[gthumb] allow to preserve the metadata when saving to a buffer

[Paolo Bacchilega <paobac src gnome org>]

commit 37098e3df820770ee0eb9ace868a4c9175a62054
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Tue Sep 4 18:26:57 2012 +0200

    allow to preserve the metadata when saving to a buffer

 .../contact_sheet/gth-contact-sheet-creator.c      |    1 +
 extensions/exiv2_tools/exiv2-utils.cpp             |   10 +-
 extensions/facebook/facebook-service.c             |    1 +
 gthumb/gth-image-saver.c                           |  149 ++++++++++++--------
 gthumb/gth-image-saver.h                           |    8 +-
 5 files changed, 99 insertions(+), 70 deletions(-)
---
diff --git a/extensions/contact_sheet/gth-contact-sheet-creator.c b/extensions/contact_sheet/gth-contact-sheet-creator.c
index be6fae8..3a4a6ea 100644
--- a/extensions/contact_sheet/gth-contact-sheet-creator.c
+++ b/extensions/contact_sheet/gth-contact-sheet-creator.c
@@ -356,6 +356,7 @@ end_page (GthContactSheetCreator  *self,
 	gth_image_set_cairo_surface (image, cairo_get_target (self->priv->cr));
 	if (! gth_image_save_to_buffer (image,
 					self->priv->mime_type,
+					NULL,
 					&buffer,
 					&size,
 					error))
diff --git a/extensions/exiv2_tools/exiv2-utils.cpp b/extensions/exiv2_tools/exiv2-utils.cpp
index c0e52b0..0f8ce0e 100644
--- a/extensions/exiv2_tools/exiv2-utils.cpp
+++ b/extensions/exiv2_tools/exiv2-utils.cpp
@@ -1062,7 +1062,13 @@ exiv2_write_metadata_private (Exiv2::Image::AutoPtr  image,
 		scale_keeping_ratio (&width, &height, 128, 128, FALSE);
 		thumbnail = _cairo_image_surface_scale (surface, width, height, SCALE_FILTER_BEST, NULL);
 		thumbnail_data = gth_image_new_for_surface (thumbnail);
-		if (gth_image_save_to_buffer (thumbnail_data, "image/jpeg", &buffer, &buffer_size, NULL)) {
+		if (gth_image_save_to_buffer (thumbnail_data,
+					      "image/jpeg",
+					      NULL,
+					      &buffer,
+					      &buffer_size,
+					      NULL))
+		{
 			thumb.setJpegThumbnail ((Exiv2::byte *) buffer, buffer_size);
 			ed["Exif.Thumbnail.XResolution"] = 72;
 			ed["Exif.Thumbnail.YResolution"] = 72;
@@ -1229,7 +1235,7 @@ extern "C"
 gboolean
 exiv2_write_metadata (GthImageSaveData *data)
 {
-	if (exiv2_supports_writes (data->mime_type)) {
+	if (exiv2_supports_writes (data->mime_type) && (data->file_data != NULL)) {
 		try {
 			Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open ((Exiv2::byte*) data->buffer, data->buffer_size);
 			g_assert (image.get() != 0);
diff --git a/extensions/facebook/facebook-service.c b/extensions/facebook/facebook-service.c
index 1093c8a..8874834 100644
--- a/extensions/facebook/facebook-service.c
+++ b/extensions/facebook/facebook-service.c
@@ -779,6 +779,7 @@ upload_photo_file_buffer_ready_cb (void     **buffer,
 		gth_image_set_cairo_surface (image, surface);
 		if (! gth_image_save_to_buffer (image,
 						gth_file_data_get_mime_type (file_data),
+						file_data,
 					        (char **) buffer,
 					        &count,
 					        &error))
diff --git a/gthumb/gth-image-saver.c b/gthumb/gth-image-saver.c
index 6cb807f..967d84d 100644
--- a/gthumb/gth-image-saver.c
+++ b/gthumb/gth-image-saver.c
@@ -163,61 +163,60 @@ gth_image_saver_save_image (GthImageSaver  *self,
 }
 
 
-gboolean
-gth_image_save_to_buffer (GthImage    *image,
-			  const char  *mime_type,
-			  char       **buffer,
-			  gsize       *buffer_size,
-			  GError     **p_error)
+static GthImageSaveData *
+_gth_image_save_to_buffer_common (GthImage     *image,
+				  const char   *mime_type,
+				  GthFileData  *file_data,
+				  GError      **p_error)
 {
-	GthImageSaver *saver;
-	gboolean       result;
-	GError        *error = NULL;
+	GthImageSaver    *saver;
+	char             *buffer;
+	gsize             buffer_size;
+	GError           *error = NULL;
+	GthImageSaveData *save_data = NULL;
 
 	saver = gth_main_get_image_saver (mime_type);
 	if (saver == NULL) {
 		if (p_error != NULL)
 			*p_error = g_error_new (GTH_ERROR, GTH_ERROR_GENERIC, _("Could not find a suitable module to save the image as \"%s\""), mime_type);
-		return FALSE;
+		return NULL;
 	}
 
-	result = gth_image_saver_save_image (saver, image, buffer, buffer_size, mime_type, &error);
-
-	if (p_error != NULL)
-		*p_error = error;
-	else
-		_g_error_free (error);
+	if (gth_image_saver_save_image (saver,
+					image,
+					&buffer,
+					&buffer_size,
+					mime_type,
+					&error))
+	{
+		save_data = g_new0 (GthImageSaveData, 1);
+		save_data->file_data = _g_object_ref (file_data);
+		save_data->image = gth_image_copy (image);
+		save_data->mime_type = mime_type;
+		save_data->buffer = buffer;
+		save_data->buffer_size = buffer_size;
+		save_data->files = NULL;
+		save_data->error = NULL;
+
+		if (save_data->file_data != NULL)
+			gth_hook_invoke ("save-image", save_data);
+
+		if ((save_data->error != NULL) && (p_error != NULL))
+			*p_error = g_error_copy (*save_data->error);
+	}
+	else {
+		if (p_error != NULL)
+			*p_error = error;
+		else
+			_g_error_free (error);
+	}
 
 	g_object_unref (saver);
 
-	return result;
+	return save_data;
 }
 
 
-/*
-gboolean
-_cairo_image_surface_to_mime_type (cairo_surface_t  *image,
-				   char            **buffer,
-				   gsize            *buffer_size,
-				   const char       *mime_type,
-				   GError          **error)
-{
-
-}
-*/
-
-
-/* -- gth_image_save_to_file -- */
-
-
-typedef struct {
-	GthImageSaveData *data;
-	GthFileDataFunc   ready_func;
-	gpointer          ready_data;
-	GList            *current;
-} SaveData;
-
-
 static void
 gth_image_save_file_free (GthImageSaveFile *file)
 {
@@ -230,7 +229,7 @@ gth_image_save_file_free (GthImageSaveFile *file)
 static void
 gth_image_save_data_free (GthImageSaveData *data)
 {
-	g_object_unref (data->file_data);
+	_g_object_unref (data->file_data);
 	g_object_unref (data->image);
 	g_list_foreach (data->files, (GFunc) gth_image_save_file_free, NULL);
 	g_list_free (data->files);
@@ -238,6 +237,46 @@ gth_image_save_data_free (GthImageSaveData *data)
 }
 
 
+gboolean
+gth_image_save_to_buffer (GthImage     *image,
+			  const char   *mime_type,
+			  GthFileData  *file_data,
+			  char        **buffer,
+			  gsize        *buffer_size,
+			  GError      **p_error)
+{
+	GthImageSaveData *save_data;
+
+	g_return_val_if_fail (image != NULL, FALSE);
+
+	save_data = _gth_image_save_to_buffer_common (image,
+						      mime_type,
+						      file_data,
+						      p_error);
+
+	if (save_data != NULL) {
+		*buffer = save_data->buffer;
+		*buffer_size = save_data->buffer_size;
+		gth_image_save_data_free (save_data);
+		return TRUE;
+	}
+
+	return FALSE;
+
+}
+
+
+/* -- gth_image_save_to_file -- */
+
+
+typedef struct {
+	GthImageSaveData *data;
+	GthFileDataFunc   ready_func;
+	gpointer          ready_data;
+	GList            *current;
+} SaveData;
+
+
 static void
 save_completed (SaveData *save_data)
 {
@@ -321,31 +360,20 @@ gth_image_save_to_file (GthImage        *image,
 			GthFileDataFunc  ready_func,
 			gpointer         user_data)
 {
-	void             *buffer;
-	gsize             buffer_size;
-	GError           *error = NULL;
 	GthImageSaveData *data;
+	GError           *error = NULL;
 
-	if (! gth_image_save_to_buffer (image,
-					mime_type,
-					(char **) &buffer,
-					&buffer_size,
-					&error))
-	{
+	data = _gth_image_save_to_buffer_common (image,
+						 mime_type,
+						 file_data,
+						 &error);
+
+	if (data == NULL) {
 		gth_file_data_ready_with_error (file_data, ready_func, user_data, error);
 		return;
 	}
 
-	data = g_new0 (GthImageSaveData, 1);
-	data->file_data = g_object_ref (file_data);
-	data->image = gth_image_copy (image);
-	data->mime_type = mime_type;
 	data->replace = replace;
-	data->buffer = buffer;
-	data->buffer_size = buffer_size;
-	data->files = NULL;
-	data->error = NULL;
-	gth_hook_invoke ("save-image", data);
 
 	if (data->error == NULL) {
 		GthImageSaveFile *file;
@@ -358,7 +386,6 @@ gth_image_save_to_file (GthImage        *image,
 	}
 	else {
 		gth_image_save_data_free (data);
-		g_free (buffer);
 		gth_file_data_ready_with_error (file_data, ready_func, user_data, error);
 		return;
 	}
diff --git a/gthumb/gth-image-saver.h b/gthumb/gth-image-saver.h
index 5ba1522..edf417b 100644
--- a/gthumb/gth-image-saver.h
+++ b/gthumb/gth-image-saver.h
@@ -102,16 +102,10 @@ gboolean      gth_image_saver_can_save          (GthImageSaver    *self,
 					         const char       *mime_type);
 gboolean      gth_image_save_to_buffer          (GthImage         *image,
 						 const char       *mime_type,
+						 GthFileData      *file_data,
 						 char            **buffer,
 						 gsize            *buffer_size,
 						 GError          **error);
-/*
-gboolean      _cairo_image_surface_to_mime_type (cairo_surface_t  *image,
-						 char            **buffer,
-						 gsize            *buffer_size,
-						 const char       *mime_type,
-						 GError          **error);
-*/
 void          gth_image_save_to_file            (GthImage         *image,
 						 const char       *mime_type,
 						 GthFileData      *file_data,