[gvfs] google: Fix make_directory to create folders with volatile entries

[Ondrej Holy <oholy src gnome org>]

commit eb21143f49ca5ebea73b78bb61b4ac1fda402a97
Author: Mayank Sharma <mayank8019 gmail com>
Date:   Sun Aug 18 03:14:30 2019 +0530

    google: Fix make_directory to create folders with volatile entries
    
    While copying a folder recursively, nautilus calls make_directory
    operation with the ID of the folder (instead of the title). Although
    this successfully copies the folder (and its contents too), the titles
    of all the folders (nested within) are lost.
    
    We fix this behaviour of make_directory by checking if the basename is
    some other folder's ID, and conditionally inserting Source_ID_Property
    and Parent_ID_Property on the new folder (to create a volatile entry).

 daemon/gvfsbackendgoogle.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)
---
diff --git a/daemon/gvfsbackendgoogle.c b/daemon/gvfsbackendgoogle.c
index d4842c59..1e9850cc 100644
--- a/daemon/gvfsbackendgoogle.c
+++ b/daemon/gvfsbackendgoogle.c
@@ -2152,6 +2152,7 @@ g_vfs_backend_google_make_directory (GVfsBackend          *_self,
   GDataEntry *existing_entry;
   GDataEntry *parent;
   GDataEntry *summary_entry;
+  GDataEntry *same_id_entry;
   GError *error;
   const gchar *summary;
   gchar *entry_path = NULL;
@@ -2192,7 +2193,48 @@ g_vfs_backend_google_make_directory (GVfsBackend          *_self,
     }
 
   folder = gdata_documents_folder_new (NULL);
-  gdata_entry_set_title (GDATA_ENTRY (folder), basename);
+
+  /* This case is particularly troublesome. Normally, when we call
+   * make_directory, the title supplied by the user or client is used to create
+   * a file with same title. But strangely, when we're trying to copy a folder
+   * over to another directory (i.e. to a different parent), the copy operation
+   * would return G_IO_ERROR_WOULD_RECURSE. This means that nautilus will
+   * manually create the folders (using make_directory) and copy each file.
+   *
+   * The major issue here is that nautilus calls make_directory with the title
+   * of folder set to ID of the original folder. Suppose, we had a folder "folder1"
+   * which needs to be copied. Now, copy operation would return
+   * G_IO_ERROR_WOULD_RECURSE (if the parents are different), but nautilus will
+   * call make_directory with ID of "folder1" instead of title of "folder1".
+   * Furthermore, nautilus calls query_info on the "filename" argument right
+   * after it has done make_directory hence we need to create a volatile entry
+   * for the folder too.
+   *
+   * Below fix is hack-ish and will fail if we wish to create a folder
+   * whose title equals the ID of any other folder. */
+  if ((same_id_entry = g_hash_table_lookup (self->entries, basename)) != NULL)
+    {
+      GDataDocumentsProperty *source_id_property, *parent_id_property;
+
+      source_id_property = gdata_documents_property_new (SOURCE_ID_PROPERTY_KEY);
+      gdata_documents_property_set_visibility (source_id_property, 
GDATA_DOCUMENTS_PROPERTY_VISIBILITY_PRIVATE);
+      gdata_documents_property_set_value (source_id_property, basename);
+
+      parent_id_property = gdata_documents_property_new (PARENT_ID_PROPERTY_KEY);
+      gdata_documents_property_set_visibility (parent_id_property, 
GDATA_DOCUMENTS_PROPERTY_VISIBILITY_PRIVATE);
+      gdata_documents_property_set_value (parent_id_property, gdata_entry_get_id (parent));
+
+      gdata_documents_entry_add_documents_property (GDATA_DOCUMENTS_ENTRY (folder), source_id_property);
+      gdata_documents_entry_add_documents_property (GDATA_DOCUMENTS_ENTRY (folder), parent_id_property);
+
+      gdata_entry_set_title (GDATA_ENTRY (folder), gdata_entry_get_title (same_id_entry));
+
+      g_clear_object (&source_id_property);
+      g_clear_object (&parent_id_property);
+    }
+  else
+    gdata_entry_set_title (GDATA_ENTRY (folder), basename);
+
   gdata_entry_set_summary (GDATA_ENTRY (folder), summary);
 
   error = NULL;