[evolution] I#1919 - Drag&Drop creates many identical temporary files

[Milan Crha <mcrha src gnome org>]

commit 01f36a186b216c7b175a19bf364a96cbfdad8e82
Author: Milan Crha <mcrha redhat com>
Date:   Wed Jun 1 22:17:53 2022 +0200

    I#1919 - Drag&Drop creates many identical temporary files
    
    Closes https://gitlab.gnome.org/GNOME/evolution/-/issues/1919

 src/e-util/e-attachment-view.c | 14 ++++++++++++--
 src/mail/em-folder-tree.c      |  2 +-
 src/mail/em-utils.c            | 29 ++++++++++++++++++++++++++---
 src/mail/em-utils.h            |  2 +-
 src/mail/message-list.c        |  2 +-
 5 files changed, 41 insertions(+), 8 deletions(-)
---
diff --git a/src/e-util/e-attachment-view.c b/src/e-util/e-attachment-view.c
index da89238e3f..210fad648e 100644
--- a/src/e-util/e-attachment-view.c
+++ b/src/e-util/e-attachment-view.c
@@ -1674,6 +1674,13 @@ e_attachment_view_drag_data_get (EAttachmentView *view,
        g_return_if_fail (GDK_IS_DRAG_CONTEXT (context));
        g_return_if_fail (selection != NULL);
 
+       status.uris = g_object_get_data (G_OBJECT (context), "evo-attach-urilist");
+
+       if (status.uris) {
+               gtk_selection_data_set_uris (selection, status.uris);
+               return;
+       }
+
        status.uris = NULL;
        status.done = FALSE;
 
@@ -1693,10 +1700,13 @@ e_attachment_view_drag_data_get (EAttachmentView *view,
                if (gtk_main_iteration ())
                        break;
 
-       if (status.uris != NULL)
+       if (status.uris) {
                gtk_selection_data_set_uris (selection, status.uris);
 
-       g_strfreev (status.uris);
+               /* Remember it, to not regenerate it, when the target widget asks for the data again */
+               g_object_set_data_full (G_OBJECT (context), "evo-attach-urilist",
+                       status.uris, (GDestroyNotify) g_strfreev);
+       }
 }
 
 void
diff --git a/src/mail/em-folder-tree.c b/src/mail/em-folder-tree.c
index 6583489f24..8fc3fa8437 100644
--- a/src/mail/em-folder-tree.c
+++ b/src/mail/em-folder-tree.c
@@ -2149,7 +2149,7 @@ tree_drag_data_get (GtkWidget *widget,
 
                        GPtrArray *uids = camel_folder_get_uids (folder);
 
-                       em_utils_selection_set_urilist (selection, folder, uids);
+                       em_utils_selection_set_urilist (context, selection, folder, uids);
                        camel_folder_free_uids (folder, uids);
                        g_object_unref (folder);
                }
diff --git a/src/mail/em-utils.c b/src/mail/em-utils.c
index 876fce7f4e..e149100aaa 100644
--- a/src/mail/em-utils.c
+++ b/src/mail/em-utils.c
@@ -964,6 +964,7 @@ em_utils_build_export_basename (CamelFolder *folder,
 
 /**
  * em_utils_selection_set_urilist:
+ * @context:
  * @data:
  * @folder:
  * @uids:
@@ -973,7 +974,8 @@ em_utils_build_export_basename (CamelFolder *folder,
  * up when the application quits.
  **/
 void
-em_utils_selection_set_urilist (GtkSelectionData *data,
+em_utils_selection_set_urilist (GdkDragContext *context,
+                               GtkSelectionData *data,
                                 CamelFolder *folder,
                                 GPtrArray *uids)
 {
@@ -993,6 +995,20 @@ em_utils_selection_set_urilist (GtkSelectionData *data,
        if (!uids->len)
                return;
 
+       /* Use cached value from the last call, if exists */
+       tmpdir = g_object_get_data (G_OBJECT (context), "evo-urilist");
+       if (tmpdir) {
+               GdkAtom type;
+
+               type = gtk_selection_data_get_target (data);
+               gtk_selection_data_set (
+                       data, type, 8,
+                       (guchar *) tmpdir,
+                       strlen (tmpdir));
+
+               return;
+       }
+
        tmpdir = e_mkdtemp ("drag-n-drop-XXXXXX");
        if (tmpdir == NULL)
                return;
@@ -1052,7 +1068,9 @@ em_utils_selection_set_urilist (GtkSelectionData *data,
                                        data, type, 8,
                                        (guchar *) uri_crlf,
                                        strlen (uri_crlf));
-                               g_free (uri_crlf);
+
+                               /* Remember it, to not regenerate it, when the target widget asks for the 
data again */
+                               g_object_set_data_full (G_OBJECT (context), "evo-urilist", uri_crlf, g_free);
                        }
                        g_object_unref (fstream);
                } else
@@ -1102,7 +1120,12 @@ em_utils_selection_set_urilist (GtkSelectionData *data,
                        g_free (filename);
                }
 
-               gtk_selection_data_set_uris (data, uris);
+               if (gtk_selection_data_set_uris (data, uris)) {
+                       /* Remember it, to not regenerate it, when the target widget asks for the data again 
*/
+                       g_object_set_data_full (G_OBJECT (context), "evo-urilist",
+                               g_strndup ((const gchar *) gtk_selection_data_get_data (data), 
gtk_selection_data_get_length (data)),
+                               g_free);
+               }
 
                g_strfreev (uris);
        }
diff --git a/src/mail/em-utils.h b/src/mail/em-utils.h
index e000ef43d6..dedf83b84b 100644
--- a/src/mail/em-utils.h
+++ b/src/mail/em-utils.h
@@ -55,7 +55,7 @@ void em_utils_selection_get_mailbox (GtkSelectionData *data, CamelFolder *folder
 void em_utils_selection_get_message (GtkSelectionData *data, CamelFolder *folder);
 void em_utils_selection_set_uidlist (GtkSelectionData *data, CamelFolder *folder, GPtrArray *uids);
 void em_utils_selection_get_uidlist (GtkSelectionData *data, EMailSession *session, CamelFolder *dest, gint 
move, GCancellable *cancellable, GError **error);
-void em_utils_selection_set_urilist (GtkSelectionData *data, CamelFolder *folder, GPtrArray *uids);
+void em_utils_selection_set_urilist (GdkDragContext *context, GtkSelectionData *data, CamelFolder *folder, 
GPtrArray *uids);
 void em_utils_selection_get_urilist (GtkSelectionData *data, CamelFolder *folder);
 
 /* Return TRUE to continue, FALSE to stop further processing */
diff --git a/src/mail/message-list.c b/src/mail/message-list.c
index d60c064c20..51e3fd79e0 100644
--- a/src/mail/message-list.c
+++ b/src/mail/message-list.c
@@ -2627,7 +2627,7 @@ ml_tree_drag_data_get (ETree *tree,
                        em_utils_selection_set_uidlist (data, folder, uids);
                        break;
                case DND_TEXT_URI_LIST:
-                       em_utils_selection_set_urilist (data, folder, uids);
+                       em_utils_selection_set_urilist (context, data, folder, uids);
                        break;
                }
        }