[evolution/wip/webkit-composer] Add support for Drag&Drop of CID images from message preview into composer

[Tomas Popela <tpopela src gnome org>]

commit 497043d2c08316e33c1af8e729b7e5abd08a0deb
Author: Tomas Popela <tpopela redhat com>
Date:   Thu Feb 6 10:32:00 2014 +0100

    Add support for Drag&Drop of CID images from message preview into composer

 mail/e-mail-display.c |  122 +++++++++++++++++++++++++++++++++++++++----------
 1 files changed, 97 insertions(+), 25 deletions(-)
---
diff --git a/mail/e-mail-display.c b/mail/e-mail-display.c
index 4b6f91c..a9c19bf 100644
--- a/mail/e-mail-display.c
+++ b/mail/e-mail-display.c
@@ -1334,39 +1334,46 @@ chainup:
                redirect_uri (web_view, uri);
 }
 
-static gchar *
-mail_display_suggest_filename (EWebView *web_view,
-                               const gchar *uri)
+static CamelMimePart *
+camel_mime_part_from_cid (EMailDisplay *display,
+                          const gchar *uri)
 {
-       if (g_str_has_prefix (uri, "cid:")) {
-               EMailDisplay *display;
-               EMailPartList *part_list;
-               CamelMimeMessage *message;
-               CamelMimePart *mime_part;
-               const gchar *filename;
+       EMailPartList *part_list;
+       CamelMimeMessage *message;
+       CamelMimePart *mime_part;
 
-               /* Note, this assumes the URI comes
-                * from the currently loaded message. */
+       if (!g_str_has_prefix (uri, "cid:"))
+               return NULL;
 
-               display = E_MAIL_DISPLAY (web_view);
+       part_list = e_mail_display_get_part_list (display);
+       if (!part_list)
+               return NULL;
 
-               part_list = e_mail_display_get_part_list (display);
-               if (part_list == NULL)
-                       return NULL;
+       message = e_mail_part_list_get_message (part_list);
+       if (!message)
+               return NULL;
 
-               message = e_mail_part_list_get_message (part_list);
-               if (message == NULL)
-                       return NULL;
+       mime_part = camel_mime_message_get_part_by_content_id (
+               message, uri + 4);
 
-               mime_part = camel_mime_message_get_part_by_content_id (
-                       message, uri + 4);
-               if (mime_part == NULL)
-                       return NULL;
+       return mime_part;
+}
 
-               filename = camel_mime_part_get_filename (mime_part);
+static gchar *
+mail_display_suggest_filename (EWebView *web_view,
+                               const gchar *uri)
+{
+       EMailDisplay *display;
+       CamelMimePart *mime_part;
 
-               return g_strdup (filename);
-       }
+       /* Note, this assumes the URI comes
+        * from the currently loaded message. */
+       display = E_MAIL_DISPLAY (web_view);
+
+       mime_part = camel_mime_part_from_cid (display, uri);
+
+       if (mime_part)
+               return g_strdup (camel_mime_part_get_filename (mime_part));
 
        /* Chain up to parent's suggest_filename() method. */
        return E_WEB_VIEW_CLASS (e_mail_display_parent_class)->
@@ -1406,6 +1413,68 @@ mail_display_set_fonts (EWebView *web_view,
 }
 
 static void
+mail_display_drag_data_get (GtkWidget *widget,
+                            GdkDragContext *context,
+                            GtkSelectionData *data,
+                            guint info,
+                            guint time,
+                            EMailDisplay *display)
+{
+       CamelDataWrapper *dw;
+       CamelMimePart *mime_part;
+       CamelStream *stream;
+       gchar *src, *base64_encoded, *mime_type, *uri;
+       const gchar *filename;
+       const guchar *data_from_webkit;
+       gint length;
+       GByteArray *byte_array;
+
+       data_from_webkit = gtk_selection_data_get_data (data);
+       length = gtk_selection_data_get_length (data);
+
+       uri = g_strndup ((const gchar *) data_from_webkit, length);
+
+       mime_part = camel_mime_part_from_cid (display, uri);
+
+       if (!mime_part)
+               goto out;
+
+       stream = camel_stream_mem_new ();
+       dw = camel_medium_get_content (CAMEL_MEDIUM (mime_part));
+       g_return_if_fail (dw);
+
+       mime_type = camel_data_wrapper_get_mime_type (dw);
+       camel_data_wrapper_decode_to_stream_sync (dw, stream, NULL, NULL);
+       camel_stream_close (stream, NULL, NULL);
+
+       byte_array = camel_stream_mem_get_byte_array (CAMEL_STREAM_MEM (stream));
+
+       if (!byte_array->data) {
+               g_object_unref (stream);
+               goto out;
+       }
+
+       base64_encoded = g_base64_encode ((const guchar *) byte_array->data, byte_array->len);
+
+       filename = camel_mime_part_get_filename (mime_part);
+       /* Insert filename before base64 data */
+       src = g_strconcat (filename, ";data:", mime_type, ";base64,", base64_encoded, NULL);
+
+       gtk_selection_data_set (
+               data,
+               gtk_selection_data_get_data_type (data),
+               gtk_selection_data_get_format (data),
+               (const guchar *) src, strlen (src));
+
+       g_free (src);
+       g_free (base64_encoded);
+       g_free (mime_type);
+       g_object_unref (stream);
+ out:
+       g_free (uri);
+}
+
+static void
 e_mail_display_class_init (EMailDisplayClass *class)
 {
        GObjectClass *object_class;
@@ -1526,6 +1595,9 @@ e_mail_display_init (EMailDisplay *display)
        g_signal_connect (
                display, "notify::uri",
                G_CALLBACK (mail_display_uri_changed), NULL);
+       g_signal_connect_after (
+               display, "drag-data-get",
+               G_CALLBACK (mail_display_drag_data_get), display);
 
        display->priv->settings = g_settings_new ("org.gnome.evolution.mail");
        g_signal_connect_swapped (