Refactor stream copying: move `copyStreamData` logic into `Stream::copy_data_to`…

… and streamline stream handling.

Refactor stream copying: move `copyStreamData` logic into `Stream::copy_data_to`…
… and streamline stream handling.
m-holger
1 parent 171027b1
Showing 5 changed files with 49 additions and 56 deletions
include/qpdf/QPDF.hh
libqpdf/QPDF.cc
libqpdf/QPDF_Stream.cc
libqpdf/qpdf/QPDFObjectHandle_private.hh
libqpdf/qpdf/QPDF_private.hh
@@ -800,9 +800,6 @@ class QPDF
         bool is_root_metadata,
         std::unique_ptr<Pipeline>& heap);
  
-    // Methods to support object copying
-    void copyStreamData(QPDFObjectHandle dest_stream, QPDFObjectHandle src_stream);
-
     struct HPageOffsetEntry;
     struct HPageOffset;
     struct HSharedObjectEntry;
@@ -112,14 +112,14 @@ namespace
     };
 } // namespace
  
-Streams::Copier::Data::Data(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(foreign.getLength()),
-    local_dict(local_dict),
-    is_root_metadata(foreign.isRootMetadata())
+Streams::Copier::Data::Data(Stream& source, QPDFObjectHandle const& dest_dict) :
+    encp(source.qpdf()->m->encp),
+    file(source.qpdf()->m->file),
+    source_og(source.id_gen()),
+    offset(source.offset()),
+    length(source.getLength()),
+    dest_dict(dest_dict),
+    is_root_metadata(source.isRootMetadata())
 {
 }
  
@@ -141,10 +141,10 @@ Streams::Copier::provideStreamData(
                 fd.encp,
                 fd.file,
                 streams.qpdf(),
-                fd.foreign_og,
+                fd.source_og,
                 fd.offset,
                 fd.length,
-                fd.local_dict,
+                fd.dest_dict,
                 fd.is_root_metadata,
                 pipeline,
                 suppress_warnings,
@@ -667,7 +667,7 @@ Objects::Foreign::Copier::replace_indirect_object(QPDFObjectHandle const&amp; foreig
                 dict.replaceKey(key, replace_indirect_object(value));
             }
         }
-        qpdf.copyStreamData(result, foreign);
+        stream.copy_data_to(result);
         return result;
     }
  
@@ -27,6 +27,12 @@ using namespace qpdf;
  
 using Streams = QPDF::Doc::Objects::Streams;
  
+bool
+Streams::immediate_copy_from() const
+{
+    return qpdf_.m->immediate_copy_from;
+}
+
 namespace
 {
     class SF_Crypt final: public QPDFStreamFilter
@@ -188,50 +194,42 @@ Stream::Stream(
 }
  
 Stream
-Stream::copy() const
+Stream::copy()
 {
     Stream result = qpdf()->newStream();
     result.stream()->stream_dict = getDict().copy();
-    Streams::copyStreamData(qpdf(), result, *this);
+    copy_data_to(result);
     return result;
 }
  
 void
-QPDF::copyStreamData(QPDFObjectHandle dest, QPDFObjectHandle source_oh)
+Stream::copy_data_to(Stream& dest)
 {
-    Dictionary dict = dest.getDict();
-    Dictionary old_dict = source_oh.getDict();
-    QPDFObjGen local_og(dest.getObjGen());
-    // Copy information from the foreign stream so we can pipe its data later without keeping the
-    // original QPDF object around.
+    qpdf_expect(dest);
+    auto s = stream();
+    auto& streams = qpdf()->doc().objects().streams();
+    auto& d_streams = dest.qpdf()->doc().objects().streams();
  
-    QPDF& source_qpdf = source_oh.getQPDF("unable to retrieve owning qpdf from foreign stream");
+    auto dict = dest.getDict();
  
-    Stream source = source_oh;
-    if (!source) {
-        throw std::logic_error("unable to retrieve underlying stream object from foreign stream");
-    }
-    std::shared_ptr<Buffer> stream_buffer = source.getStreamDataBuffer();
-    if (source_qpdf.m->immediate_copy_from && !stream_buffer) {
+    // Copy information from the foreign stream so we can pipe its data later without keeping the
+    // original QPDF object around.
+    if (streams.immediate_copy_from() && !s->stream_data) {
         // 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.
-        source.replaceStreamData(
-            source.getRawStreamData(), old_dict["/Filter"], old_dict["/DecodeParms"]);
-        stream_buffer = source.getStreamDataBuffer();
-    }
-    auto stream_provider = source.getStreamDataProvider();
-    if (stream_buffer) {
-        dest.replaceStreamData(stream_buffer, dict["/Filter"], dict["/DecodeParms"]);
-    } else if (stream_provider) {
-        // In this case, the remote stream's QPDF must stay in scope.
-        m->objects.streams().copier()->register_copy(local_og, source_oh);
-        dest.replaceStreamData(
-            m->objects.streams().copier(), dict["/Filter"], dict["/DecodeParms"]);
+        replaceStreamData(
+            getRawStreamData(), s->stream_dict["/Filter"], s->stream_dict["/DecodeParms"]);
+    }
+    if (s->stream_data) {
+        dest.replaceStreamData(s->stream_data, dict["/Filter"], dict["/DecodeParms"]);
+    } else if (s->stream_provider) {
+        // In this case, the source stream's QPDF must stay in scope.
+        d_streams.copier()->register_copy(dest, *this);
+        dest.replaceStreamData(d_streams.copier(), dict["/Filter"], dict["/DecodeParms"]);
     } else {
-        m->objects.streams().copier()->register_copy(local_og, source, source.offset(), dict);
-        dest.replaceStreamData(
-            m->objects.streams().copier(), dict["/Filter"], dict["/DecodeParms"]);
+        d_streams.copier()->register_copy(dest, *this, offset(), dict);
+        dest.replaceStreamData(d_streams.copier(), dict["/Filter"], dict["/DecodeParms"]);
     }
 }
  
@@ -469,7 +469,9 @@ namespace qpdf
             qpdf_offset_t offset,
             size_t length);
  
-        Stream copy() const;
+        Stream copy();
+
+        void copy_data_to(Stream& target);
  
         Dictionary
         getDict() const
@@ -587,15 +587,15 @@ class QPDF::Doc
                     friend class Streams;
  
                   public:
-                    Data(Stream& foreign, qpdf_offset_t offset, QPDFObjectHandle local_dict);
+                    Data(Stream& source, QPDFObjectHandle const& dest_dict);
  
                   private:
                     std::shared_ptr<EncryptionParameters> encp;
                     std::shared_ptr<InputSource> file;
-                    QPDFObjGen foreign_og;
+                    QPDFObjGen source_og;
                     qpdf_offset_t offset;
                     size_t length;
-                    QPDFObjectHandle local_dict;
+                    QPDFObjectHandle dest_dict;
                     bool is_root_metadata{false};
                 };
  
@@ -628,7 +628,7 @@ class QPDF::Doc
                     qpdf_offset_t offset,
                     QPDFObjectHandle const& local_dict)
                 {
-                    copied_data.insert_or_assign(local_og, Data(foreign, offset, local_dict));
+                    copied_data.insert_or_assign(local_og, Data(foreign, local_dict));
                 }
  
               private:
@@ -675,12 +675,6 @@ class QPDF::Doc
                     will_retry);
             }
  
-            static void
-            copyStreamData(QPDF* qpdf, QPDFObjectHandle const& dest, QPDFObjectHandle const& src)
-            {
-                qpdf->copyStreamData(dest, src);
-            }
-
             QPDF&
             qpdf() const
             {
@@ -693,11 +687,13 @@ class QPDF::Doc
                 return copier_;
             }
  
+            bool immediate_copy_from() const;
+
           private:
             QPDF& qpdf_;
  
             std::shared_ptr<Copier> copier_;
-        };
+        }; // class QPDF::Doc::Objects::Streams
  
       public:
         Objects() = delete;