Attach the image's ExifData to a tag when it is assigned to an image.

Remove redundant code that would set the value of a tag twice (in the tag itself, and in the image).
Remove the now useless metadata attribute.

5 files changed, 21 insertions, 33 deletions

diff --git a/src/exiv2wrapper.cpp b/src/exiv2wrapper.cpp
index cc2d455..c579b87 100644
--- a/src/exiv2wrapper.cpp
+++ b/src/exiv2wrapper.cpp
@@ -281,13 +281,6 @@ const ExifTag Image::getExifTag(std::string key)
     return ExifTag(key, &_exifData[key], &_exifData);
 }
 
-void Image::setExifTagValue(std::string key, std::string value)
-{
-    CHECK_METADATA_READ
-
-    _exifData[key] = value;
-}
-
 void Image::deleteExifTag(std::string key)
 {
     CHECK_METADATA_READ
@@ -571,6 +564,15 @@ void ExifTag::setRawValue(const std::string& value)
     _datum->setValue(value);
 }
 
+void ExifTag::setParentImage(Image& image)
+{
+    _data = image.getExifData();
+    std::string value = _datum->toString();
+    delete _datum;
+    _datum = &(*_data)[_key.key()];
+    _datum->setValue(value);
+}
+
 const std::string ExifTag::getKey()
 {
     return _key.key();
diff --git a/src/exiv2wrapper.hpp b/src/exiv2wrapper.hpp
index 0408e1a..6ba62f9 100644
--- a/src/exiv2wrapper.hpp
+++ b/src/exiv2wrapper.hpp
@@ -36,6 +36,8 @@
 namespace exiv2wrapper
 {
 
+class Image;
+
 class ExifTag
 {
 public:
@@ -45,6 +47,7 @@ public:
     ~ExifTag();
 
     void setRawValue(const std::string& value);
+    void setParentImage(Image& image);
 
     const std::string getKey();
     const std::string getType();
@@ -186,10 +189,6 @@ public:
     // Throw an exception if the tag is not set.
     const ExifTag getExifTag(std::string key);
 
-    // Set the EXIF tag's value.
-    // If the tag was not previously set, it is created.
-    void setExifTagValue(std::string key, std::string value);
-
     // Delete the required EXIF tag.
     // Throw an exception if the tag was not set.
     void deleteExifTag(std::string key);
@@ -238,6 +237,10 @@ public:
     // Return the image data buffer.
     std::string getDataBuffer() const;
 
+    // Accessors
+    Exiv2::ExifData* getExifData() { return &_exifData; };
+    // ...
+
 private:
     std::string _filename;
     Exiv2::byte* _data;
diff --git a/src/exiv2wrapper_python.cpp b/src/exiv2wrapper_python.cpp
index 5a03132..e970c69 100644
--- a/src/exiv2wrapper_python.cpp
+++ b/src/exiv2wrapper_python.cpp
@@ -48,6 +48,7 @@ BOOST_PYTHON_MODULE(libexiv2python)
     class_<ExifTag>("_ExifTag", init<std::string>())
 
         .def("_setRawValue", &ExifTag::setRawValue)
+        .def("_setParentImage", &ExifTag::setParentImage)
 
         .def("_getKey", &ExifTag::getKey)
         .def("_getType", &ExifTag::getType)
@@ -130,7 +131,6 @@ BOOST_PYTHON_MODULE(libexiv2python)
 
         .def("_exifKeys", &Image::exifKeys)
         .def("_getExifTag", &Image::getExifTag)
-        .def("_setExifTagValue", &Image::setExifTagValue)
         .def("_deleteExifTag", &Image::deleteExifTag)
 
         .def("_iptcKeys", &Image::iptcKeys)
diff --git a/src/pyexiv2/exif.py b/src/pyexiv2/exif.py
index 6964b4b..2c485e2 100644
--- a/src/pyexiv2/exif.py
+++ b/src/pyexiv2/exif.py
@@ -72,9 +72,6 @@ class ExifTag(ListenerInterface):
     - Short, SShort: [list of] int
     - Rational, SRational: [list of] :class:`pyexiv2.utils.Rational`
     - Undefined: string
-
-    :attribute metadata: the parent metadata if any, or None
-    :type metadata: :class:`pyexiv2.metadata.ImageMetadata`
     """
 
     # According to the EXIF specification, the only accepted format for an Ascii
@@ -100,13 +97,15 @@ class ExifTag(ListenerInterface):
             self._tag = _tag
         else:
             self._tag = libexiv2python._ExifTag(key)
-        self.metadata = None
         self._raw_value = None
         self._value = None
         self._value_cookie = False
         if value is not None:
             self._set_value(value)
 
+    def _set_owner(self, metadata):
+        self._tag._setParentImage(metadata._image)
+
     @staticmethod
     def _from_existing_tag(_tag):
         # Build a tag from an already existing libexiv2python._ExifTag.
@@ -159,8 +158,6 @@ class ExifTag(ListenerInterface):
 
     def _set_raw_value(self, value):
         self._tag._setRawValue(value)
-        if self.metadata is not None:
-            self.metadata._set_exif_tag_value(self.key, value)
         self._raw_value = value
         self._value_cookie = True
 
diff --git a/src/pyexiv2/metadata.py b/src/pyexiv2/metadata.py
index 730e99f..93ab4bb 100644
--- a/src/pyexiv2/metadata.py
+++ b/src/pyexiv2/metadata.py
@@ -138,7 +138,6 @@ class ImageMetadata(object):
         except KeyError:
             _tag = self._image._getExifTag(key)
             tag = ExifTag._from_existing_tag(_tag)
-            tag.metadata = self
             self._tags['exif'][key] = tag
             return tag
 
@@ -190,23 +189,10 @@ class ImageMetadata(object):
         else:
             # As a handy shortcut, accept direct value assignment.
             tag = ExifTag(key, tag_or_value)
-        self._image._setExifTagValue(tag.key, tag.raw_value)
+        tag._set_owner(self)
         self._tags['exif'][tag.key] = tag
         if tag.key not in self.exif_keys:
             self._keys['exif'].append(tag.key)
-        tag.metadata = self
-
-    def _set_exif_tag_value(self, key, value):
-        # Overwrite the tag value for an already existing tag.
-        # The tag is already in cache.
-        # Warning: this is not meant to be called directly as it doesn't update
-        # the internal cache (which would leave the object in an inconsistent
-        # state).
-        if key not in self.exif_keys:
-            raise KeyError('Cannot set the value of an inexistent tag')
-        if type(value) is not str:
-            raise TypeError('Expecting a string')
-        self._image._setExifTagValue(key, value)
 
     def _set_iptc_tag(self, key, tag_or_values):
         # Set an IPTC tag. If the tag already exists, its values are