[gnome-builder] utils: Xml utility functions

[Christian Hergert <chergert src gnome org>]

commit 7fbd5aacc8f206f75a876336fab9f431284bf9f6
Author: Dimitris Zenios <dimitris zenios gmail com>
Date:   Mon May 11 22:11:29 2015 +0300

    utils: Xml utility functions
    
    Functions include
    - in element (GtkTextIter inside an element)
    - get element tag type (opening, closing, both)
    - get element name
    - get next, previous, current element
    - find opening, closing element

 libide/Makefile.am    |    2 +
 libide/util/ide-xml.c |  319 +++++++++++++++++++++++++++++++++++++++++++++++++
 libide/util/ide-xml.h |   58 +++++++++
 3 files changed, 379 insertions(+), 0 deletions(-)
---
diff --git a/libide/Makefile.am b/libide/Makefile.am
index 4e99207..74c0cc4 100644
--- a/libide/Makefile.am
+++ b/libide/Makefile.am
@@ -311,6 +311,8 @@ libide_1_0_la_SOURCES = \
        util/ide-pango.h \
        util/ide-rgba.c \
        util/ide-rgba.h \
+       util/ide-xml.c \
+       util/ide-xml.h \
        $(NULL)
 
 libide_1_0_la_includes = \
diff --git a/libide/util/ide-xml.c b/libide/util/ide-xml.c
new file mode 100644
index 0000000..8d60f7c
--- /dev/null
+++ b/libide/util/ide-xml.c
@@ -0,0 +1,319 @@
+/* ide-xml.c
+ *
+ * Copyright (C) 2015 Dimitris Zenios <dimitris zenios gmail com>
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file 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
+ * Lesser 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.h"
+
+typedef gboolean (*iter_func) (GtkTextIter *iter);
+
+
+static gboolean
+find_end_element_char (gunichar ch,
+                       gpointer user_data)
+{
+  return g_unichar_isspace (ch) || ch == '/' || ch == '>';
+}
+
+static gboolean
+find_char (iter_func          func,
+           const GtkTextIter *iter,
+           GtkTextIter       *curr,
+           gunichar           ch)
+{
+  GtkTextIter copy = *iter;
+
+  do {
+    gunichar curr_ch;
+
+    curr_ch = gtk_text_iter_get_char (&copy);
+
+    if (curr_ch == ch)
+      {
+        *curr = copy;
+        return TRUE;
+      }
+  } while (func (&copy));
+
+  return FALSE;
+}
+
+gboolean
+ide_xml_in_element (const GtkTextIter *iter)
+{
+  GtkTextIter copy = *iter;
+
+  g_return_val_if_fail (iter != NULL, FALSE);
+
+  do {
+    gunichar ch;
+
+    ch = gtk_text_iter_get_char (&copy);
+
+    if (ch == '/')
+      {
+        gtk_text_iter_backward_char (&copy);
+        ch = gtk_text_iter_get_char (&copy);
+        if (ch == '<')
+          return TRUE;
+      }
+
+    /*
+     * If the iter char points to end of the element '>'
+     * we are still inside the element.This is the reason
+     * we check for equality of the copy and iter
+     */
+    if (ch == '>' && !gtk_text_iter_equal (&copy, iter))
+      return FALSE;
+    else if (ch == '<')
+      return TRUE;
+  } while (gtk_text_iter_backward_char (&copy));
+
+  return FALSE;
+}
+
+gboolean
+ide_xml_get_current_element (const GtkTextIter *iter,
+                             GtkTextIter       *start,
+                             GtkTextIter       *end)
+{
+  g_return_val_if_fail (ide_xml_in_element (iter), FALSE);
+  g_return_val_if_fail (start != NULL, FALSE);
+  g_return_val_if_fail (end != NULL, FALSE);
+
+
+  if(find_char (gtk_text_iter_backward_char, iter, start, '<') &&
+     find_char (gtk_text_iter_forward_char,iter, end, '>') &&
+     gtk_text_iter_compare (start, end) < 0)
+    return TRUE;
+
+  return FALSE;
+}
+
+gboolean
+ide_xml_find_next_element (const GtkTextIter *iter,
+                           GtkTextIter       *start,
+                           GtkTextIter       *end)
+{
+
+  g_return_val_if_fail (iter != NULL,  FALSE);
+  g_return_val_if_fail (start != NULL, FALSE);
+  g_return_val_if_fail (end != NULL,   FALSE);
+
+  if(find_char (gtk_text_iter_forward_char, iter, start, '<') &&
+     find_char (gtk_text_iter_forward_char,start, end, '>') &&
+     gtk_text_iter_compare (start, end) < 0)
+    return TRUE;
+
+  return FALSE;
+}
+
+gboolean
+ide_xml_find_previous_element (const GtkTextIter *iter,
+                               GtkTextIter       *start,
+                               GtkTextIter       *end)
+{
+  g_return_val_if_fail (iter != NULL,  FALSE);
+  g_return_val_if_fail (start != NULL, FALSE);
+  g_return_val_if_fail (end != NULL,   FALSE);
+
+  if(find_char (gtk_text_iter_backward_char, iter, end, '>') &&
+     find_char (gtk_text_iter_backward_char, end, start, '<') &&
+     gtk_text_iter_compare (start, end) < 0)
+    return TRUE;
+
+  return FALSE;
+}
+
+IdeXmlElementTagType
+ide_xml_get_element_tag_type (const GtkTextIter *start,
+                              const GtkTextIter *end)
+{
+
+  GtkTextIter curr_start = *start;
+  GtkTextIter curr_end = *end;
+  gunichar start_ch;
+  gunichar end_ch;
+
+
+  g_return_val_if_fail (ide_xml_in_element (start) &&
+                        gtk_text_iter_get_char (start) == '<', IDE_XML_ELEMENT_TAG_UNKNOWN);
+  g_return_val_if_fail (ide_xml_in_element (start) &&
+                        gtk_text_iter_get_char (end) == '>', IDE_XML_ELEMENT_TAG_UNKNOWN);
+  g_return_val_if_fail (gtk_text_iter_compare (start, end) < 0, IDE_XML_ELEMENT_TAG_UNKNOWN);
+
+  /*Move pass the < and > char*/
+  g_return_val_if_fail (gtk_text_iter_forward_char (&curr_start), IDE_XML_ELEMENT_TAG_UNKNOWN);
+  g_return_val_if_fail (gtk_text_iter_backward_char (&curr_end), IDE_XML_ELEMENT_TAG_UNKNOWN);
+
+  start_ch = gtk_text_iter_get_char (&curr_start);
+  end_ch = gtk_text_iter_get_char (&curr_end);
+
+  if (end_ch == '/' ||
+      (end_ch == '?' && start_ch == '?') ||
+      (end_ch == '-' && start_ch == '!'))
+    return IDE_XML_ELEMENT_TAG_START_END;
+
+  if (start_ch == '/')
+    return IDE_XML_ELEMENT_TAG_END;
+
+  return IDE_XML_ELEMENT_TAG_START;
+}
+
+gchar
+*ide_xml_get_element_name (const GtkTextIter *start,
+                           const GtkTextIter *end)
+{
+  GtkTextIter curr;
+  GtkTextIter begin = *start;
+
+  g_return_val_if_fail (ide_xml_in_element (start) &&
+                        gtk_text_iter_get_char (start) == '<', NULL);
+  g_return_val_if_fail (ide_xml_in_element (start) &&
+                        gtk_text_iter_get_char (end) == '>', NULL);
+  g_return_val_if_fail (gtk_text_iter_compare (start, end) < 0, FALSE);
+
+  /*
+   * We need to move pass by the start '<' and closing '/' char of the element
+   */
+  while (gtk_text_iter_get_char (&begin) == '<' || gtk_text_iter_get_char (&begin) == '/')
+    gtk_text_iter_forward_char (&begin);
+
+  /* Comments and elements starting with ? do not have a name */
+  if (gtk_text_iter_get_char (&begin) == '!' || gtk_text_iter_get_char (&begin) == '?')
+    return NULL;
+
+  curr = begin;
+  /*
+   * Find the end of the element name by iterating over it until we find
+   * a '/' or '>' or ' ' char
+   */
+  if (gtk_text_iter_forward_find_char (&curr, find_end_element_char, NULL, end) &&
+      gtk_text_iter_compare (&begin,&curr) < 0)
+    return gtk_text_iter_get_slice (&begin, &curr);
+
+  return NULL;
+}
+
+gboolean
+ide_xml_find_closing_element (const GtkTextIter *start,
+                              const GtkTextIter *end,
+                              GtkTextIter       *found_element_start,
+                              GtkTextIter       *found_element_end)
+{
+  IdeXmlElementTagType tag_type;
+  GQueue *element_queue;
+  guint element_queue_length = 0;
+  gchar *element_name = NULL;
+
+  g_return_val_if_fail (found_element_start != NULL, FALSE);
+  g_return_val_if_fail (found_element_end != NULL, FALSE);
+
+  tag_type = ide_xml_get_element_tag_type (start, end);
+  if (tag_type != IDE_XML_ELEMENT_TAG_START)
+    return FALSE;
+
+  element_name = ide_xml_get_element_name (start, end);
+  if (element_name == NULL)
+    return FALSE;
+
+  element_queue = g_queue_new();
+  g_queue_push_head(element_queue, element_name);
+
+  while (g_queue_get_length (element_queue) > 0 &&
+         ide_xml_find_next_element (end, found_element_start, found_element_end))
+    {
+      tag_type = ide_xml_get_element_tag_type (found_element_start, found_element_end);
+      if (tag_type == IDE_XML_ELEMENT_TAG_START)
+        {
+          element_name = ide_xml_get_element_name (found_element_start, found_element_end);
+          if (element_name != NULL)
+            g_queue_push_head(element_queue, element_name);
+        }
+      else if (tag_type == IDE_XML_ELEMENT_TAG_END)
+        {
+          element_name = ide_xml_get_element_name (found_element_start, found_element_end);
+          if (element_name != NULL)
+            {
+              if(g_strcmp0 (g_queue_peek_head (element_queue), element_name) == 0)
+                 g_free (g_queue_pop_head (element_queue));
+              g_free (element_name);
+            }
+        }
+      end = found_element_end;
+    }
+
+  element_queue_length = g_queue_get_length (element_queue);
+  g_queue_free_full (element_queue, g_free);
+
+  return element_queue_length > 0 ? FALSE : TRUE;
+}
+
+gboolean
+ide_xml_find_opening_element (const GtkTextIter *start,
+                              const GtkTextIter *end,
+                              GtkTextIter       *found_element_start,
+                              GtkTextIter       *found_element_end)
+{
+  IdeXmlElementTagType tag_type;
+  GQueue *element_queue;
+  guint element_queue_length = 0;
+  gchar *element_name = NULL;
+
+  g_return_val_if_fail (found_element_start != NULL, FALSE);
+  g_return_val_if_fail (found_element_end != NULL, FALSE);
+
+  tag_type = ide_xml_get_element_tag_type (start, end);
+  if (tag_type != IDE_XML_ELEMENT_TAG_END)
+    return FALSE;
+
+  element_name = ide_xml_get_element_name (start, end);
+  if (element_name == NULL)
+    return FALSE;
+
+  element_queue = g_queue_new();
+  g_queue_push_head(element_queue, element_name);
+
+  while (g_queue_get_length (element_queue) > 0 &&
+         ide_xml_find_previous_element (start, found_element_start, found_element_end))
+    {
+      tag_type = ide_xml_get_element_tag_type (found_element_start, found_element_end);
+      if (tag_type == IDE_XML_ELEMENT_TAG_END)
+        {
+          element_name = ide_xml_get_element_name (found_element_start, found_element_end);
+          if (element_name != NULL)
+            g_queue_push_head(element_queue, element_name);
+        }
+      else if (tag_type == IDE_XML_ELEMENT_TAG_START)
+        {
+          element_name = ide_xml_get_element_name (found_element_start, found_element_end);
+          if (element_name != NULL)
+            {
+              if(g_strcmp0 (g_queue_peek_head(element_queue), element_name) == 0)
+                g_free (g_queue_pop_head (element_queue));
+              g_free (element_name);
+            }
+        }
+      start = found_element_start;
+    }
+
+  element_queue_length = g_queue_get_length (element_queue);
+  g_queue_free_full (element_queue, g_free);
+
+  return element_queue_length > 0 ? FALSE : TRUE;
+}
+
+
diff --git a/libide/util/ide-xml.h b/libide/util/ide-xml.h
new file mode 100644
index 0000000..8e1e5db
--- /dev/null
+++ b/libide/util/ide-xml.h
@@ -0,0 +1,58 @@
+/* ide-xml.h
+ *
+ * Copyright (C) 2015 Dimitris Zenios <dimitris zenios gmail com>
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file 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
+ * Lesser 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_H
+#define IDE_XML_H
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+typedef enum {
+  IDE_XML_ELEMENT_TAG_UNKNOWN    = 0,
+  IDE_XML_ELEMENT_TAG_START      = 1,
+  IDE_XML_ELEMENT_TAG_END        = 2,
+  IDE_XML_ELEMENT_TAG_START_END  = 3,
+} IdeXmlElementTagType;
+
+gboolean             ide_xml_in_element            (const GtkTextIter *iter);
+gboolean             ide_xml_find_next_element     (const GtkTextIter *iter,
+                                                    GtkTextIter       *start,
+                                                    GtkTextIter       *end);
+gboolean             ide_xml_get_current_element   (const GtkTextIter *iter,
+                                                    GtkTextIter       *start,
+                                                    GtkTextIter       *end);
+gboolean             ide_xml_find_previous_element (const GtkTextIter *iter,
+                                                    GtkTextIter       *start,
+                                                    GtkTextIter       *end);
+gboolean             ide_xml_find_closing_element  (const GtkTextIter *start,
+                                                    const GtkTextIter *end,
+                                                    GtkTextIter       *found_element_start,
+                                                    GtkTextIter       *found_element_end);
+gboolean             ide_xml_find_opening_element  (const GtkTextIter *start,
+                                                    const GtkTextIter *end,
+                                                    GtkTextIter       *found_element_start,
+                                                    GtkTextIter       *found_element_end);
+gchar               *ide_xml_get_element_name      (const GtkTextIter *start,
+                                                    const GtkTextIter *end);
+IdeXmlElementTagType ide_xml_get_element_tag_type  (const GtkTextIter *start,
+                                                    const GtkTextIter *end);
+
+G_END_DECLS
+
+#endif /* IDE_XML_H */