Merge pull request #1554 from m-holger/foreign_stream

Refactor foreign object copying

Merge pull request #1554 from m-holger/foreign_stream
Refactor foreign object copying
m-holger · GitHub
2 parents 6324d438 c5bf0fdf
Showing 12 changed files with 306 additions and 311 deletions
include/qpdf/ObjectHandle.hh
include/qpdf/QPDF.hh
libqpdf/QPDF.cc
libqpdf/QPDFObjectHandle.cc
libqpdf/QPDFWriter.cc
libqpdf/QPDF_Stream.cc
libqpdf/QPDF_json.cc
libqpdf/QPDF_objects.cc
libqpdf/qpdf/QPDFObjectHandle_private.hh
libqpdf/qpdf/QPDFObject_private.hh
libqpdf/qpdf/QPDF_private.hh
qpdf/qpdf.testcov
@@ -94,6 +94,7 @@ namespace qpdf
         inline QPDFObjGen id_gen() const;
         inline bool indirect() const;
         inline bool null() const;
+        inline qpdf_offset_t offset() const;
         inline QPDF* qpdf() const;
         inline qpdf_object_type_e raw_type_code() const;
         inline qpdf_object_type_e resolved_type_code() const;
@@ -742,7 +742,6 @@ class QPDF
     static std::string const qpdf_version;
     class ObjCache;
-    class ObjCopier;
     class EncryptionParameters;
     class ForeignStreamData;
     class CopiedStreamDataProvider;
@@ -775,8 +774,8 @@ class QPDF
         Pipeline* pipeline,
         bool suppress_warnings,
         bool will_retry);
-    bool pipeForeignStreamData(
-        std::shared_ptr<ForeignStreamData>, Pipeline*, bool suppress_warnings, bool will_retry);
+    bool
+    pipeForeignStreamData(ForeignStreamData&, Pipeline*, bool suppress_warnings, bool will_retry);
     static bool pipeStreamData(
         std::shared_ptr<QPDF::EncryptionParameters> encp,
         std::shared_ptr<InputSource> file,
@@ -790,27 +789,6 @@ class QPDF
         bool suppress_warnings,
         bool will_retry);
-    // For QPDFWriter:
-
-    std::map<QPDFObjGen, QPDFXRefEntry> const& getXRefTableInternal();
-    // Get a list of objects that would be permitted in an object stream.
-    template <typename T>
-    std::vector<T> getCompressibleObjGens();
-    std::vector<QPDFObjGen> getCompressibleObjVector();
-    std::vector<bool> getCompressibleObjSet();
-
-    // methods to support page handling
-
-    void getAllPagesInternal(
-        QPDFObjectHandle cur_pages,
-        QPDFObjGen::set& visited,
-        QPDFObjGen::set& seen,
-        bool media_box,
-        bool resources);
-    void insertPage(QPDFObjectHandle newpage, int pos);
-    void flattenPagesTree();
-    void insertPageobjToPage(QPDFObjectHandle const& obj, int pos, bool check_duplicate);
-
     // methods to support encryption -- implemented in QPDF_encryption.cc
     void initializeEncryption();
     static std::string
@@ -827,9 +805,6 @@ class QPDF
         std::unique_ptr<Pipeline>& heap);
     // Methods to support object copying
-    void reserveObjects(QPDFObjectHandle foreign, ObjCopier& obj_copier, bool top);
-    QPDFObjectHandle
-    replaceForeignIndirectObjects(QPDFObjectHandle foreign, ObjCopier& obj_copier, bool top);
     void copyStreamData(QPDFObjectHandle dest_stream, QPDFObjectHandle src_stream);
     struct HPageOffsetEntry;
@@ -27,6 +27,8 @@
 using namespace qpdf;
 using namespace std::literals;
+using Objects = QPDF::Doc::Objects;
+
 // This must be a fixed value. This API returns a const reference to it, and the C API relies on its
 // being static as well.
 std::string const QPDF::qpdf_version(QPDF_VERSION);
@@ -109,20 +111,14 @@ namespace
 } // namespace
 QPDF::ForeignStreamData::ForeignStreamData(
-    std::shared_ptr<EncryptionParameters> encp,
-    std::shared_ptr<InputSource> file,
-    QPDFObjGen foreign_og,
-    qpdf_offset_t offset,
-    size_t length,
-    QPDFObjectHandle local_dict,
-    bool is_root_metadata) :
-    encp(encp),
-    file(file),
-    foreign_og(foreign_og),
+    Stream& foreign, qpdf_offset_t offset, QPDFObjectHandle local_dict) :
+    encp(foreign.qpdf()->m->encp),
+    file(foreign.qpdf()->m->file),
+    foreign_og(foreign.id_gen()),
     offset(offset),
-    length(length),
+    length(foreign.getLength()),
     local_dict(local_dict),
-    is_root_metadata(is_root_metadata)
+    is_root_metadata(foreign.isRootMetadata())
 {
 }
@@ -136,11 +132,11 @@ bool
 QPDF::CopiedStreamDataProvider::provideStreamData(
     QPDFObjGen const& og, Pipeline* pipeline, bool suppress_warnings, bool will_retry)
 {
-    std::shared_ptr<ForeignStreamData> foreign_data = foreign_stream_data[og];
+    auto foreign_data = foreign_stream_data.find(og);
     bool result = false;
-    if (foreign_data.get()) {
+    if (foreign_data != foreign_stream_data.end()) {
         result = destination_qpdf.pipeForeignStreamData(
-            foreign_data, pipeline, suppress_warnings, will_retry);
+            foreign_data->second, pipeline, suppress_warnings, will_retry);
         QTC::TC("qpdf", "QPDF copy foreign with data", result ? 0 : 1);
     } else {
         auto foreign_stream = foreign_streams[og];
@@ -151,20 +147,6 @@ QPDF::CopiedStreamDataProvider::provideStreamData(
     return result;
 }
-void
-QPDF::CopiedStreamDataProvider::registerForeignStream(
-    QPDFObjGen const& local_og, QPDFObjectHandle foreign_stream)
-{
-    this->foreign_streams[local_og] = foreign_stream;
-}
-
-void
-QPDF::CopiedStreamDataProvider::registerForeignStream(
-    QPDFObjGen const& local_og, std::shared_ptr<ForeignStreamData> foreign_stream)
-{
-    this->foreign_stream_data[local_og] = foreign_stream;
-}
-
 QPDF::StringDecrypter::StringDecrypter(QPDF* qpdf, QPDFObjGen og) :
     qpdf(qpdf),
     og(og)
@@ -184,8 +166,8 @@ QPDF::Members::Members(QPDF&amp; qpdf) :
     objects(doc.objects()),
     pages(doc.pages()),
     log(QPDFLogger::defaultLogger()),
-    file(new InvalidInputSource()),
-    encp(new EncryptionParameters)
+    file(std::make_shared<InvalidInputSource>()),
+    encp(std::make_shared<EncryptionParameters>())
 {
 }
@@ -491,6 +473,25 @@ QPDF::getObjectByID(int objid, int generation)
 QPDFObjectHandle
 QPDF::copyForeignObject(QPDFObjectHandle foreign)
 {
+    return m->objects.foreign().copied(foreign);
+}
+
+Objects ::Foreign::Copier&
+Objects::Foreign::copier(QPDFObjectHandle const& foreign)
+{
+    if (!foreign.isIndirect()) {
+        throw std::logic_error("QPDF::copyForeign called with direct object handle");
+    }
+    QPDF& other = *foreign.qpdf();
+    if (&other == &qpdf) {
+        throw std::logic_error("QPDF::copyForeign called with object from this QPDF");
+    }
+    return copiers.insert({other.getUniqueId(), {qpdf}}).first->second;
+}
+
+QPDFObjectHandle
+Objects::Foreign::Copier::copied(QPDFObjectHandle const& foreign)
+{
     // Here's an explanation of what's going on here.
     //
     // A QPDFObjectHandle that is an indirect object has an owning QPDF. The object ID and
@@ -499,7 +500,7 @@ QPDF::copyForeignObject(QPDFObjectHandle foreign)
     // references to the corresponding object in the local file.
     //
     // To do this, we maintain mappings from foreign object IDs to local object IDs for each foreign
-    // QPDF that we are copying from. The mapping is stored in an ObjCopier, which contains a
+    // QPDF that we are copying from. The mapping is stored in an Foreign::Copier, which contains a
     // mapping from the foreign ObjGen to the local QPDFObjectHandle.
     //
     // To copy, we do a deep traversal of the foreign object with loop detection to discover all
@@ -525,218 +526,185 @@ QPDF::copyForeignObject(QPDFObjectHandle foreign)
     // Note that we explicitly allow use of copyForeignObject on page objects. It is a documented
     // use case to copy pages this way if the intention is to not update the pages tree.
-    if (!foreign.isIndirect()) {
-        QTC::TC("qpdf", "QPDF copyForeign direct");
-        throw std::logic_error("QPDF::copyForeign called with direct object handle");
-    }
-    QPDF& other = foreign.getQPDF();
-    if (&other == this) {
-        QTC::TC("qpdf", "QPDF copyForeign not foreign");
-        throw std::logic_error("QPDF::copyForeign called with object from this QPDF");
-    }
-    ObjCopier& obj_copier = m->object_copiers[other.m->unique_id];
-    if (!obj_copier.visiting.empty()) {
-        throw std::logic_error(
-            "obj_copier.visiting is not empty at the beginning of copyForeignObject");
-    }
+    util::assertion(
+        visiting.empty(), "obj_copier.visiting is not empty at the beginning of copyForeignObject");
     // Make sure we have an object in this file for every referenced object in the old file.
     // obj_copier.object_map maps foreign QPDFObjGen to local objects.  For everything new that we
     // have to copy, the local object will be a reservation, unless it is a stream, in which case
     // the local object will already be a stream.
-    reserveObjects(foreign, obj_copier, true);
+    reserve_objects(foreign, true);
-    if (!obj_copier.visiting.empty()) {
-        throw std::logic_error("obj_copier.visiting is not empty after reserving objects");
-    }
+    util::assertion(visiting.empty(), "obj_copier.visiting is not empty after reserving objects");
     // Copy any new objects and replace the reservations.
-    for (auto& to_copy: obj_copier.to_copy) {
-        QPDFObjectHandle copy = replaceForeignIndirectObjects(to_copy, obj_copier, true);
-        if (!to_copy.isStream()) {
-            QPDFObjGen og(to_copy.getObjGen());
-            replaceReserved(obj_copier.object_map[og], copy);
+    for (auto& oh: to_copy) {
+        auto copy = replace_indirect_object(oh, true);
+        if (!oh.isStream()) {
+            qpdf.replaceReserved(object_map[oh], copy);
         }
     }
-    obj_copier.to_copy.clear();
+    to_copy.clear();
     auto og = foreign.getObjGen();
-    if (!obj_copier.object_map.contains(og)) {
-        warn(damagedPDF(
-            other.getFilename() + " object " + og.unparse(' '),
-            foreign.getParsedOffset(),
+    if (!object_map.contains(og)) {
+        qpdf.warn(qpdf.damagedPDF(
+            foreign.qpdf()->getFilename() + " object " + og.unparse(' '),
+            foreign.offset(),
             "unexpected reference to /Pages object while copying foreign object; replacing with "
             "null"));
         return QPDFObjectHandle::newNull();
     }
-    return obj_copier.object_map[foreign.getObjGen()];
+    return object_map[foreign];
 }
 void
-QPDF::reserveObjects(QPDFObjectHandle foreign, ObjCopier& obj_copier, bool top)
+Objects::Foreign::Copier::reserve_objects(QPDFObjectHandle const& foreign, bool top)
 {
-    auto foreign_tc = foreign.getTypeCode();
-    if (foreign_tc == ::ot_reserved) {
-        throw std::logic_error("QPDF: attempting to copy a foreign reserved object");
-    }
+    auto foreign_tc = foreign.type_code();
+    util::assertion(
+        foreign_tc != ::ot_reserved, "QPDF: attempting to copy a foreign reserved object");
     if (foreign.isPagesObject()) {
         return;
     }
-    if (foreign.isIndirect()) {
+    if (foreign.indirect()) {
         QPDFObjGen foreign_og(foreign.getObjGen());
-        if (!obj_copier.visiting.add(foreign_og)) {
+        if (!visiting.add(foreign_og)) {
             return;
         }
-        if (obj_copier.object_map.contains(foreign_og)) {
-            if (!(top && foreign.isPageObject() && obj_copier.object_map[foreign_og].null())) {
-                obj_copier.visiting.erase(foreign);
+        if (object_map.contains(foreign_og)) {
+            if (!(top && foreign.isPageObject() && object_map[foreign_og].null())) {
+                visiting.erase(foreign);
                 return;
             }
         } else {
-            obj_copier.object_map[foreign_og] =
-                foreign.isStream() ? newStream() : newIndirectNull();
+            object_map[foreign_og] = foreign.isStream() ? qpdf.newStream() : qpdf.newIndirectNull();
             if (!top && foreign.isPageObject()) {
-                obj_copier.visiting.erase(foreign_og);
+                visiting.erase(foreign_og);
                 return;
             }
         }
-        obj_copier.to_copy.emplace_back(foreign);
+        to_copy.emplace_back(foreign);
     }
     if (foreign_tc == ::ot_array) {
-        for (auto const& item: foreign.as_array()) {
-            reserveObjects(item, obj_copier, false);
+        for (auto const& item: Array(foreign)) {
+            reserve_objects(item);
         }
     } else if (foreign_tc == ::ot_dictionary) {
-        for (auto const& item: foreign.as_dictionary()) {
+        for (auto const& item: Dictionary(foreign)) {
             if (!item.second.null()) {
-                reserveObjects(item.second, obj_copier, false);
+                reserve_objects(item.second);
             }
         }
     } else if (foreign_tc == ::ot_stream) {
-        reserveObjects(foreign.getDict(), obj_copier, false);
+        reserve_objects(foreign.getDict());
     }
-    obj_copier.visiting.erase(foreign);
+    visiting.erase(foreign);
 }
 QPDFObjectHandle
-QPDF::replaceForeignIndirectObjects(QPDFObjectHandle foreign, ObjCopier& obj_copier, bool top)
-{
-    auto foreign_tc = foreign.getTypeCode();
-    QPDFObjectHandle result;
-    if ((!top) && foreign.isIndirect()) {
-        QTC::TC("qpdf", "QPDF replace indirect");
-        auto mapping = obj_copier.object_map.find(foreign.getObjGen());
-        if (mapping == obj_copier.object_map.end()) {
+Objects::Foreign::Copier::replace_indirect_object(QPDFObjectHandle const& foreign, bool top)
+{
+    auto foreign_tc = foreign.type_code();
+
+    if (!top && foreign.indirect()) {
+        auto mapping = object_map.find(foreign.id_gen());
+        if (mapping == object_map.end()) {
             // This case would occur if this is a reference to a Pages object that we didn't
             // traverse into.
-            QTC::TC("qpdf", "QPDF replace foreign indirect with null");
-            result = QPDFObjectHandle::newNull();
-        } else {
-            result = mapping->second;
+            return QPDFObjectHandle::newNull();
         }
-    } else if (foreign_tc == ::ot_array) {
-        QTC::TC("qpdf", "QPDF replace array");
-        result = QPDFObjectHandle::newArray();
-        for (auto const& item: foreign.as_array()) {
-            result.appendItem(replaceForeignIndirectObjects(item, obj_copier, false));
+        return mapping->second;
+    }
+
+    if (foreign_tc == ::ot_array) {
+        Array array = foreign;
+        std::vector<QPDFObjectHandle> result;
+        result.reserve(array.size());
+        for (auto const& item: array) {
+            result.emplace_back(replace_indirect_object(item));
         }
-    } else if (foreign_tc == ::ot_dictionary) {
-        QTC::TC("qpdf", "QPDF replace dictionary");
-        result = QPDFObjectHandle::newDictionary();
-        for (auto const& [key, value]: foreign.as_dictionary()) {
+        return Array(std::move(result));
+    }
+
+    if (foreign_tc == ::ot_dictionary) {
+        auto result = Dictionary::empty();
+        for (auto const& [key, value]: Dictionary(foreign)) {
             if (!value.null()) {
-                result.replaceKey(key, replaceForeignIndirectObjects(value, obj_copier, false));
+                result.replaceKey(key, replace_indirect_object(value));
             }
         }
-    } else if (foreign_tc == ::ot_stream) {
-        QTC::TC("qpdf", "QPDF replace stream");
-        result = obj_copier.object_map[foreign.getObjGen()];
-        QPDFObjectHandle dict = result.getDict();
-        QPDFObjectHandle old_dict = foreign.getDict();
-        for (auto const& [key, value]: old_dict.as_dictionary()) {
+        return result;
+    }
+
+    if (foreign_tc == ::ot_stream) {
+        Stream stream = foreign;
+        Stream result = object_map[foreign];
+        auto dict = result.getDict();
+        for (auto const& [key, value]: stream.getDict()) {
             if (!value.null()) {
-                dict.replaceKey(key, replaceForeignIndirectObjects(value, obj_copier, false));
+                dict.replaceKey(key, replace_indirect_object(value));
             }
         }
-        copyStreamData(result, foreign);
-    } else {
-        foreign.assertScalar();
-        result = foreign;
-        result.makeDirect();
-    }
-
-    if (top && (!result.isStream()) && result.isIndirect()) {
-        throw std::logic_error("replacement for foreign object is indirect");
+        qpdf.copyStreamData(result, foreign);
+        return result;
     }
+    foreign.assertScalar();
+    auto result = foreign;
+    result.makeDirect();
     return result;
 }
 void
-QPDF::copyStreamData(QPDFObjectHandle result, QPDFObjectHandle foreign)
+QPDF::copyStreamData(QPDFObjectHandle result, QPDFObjectHandle foreign_oh)
 {
     // This method was originally written for copying foreign streams, but it is used by
-    // QPDFObjectHandle to copy streams from the same QPDF object as well.
-
-    QPDFObjectHandle dict = result.getDict();
-    QPDFObjectHandle old_dict = foreign.getDict();
-    if (m->copied_stream_data_provider == nullptr) {
-        m->copied_stream_data_provider = new CopiedStreamDataProvider(*this);
-        m->copied_streams =
-            std::shared_ptr<QPDFObjectHandle::StreamDataProvider>(m->copied_stream_data_provider);
+    // Stream::copy to copy streams from the same QPDF object as well.
+
+    Dictionary dict = result.getDict();
+    Dictionary old_dict = foreign_oh.getDict();
+    if (!m->copied_stream_data_provider) {
+        m->copied_stream_data_provider = std::make_shared<CopiedStreamDataProvider>(*this);
     }
     QPDFObjGen local_og(result.getObjGen());
     // Copy information from the foreign stream so we can pipe its data later without keeping the
     // original QPDF object around.
     QPDF& foreign_stream_qpdf =
-        foreign.getQPDF("unable to retrieve owning qpdf from foreign stream");
+        foreign_oh.getQPDF("unable to retrieve owning qpdf from foreign stream");
-    auto stream = foreign.as_stream();
-    if (!stream) {
+    Stream foreign = foreign_oh;
+    if (!foreign) {
         throw std::logic_error("unable to retrieve underlying stream object from foreign stream");
     }
-    std::shared_ptr<Buffer> stream_buffer = stream.getStreamDataBuffer();
-    if ((foreign_stream_qpdf.m->immediate_copy_from) && (stream_buffer == nullptr)) {
+    std::shared_ptr<Buffer> stream_buffer = foreign.getStreamDataBuffer();
+    if (foreign_stream_qpdf.m->immediate_copy_from && !stream_buffer) {
         // Pull the stream data into a buffer before attempting the copy operation. Do it on the
         // source stream so that if the source stream is copied multiple times, we don't have to
         // keep duplicating the memory.
-        QTC::TC("qpdf", "QPDF immediate copy stream data");
         foreign.replaceStreamData(
-            foreign.getRawStreamData(),
-            old_dict.getKey("/Filter"),
-            old_dict.getKey("/DecodeParms"));
-        stream_buffer = stream.getStreamDataBuffer();
+            foreign.getRawStreamData(), old_dict["/Filter"], old_dict["/DecodeParms"]);
+        stream_buffer = foreign.getStreamDataBuffer();
     }
-    std::shared_ptr<QPDFObjectHandle::StreamDataProvider> stream_provider =
-        stream.getStreamDataProvider();
-    if (stream_buffer.get()) {
-        QTC::TC("qpdf", "QPDF copy foreign stream with buffer");
-        result.replaceStreamData(
-            stream_buffer, dict.getKey("/Filter"), dict.getKey("/DecodeParms"));
-    } else if (stream_provider.get()) {
+    auto stream_provider = foreign.getStreamDataProvider();
+    if (stream_buffer) {
+        result.replaceStreamData(stream_buffer, dict["/Filter"], dict["/DecodeParms"]);
+    } else if (stream_provider) {
         // In this case, the remote stream's QPDF must stay in scope.
-        QTC::TC("qpdf", "QPDF copy foreign stream with provider");
-        m->copied_stream_data_provider->registerForeignStream(local_og, foreign);
+        m->copied_stream_data_provider->registerForeignStream(local_og, foreign_oh);
         result.replaceStreamData(
-            m->copied_streams, dict.getKey("/Filter"), dict.getKey("/DecodeParms"));
+            m->copied_stream_data_provider, dict["/Filter"], dict["/DecodeParms"]);
     } else {
-        auto foreign_stream_data = std::make_shared<ForeignStreamData>(
-            foreign_stream_qpdf.m->encp,
-            foreign_stream_qpdf.m->file,
-            foreign,
-            foreign.getParsedOffset(),
-            stream.getLength(),
-            dict,
-            stream.isRootMetadata());
+        auto foreign_stream_data = ForeignStreamData(foreign, foreign_oh.offset(), dict);
         m->copied_stream_data_provider->registerForeignStream(local_og, foreign_stream_data);
         result.replaceStreamData(
-            m->copied_streams, dict.getKey("/Filter"), dict.getKey("/DecodeParms"));
+            m->copied_stream_data_provider, dict["/Filter"], dict["/DecodeParms"]);
     }
 }
@@ -820,11 +788,11 @@ QPDF::getRoot()
 std::map<QPDFObjGen, QPDFXRefEntry>
 QPDF::getXRefTable()
 {
-    return getXRefTableInternal();
+    return m->objects.getXRefTableInternal();
 }
 std::map<QPDFObjGen, QPDFXRefEntry> const&
-QPDF::getXRefTableInternal()
+Objects::getXRefTableInternal()
 {
     if (!m->parsed) {
         throw std::logic_error("QPDF::getXRefTable called before parsing.");
@@ -927,23 +895,20 @@ QPDF::pipeStreamData(
 bool
 QPDF::pipeForeignStreamData(
-    std::shared_ptr<ForeignStreamData> foreign,
-    Pipeline* pipeline,
-    bool suppress_warnings,
-    bool will_retry)
+    ForeignStreamData& foreign, Pipeline* pipeline, bool suppress_warnings, bool will_retry)
 {
-    if (foreign->encp->encrypted) {
+    if (foreign.encp->encrypted) {
         QTC::TC("qpdf", "QPDF pipe foreign encrypted stream");
     }
     return pipeStreamData(
-        foreign->encp,
-        foreign->file,
+        foreign.encp,
+        foreign.file,
         *this,
-        foreign->foreign_og,
-        foreign->offset,
-        foreign->length,
-        foreign->local_dict,
-        foreign->is_root_metadata,
+        foreign.foreign_og,
+        foreign.offset,
+        foreign.length,
+        foreign.local_dict,
+        foreign.is_root_metadata,
         pipeline,
         suppress_warnings,
         will_retry);
@@ -1690,7 +1690,7 @@ QPDFObjectHandle::parse(
 qpdf_offset_t
 QPDFObjectHandle::getParsedOffset() const
 {
-    return obj ? obj->getParsedOffset() : -1;
+    return offset();
 }
 QPDFObjectHandle
@@ -1935,24 +1935,6 @@ QPDFObjectHandle::makeDirect(QPDFObjGen::set&amp; visited, bool stop_at_streams)
     visited.erase(cur_og);
 }
-QPDFObjectHandle
-QPDFObjectHandle::copyStream()
-{
-    assertStream();
-    QPDFObjectHandle result = newStream(getOwningQPDF());
-    QPDFObjectHandle dict = result.getDict();
-    QPDFObjectHandle old_dict = getDict();
-    for (auto& iter: QPDFDictItems(old_dict)) {
-        if (iter.second.isIndirect()) {
-            dict.replaceKey(iter.first, iter.second);
-        } else {
-            dict.replaceKey(iter.first, iter.second.shallowCopy());
-        }
-    }
-    QPDF::Doc::StreamCopier::copyStreamData(getOwningQPDF(), result, *this);
-    return result;
-}
-
 void
 QPDFObjectHandle::makeDirect(bool allow_streams)
 {
@@ -320,7 +320,7 @@ class QPDF::Doc::Writer
     std::map<QPDFObjGen, QPDFXRefEntry> const&
     getXRefTable()
     {
-        return pdf.getXRefTableInternal();
+        return objects.getXRefTableInternal();
     }
     size_t
@@ -4,7 +4,6 @@
 #include <qpdf/JSON_writer.hh>
 #include <qpdf/Pipeline.hh>
 #include <qpdf/Pipeline_private.hh>
-#include <qpdf/Pl_Base64.hh>
 #include <qpdf/Pl_Buffer.hh>
 #include <qpdf/Pl_Count.hh>
 #include <qpdf/Pl_Discard.hh>
@@ -45,6 +44,12 @@ class QPDF::Doc::Streams
         return qpdf->pipeStreamData(
             og, offset, length, dict, is_root_metadata, pipeline, suppress_warnings, will_retry);
     }
+
+    static void
+    copyStreamData(QPDF* qpdf, QPDFObjectHandle const& dest, QPDFObjectHandle const& src)
+    {
+        qpdf->copyStreamData(dest, src);
+    }
 };
 namespace
@@ -207,6 +212,15 @@ Stream::Stream(
     setDictDescription();
 }
+Stream
+Stream::copy() const
+{
+    Stream result = qpdf()->newStream();
+    result.stream()->stream_dict = getDict().copy();
+    QPDF::Doc::Streams::copyStreamData(qpdf(), result, *this);
+    return result;
+}
+
 void
 Stream::registerStreamFilter(
     std::string const& filter_name, std::function<std::shared_ptr<QPDFStreamFilter>()> factory)
@@ -350,12 +364,11 @@ Stream::getStreamData(qpdf_stream_decode_level_e decode_level)
     if (!filtered) {
         throw QPDFExc(
             qpdf_e_unsupported,
-            obj->getQPDF()->getFilename(),
+            qpdf()->getFilename(),
             "",
-            obj->getParsedOffset(),
+            offset(),
             "getStreamData called on unfilterable stream");
     }
-    QTC::TC("qpdf", "QPDF_Stream getStreamData");
     return result;
 }
@@ -367,23 +380,21 @@ Stream::getRawStreamData()
     if (!pipeStreamData(&buf, nullptr, 0, qpdf_dl_none, false, false)) {
         throw QPDFExc(
             qpdf_e_unsupported,
-            obj->getQPDF()->getFilename(),
+            qpdf()->getFilename(),
             "",
-            obj->getParsedOffset(),
+            offset(),
             "error getting raw stream data");
     }
-    QTC::TC("qpdf", "QPDF_Stream getRawStreamData");
     return result;
 }
 bool
 Stream::isRootMetadata() const
 {
-    if (!getDict().isDictionaryOfType("/Metadata", "/XML")) {
+    if (!stream()->stream_dict.isDictionaryOfType("/Metadata", "/XML")) {
         return false;
     }
-    auto root_metadata = qpdf()->getRoot().getKey("/Metadata");
-    return root_metadata.isSameObjectAs(obj);
+    return qpdf()->getRoot()["/Metadata"].isSameObjectAs(obj);
 }
 bool
@@ -579,15 +590,13 @@ Stream::pipeStreamData(
             s->stream_dict.replaceKey("/Length", QPDFObjectHandle::newInteger(actual_length));
         }
     } else {
-        if (obj->getParsedOffset() == 0) {
-            QTC::TC("qpdf", "QPDF_Stream pipe no stream data");
+        if (offset() == 0) {
             throw std::logic_error("pipeStreamData called for stream with no data");
         }
-        QTC::TC("qpdf", "QPDF_Stream pipe original stream data");
         if (!QPDF::Doc::Streams::pipeStreamData(
-                obj->getQPDF(),
-                obj->getObjGen(),
-                obj->getParsedOffset(),
+                qpdf(),
+                id_gen(),
+                offset(),
                 s->length,
                 s->stream_dict,
                 isRootMetadata(),
@@ -619,6 +628,16 @@ Stream::pipeStreamData(
 void
 Stream::replaceStreamData(
+    std::string&& data, QPDFObjectHandle const& filter, QPDFObjectHandle const& decode_parms)
+{
+    auto s = stream();
+    s->stream_data = std::make_shared<Buffer>(std::move(data));
+    s->stream_provider = nullptr;
+    replaceFilterData(filter, decode_parms, s->stream_data->getSize());
+}
+
+void
+Stream::replaceStreamData(
     std::shared_ptr<Buffer> data,
     QPDFObjectHandle const& filter,
     QPDFObjectHandle const& decode_parms)
@@ -626,7 +645,7 @@ Stream::replaceStreamData(
     auto s = stream();
     s->stream_data = data;
     s->stream_provider = nullptr;
-    replaceFilterData(filter, decode_parms, data->getSize());
+    replaceFilterData(filter, decode_parms, data->size());
 }
 void
@@ -664,7 +683,7 @@ Stream::replaceFilterData(
 void
 Stream::warn(std::string const& message)
 {
-    obj->getQPDF()->warn(qpdf_e_damaged_pdf, "", obj->getParsedOffset(), message);
+    qpdf()->warn(qpdf_e_damaged_pdf, "", offset(), message);
 }
 QPDFObjectHandle
@@ -772,12 +791,8 @@ void
 QPDFObjectHandle::replaceStreamData(
     std::string const& data, QPDFObjectHandle const& filter, QPDFObjectHandle const& decode_parms)
 {
-    auto b = std::make_shared<Buffer>(data.length());
-    unsigned char* bp = b->getBuffer();
-    if (bp) {
-        memcpy(bp, data.c_str(), data.length());
-    }
-    as_stream(error).replaceStreamData(b, filter, decode_parms);
+    std::string s(data);
+    as_stream(error).replaceStreamData(std::move(s), filter, decode_parms);
 }
 void
@@ -856,3 +871,9 @@ QPDFObjectHandle::getStreamJSON(
 {
     return as_stream(error).getStreamJSON(json_version, json_data, decode_level, p, data_filename);
 }
+
+QPDFObjectHandle
+QPDFObjectHandle::copyStream()
+{
+    return as_stream(error).copy();
+}
@@ -424,8 +424,7 @@ QPDF::JSONReactor::replaceObject(QPDFObjectHandle&amp;&amp; replacement, JSON const&amp; val
     auto og = tos.object.getObjGen();
     if (replacement.isIndirect() && !(replacement.isStream() && replacement.getObjGen() == og)) {
         error(
-            replacement.getParsedOffset(),
-            "the value of an object may not be an indirect object reference");
+            replacement.offset(), "the value of an object may not be an indirect object reference");
         return;
     }
     pdf.replaceObject(og, replacement);
@@ -885,7 +884,7 @@ QPDF::writeJSON(
             } else {
                 jw << "\n      },\n      \"" << key;
             }
-            if (auto stream = obj.as_stream()) {
+            if (Stream stream = obj) {
                 jw << "\": {\n        \"stream\": ";
                 if (json_stream_data == qpdf_sj_file) {
                     writeJSONStreamFile(
@@ -1634,7 +1634,7 @@ Objects::resolveObjectsInStream(int obj_stream_number)
     }
     m->resolved_object_streams.insert(obj_stream_number);
     // Force resolution of object stream
-    auto obj_stream = qpdf.getObject(obj_stream_number, 0).as_stream();
+    Stream obj_stream = qpdf.getObject(obj_stream_number, 0);
     if (!obj_stream) {
         throw qpdf.damagedPDF(
             "object " + std::to_string(obj_stream_number) + " 0",
@@ -445,6 +445,23 @@ namespace qpdf
         {
         }
+        Stream() = default;
+        Stream(Stream const&) = default;
+        Stream(Stream&&) = default;
+        Stream& operator=(Stream const&) = default;
+        Stream& operator=(Stream&&) = default;
+        ~Stream() = default;
+
+        Stream(QPDFObjectHandle const& oh) :
+            BaseHandle(oh.type_code() == ::ot_stream ? oh : QPDFObjectHandle())
+        {
+        }
+
+        Stream(QPDFObjectHandle&& oh) :
+            BaseHandle(oh.type_code() == ::ot_stream ? std::move(oh) : QPDFObjectHandle())
+        {
+        }
+
         Stream(
             QPDF& qpdf,
             QPDFObjGen og,
@@ -452,10 +469,12 @@ namespace qpdf
             qpdf_offset_t offset,
             size_t length);
-        QPDFObjectHandle
+        Stream copy() const;
+
+        Dictionary
         getDict() const
         {
-            return stream()->stream_dict;
+            return {stream()->stream_dict};
         }
         bool
         isDataModified() const
@@ -501,6 +520,10 @@ namespace qpdf
         std::string getStreamData(qpdf_stream_decode_level_e level);
         std::string getRawStreamData();
         void replaceStreamData(
+            std::string&& data,
+            QPDFObjectHandle const& filter,
+            QPDFObjectHandle const& decode_parms);
+        void replaceStreamData(
             std::shared_ptr<Buffer> data,
             QPDFObjectHandle const& filter,
             QPDFObjectHandle const& decode_parms);
@@ -657,6 +680,12 @@ namespace qpdf
         return !obj || type_code() == ::ot_null;
     }
+    inline qpdf_offset_t
+    BaseHandle::offset() const
+    {
+        return obj ? obj->parsed_offset : -1;
+    }
+
     inline QPDF*
     BaseHandle::qpdf() const
     {
@@ -438,11 +438,6 @@ class QPDFObject
             parsed_offset = offset;
         }
     }
-    qpdf_offset_t
-    getParsedOffset()
-    {
-        return parsed_offset;
-    }
     QPDF*
     getQPDF()
     {
@@ -13,10 +13,14 @@
 using namespace qpdf;
-namespace qpdf::is
+namespace qpdf
 {
-    class OffsetBuffer;
-} // namespace qpdf::is
+    class Stream;
+    namespace is
+    {
+        class OffsetBuffer;
+    } // namespace is
+} // namespace qpdf
 class BitStream;
 class BitWriter;
@@ -40,14 +44,6 @@ class QPDF::ObjCache
     qpdf_offset_t end_after_space{0};
 };
-class QPDF::ObjCopier
-{
-  public:
-    std::map<QPDFObjGen, QPDFObjectHandle> object_map;
-    std::vector<QPDFObjectHandle> to_copy;
-    QPDFObjGen::set visiting;
-};
-
 class QPDF::EncryptionParameters
 {
     friend class QPDF;
@@ -98,14 +94,7 @@ class QPDF::ForeignStreamData
     friend class QPDF;
   public:
-    ForeignStreamData(
-        std::shared_ptr<EncryptionParameters> encp,
-        std::shared_ptr<InputSource> file,
-        QPDFObjGen foreign_og,
-        qpdf_offset_t offset,
-        size_t length,
-        QPDFObjectHandle local_dict,
-        bool is_root_metadata);
+    ForeignStreamData(Stream& foreign, qpdf_offset_t offset, QPDFObjectHandle local_dict);
   private:
     std::shared_ptr<EncryptionParameters> encp;
@@ -117,20 +106,29 @@ class QPDF::ForeignStreamData
     bool is_root_metadata{false};
 };
-class QPDF::CopiedStreamDataProvider: public QPDFObjectHandle::StreamDataProvider
+class QPDF::CopiedStreamDataProvider final: public QPDFObjectHandle::StreamDataProvider
 {
   public:
     CopiedStreamDataProvider(QPDF& destination_qpdf);
-    ~CopiedStreamDataProvider() override = default;
+    ~CopiedStreamDataProvider() final = default;
     bool provideStreamData(
-        QPDFObjGen const& og, Pipeline* pipeline, bool suppress_warnings, bool will_retry) override;
-    void registerForeignStream(QPDFObjGen const& local_og, QPDFObjectHandle foreign_stream);
-    void registerForeignStream(QPDFObjGen const& local_og, std::shared_ptr<ForeignStreamData>);
+        QPDFObjGen const& og, Pipeline* pipeline, bool suppress_warnings, bool will_retry) final;
+    void
+    registerForeignStream(QPDFObjGen const& local_og, QPDFObjectHandle foreign_stream)
+    {
+        foreign_streams.insert_or_assign(local_og, foreign_stream);
+    }
+
+    void
+    registerForeignStream(QPDFObjGen local_og, ForeignStreamData foreign_stream)
+    {
+        foreign_stream_data.insert_or_assign(local_og, foreign_stream);
+    }
   private:
     QPDF& destination_qpdf;
     std::map<QPDFObjGen, QPDFObjectHandle> foreign_streams;
-    std::map<QPDFObjGen, std::shared_ptr<ForeignStreamData>> foreign_stream_data;
+    std::map<QPDFObjGen, ForeignStreamData> foreign_stream_data;
 };
 class QPDF::StringDecrypter final: public QPDFObjectHandle::StringDecrypter
@@ -572,6 +570,57 @@ class QPDF::Doc
     class Objects
     {
       public:
+        class Foreign
+        {
+            class Copier
+            {
+              public:
+                Copier(QPDF& qpdf) :
+                    qpdf(qpdf)
+                {
+                }
+
+                QPDFObjectHandle copied(QPDFObjectHandle const& foreign);
+
+              private:
+                QPDFObjectHandle
+                replace_indirect_object(QPDFObjectHandle const& foreign, bool top = false);
+                void reserve_objects(QPDFObjectHandle const& foreign, bool top = false);
+
+                QPDF& qpdf;
+                std::map<QPDFObjGen, QPDFObjectHandle> object_map;
+                std::vector<QPDFObjectHandle> to_copy;
+                QPDFObjGen::set visiting;
+            };
+
+          public:
+            Foreign(QPDF& qpdf) :
+                qpdf(qpdf)
+            {
+            }
+
+            Foreign() = delete;
+            Foreign(Foreign const&) = delete;
+            Foreign(Foreign&&) = delete;
+            Foreign& operator=(Foreign const&) = delete;
+            Foreign& operator=(Foreign&&) = delete;
+            ~Foreign() = default;
+
+            // Return a local handle to the foreign object. Copy the foreign object if necessary.
+            QPDFObjectHandle
+            copied(QPDFObjectHandle const& foreign)
+            {
+                return copier(foreign).copied(foreign);
+            }
+
+          private:
+            Copier& copier(QPDFObjectHandle const& foreign);
+
+            QPDF& qpdf;
+            std::map<unsigned long long, Copier> copiers;
+        }; // class QPDF::Doc::Objects::Foreign
+
+      public:
         Objects() = delete;
         Objects(Objects const&) = delete;
         Objects(Objects&&) = delete;
@@ -581,10 +630,17 @@ class QPDF::Doc
         Objects(QPDF& qpdf, QPDF::Members* m) :
             qpdf(qpdf),
-            m(m)
+            m(m),
+            foreign_(qpdf)
         {
         }
+        Foreign&
+        foreign()
+        {
+            return foreign_;
+        }
+
         void parse(char const* password);
         std::shared_ptr<QPDFObject> const& resolve(QPDFObjGen og);
         void inParse(bool);
@@ -607,6 +663,7 @@ class QPDF::Doc
         // For QPDFWriter:
+        std::map<QPDFObjGen, QPDFXRefEntry> const& getXRefTableInternal();
         // Get a list of objects that would be permitted in an object stream.
         template <typename T>
         std::vector<T> getCompressibleObjGens();
@@ -656,9 +713,10 @@ class QPDF::Doc
         bool isUnresolved(QPDFObjGen og);
         void setLastObjectDescription(std::string const& description, QPDFObjGen og);
-      private:
         QPDF& qpdf;
         QPDF::Members* m;
+
+        Foreign foreign_;
     }; // class QPDF::Doc::Objects
     // This class is used to represent a PDF Pages tree.
@@ -699,19 +757,6 @@ class QPDF::Doc
         QPDF::Members* m;
     }; // class QPDF::Doc::Pages
-    // StreamCopier class is restricted to QPDFObjectHandle so it can copy stream data.
-    class StreamCopier
-    {
-        friend class QPDFObjectHandle;
-
-      private:
-        static void
-        copyStreamData(QPDF* qpdf, QPDFObjectHandle const& dest, QPDFObjectHandle const& src)
-        {
-            qpdf->copyStreamData(dest, src);
-        }
-    };
-
     Doc() = delete;
     Doc(Doc const&) = delete;
     Doc(Doc&&) = delete;
@@ -853,10 +898,7 @@ class QPDF::Members
     bool ever_pushed_inherited_attributes_to_pages{false};
     bool ever_called_get_all_pages{false};
     std::vector<QPDFExc> warnings;
-    std::map<unsigned long long, ObjCopier> object_copiers;
-    std::shared_ptr<QPDFObjectHandle::StreamDataProvider> copied_streams;
-    // copied_stream_data_provider is owned by copied_streams
-    CopiedStreamDataProvider* copied_stream_data_provider{nullptr};
+    std::shared_ptr<CopiedStreamDataProvider> copied_stream_data_provider;
     bool reconstructed_xref{false};
     bool in_read_xref_stream{false};
     bool fixed_dangling_refs{false};
@@ -98,16 +98,12 @@ qpdf-c called qpdf_set_r4_encryption_parameters_insecure 0
 qpdf-c called qpdf_set_static_aes_IV 0
 qpdf-c called qpdf_has_error 0
 qpdf-c called qpdf_get_qpdf_version 0
-QPDF_Stream pipe original stream data 0
 QPDF_Stream pipe replaced stream data 0
 QPDF_Stream provider length mismatch 0
 QPDFObjectHandle newStream 0
 QPDFObjectHandle newStream with data 0
-QPDF_Stream pipe no stream data 0
 QPDFObjectHandle prepend page contents 0
 QPDFObjectHandle append page contents 0
-QPDF_Stream getRawStreamData 0
-QPDF_Stream getStreamData 0
 qpdf-c called qpdf_read_memory 0
 QPDF stream with CRNL 0
 QPDFWriter copy encrypt metadata 1
@@ -128,13 +124,6 @@ QPDFObjectHandle newStream with string 0
 QPDF_Stream provider length not provided 0
 QPDF_Stream unknown stream length 0
 QPDF replaceReserved 0
-QPDF copyForeign direct 0
-QPDF copyForeign not foreign 0
-QPDF replace indirect 0
-QPDF replace array 0
-QPDF replace dictionary 0
-QPDF replace stream 0
-QPDF replace foreign indirect with null 0
 QPDFWriter copy use_aes 1
 QPDFParser indirect without context 0
 QPDFObjectHandle trailing data in parse 0
@@ -256,9 +245,6 @@ QPDFJob image optimize no pipeline 0
 QPDFJob image optimize no shrink 0
 QPDFJob image optimize too small 0
 QPDF pipe foreign encrypted stream 0
-QPDF copy foreign stream with provider 0
-QPDF copy foreign stream with buffer 0
-QPDF immediate copy stream data 0
 QPDFJob copy same page more than once 1
 QPDFPageObjectHelper bad token finding names 0
 QPDFJob password mode bytes 0