[gnome-maps/wip/osm-edit: 1/47] osmShim: Add OSM XML to Json shim library using libxml2.

[Marcus Lundblad <mlundblad src gnome org>]

commit ff62bdb39b92192b1c04eac383d48f702e78fc93
Author: Marcus Lundblad <ml update uu se>
Date:   Mon Jan 19 22:24:34 2015 +0100

    osmShim: Add OSM XML to Json shim library using libxml2.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=726628

 configure.ac    |    1 +
 lib/Makefile.am |    4 +-
 lib/maps-osm.c  |  477 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/maps-osm.h  |   34 ++++
 4 files changed, 514 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 1d518b2..306cd2b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -50,6 +50,7 @@ PKG_CHECK_MODULES(GNOME_MAPS_LIB, [
     folks                        >= $FOLKS_MIN_VERSION
     geocode-glib-1.0             >= $GEOCODE_MIN_VERSION
     champlain-0.12               >= $CHAMPLAIN_MIN_VERSION
+    libxml-2.0
 ])
 AC_SUBST(GNOME_MAPS_LIB_CFLAGS)
 AC_SUBST(GNOME_MAPS_LIB_LIBS)
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 35203da..ddbd06d 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -4,8 +4,8 @@ BUILT_SOURCES =                                                 \
        maps-enum-types.c                                               \
        maps-enum-types.h
 
-libgnome_maps_headers_private = maps-contact-store.h maps-contact.h maps.h
-libgnome_maps_sources = maps-contact-store.c maps-contact.c
+libgnome_maps_headers_private = maps-contact-store.h maps-contact.h maps.h maps-osm.h
+libgnome_maps_sources = maps-contact-store.c maps-contact.c maps-osm.c
 libgnome_maps_la_SOURCES =                                             \
        $(libgnome_maps_sources)                                        \
        $(libgnome_maps_headers_private)                                \
diff --git a/lib/maps-osm.c b/lib/maps-osm.c
new file mode 100644
index 0000000..88dba0d
--- /dev/null
+++ b/lib/maps-osm.c
@@ -0,0 +1,477 @@
+/*
+ * Copyright (c) 2015 Marcus Lundblad
+ *
+ * GNOME Maps 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 2 of the License, or (at your
+ * option) any later version.
+ *
+ * GNOME Maps 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 GNOME Maps; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Author: Marcus Lundblad <ml update uu se>
+ */
+
+#include "maps-osm.h"
+
+#include <libxml/parser.h>
+#include <libxml/xpath.h>
+
+void maps_osm_init (void)
+{
+  LIBXML_TEST_VERSION;
+}
+
+void maps_osm_finalize (void)
+{
+  xmlCleanupParser ();
+}
+
+static xmlDocPtr _read_xml_doc (const gchar *content, guint length)
+{
+  xmlDoc *doc;
+
+  doc = xmlReadMemory (content, length, "noname.xml", NULL, 0);
+
+  if (!doc) {
+    g_error ("Failed to parse to XML document");
+    return NULL;
+  }
+
+  return doc;
+}
+
+static gchar *_parse_tag (const xmlAttr *attrs)
+{
+  const xmlAttr *cur_attr;
+  gchar *key;
+  gchar *value;
+  gchar *result;
+
+  key = NULL;
+  value = NULL;
+  
+  for (cur_attr = attrs; cur_attr; cur_attr = cur_attr->next) {
+    if (g_str_equal (cur_attr->name, "k")) {
+      key = g_strescape (cur_attr->children->content, "");
+    } else if (g_str_equal (cur_attr->name, "v")) {
+      value = g_strescape (cur_attr->children->content, "");
+    } else {
+      g_warning ("Unexpected tag property: %s\n", cur_attr->name);
+    }
+  }
+
+  result = g_strdup_printf ("\"%s\": \"%s\"", key, value);
+
+  if (key)
+    g_free (key);
+
+  if (value)
+    g_free (value);
+
+  return result;
+}
+
+static GHashTable *_parse_attributes (const xmlNode *node)
+{
+  GHashTable *attributes;
+  const xmlAttr *cur_attr;
+  
+  attributes = g_hash_table_new (g_str_hash, g_str_equal);
+
+  for (cur_attr = node->properties; cur_attr; cur_attr = cur_attr->next) {
+    g_hash_table_insert (attributes,
+                        (gpointer) cur_attr->name,
+                        (gpointer) cur_attr->children->content);
+  }
+
+  return attributes;
+}
+
+static GList *_parse_tags (const xmlNode *tag_child)
+{
+  GList *tags;
+  const xmlNode *cur_node;
+  
+  tags = NULL;
+
+  for (cur_node = tag_child; cur_node; cur_node = cur_node->next) {
+    /* skip non-element nodes */
+    if (cur_node->type != XML_ELEMENT_NODE) {
+      continue;
+    }
+
+    if (g_str_equal (cur_node->name, "tag")) {
+      gchar *tag;
+
+      tag = _parse_tag (cur_node->properties);
+
+      if (tag) {
+       tags = g_list_append (tags, tag);
+      }
+    }
+  }
+  
+  return tags;
+}
+
+static GList *_parse_node_refs (const xmlNode *node_ref_child)
+{
+  GList *node_refs;
+  const xmlNode *cur_node;
+
+  node_refs = NULL;
+
+  for (cur_node = node_ref_child; cur_node; cur_node = cur_node->next) {
+    /* skip non-element nodes */
+    if (cur_node->type != XML_ELEMENT_NODE) {
+      continue;
+    }
+
+    if (g_str_equal (cur_node->name, "nd")) {
+      gchar *ref;
+      GHashTable *attributes;
+
+      attributes = _parse_attributes (cur_node);
+      ref = g_hash_table_lookup (attributes, "ref");
+
+      if (ref) {
+       node_refs = g_list_append (node_refs, ref);
+      }
+
+      g_hash_table_destroy (attributes);
+    }
+  }
+
+  return node_refs;
+}
+
+static xmlNode *_get_sub_node (xmlDoc *doc, const gchar *name)
+{
+  xmlNode *node;
+  xmlXPathContext *xpath_ctx;
+  xmlXPathObject * xpath_obj;
+  gchar *xpath;
+
+  xpath = g_strdup_printf ("/osm/%s", name);
+  xpath_ctx = xmlXPathNewContext (doc);
+  xpath_obj = xmlXPathEvalExpression (xpath, xpath_ctx);
+
+  if (xpath_obj && xpath_obj->nodesetval && xpath_obj->nodesetval->nodeNr > 0) {
+    node = xmlCopyNode (xpath_obj->nodesetval->nodeTab[0], 1);
+  } else {
+    g_warning ("Couldn't find element %s\n", name);
+    node = NULL;
+  }
+
+  xmlXPathFreeObject (xpath_obj);
+  xmlXPathFreeContext (xpath_ctx);
+  g_free (xpath);
+
+  return node;
+}
+
+static void _fill_tags (GString *buffer, const GList *tag_list)
+{
+  const GList *cur_tag;
+
+  g_string_append (buffer, "\t\"tags\": {\n");
+
+  for (cur_tag = tag_list; cur_tag; cur_tag = g_list_next (cur_tag)) {
+    g_string_append_printf (buffer, "\t\t%s", cur_tag->data);
+
+    if (g_list_next (cur_tag))
+      g_string_append (buffer, ",");
+
+    g_string_append (buffer, "\n");
+  }
+
+  g_string_append (buffer, "\t}\n");
+}
+
+static void _fill_node_ref_list (GString *buffer, const GList *node_list)
+{
+  const GList *cur_tag;
+
+  g_string_append (buffer, "\t\"nodeRefs\": [\n");
+
+  for (cur_tag = node_list; cur_tag; cur_tag = g_list_next (cur_tag)) {
+    g_string_append_printf (buffer, "\t\t%s", cur_tag->data);
+
+    if (g_list_next (cur_tag))
+      g_string_append (buffer, ",");
+
+    g_string_append (buffer, "\n");
+  }
+
+  g_string_append (buffer, "\t]\n");
+
+}
+
+/**
+ * maps_osm_parse_node:
+ * @content: XML data
+ * @length: Length of data
+ */
+gchar *maps_osm_parse_node (const gchar *content, guint length)
+{
+  xmlDoc *doc;
+  xmlNode *node;
+
+  const gchar *id;
+  const gchar *changeset;
+  const gchar *version;
+  const gchar *lat;
+  const gchar *lon;
+
+  const xmlAttr *cur_attr;
+
+  GString *buffer;
+
+  GList *tag_list;
+  GHashTable *attributes;
+  
+  doc = _read_xml_doc (content, length);
+
+  if (!doc) {
+    return NULL;
+  }
+
+  node = _get_sub_node (doc, "node");
+
+  if (!node) {
+    xmlFreeDoc (doc);
+    return NULL;
+  }
+
+  attributes = _parse_attributes (node);
+  
+  id = g_hash_table_lookup (attributes, "id");
+  changeset = g_hash_table_lookup (attributes, "changeset");
+  version = g_hash_table_lookup (attributes, "version");
+  lat = g_hash_table_lookup (attributes, "lat");
+  lon = g_hash_table_lookup (attributes, "lon");
+    
+  if (!id || !changeset || !version || !lat || !lon) {
+    g_error ("Missing required attributes\n");
+    xmlFreeDoc (doc);
+    xmlFreeNode (node);
+    g_hash_table_destroy (attributes);
+    return NULL;
+  }
+
+  buffer = g_string_new (NULL);
+
+  g_string_append (buffer, "{\n");
+  g_string_append_printf (buffer, "\t\"id\": \"%s\",\n", id);
+  g_string_append_printf (buffer, "\t\"changeset\": \"%s\",\n", changeset);
+  g_string_append_printf (buffer, "\t\"version\": \"%s\",\n", version);
+  g_string_append_printf (buffer, "\t\"lat\": \"%s\",\n", lat);
+  g_string_append_printf (buffer, "\t\"lon\": \"%s\",\n", lon);
+
+  g_hash_table_destroy (attributes);
+  
+  tag_list = _parse_tags (node->children);
+  _fill_tags (buffer, tag_list);
+
+  g_list_free_full (tag_list, g_free);
+  g_string_append (buffer, "}\n");
+
+  xmlFreeDoc (doc);
+  xmlFreeNode (node);
+
+  return g_string_free (buffer, FALSE);
+}
+
+gchar *maps_osm_parse_way (const gchar *content, guint length)
+{
+  xmlDoc *doc;
+  xmlNode *way;
+  GHashTable *attributes;
+  GList *tag_list;
+  GList *node_refs_list;
+  GString *buffer;
+  
+  const gchar *id;
+  const gchar *changeset;
+  const gchar *version;
+  
+  doc = _read_xml_doc (content, length);
+
+  if (!doc) {
+    return NULL;
+  }
+
+  way = _get_sub_node (doc, "way");
+
+  if (!way) {
+    xmlFreeDoc (doc);
+    return NULL;
+  }
+
+  attributes = _parse_attributes (way);
+  
+  id = g_hash_table_lookup (attributes, "id");
+  changeset = g_hash_table_lookup (attributes, "changeset");
+  version = g_hash_table_lookup (attributes, "version");
+
+  if (!id || !changeset || !version) {
+    g_error ("Missing required attributes\n");
+    xmlFreeDoc (doc);
+    xmlFreeNode (way);
+    g_hash_table_destroy (attributes);
+    return NULL;
+  }
+
+  buffer = g_string_new (NULL);
+
+  g_string_append (buffer, "{\n");
+  g_string_append_printf (buffer, "\t\"id\": \"%s\",\n", id);
+  g_string_append_printf (buffer, "\t\"changeset\": \"%s\",\n", changeset);
+  g_string_append_printf (buffer, "\t\"version\": \"%s\",\n", version);
+
+  g_hash_table_destroy (attributes);
+
+  tag_list = _parse_tags (way->children);
+  _fill_tags (buffer, tag_list);
+  g_list_free_full (tag_list, g_free);
+
+  g_string_append (buffer, "\t,\n");
+  
+  node_refs_list = _parse_node_refs (way->children);
+  _fill_node_ref_list (buffer, node_refs_list);
+  g_list_free (node_refs_list);
+
+  g_string_append (buffer, "}\n");
+
+  xmlFreeDoc (doc);
+  xmlFreeNode (way);
+
+  return g_string_free (buffer, FALSE);
+}
+
+
+static GList *_parse_members (const xmlNode *member_child)
+{
+  const xmlNode *cur_node;
+  GList *members;
+
+  members = NULL;
+
+  for (cur_node = member_child; cur_node; cur_node = cur_node->next) {
+    /* skip non-element nodes */
+    if (cur_node->type != XML_ELEMENT_NODE) {
+      continue;
+    }
+
+    if (g_str_equal (cur_node->name, "member")) {
+      GHashTable *attributes;
+
+      attributes = _parse_attributes (cur_node);
+      members = g_list_append (members, attributes);
+    }
+  }
+  
+  return members;
+}
+
+static void _fill_members (GString *buffer, const GList *members)
+{
+  const GList *cur;
+
+  g_string_append (buffer, "\t\"members\":[\n");
+  
+  for (cur = members; cur; cur = g_list_next (cur)) {
+    GHashTable *attributes = (GHashTable *) cur->data;
+    const gchar *type = g_hash_table_lookup (attributes, "type");
+    const gchar *role = g_hash_table_lookup (attributes, "role");
+    const gchar *ref = g_hash_table_lookup (attributes, "ref");
+    
+    g_string_append (buffer, "\t\t{");
+    if (type)
+      g_string_append_printf (buffer, "\"type\": \"%s\", ", type);
+    if (role)
+      g_string_append_printf (buffer, "\"role\": \"%s\", ", role);
+    if (ref)
+      g_string_append_printf (buffer, "\"ref\": \"%s\"", ref);
+
+    g_string_append (buffer, "}");
+    
+    if (g_list_next (cur))
+      g_string_append (buffer, ",");
+    g_string_append (buffer, "\n");
+  }
+
+  g_string_append (buffer, "\t]\n");
+}
+
+gchar *maps_osm_parse_relation (const gchar *content, guint length)
+{
+  xmlDoc *doc;
+  xmlNode *relation;
+  GHashTable *attributes;
+  GList *tag_list;
+  GList *member_list;
+  GString *buffer;
+  
+  const gchar *id;
+  const gchar *changeset;
+  const gchar *version;
+  
+  doc = _read_xml_doc (content, length);
+
+  if (!doc) {
+    return NULL;
+  }
+
+  relation = _get_sub_node (doc, "relation");
+
+  if (!relation) {
+    xmlFreeDoc (doc);
+    return NULL;
+  }
+
+  attributes = _parse_attributes (relation);
+  id = g_hash_table_lookup (attributes, "id");
+  changeset = g_hash_table_lookup (attributes, "changeset");
+  version = g_hash_table_lookup (attributes, "version");  
+  
+  if (!id || !changeset || !version) {
+    g_error ("Missing required attributes\n");
+    xmlFreeDoc (doc);
+    xmlFreeNode (relation);
+    g_hash_table_destroy (attributes);
+    return NULL;
+  }
+
+  buffer = g_string_new (NULL);
+
+  g_string_append (buffer, "{\n");
+  g_string_append_printf (buffer, "\t\"id\": \"%s\",\n", id);
+  g_string_append_printf (buffer, "\t\"changeset\": \"%s\",\n", changeset);
+  g_string_append_printf (buffer, "\t\"version\": \"%s\",\n", version);
+
+  g_hash_table_destroy (attributes);
+  
+  tag_list = _parse_tags (relation->children);
+  _fill_tags (buffer, tag_list);
+  g_string_append (buffer, "\t,\n");
+  g_list_free_full (tag_list, g_free);
+
+  member_list = _parse_members (relation->children);
+  _fill_members (buffer, member_list);
+  g_list_free_full (member_list, (GDestroyNotify) g_hash_table_destroy);
+
+  g_string_append (buffer, "}\n");
+
+  xmlFreeDoc (doc);
+  xmlFreeNode (relation);
+
+  return g_string_free (buffer, FALSE);  
+}
diff --git a/lib/maps-osm.h b/lib/maps-osm.h
new file mode 100644
index 0000000..6728ae6
--- /dev/null
+++ b/lib/maps-osm.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2015 Marcus Lundblad
+ *
+ * GNOME Maps 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 2 of the License, or (at your
+ * option) any later version.
+ *
+ * GNOME Maps 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 GNOME Maps; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Author: Marcus Lundblad <ml update uu se>
+ */
+
+#ifndef __MAPSC_OSM_H__
+#define __MAPSC_OSM_H__
+
+#include <glib.h>
+
+void maps_osm_init (void);
+void maps_osm_finalize (void);
+
+gchar *maps_osm_parse_node (const gchar *content, guint length);
+gchar *maps_osm_parse_way (const gchar *content, guint length);
+gchar *maps_osm_parse_relation (const gchar *content, guint length);
+
+#endif
+