more work on synchronizing metadata with xmp sidecars

(cherry picked from commit 81bbff6e6ae87bd35e8050a1cc621297ca24939b)

rtengine/metadata.h

@@ -0,0 +1,80 @@
+/* -*- C++ -*-
+ *
+ *  This file is part of RawTherapee.
+ *
+ *  Copyright (c) 2019 Alberto Griggio <alberto.griggio@gmail.com>
+ *
+ *  RawTherapee is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  RawTherapee is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with RawTherapee.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <glibmm.h>
+#include <exiv2/exiv2.hpp>
+#include <memory>
+#include "procparams.h"
+
+namespace rtengine {
+
+class Exiv2Metadata final
+{
+public:
+    Exiv2Metadata();
+    explicit Exiv2Metadata(const Glib::ustring& path);
+    Exiv2Metadata(const Glib::ustring& path, bool merge_xmp_sidecar);
+
+    void load() const;
+    
+    Exiv2::ExifData& exifData();
+    const Exiv2::ExifData& exifData() const;
+    
+    Exiv2::IptcData& iptcData();
+    const Exiv2::IptcData& iptcData() const;
+    
+    Exiv2::XmpData& xmpData();
+    const Exiv2::XmpData& xmpData() const;
+
+    const Glib::ustring& filename() const;
+    const rtengine::procparams::ExifPairs& exif() const;
+    const rtengine::procparams::IPTCPairs& iptc() const;
+    void setExif(const rtengine::procparams::ExifPairs& exif);
+    void setIptc(const rtengine::procparams::IPTCPairs& iptc);
+    
+    void saveToImage(const Glib::ustring& path) const;
+    void saveToXmp(const Glib::ustring& path) const;
+
+    static Glib::ustring xmpSidecarPath(const Glib::ustring& path);
+    static Exiv2::XmpData getXmpSidecar(const Glib::ustring& path);
+   
+private:
+    void do_merge_xmp(Exiv2::Image* dst) const;
+    void import_exif_pairs(Exiv2::ExifData& out) const;
+    void import_iptc_pairs(Exiv2::IptcData& out) const;
+    
+    Glib::ustring src_;
+    bool merge_xmp_;
+    mutable std::shared_ptr<Exiv2::Image> image_;
+    std::unique_ptr<rtengine::procparams::ExifPairs> exif_;
+    std::unique_ptr<rtengine::procparams::IPTCPairs> iptc_;
+    Exiv2::ExifData exif_data_;
+    Exiv2::IptcData iptc_data_;
+    Exiv2::XmpData xmp_data_;
+};
+
+// Glib::ustring get_xmp_sidecar_path(const Glib::ustring &path);
+// Exiv2::Image::AutoPtr open_exiv2(const Glib::ustring &fname,
+//                                  bool merge_xmp_sidecar);
+// Exiv2::XmpData read_exiv2_xmp(const Glib::ustring &fname);
+
+} // namespace rtengine