[gnome-builder/wip/slaf/xml-pack: 249/254] xml-pack: fetch and show elements and attributes

[Sébastien Lafargue <slafargue src gnome org>]

commit 8c940d1e58ac2a74642301a88b5f1d88773c9654
Author: Sebastien Lafargue <slafargue gnome org>
Date:   Sun Jul 9 16:12:05 2017 +0200

    xml-pack: fetch and show elements and attributes
    
    Now we get some proposals for elements and attributes

 plugins/xml-pack/ide-xml-completion-attributes.c |  551 ++++++++++++++++++++++
 plugins/xml-pack/ide-xml-completion-attributes.h |   43 ++
 plugins/xml-pack/ide-xml-completion-provider.c   |  177 ++++++--
 plugins/xml-pack/ide-xml-rng-define.h            |    1 +
 plugins/xml-pack/ide-xml-rng-parser.c            |    4 +-
 plugins/xml-pack/meson.build                     |    6 +-
 6 files changed, 738 insertions(+), 44 deletions(-)
---
diff --git a/plugins/xml-pack/ide-xml-completion-attributes.c 
b/plugins/xml-pack/ide-xml-completion-attributes.c
new file mode 100644
index 0000000..2b2dfa9
--- /dev/null
+++ b/plugins/xml-pack/ide-xml-completion-attributes.c
@@ -0,0 +1,551 @@
+/* ide-xml-completion-attributes.c
+ *
+ * Copyright (C) 2017 Sebastien Lafargue <slafargue gnome org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "ide-xml-completion-attributes.h"
+
+#include "ide-xml-position.h"
+
+typedef struct _MatchingState
+{
+  GArray           *stack;
+  IdeXmlSymbolNode *node;
+  IdeXmlRngDefine  *define;
+  GPtrArray        *node_attr;
+  GPtrArray        *match_children;
+
+  guint             is_initial_state : 1;
+  guint             is_optional : 1;
+} MatchingState;
+
+typedef struct _StateStackItem
+{
+  GPtrArray        *children;
+} StateStackItem;
+
+static GPtrArray * process_matching_state (MatchingState   *state,
+                                           IdeXmlRngDefine *define);
+
+static MatchItem *
+match_item_new (const gchar *attr_name,
+                gint         attr_pos,
+                gboolean     is_optional)
+{
+  MatchItem *item;
+
+  g_assert (!ide_str_empty0 (attr_name));
+
+  item = g_slice_new0 (MatchItem);
+
+  item->name = g_strdup (attr_name);
+  item->pos = attr_pos;
+  item->is_optional = is_optional;
+
+  return item;
+}
+
+static void
+match_item_free (gpointer data)
+{
+  MatchItem *item = (MatchItem *)data;
+
+  g_clear_pointer (&item->name, g_free);
+}
+
+static GPtrArray *
+match_children_new (void)
+{
+  GPtrArray *ar;
+
+  ar = g_ptr_array_new_with_free_func ((GDestroyNotify)match_item_free);
+  return ar;
+}
+
+static void
+match_children_add (GPtrArray *to_children,
+                    GPtrArray *from_children)
+{
+  MatchItem *to_item;
+  MatchItem *from_item;
+
+  g_assert (to_children != NULL);
+  g_assert (from_children != NULL);
+
+  for (gint i = 0; i < from_children->len; ++i)
+    {
+      from_item = g_ptr_array_index (from_children, i);
+      to_item = match_item_new (from_item->name, from_item->pos, from_item->is_optional);
+      g_ptr_array_add (to_children, to_item);
+    }
+}
+
+static void
+state_stack_item_free (gpointer *data)
+{
+  StateStackItem *item;
+
+  g_assert (data != NULL);
+
+  item = (StateStackItem *)data;
+  g_ptr_array_unref (item->children);
+}
+
+static GArray *
+state_stack_new (void)
+{
+  GArray *stack;
+
+  stack = g_array_new (FALSE, TRUE, sizeof (StateStackItem));
+  g_array_set_clear_func (stack, (GDestroyNotify)state_stack_item_free);
+
+  return stack;
+}
+
+static void
+state_stack_push (MatchingState *state)
+{
+  StateStackItem item;
+
+  g_assert (state->stack != NULL);
+
+  g_array_append_val (state->stack, item);
+}
+
+static gboolean
+state_stack_pop (MatchingState *state)
+{
+  StateStackItem *item;
+  guint len;
+
+  g_assert (state->stack != NULL);
+
+  if (0 == (len = state->stack->len))
+    return FALSE;
+
+  item = &g_array_index (state->stack, StateStackItem, len - 1);
+  //g_clear_pointer (&state->children, g_ptr_array_unref);
+
+  //state->children = item->children;
+
+  g_array_remove_index (state->stack, len - 1);
+  return TRUE;
+}
+
+static gboolean
+state_stack_drop (MatchingState *state)
+{
+  guint len;
+
+  g_assert (state->stack != NULL);
+
+  if (0 == (len = state->stack->len))
+    return FALSE;
+
+  g_array_remove_index (state->stack, len - 1);
+  return TRUE;
+}
+
+static gboolean
+state_stack_copy (MatchingState *state)
+{
+  StateStackItem *item;
+  guint len;
+
+  g_assert (state->stack != NULL);
+
+  if (0 == (len = state->stack->len))
+    return FALSE;
+
+  item = &g_array_index (state->stack, StateStackItem, len - 1);
+  //state->children = copy_children (item->children);
+
+  g_array_remove_index (state->stack, len - 1);
+  return TRUE;
+}
+
+static MatchingState *
+matching_state_new (IdeXmlRngDefine  *define,
+                    IdeXmlSymbolNode *node)
+{
+  MatchingState *state;
+
+  g_assert (define != NULL);
+
+  state = g_slice_new0 (MatchingState);
+
+  state->define = define;
+  state->node = node;
+
+  state->node_attr = g_ptr_array_new_with_free_func (g_free);
+  state->stack = state_stack_new ();
+  state->is_initial_state = FALSE;
+  state->is_optional = FALSE;
+
+  return state;
+}
+
+static void
+matching_state_free (MatchingState *state)
+{
+  g_clear_object (&state->node);
+
+  g_clear_pointer (&state->node_attr, g_ptr_array_unref);
+  g_clear_pointer (&state->stack, g_array_unref);
+}
+
+static GPtrArray *
+process_attribute (MatchingState *state)
+{
+  GPtrArray *match_children;
+  MatchItem *item;
+  const gchar *name;
+  const gchar *attr;
+
+  g_assert (state->define->type == IDE_XML_RNG_DEFINE_ATTRIBUTE);
+
+  match_children = match_children_new ();
+  name = (gchar *)state->define->name;
+  /* XXX: we skip element without a name for now */
+  if (ide_str_empty0 (name))
+    return match_children;
+
+  for (gint i = 0; i < state->node_attr->len; i++)
+    {
+      attr = g_ptr_array_index (state->node_attr, i);
+      if (ide_str_equal0 (name, attr))
+        {
+          item = match_item_new (name, i, state->is_optional);
+          g_ptr_array_add (match_children, item);
+
+          return match_children;
+        }
+    }
+
+  item = match_item_new (name, -1, state->is_optional);
+  g_ptr_array_add (match_children, item);
+
+  return match_children;
+}
+
+static gint
+get_match_children_min_pos (GPtrArray *match_children)
+{
+  MatchItem *item;
+  gint min_pos = G_MAXINT;
+
+  g_assert (match_children != NULL);
+
+  for (gint i = 0; i < match_children->len; i++)
+    {
+      item = g_ptr_array_index (match_children, i);
+      if (item->pos == -1)
+        continue;
+
+      if (item->pos < min_pos)
+        min_pos = item->pos;
+    }
+
+  if (min_pos == G_MAXINT)
+    return -1;
+  else
+    return min_pos;
+}
+
+static GPtrArray *
+process_choice (MatchingState *state)
+{
+  GPtrArray *match_children;
+  GPtrArray *match;
+  GPtrArray *tmp_matches;
+  GPtrArray *min_pos_match = NULL;
+  IdeXmlRngDefine *defines;
+  gboolean node_has_attr;
+  gint min_pos = G_MAXINT;
+  gint pos;
+
+  g_assert (state->define->type == IDE_XML_RNG_DEFINE_CHOICE);
+
+  match_children = match_children_new ();
+  if (NULL == (defines = state->define->content))
+    return match_children;
+
+  tmp_matches = g_ptr_array_new_with_free_func ((GDestroyNotify)g_ptr_array_unref);
+  node_has_attr = (state->node_attr->len > 0);
+  while (defines != NULL)
+    {
+      if (NULL != (match = process_matching_state (state, defines)))
+        {
+          pos = get_match_children_min_pos (match);
+          if (pos != -1 && pos < min_pos)
+            {
+              g_clear_pointer (&min_pos_match, g_ptr_array_unref);
+
+              min_pos = pos;
+              min_pos_match = g_ptr_array_ref (match);
+            }
+
+          g_ptr_array_add (tmp_matches, match);
+        }
+
+      defines = defines->next;
+    }
+
+  if (min_pos_match != NULL)
+    {
+      g_ptr_array_unref (match_children);
+      g_ptr_array_unref (tmp_matches);
+
+      return min_pos_match;
+    }
+  else
+    {
+      for (gint i = 0; i < tmp_matches->len; i++)
+        match_children_add (match_children, g_ptr_array_index (tmp_matches, i));
+
+      return match_children;
+    }
+}
+
+static GPtrArray *
+process_group (MatchingState *state)
+{
+  GPtrArray *match_children;
+  GPtrArray *match;
+  IdeXmlRngDefine *defines;
+
+  g_assert (state->define->type == IDE_XML_RNG_DEFINE_GROUP ||
+            state->define->type == IDE_XML_RNG_DEFINE_ATTRIBUTE ||
+            state->define->type == IDE_XML_RNG_DEFINE_ZEROORMORE ||
+            state->define->type == IDE_XML_RNG_DEFINE_ONEORMORE ||
+            state->define->type == IDE_XML_RNG_DEFINE_OPTIONAL);
+
+  match_children = match_children_new ();
+  if (NULL == (defines = state->define->content))
+    return match_children;
+
+  while (defines != NULL)
+    {
+      if (NULL != (match = process_matching_state (state, defines)))
+        {
+          /* TODO: use move */
+          match_children_add (match_children, match);
+          g_ptr_array_unref (match);
+        }
+
+      defines = defines->next;
+    }
+
+  //state->retry = FALSE;
+  return match_children;
+}
+
+static GPtrArray *
+process_attributes_group (MatchingState *state)
+{
+  GPtrArray *match_children;
+  GPtrArray *match;
+  IdeXmlRngDefine *defines;
+
+  g_assert (state->define->type == IDE_XML_RNG_DEFINE_ELEMENT);
+
+  match_children = match_children_new ();
+  if (NULL == (defines = state->define->attributes))
+    return match_children;
+
+  while (defines != NULL)
+    {
+      if (NULL != (match = process_matching_state (state, defines)))
+        {
+          /* TODO: use move */
+          match_children_add (match_children, match);
+          g_ptr_array_unref (match);
+        }
+
+      defines = defines->next;
+    }
+
+  return match_children;
+}
+
+static GPtrArray *
+process_matching_state (MatchingState   *state,
+                        IdeXmlRngDefine *define)
+{
+  IdeXmlRngDefine *old_define;
+  IdeXmlRngDefineType type;
+  GPtrArray *match_children;
+  gboolean old_optional;
+
+  g_assert (state != NULL);
+  g_assert (define != NULL);
+
+  old_define = state->define;
+  state->define = define;
+
+  if (state->is_initial_state)
+    {
+      state->is_initial_state = FALSE;
+      type = IDE_XML_RNG_DEFINE_ATTRIBUTES_GROUP;
+    }
+  else
+    type = define->type;
+
+  printf ("ATTR process_matching_state: def:%s\n", ide_xml_rng_define_get_type_name (define));
+
+  switch (type)
+    {
+    case IDE_XML_RNG_DEFINE_ATTRIBUTE:
+      match_children = process_attribute (state);
+      break;
+
+    case IDE_XML_RNG_DEFINE_NOOP:
+    case IDE_XML_RNG_DEFINE_NOTALLOWED:
+    case IDE_XML_RNG_DEFINE_TEXT:
+    case IDE_XML_RNG_DEFINE_DATATYPE:
+    case IDE_XML_RNG_DEFINE_VALUE:
+    case IDE_XML_RNG_DEFINE_EMPTY:
+    case IDE_XML_RNG_DEFINE_ELEMENT:
+    case IDE_XML_RNG_DEFINE_START:
+    case IDE_XML_RNG_DEFINE_PARAM:
+    case IDE_XML_RNG_DEFINE_EXCEPT:
+    case IDE_XML_RNG_DEFINE_LIST:
+      match_children = NULL;
+      break;
+
+    case IDE_XML_RNG_DEFINE_DEFINE:
+    case IDE_XML_RNG_DEFINE_REF:
+    case IDE_XML_RNG_DEFINE_PARENTREF:
+    case IDE_XML_RNG_DEFINE_EXTERNALREF:
+      match_children = process_matching_state (state, define->content);
+      break;
+
+    case IDE_XML_RNG_DEFINE_ZEROORMORE:
+    case IDE_XML_RNG_DEFINE_ONEORMORE:
+    case IDE_XML_RNG_DEFINE_OPTIONAL:
+      old_optional = state->is_optional;
+      if (type == IDE_XML_RNG_DEFINE_ZEROORMORE || type == IDE_XML_RNG_DEFINE_OPTIONAL)
+        state->is_optional = TRUE;
+
+      match_children = process_group (state);
+      state->is_optional = old_optional;
+      break;
+
+    case IDE_XML_RNG_DEFINE_CHOICE:
+      match_children = process_choice (state);
+      break;
+
+    case IDE_XML_RNG_DEFINE_INTERLEAVE:
+    case IDE_XML_RNG_DEFINE_GROUP:
+      match_children = process_group (state);
+      break;
+
+    case IDE_XML_RNG_DEFINE_ATTRIBUTES_GROUP:
+      match_children = process_attributes_group (state);
+      break;
+
+    default:
+      g_assert_not_reached ();
+    }
+
+  state->define = old_define;
+
+  return match_children;
+}
+
+static MatchingState *
+create_initial_matching_state (IdeXmlRngDefine  *define,
+                               IdeXmlSymbolNode *node)
+{
+  MatchingState *state;
+  const gchar **attributes;
+
+  g_assert (define != NULL);
+
+  state = matching_state_new (define, node);
+  if (node != NULL)
+    {
+      if (NULL != (attributes = ide_xml_symbol_node_get_attributes_names (node)))
+        {
+          for (gint i = 0; attributes [i] != NULL; i++)
+            {
+              printf ("orig ATTR:'%s'\n", attributes [i]);
+              g_ptr_array_add (state->node_attr, (gchar *)attributes [i]);
+            }
+        }
+    }
+
+  state->is_initial_state = TRUE;
+
+  return state;
+}
+
+static gboolean
+compare_attribute_names (gpointer a,
+                         gpointer b)
+{
+  MatchItem *match;
+  const gchar *attr_name;
+
+  attr_name = (const gchar *)a;
+  match = (MatchItem *)b;
+
+  return ide_str_equal0 (match->name, attr_name);
+}
+
+/* Remove completion items already in the current node */
+static void
+match_children_filter (GPtrArray *match_children,
+                       GPtrArray *node_attributes)
+{
+  MatchItem *match;
+  guint index;
+  gint i = 0;
+
+  g_assert (match_children != NULL);
+  g_assert (node_attributes != NULL);
+
+  while (i < match_children->len)
+    {
+      match = g_ptr_array_index (match_children, i);
+      if (g_ptr_array_find_with_equal_func (node_attributes, match, (GEqualFunc)compare_attribute_names, 
&index))
+        g_ptr_array_remove_index_fast (match_children, i);
+      else
+        ++i;
+    }
+}
+
+/* Return an array of MatchItem */
+GPtrArray *
+ide_xml_completion_attributes_get_matches (IdeXmlRngDefine  *define,
+                                           IdeXmlSymbolNode *node)
+{
+  MatchingState *initial_state;
+  GPtrArray *match_children;
+
+  g_return_val_if_fail (define != NULL, NULL);
+  g_return_val_if_fail (IDE_IS_XML_SYMBOL_NODE (node) || node == NULL, NULL);
+
+  if (define->attributes == NULL)
+    return NULL;
+
+  initial_state = create_initial_matching_state (define, node);
+  match_children = process_matching_state (initial_state, define);
+  match_children_filter (match_children, initial_state->node_attr);
+
+  matching_state_free (initial_state);
+  return match_children;
+}
diff --git a/plugins/xml-pack/ide-xml-completion-attributes.h 
b/plugins/xml-pack/ide-xml-completion-attributes.h
new file mode 100644
index 0000000..bcd7cef
--- /dev/null
+++ b/plugins/xml-pack/ide-xml-completion-attributes.h
@@ -0,0 +1,43 @@
+/* ide-xml-completion-attributes.h
+ *
+ * Copyright (C) 2017 Sebastien Lafargue <slafargue gnome org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef IDE_XML_COMPLETION_ATTRIBUTES_H
+#define IDE_XML_COMPLETION_ATTRIBUTES_H
+
+#include <glib.h>
+
+#include <ide.h>
+
+#include "ide-xml-rng-define.h"
+#include "ide-xml-symbol-node.h"
+
+G_BEGIN_DECLS
+
+typedef struct _MatchItem
+{
+  gchar    *name;
+  gint      pos;
+  gboolean  is_optional;
+} MatchItem;
+
+GPtrArray           *ide_xml_completion_attributes_get_matches       (IdeXmlRngDefine     *define,
+                                                                      IdeXmlSymbolNode    *node);
+
+G_END_DECLS
+
+#endif /* IDE_XML_COMPLETION_ATTRIBUTES_H */
diff --git a/plugins/xml-pack/ide-xml-completion-provider.c b/plugins/xml-pack/ide-xml-completion-provider.c
index 5119fc0..d3c5792 100644
--- a/plugins/xml-pack/ide-xml-completion-provider.c
+++ b/plugins/xml-pack/ide-xml-completion-provider.c
@@ -23,10 +23,13 @@
 #include "ide-xml-completion-provider.h"
 
 #include "ide.h"
+#include "ide-xml-completion-attributes.h"
 #include "ide-xml-path.h"
 #include "ide-xml-position.h"
+#include "ide-xml-rng-define.h"
 #include "ide-xml-schema-cache-entry.h"
 #include "ide-xml-service.h"
+#include "ide-xml-symbol-node.h"
 #include "ide-xml-types.h"
 
 struct _IdeXmlCompletionProvider
@@ -69,8 +72,8 @@ typedef struct
 
 typedef struct _CompletionItem
 {
-  gchar *label;
-  gchar *content;
+  gchar           *label;
+  IdeXmlRngDefine *define;
 } CompletionItem;
 
 static void      completion_provider_init (GtkSourceCompletionProviderIface *);
@@ -295,6 +298,7 @@ get_matching_nodes (IdeXmlPath       *path,
         case IDE_XML_RNG_DEFINE_PARAM:
         case IDE_XML_RNG_DEFINE_EXCEPT:
         case IDE_XML_RNG_DEFINE_LIST:
+        case IDE_XML_RNG_DEFINE_ATTRIBUTES_GROUP:
           break;
 
         case IDE_XML_RNG_DEFINE_DEFINE:
@@ -365,18 +369,18 @@ get_matching_candidates (IdeXmlCompletionProvider *self,
 }
 
 static CompletionItem *
-completion_item_new (const gchar *label,
-                     const gchar *content)
+completion_item_new (const gchar     *label,
+                     IdeXmlRngDefine *define)
 {
   CompletionItem *item;
 
   g_assert (!ide_str_empty0 (label));
-  g_assert (!ide_str_empty0 (content));
+  g_assert (define != NULL);
 
   item = g_slice_new0 (CompletionItem);
 
   item->label = g_strdup (label);
-  item->content = g_strdup (content);
+  item->define = ide_xml_rng_define_ref (define);
 
   return item;
 }
@@ -385,7 +389,7 @@ static void
 completion_item_free (CompletionItem *item)
 {
   g_clear_pointer (&item->label, g_free);
-  g_clear_pointer (&item->content, g_free);
+  g_clear_pointer (&item->define, ide_xml_rng_define_unref);
 }
 
 static MatchingState *
@@ -442,8 +446,6 @@ matching_state_copy (MatchingState *state)
         g_ptr_array_add (new_state->children, g_ptr_array_index (state->children, i));
     }
 
-  new_state->items = state->items;
-
   return new_state;
 }
 
@@ -531,7 +533,7 @@ is_element_matching (MatchingState *state)
           state->candidate_node = NULL;
           state->retry = TRUE;
 
-          item = completion_item_new (name, name);
+          item = completion_item_new (name, state->define);
           g_ptr_array_add (state->items, item);
 
           return TRUE;
@@ -723,6 +725,7 @@ process_matching_state (MatchingState   *state,
     case IDE_XML_RNG_DEFINE_PARAM:
     case IDE_XML_RNG_DEFINE_EXCEPT:
     case IDE_XML_RNG_DEFINE_LIST:
+    case IDE_XML_RNG_DEFINE_ATTRIBUTES_GROUP:
       is_matching = FALSE;
       break;
 
@@ -760,6 +763,78 @@ process_matching_state (MatchingState   *state,
   return is_matching;
 }
 
+static GList *
+get__element_proposals (IdeXmlPosition *position,
+                        GPtrArray      *items)
+{
+  CompletionItem *completion_item;
+  GtkSourceCompletionItem *item;
+  GList *results = NULL;
+  gchar *start = "";
+
+  g_assert (position != NULL);
+  g_assert (items != NULL);
+
+  if (ide_xml_position_get_kind (position) == IDE_XML_POSITION_KIND_IN_CONTENT)
+    start = "<";
+
+  for (gint j = 0; j < items->len; ++j)
+    {
+      g_autofree gchar *label = NULL;
+      g_autofree gchar *text = NULL;
+
+      completion_item = g_ptr_array_index (items, j);
+      label = g_strconcat ("<", completion_item->label, ">", NULL);
+      text = g_strconcat (start, completion_item->label, ">", "</", completion_item->label, ">", NULL);
+      item = g_object_new (GTK_SOURCE_TYPE_COMPLETION_ITEM,
+                           "text", text,
+                           "label", label,
+                           NULL);
+
+      results = g_list_prepend (results, item);
+    }
+
+  return results;
+}
+
+static GList *
+get_attributes_proposals (IdeXmlPosition  *position,
+                          IdeXmlRngDefine *define)
+{
+  IdeXmlSymbolNode *node;
+  GtkSourceCompletionItem *item;
+  g_autoptr(GPtrArray) attributes = NULL;
+  GList *results = NULL;
+
+  node = ide_xml_position_get_child_node (position);
+  if (NULL != (attributes = ide_xml_completion_attributes_get_matches (define, node)))
+    {
+      for (gint j = 0; j < attributes->len; ++j)
+        {
+          g_autofree gchar *name = NULL;
+          g_autofree gchar *text = NULL;
+          MatchItem *match_item;
+
+          match_item = g_ptr_array_index (attributes, j);
+          /* XXX: can't get the markup working, add () */
+          if (match_item->is_optional)
+            name = g_strconcat ("<i>(", match_item->name, ")</i>", NULL);
+          else
+            name = g_strdup (match_item->name);
+
+          text = g_strconcat (match_item->name, "=\"\"", NULL);
+          item = g_object_new (GTK_SOURCE_TYPE_COMPLETION_ITEM,
+                               "markup", name,
+                               "text", text,
+                               NULL);
+
+          results = g_list_prepend (results, item);
+        }
+    }
+
+  return results;
+}
+
 static void
 populate_cb (GObject      *object,
              GAsyncResult *result,
@@ -774,16 +849,14 @@ populate_cb (GObject      *object,
   IdeXmlPositionKind kind;
   IdeXmlPositionDetail detail;
   g_autoptr (IdeXmlPath) path = NULL;
-  GtkSourceCompletionItem *item;
-  g_autoptr (GList) results = NULL;
   GPtrArray *schemas;
   g_autoptr (GPtrArray) candidates = NULL;
   IdeXmlRngDefine *def;
   MatchingState *initial_state;
   g_autoptr (GPtrArray) items = NULL;
-  CompletionItem *completion_item;
   GError *error = NULL;
   gint child_pos;
+  gboolean complete_attributes;
 
   g_assert (IDE_IS_XML_COMPLETION_PROVIDER (self));
   g_assert (IDE_IS_XML_SERVICE (service));
@@ -797,49 +870,69 @@ populate_cb (GObject      *object,
   detail = ide_xml_position_get_detail (position);
   child_pos = ide_xml_position_get_child_pos (position);
 
-  path = get_path (node, root_node);
+  complete_attributes = ((kind == IDE_XML_POSITION_KIND_IN_START_TAG || kind == 
IDE_XML_POSITION_KIND_IN_END_TAG) &&
+                         detail == IDE_XML_POSITION_DETAIL_IN_ATTRIBUTE_NAME);
+
+  if (complete_attributes)
+    {
+      IdeXmlSymbolNode *child_node;
+
+      child_node = ide_xml_position_get_child_node (position);
+      g_assert (child_node != NULL);
+
+      path = get_path (child_node, root_node);
+    }
+  else
+    path = get_path (node, root_node);
 
   if (schemas == NULL)
     goto cleanup;
 
-  candidates = get_matching_candidates (self, schemas, path);
-  if (candidates != NULL)
+  if (NULL != (candidates = get_matching_candidates (self, schemas, path)))
     {
 
-      if (child_pos != -1)
+      if (complete_attributes)
         {
-          candidate_node = ide_xml_symbol_node_new ("internal", NULL, "", IDE_SYMBOL_XML_ELEMENT);
-          ide_xml_position_set_child_node (position, candidate_node);
+          for (gint i = 0; i < candidates->len; ++i)
+            {
+              g_autoptr (GList) results = NULL;
+
+              def = g_ptr_array_index (candidates, i);
+              results = get_attributes_proposals (position, def);
+              gtk_source_completion_context_add_proposals (state->completion_context,
+                                                           GTK_SOURCE_COMPLETION_PROVIDER (self),
+                                                           results,
+                                                           TRUE);
+            }
         }
-
-      items = g_ptr_array_new_with_free_func ((GDestroyNotify)completion_item_free);
-      for (gint i = 0; i < candidates->len; ++i)
+      else
         {
-          def = g_ptr_array_index (candidates, i);
-          ide_xml_rng_define_dump_tree (def, FALSE);
+          g_autoptr (GList) results = NULL;
 
-          initial_state = create_initial_matching_state (position, def, items);
-          process_matching_state (initial_state, def);
-          matching_state_free (initial_state);
+          items = g_ptr_array_new_with_free_func ((GDestroyNotify)completion_item_free);
+          if (child_pos != -1)
+            {
+              candidate_node = ide_xml_symbol_node_new ("internal", NULL, "", IDE_SYMBOL_XML_ELEMENT);
+              ide_xml_position_set_child_node (position, candidate_node);
+            }
 
-          printf ("----------\n");
-        }
+          for (gint i = 0; i < candidates->len; ++i)
+            {
+              def = g_ptr_array_index (candidates, i);
+              ide_xml_rng_define_dump_tree (def, FALSE);
+              printf ("----------\n");
 
-      for (gint j = 0; j < items->len; ++j)
-        {
-          completion_item = g_ptr_array_index (items, j);
-          item = g_object_new (GTK_SOURCE_TYPE_COMPLETION_ITEM,
-                               "text", completion_item->content,
-                               "label", completion_item->label,
-                               NULL);
+              initial_state = create_initial_matching_state (position, def, items);
+              process_matching_state (initial_state, def);
+              matching_state_free (initial_state);
+            }
 
-          results = g_list_prepend (results, item);
+          results = get__element_proposals (position, items);
+          gtk_source_completion_context_add_proposals (state->completion_context,
+                                                       GTK_SOURCE_COMPLETION_PROVIDER (self),
+                                                       results,
+                                                       TRUE);
         }
-
-      gtk_source_completion_context_add_proposals (state->completion_context,
-                                                   GTK_SOURCE_COMPLETION_PROVIDER (self),
-                                                   results,
-                                                   TRUE);
     }
 
 cleanup:
diff --git a/plugins/xml-pack/ide-xml-rng-define.h b/plugins/xml-pack/ide-xml-rng-define.h
index 28136e9..2d08574 100644
--- a/plugins/xml-pack/ide-xml-rng-define.h
+++ b/plugins/xml-pack/ide-xml-rng-define.h
@@ -48,6 +48,7 @@ typedef enum
   IDE_XML_RNG_DEFINE_OPTIONAL,
   IDE_XML_RNG_DEFINE_CHOICE,
   IDE_XML_RNG_DEFINE_GROUP,
+  IDE_XML_RNG_DEFINE_ATTRIBUTES_GROUP,
   IDE_XML_RNG_DEFINE_INTERLEAVE,
   IDE_XML_RNG_DEFINE_ATTRIBUTE,
   IDE_XML_RNG_DEFINE_START,
diff --git a/plugins/xml-pack/ide-xml-rng-parser.c b/plugins/xml-pack/ide-xml-rng-parser.c
index d52ede5..e1f4ffd 100644
--- a/plugins/xml-pack/ide-xml-rng-parser.c
+++ b/plugins/xml-pack/ide-xml-rng-parser.c
@@ -703,7 +703,7 @@ parse_name_class (IdeXmlRngParser *self,
       _xmlfree (&def->ns);
 
       def->name = _strip (xmlNodeGetContent(node));
-      def->ns = xmlGetProp(node, NS_PROP);
+      def->ns = xmlGetProp (node, NS_PROP);
     }
   else if (is_valid_rng_node (node, "anyName"))
     {
@@ -1011,6 +1011,7 @@ parse_attribute (IdeXmlRngParser *self,
             ide_xml_rng_define_unref (current);
             break;
 
+          case IDE_XML_RNG_DEFINE_ATTRIBUTES_GROUP:
           default:
             g_assert_not_reached ();
           }
@@ -1246,6 +1247,7 @@ parse_element (IdeXmlRngParser *self,
             case IDE_XML_RNG_DEFINE_NOOP:
               break;
 
+            case IDE_XML_RNG_DEFINE_ATTRIBUTES_GROUP:
             default:
               g_assert_not_reached ();
             }
diff --git a/plugins/xml-pack/meson.build b/plugins/xml-pack/meson.build
index eaf8cdc..2459b2d 100644
--- a/plugins/xml-pack/meson.build
+++ b/plugins/xml-pack/meson.build
@@ -3,6 +3,8 @@ if get_option('with_xml_pack')
 xml_pack_sources = [
   'ide-xml-analysis.c',
   'ide-xml-analysis.h',
+  'ide-xml-completion-attributes.c',
+  'ide-xml-completion-attributes.h',
   'ide-xml-completion-provider.c',
   'ide-xml-completion-provider.h',
   'ide-xml-diagnostic-provider.c',
@@ -19,6 +21,7 @@ xml_pack_sources = [
   'ide-xml-parser-generic.h',
   'ide-xml-parser-private.h',
   'ide-xml-parser-ui.c',
+  'ide-xml-parser-ui.h',
   'ide-xml-path.c',
   'ide-xml-path.h',
   'ide-xml-position.c',
@@ -49,8 +52,9 @@ xml_pack_sources = [
   'ide-xml-tree-builder.h',
   'ide-xml-tree-builder-utils.c',
   'ide-xml-tree-builder-utils-private.h',
+  'ide-xml-types.h',
   'ide-xml-utils.c',
-  'ide-xml-utils.c',
+  'ide-xml-utils.h',
   'ide-xml-validator.c',
   'ide-xml-validator.h',
   'ide-xml.c',