
}
}
// Now attach a token filter to replace the actual resources.
ResourceFinder rf;
try {
auto nwarnings = this->qpdf.numWarnings();
stream.parseAsContents(&rf);
if (this->qpdf.numWarnings() > nwarnings) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper AP parse error");
}
auto rr = new ResourceReplacer(dr_map, rf.getNamesByResourceType());
auto tf = std::shared_ptr<QPDFObjectHandle::TokenFilter>(rr);
stream.addTokenFilter(tf);
} catch (std::exception& e) {
// No way to reproduce in test suite right now since error conditions are converted to
// warnings.
stream.warnIfPossible(std::string("Unable to parse appearance stream: ") + e.what());
}
}
void
QPDFAcroFormDocumentHelper::transformAnnotations(
QPDFObjectHandle old_annots,
std::vector<QPDFObjectHandle>& new_annots,
std::vector<QPDFObjectHandle>& new_fields,
std::set<QPDFObjGen>& old_fields,
QPDFMatrix const& cm,
QPDF* from_qpdf,
QPDFAcroFormDocumentHelper* from_afdh)
{
std::shared_ptr<QPDFAcroFormDocumentHelper> afdhph;
if (!from_qpdf) {
// Assume these are from the same QPDF.
from_qpdf = &this->qpdf;
from_afdh = this;
} else if ((from_qpdf != &this->qpdf) && (!from_afdh)) {
afdhph = std::make_shared<QPDFAcroFormDocumentHelper>(*from_qpdf);
from_afdh = afdhph.get();
}
bool foreign = (from_qpdf != &this->qpdf);
// It's possible that we will transform annotations that don't include any form fields. This
// code takes care not to muck around with /AcroForm unless we have to.
QPDFObjectHandle acroform = this->qpdf.getRoot().getKey("/AcroForm");
QPDFObjectHandle from_acroform = from_qpdf->getRoot().getKey("/AcroForm");
// /DA and /Q may be inherited from the document-level /AcroForm dictionary. If we are copying a
// foreign stream and the stream is getting one of these values from its document's /AcroForm,
// we will need to copy the value explicitly so that it doesn't start getting its default from
// the destination document.
bool override_da = false;
bool override_q = false;
std::string from_default_da;
int from_default_q = 0;
// If we copy any form fields, we will need to merge the source document's /DR into this
// document's /DR.
QPDFObjectHandle from_dr = QPDFObjectHandle::newNull();
if (foreign) {
std::string default_da;
int default_q = 0;
if (acroform.isDictionary()) {
if (acroform.getKey("/DA").isString()) {
default_da = acroform.getKey("/DA").getUTF8Value();
}
if (acroform.getKey("/Q").isInteger()) {
default_q = acroform.getKey("/Q").getIntValueAsInt();
}
}
if (from_acroform.isDictionary()) {
if (from_acroform.getKey("/DR").isDictionary()) {
from_dr = from_acroform.getKey("/DR");
if (!from_dr.isIndirect()) {
from_dr = from_qpdf->makeIndirectObject(from_dr);
}
from_dr = this->qpdf.copyForeignObject(from_dr);
}
if (from_acroform.getKey("/DA").isString()) {
from_default_da = from_acroform.getKey("/DA").getUTF8Value();
}
if (from_acroform.getKey("/Q").isInteger()) {
from_default_q = from_acroform.getKey("/Q").getIntValueAsInt();
}
}
if (from_default_da != default_da) {
override_da = true;
}
if (from_default_q != default_q) {
override_q = true;
}
}
// If we have to merge /DR, we will need a mapping of conflicting keys for rewriting /DA. Set
// this up for lazy initialization in case we encounter any form fields.
std::map<std::string, std::map<std::string, std::string>> dr_map;
bool initialized_dr_map = false;
QPDFObjectHandle dr = QPDFObjectHandle::newNull();
auto init_dr_map = [&]() {
if (!initialized_dr_map) {
initialized_dr_map = true;
// Ensure that we have a /DR that is an indirect
// dictionary object.
if (!acroform.isDictionary()) {
acroform = getOrCreateAcroForm();
}
dr = acroform.getKey("/DR");
if (!dr.isDictionary()) {
dr = QPDFObjectHandle::newDictionary();
}
dr.makeResourcesIndirect(this->qpdf);
if (!dr.isIndirect()) {
dr = acroform.replaceKeyAndGetNew("/DR", this->qpdf.makeIndirectObject(dr));
}
// Merge the other document's /DR, creating a conflict map. mergeResources checks to
// make sure both objects are dictionaries. By this point, if this is foreign, from_dr
// has been copied, so we use the target qpdf as the owning qpdf.
from_dr.makeResourcesIndirect(this->qpdf);
dr.mergeResources(from_dr, &dr_map);
if (from_afdh->getNeedAppearances()) {
setNeedAppearances(true);
}
}
};
// This helper prevents us from copying the same object multiple times.
std::map<QPDFObjGen, QPDFObjectHandle> orig_to_copy;
auto maybe_copy_object = [&](QPDFObjectHandle& to_copy) {
auto og = to_copy.getObjGen();
if (orig_to_copy.count(og)) {
to_copy = orig_to_copy[og];
return false;
} else {
to_copy = this->qpdf.makeIndirectObject(to_copy.shallowCopy());
orig_to_copy[og] = to_copy;
return true;
}
};
// Now do the actual copies.
QPDFObjGen::set added_new_fields;
for (auto annot: old_annots.aitems()) {
if (annot.isStream()) {
annot.warnIfPossible("ignoring annotation that's a stream");
continue;
}
// Make copies of annotations and fields down to the appearance streams, preserving all
// internal referential integrity. When the incoming annotations are from a different file,
// we first copy them locally. Then, whether local or foreign, we copy them again so that if
// we bring the same annotation in multiple times (e.g. overlaying a foreign page onto
// multiple local pages or a local page onto multiple other local pages), we don't create
// annotations that are referenced in more than one place. If we did that, the effect of
// applying transformations would be cumulative, which is definitely not what we want.
// Besides, annotations and fields are not intended to be referenced in multiple places.
// Determine if this annotation is attached to a form field. If so, the annotation may be
// the same object as the form field, or the form field may have the annotation as a kid. In
// either case, we have to walk up the field structure to find the top-level field. Within
// one iteration through a set of annotations, we don't want to copy the same item more than
// once. For example, suppose we have field A with kids B, C, and D, each of which has
// annotations BA, CA, and DA. When we get to BA, we will find that BA is a kid of B which
// is under A. When we do a copyForeignObject of A, it will also copy everything else
// because of the indirect references. When we clone BA, we will want to clone A and then
// update A's clone's kid to point B's clone and B's clone's parent to point to A's clone.
// The same thing holds for annotations. Next, when we get to CA, we will again discover
// that A is the top, but we don't want to re-copy A. We want CA's clone to be linked to the
// same clone as BA's. Failure to do this will break up things like radio button groups,
// which all have to kids of the same parent.
auto ffield = from_afdh->getFieldForAnnotation(annot);
auto ffield_oh = ffield.getObjectHandle();
QPDFObjectHandle top_field;
bool have_field = false;
bool have_parent = false;
if (ffield_oh.isStream()) {
ffield_oh.warnIfPossible("ignoring form field that's a stream");
} else if ((!ffield_oh.isNull()) && (!ffield_oh.isIndirect())) {
ffield_oh.warnIfPossible("ignoring form field not indirect");
} else if (!ffield_oh.isNull()) {
// A field and its associated annotation can be the same object. This matters because we
// don't want to clone the annotation and field separately in this case.
have_field = true;
// Find the top-level field. It may be the field itself.
top_field = ffield.getTopLevelField(&have_parent).getObjectHandle();
if (foreign) {
// copyForeignObject returns the same value if called multiple times with the same
// field. Create/retrieve the local copy of the original field. This pulls over
// everything the field references including annotations and appearance streams, but
// it's harmless to call copyForeignObject on them too. They will already be copied,
// so we'll get the right object back.
// top_field and ffield_oh are known to be indirect.
top_field = this->qpdf.copyForeignObject(top_field);
ffield_oh = this->qpdf.copyForeignObject(ffield_oh);
} else {
// We don't need to add top_field to old_fields if it's foreign because the new copy
// of the foreign field won't be referenced anywhere. It's just the starting point
// for us to make an additional local copy of.
old_fields.insert(top_field.getObjGen());
}
// Traverse the field, copying kids, and preserving integrity.
std::list<QPDFObjectHandle> queue;
QPDFObjGen::set seen;
if (maybe_copy_object(top_field)) {
queue.push_back(top_field);
}
for (; !queue.empty(); queue.pop_front()) {
auto& obj = queue.front();
if (seen.add(obj)) {
auto parent = obj.getKey("/Parent");
if (parent.isIndirect()) {
auto parent_og = parent.getObjGen();
if (orig_to_copy.count(parent_og)) {
obj.replaceKey("/Parent", orig_to_copy[parent_og]);
} else {
parent.warnIfPossible(
"while traversing field " + obj.getObjGen().unparse(',') +
", found parent (" + parent_og.unparse(',') +
") that had not been seen, indicating likely invalid field "
"structure");
}
}
auto kids = obj.getKey("/Kids");
if (kids.isArray()) {
for (int i = 0; i < kids.getArrayNItems(); ++i) {
auto kid = kids.getArrayItem(i);
if (maybe_copy_object(kid)) {
kids.setArrayItem(i, kid);
queue.push_back(kid);
}
}
}
if (override_da || override_q) {
adjustInheritedFields(
obj, override_da, from_default_da, override_q, from_default_q);
}
if (foreign) {
// Lazily initialize our /DR and the conflict map.
init_dr_map();
// The spec doesn't say anything about /DR on the field, but lots of writers
// put one there, and it is frequently the same as the document-level /DR.
// To avoid having the field's /DR point to information that we are not
// maintaining, just reset it to that if it exists. Empirical evidence
// suggests that many readers, including Acrobat, Adobe Acrobat Reader,
// chrome, firefox, the mac Preview application, and several of the free
// readers on Linux all ignore /DR at the field level.
if (obj.hasKey("/DR")) {
obj.replaceKey("/DR", dr);
}
}
if (foreign && obj.getKey("/DA").isString() && (!dr_map.empty())) {
adjustDefaultAppearances(obj, dr_map);
}
}
}
// Now switch to copies. We already switched for top_field
maybe_copy_object(ffield_oh);
ffield = QPDFFormFieldObjectHelper(ffield_oh);
}
QTC::TC(
"qpdf",
"QPDFAcroFormDocumentHelper copy annotation",
(have_field ? 1 : 0) | (foreign ? 2 : 0));
if (have_field) {
QTC::TC(
"qpdf",
"QPDFAcroFormDocumentHelper field with parent",
(have_parent ? 1 : 0) | (foreign ? 2 : 0));
}
if (foreign) {
if (!annot.isIndirect()) {
annot = from_qpdf->makeIndirectObject(annot);
}
annot = this->qpdf.copyForeignObject(annot);
}
maybe_copy_object(annot);
// Now we have copies, so we can safely mutate.
if (have_field && added_new_fields.add(top_field)) {
new_fields.push_back(top_field);
}
new_annots.push_back(annot);
// Identify and copy any appearance streams
auto ah = QPDFAnnotationObjectHelper(annot);
auto apdict = ah.getAppearanceDictionary();
std::vector<QPDFObjectHandle> streams;
auto replace_stream = [](auto& dict, auto& key, auto& old) {
return dict.replaceKeyAndGetNew(key, old.copyStream());
};
if (apdict.isDictionary()) {
for (auto& ap: apdict.ditems()) {
if (ap.second.isStream()) {
streams.push_back(replace_stream(apdict, ap.first, ap.second));
} else if (ap.second.isDictionary()) {
for (auto& ap2: ap.second.ditems()) {
if (ap2.second.isStream()) {
streams.push_back(
// line-break
replace_stream(ap.second, ap2.first, ap2.second));
}
}
}
}
}
// Now we can safely mutate the annotation and its appearance streams.
for (auto& stream: streams) {
auto dict = stream.getDict();
auto omatrix = dict.getKey("/Matrix");
QPDFMatrix apcm;
if (omatrix.isArray()) {
QTC::TC("qpdf", "QPDFAcroFormDocumentHelper modify ap matrix");
auto m1 = omatrix.getArrayAsMatrix();
apcm = QPDFMatrix(m1);
}
apcm.concat(cm);
auto new_matrix = QPDFObjectHandle::newFromMatrix(apcm);
if (omatrix.isArray() || (apcm != QPDFMatrix())) {
dict.replaceKey("/Matrix", new_matrix);
}
auto resources = dict.getKey("/Resources");
if ((!dr_map.empty()) && resources.isDictionary()) {
adjustAppearanceStream(stream, dr_map);
}
}
auto rect = cm.transformRectangle(annot.getKey("/Rect").getArrayAsRectangle());
annot.replaceKey("/Rect", QPDFObjectHandle::newFromRectangle(rect));
}
}
void
QPDFAcroFormDocumentHelper::fixCopiedAnnotations(
QPDFObjectHandle to_page,
QPDFObjectHandle from_page,
QPDFAcroFormDocumentHelper& from_afdh,
std::set<QPDFObjGen>* added_fields)
{
auto old_annots = from_page.getKey("/Annots");
if ((!old_annots.isArray()) || (old_annots.getArrayNItems() == 0)) {
return;
}
std::vector<QPDFObjectHandle> new_annots;
std::vector<QPDFObjectHandle> new_fields;
std::set<QPDFObjGen> old_fields;
transformAnnotations(
old_annots,
new_annots,
new_fields,
old_fields,
QPDFMatrix(),
&(from_afdh.getQPDF()),
&from_afdh);
to_page.replaceKey("/Annots", QPDFObjectHandle::newArray(new_annots));
addAndRenameFormFields(new_fields);
if (added_fields) {
for (auto const& f: new_fields) {
added_fields->insert(f.getObjGen());
}
}
}
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