QPDFObjectHandle::copyStream

2 files changed, 30 insertions, 1 deletions

diff --git a/include/qpdf/QPDF.hh b/include/qpdf/QPDF.hh
index ee00b23f..d4b7e775 100644
--- a/include/qpdf/QPDF.hh
+++ b/include/qpdf/QPDF.hh
@@ -700,6 +700,21 @@ class QPDF
     };
     friend class Resolver;
 
+    // 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);
+	}
+    };
+    friend class Resolver;
+
     // ParseGuard class allows QPDFObjectHandle to detect re-entrant
     // resolution
     class ParseGuard
diff --git a/include/qpdf/QPDFObjectHandle.hh b/include/qpdf/QPDFObjectHandle.hh
index bb877622..07c5b427 100644
--- a/include/qpdf/QPDFObjectHandle.hh
+++ b/include/qpdf/QPDFObjectHandle.hh
@@ -761,7 +761,8 @@ class QPDFObjectHandle
     // the same place. In the strictest sense, this is not a shallow
     // copy because it recursively descends arrays and dictionaries;
     // it just doesn't cross over indirect objects. See also
-    // unsafeShallowCopy().
+    // unsafeShallowCopy(). You can't copy a stream this way. See
+    // copyStream() instead.
     QPDF_DLL
     QPDFObjectHandle shallowCopy();
 
@@ -776,6 +777,19 @@ class QPDFObjectHandle
     QPDF_DLL
     QPDFObjectHandle unsafeShallowCopy();
 
+    // Create a copy of this stream. The new stream and the old stream
+    // are independent: after the copy, either the original or the
+    // copy's dictionary or data can be modified without affecting the
+    // other. This uses StreamDataProvider internally, so no
+    // unnecessary copies of the stream's data are made. If the source
+    // stream's data is already being provided by a
+    // StreamDataProvider, the new stream will use the same one, so
+    // you have to make sure your StreamDataProvider can handle that
+    // case. But if you're already using a StreamDataProvider, you
+    // probably don't need to call this method.
+    QPDF_DLL
+    QPDFObjectHandle copyStream();
+
     // Mutator methods.  Use with caution.
 
     // Recursively copy this object, making it direct. An exception is