/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8; coding: utf-8 -*- */
/* gtksourcelanguage.c
 * This file is part of GtkSourceView
 *
 * Copyright (C) 2003 - Paolo Maggi <paolo.maggi@polito.it>
 *
 * GtkSourceView 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.
 *
 * GtkSourceView 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 Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <string.h>
#include <fcntl.h>

#include <libxml/xmlreader.h>
#include <glib/gstdio.h>
#include "gtksourceview-i18n.h"
#include "gtksourcelanguage-private.h"
#include "gtksourcelanguage.h"

#ifdef G_OS_WIN32
#include <io.h>
#endif

/**
 * SECTION:language
 * @Short_description: Represents a syntax highlighted language
 * @Title: GtkSourceLanguage
 * @See_also: #GtkSourceLanguageManager
 *
 * A #GtkSourceLanguage represents a programming or markup language, affecting
 * syntax highlighting and [context classes][context-classes].
 *
 * Use #GtkSourceLanguageManager to obtain a #GtkSourceLanguage instance, and
 * gtk_source_buffer_set_language() to apply it to a #GtkSourceBuffer.
 */

#define DEFAULT_SECTION _("Others")

enum {
	PROP_0,
	PROP_ID,
	PROP_NAME,
	PROP_SECTION,
	PROP_HIDDEN
};

G_DEFINE_TYPE_WITH_PRIVATE (GtkSourceLanguage, gtk_source_language, G_TYPE_OBJECT)

static GtkSourceLanguage *process_language_node (xmlTextReaderPtr	 reader,
						 const gchar		*filename);
static gboolean		  force_styles		(GtkSourceLanguage	*language);

GtkSourceLanguage *
_gtk_source_language_new_from_file (const gchar              *filename,
				    GtkSourceLanguageManager *lm)
{
	GtkSourceLanguage *lang = NULL;
	xmlTextReaderPtr reader = NULL;
	gint ret;
	gint fd;

	g_return_val_if_fail (filename != NULL, NULL);
	g_return_val_if_fail (lm != NULL, NULL);

	/*
	 * Use fd instead of filename so that it's utf8 safe on w32.
	 */
	fd = g_open (filename, O_RDONLY, 0);
	if (fd != -1)
		reader = xmlReaderForFd (fd, filename, NULL, 0);

	if (reader != NULL)
	{
        	ret = xmlTextReaderRead (reader);

        	while (ret == 1)
		{
			if (xmlTextReaderNodeType (reader) == 1)
			{
				xmlChar *name;

				name = xmlTextReaderName (reader);

				if (xmlStrcmp (name, BAD_CAST "language") == 0)
				{
					lang = process_language_node (reader, filename);
					ret = 0;
				}

				xmlFree (name);
			}

			if (ret == 1)
				ret = xmlTextReaderRead (reader);
		}

		xmlFreeTextReader (reader);
		close (fd);

		if (ret != 0)
		{
	            g_warning("Failed to parse '%s'", filename);
		    return NULL;
		}
        }
	else
	{
		g_warning ("Unable to open '%s'", filename);

		if (fd != -1)
		{
			close (fd);
		}
    	}

	if (lang != NULL)
	{
		lang->priv->language_manager = lm;
		g_object_add_weak_pointer (G_OBJECT (lm),
					   (gpointer) &lang->priv->language_manager);
	}

	return lang;
}

static void
gtk_source_language_get_property (GObject    *object,
				  guint       prop_id,
				  GValue     *value,
				  GParamSpec *pspec)
{
	GtkSourceLanguage *language;

	g_return_if_fail (GTK_SOURCE_IS_LANGUAGE (object));

	language = GTK_SOURCE_LANGUAGE (object);

	switch (prop_id)
	{
		case PROP_ID:
			g_value_set_string (value, language->priv->id);
			break;

		case PROP_NAME:
			g_value_set_string (value, language->priv->name);
			break;

		case PROP_SECTION:
			g_value_set_string (value, language->priv->section);
			break;

		case PROP_HIDDEN:
			g_value_set_boolean (value, language->priv->hidden);
			break;

		default:
			G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
			break;
	}
}

static void
gtk_source_language_dispose (GObject *object)
{
	GtkSourceLanguage *lang;

	lang = GTK_SOURCE_LANGUAGE (object);

	if (lang->priv->language_manager != NULL)
	{
		g_object_remove_weak_pointer (G_OBJECT (lang->priv->language_manager),
					      (gpointer) &lang->priv->language_manager);
		lang->priv->language_manager = NULL;
	}

	G_OBJECT_CLASS (gtk_source_language_parent_class)->dispose (object);
}

static void
gtk_source_language_finalize (GObject *object)
{
	GtkSourceLanguage *lang;

	lang = GTK_SOURCE_LANGUAGE (object);

	if (lang->priv->ctx_data != NULL)
		g_critical ("context data not freed in gtk_source_language_finalize");

	g_free (lang->priv->lang_file_name);
	g_free (lang->priv->translation_domain);
	g_free (lang->priv->name);
	g_free (lang->priv->section);
	g_free (lang->priv->id);
	g_hash_table_destroy (lang->priv->properties);

	g_hash_table_destroy (lang->priv->styles);

	G_OBJECT_CLASS (gtk_source_language_parent_class)->finalize (object);
}

static void
gtk_source_language_class_init (GtkSourceLanguageClass *klass)
{
	GObjectClass *object_class = G_OBJECT_CLASS (klass);

	object_class->get_property = gtk_source_language_get_property;
	object_class->dispose = gtk_source_language_dispose;
	object_class->finalize = gtk_source_language_finalize;

	g_object_class_install_property (object_class,
					 PROP_ID,
					 g_param_spec_string ("id",
						 	      "Language id",
							      "Language id",
							      NULL,
							      G_PARAM_READABLE |
							      G_PARAM_STATIC_STRINGS));

	g_object_class_install_property (object_class,
					 PROP_NAME,
					 g_param_spec_string ("name",
						 	      "Language name",
							      "Language name",
							      NULL,
							      G_PARAM_READABLE |
							      G_PARAM_STATIC_STRINGS));

	g_object_class_install_property (object_class,
					 PROP_SECTION,
					 g_param_spec_string ("section",
						 	      "Language section",
							      "Language section",
							      NULL,
							      G_PARAM_READABLE |
							      G_PARAM_STATIC_STRINGS));

	g_object_class_install_property (object_class,
					 PROP_HIDDEN,
					 g_param_spec_boolean ("hidden",
							       "Hidden",
							       "Whether the language should be hidden from the user",
							       FALSE,
							       G_PARAM_READABLE |
							       G_PARAM_STATIC_STRINGS));
}

static void
gtk_source_language_init (GtkSourceLanguage *lang)
{
	lang->priv = gtk_source_language_get_instance_private (lang);

	lang->priv->styles = g_hash_table_new_full (g_str_hash,
						    g_str_equal,
						    g_free,
						    (GDestroyNotify)_gtk_source_style_info_free);
	lang->priv->properties = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_free);
}

static gboolean
string_to_bool (const gchar *string)
{
	if (!g_ascii_strcasecmp (string, "yes") ||
	    !g_ascii_strcasecmp (string, "true") ||
	    !g_ascii_strcasecmp (string, "1"))
		return TRUE;
	else if (!g_ascii_strcasecmp (string, "no") ||
		 !g_ascii_strcasecmp (string, "false") ||
		 !g_ascii_strcasecmp (string, "0"))
		return FALSE;
	else
		g_return_val_if_reached (FALSE);
}

static void
process_properties (xmlTextReaderPtr   reader,
		    GtkSourceLanguage *language)
{
	xmlNodePtr child;
	xmlNodePtr node = NULL;

	while (node == NULL && xmlTextReaderRead (reader) == 1)
	{
		xmlChar *name;

		if (xmlTextReaderNodeType (reader) != 1)
			continue;

		name = xmlTextReaderName (reader);

		if (xmlStrcmp (name, BAD_CAST "metadata") != 0)
		{
			xmlFree (name);
			continue;
		}

		xmlFree (name);

		node = xmlTextReaderExpand (reader);

		if (node == NULL)
			return;
	}

	if (node == NULL)
		return;

	for (child = node->children; child != NULL; child = child->next)
	{
		xmlChar *name;
		xmlChar *content;

		if (child->type != XML_ELEMENT_NODE ||
		    xmlStrcmp (child->name, BAD_CAST "property") != 0)
			continue;

		name = xmlGetProp (child, BAD_CAST "name");
		content = xmlNodeGetContent (child);

		if (name != NULL && content != NULL)
			g_hash_table_insert (language->priv->properties,
					     g_strdup ((gchar *) name),
					     g_strdup ((gchar *) content));

		xmlFree (name);
		xmlFree (content);
	}
}

static GtkSourceLanguage *
process_language_node (xmlTextReaderPtr reader, const gchar *filename)
{
	xmlChar *version;
	xmlChar *tmp;
	xmlChar *untranslated_name;
	GtkSourceLanguage *lang;

	lang = g_object_new (GTK_SOURCE_TYPE_LANGUAGE, NULL);

	lang->priv->lang_file_name = g_strdup (filename);

	tmp = xmlTextReaderGetAttribute (reader, BAD_CAST "translation-domain");
	lang->priv->translation_domain = g_strdup ((gchar*) tmp);
	xmlFree (tmp);

	tmp = xmlTextReaderGetAttribute (reader, BAD_CAST "hidden");
	if (tmp != NULL)
		lang->priv->hidden = string_to_bool ((gchar*) tmp);
	else
		lang->priv->hidden = FALSE;
	xmlFree (tmp);

	tmp = xmlTextReaderGetAttribute (reader, BAD_CAST "mimetypes");
	if (tmp != NULL)
		g_hash_table_insert (lang->priv->properties,
				     g_strdup ("mimetypes"),
				     g_strdup ((char*) tmp));
	xmlFree (tmp);

	tmp = xmlTextReaderGetAttribute (reader, BAD_CAST "globs");
	if (tmp != NULL)
		g_hash_table_insert (lang->priv->properties,
				     g_strdup ("globs"),
				     g_strdup ((char*) tmp));
	xmlFree (tmp);

	tmp = xmlTextReaderGetAttribute (reader, BAD_CAST "_name");
	if (tmp == NULL)
	{
		tmp = xmlTextReaderGetAttribute (reader, BAD_CAST "name");

		if (tmp == NULL)
		{
			g_warning ("Impossible to get language name from file '%s'",
				   filename);
			g_object_unref (lang);
			return NULL;
		}

		lang->priv->name = g_strdup ((char*) tmp);
		untranslated_name = tmp;
	}
	else
	{
		lang->priv->name = _gtk_source_language_translate_string (lang, (gchar*) tmp);
		untranslated_name = tmp;
	}

	tmp = xmlTextReaderGetAttribute (reader, BAD_CAST "id");
	if (tmp != NULL)
	{
		lang->priv->id = g_ascii_strdown ((gchar*) tmp, -1);
	}
	else
	{
		lang->priv->id = g_ascii_strdown ((gchar*) untranslated_name, -1);
	}
	xmlFree (tmp);
	xmlFree (untranslated_name);

	tmp = xmlTextReaderGetAttribute (reader, BAD_CAST "_section");
	if (tmp == NULL)
	{
		tmp = xmlTextReaderGetAttribute (reader, BAD_CAST "section");

		if (tmp == NULL)
			lang->priv->section = g_strdup (DEFAULT_SECTION);
		else
			lang->priv->section = g_strdup ((gchar *) tmp);

		xmlFree (tmp);
	}
	else
	{
		lang->priv->section = _gtk_source_language_translate_string (lang, (gchar*) tmp);
		xmlFree (tmp);
	}

	version = xmlTextReaderGetAttribute (reader, BAD_CAST "version");

	if (version == NULL)
	{
		g_warning ("Impossible to get version number from file '%s'",
			   filename);
		g_object_unref (lang);
		return NULL;
	}

	if (xmlStrcmp (version , BAD_CAST "1.0") == 0)
	{
		lang->priv->version = GTK_SOURCE_LANGUAGE_VERSION_1_0;
	}
	else if (xmlStrcmp (version, BAD_CAST "2.0") == 0)
	{
		lang->priv->version = GTK_SOURCE_LANGUAGE_VERSION_2_0;
	}
	else
	{
		g_warning ("Unsupported language spec version '%s' in file '%s'",
			   (gchar*) version, filename);
		xmlFree (version);
		g_object_unref (lang);
		return NULL;
	}

	xmlFree (version);

	if (lang->priv->version == GTK_SOURCE_LANGUAGE_VERSION_2_0)
		process_properties (reader, lang);

	return lang;
}

gchar *
_gtk_source_language_translate_string (GtkSourceLanguage *language,
				       const gchar       *string)
{
	g_return_val_if_fail (string != NULL, NULL);
	return GD_(language->priv->translation_domain, string);
}

/**
 * gtk_source_language_get_id:
 * @language: a #GtkSourceLanguage.
 *
 * Returns the ID of the language. The ID is not locale-dependent.
 * The returned string is owned by @language and should not be freed
 * or modified.
 *
 * Returns: the ID of @language.
 **/
const gchar *
gtk_source_language_get_id (GtkSourceLanguage *language)
{
	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), NULL);
	g_return_val_if_fail (language->priv->id != NULL, NULL);

	return language->priv->id;
}

/**
 * gtk_source_language_get_name:
 * @language: a #GtkSourceLanguage.
 *
 * Returns the localized name of the language.
 * The returned string is owned by @language and should not be freed
 * or modified.
 *
 * Returns: the name of @language.
 **/
const gchar *
gtk_source_language_get_name (GtkSourceLanguage *language)
{
	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), NULL);
	g_return_val_if_fail (language->priv->name != NULL, NULL);

	return language->priv->name;
}

/**
 * gtk_source_language_get_section:
 * @language: a #GtkSourceLanguage.
 *
 * Returns the localized section of the language.
 * Each language belong to a section (ex. HTML belogs to the
 * Markup section).
 * The returned string is owned by @language and should not be freed
 * or modified.
 *
 * Returns: the section of @language.
 **/
const gchar *
gtk_source_language_get_section	(GtkSourceLanguage *language)
{
	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), NULL);
	g_return_val_if_fail (language->priv->section != NULL, NULL);

	return language->priv->section;
}

/**
 * gtk_source_language_get_hidden:
 * @language: a #GtkSourceLanguage
 *
 * Returns whether the language should be hidden from the user.
 *
 * Returns: %TRUE if the language should be hidden, %FALSE otherwise.
 */
gboolean
gtk_source_language_get_hidden (GtkSourceLanguage *language)
{
	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), FALSE);

	return language->priv->hidden;
}

/**
 * gtk_source_language_get_metadata:
 * @language: a #GtkSourceLanguage.
 * @name: metadata property name.
 *
 * Returns: (nullable) (transfer none): value of property @name stored in
 * the metadata of @language or %NULL if language does not contain the
 * specified metadata property.
 * The returned string is owned by @language and should not be freed
 * or modified.
 **/
const gchar *
gtk_source_language_get_metadata (GtkSourceLanguage *language,
				  const gchar       *name)
{
	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), NULL);
	g_return_val_if_fail (name != NULL, NULL);

	return g_hash_table_lookup (language->priv->properties, name);
}

/**
 * gtk_source_language_get_mime_types:
 * @language: a #GtkSourceLanguage.
 *
 * Returns the mime types associated to this language. This is just
 * an utility wrapper around gtk_source_language_get_metadata() to
 * retrieve the "mimetypes" metadata property and split it into an
 * array.
 *
 * Returns: (nullable) (array zero-terminated=1) (transfer full):
 * a newly-allocated %NULL terminated array containing the mime types
 * or %NULL if no mime types are found.
 * The returned array must be freed with g_strfreev().
 **/
gchar **
gtk_source_language_get_mime_types (GtkSourceLanguage *language)
{
	const gchar *mimetypes;

	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), NULL);

	mimetypes = gtk_source_language_get_metadata (language, "mimetypes");
	if (mimetypes == NULL)
		return NULL;

	return g_strsplit (mimetypes, ";", 0);
}

/**
 * gtk_source_language_get_globs:
 * @language: a #GtkSourceLanguage.
 *
 * Returns the globs associated to this language. This is just
 * an utility wrapper around gtk_source_language_get_metadata() to
 * retrieve the "globs" metadata property and split it into an array.
 *
 * Returns: (nullable) (array zero-terminated=1) (transfer full):
 * a newly-allocated %NULL terminated array containing the globs or %NULL
 * if no globs are found.
 * The returned array must be freed with g_strfreev().
 **/
gchar **
gtk_source_language_get_globs (GtkSourceLanguage *language)
{
	const gchar *globs;

	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), NULL);

	globs = gtk_source_language_get_metadata (language, "globs");
	if (globs == NULL)
		return NULL;

	return g_strsplit (globs, ";", 0);
}

/**
 * _gtk_source_language_get_language_manager:
 * @language: a #GtkSourceLanguage.
 *
 * Returns: (transfer none): the #GtkSourceLanguageManager for @language.
 **/
GtkSourceLanguageManager *
_gtk_source_language_get_language_manager (GtkSourceLanguage *language)
{
	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), NULL);
	g_return_val_if_fail (language->priv->id != NULL, NULL);

	return language->priv->language_manager;
}

/* Highlighting engine creation ------------------------------------------ */

static void
copy_style_info (const char         *style_id,
		 GtkSourceStyleInfo *info,
		 GHashTable         *dest)
{
	g_hash_table_insert (dest, g_strdup (style_id),
			     _gtk_source_style_info_copy (info));
}

void
_gtk_source_language_define_language_styles (GtkSourceLanguage *lang)
{
	static const gchar *alias[][2] = {
		{"Base-N Integer", "def:base-n-integer"},
		{"Character", "def:character"},
		{"Comment", "def:comment"},
		{"Function", "def:function"},
		{"Decimal", "def:decimal"},
		{"Floating Point", "def:floating-point"},
		{"Keyword", "def:keyword"},
		{"Preprocessor", "def:preprocessor"},
		{"String", "def:string"},
		{"Specials", "def:specials"},
		{"Data Type", "def:type"},
		{NULL, NULL}};

	gint i = 0;
	GtkSourceLanguageManager *lm;
	GtkSourceLanguage *def_lang;

	while (alias[i][0] != NULL)
	{
		GtkSourceStyleInfo *info;

		info = _gtk_source_style_info_new (alias[i][0], alias[i][1]);

		g_hash_table_insert (lang->priv->styles,
				     g_strdup (alias[i][0]),
				     info);

		++i;
	}

	/* We translate String to def:string, but def:string is mapped-to
	 * def:constant in def.lang, so we got to take style mappings from def.lang */

	lm = _gtk_source_language_get_language_manager (lang);
	def_lang = gtk_source_language_manager_get_language (lm, "def");

	if (def_lang != NULL)
	{
		force_styles (def_lang);
		g_hash_table_foreach (def_lang->priv->styles,
				      (GHFunc) copy_style_info,
				      lang->priv->styles);
	}
}

/* returns new reference, which _must_ be unref'ed */
static GtkSourceContextData *
gtk_source_language_parse_file (GtkSourceLanguage *language)
{
	if (language->priv->ctx_data == NULL)
	{
		gboolean success = FALSE;
		GtkSourceContextData *ctx_data;

		if (language->priv->language_manager == NULL)
		{
			g_critical ("_gtk_source_language_create_engine() is called after "
				    "language manager was finalized");
		}
		else
		{
			ctx_data = _gtk_source_context_data_new	(language);

			switch (language->priv->version)
			{
				case GTK_SOURCE_LANGUAGE_VERSION_1_0:
					success = _gtk_source_language_file_parse_version1 (language, ctx_data);
					break;

				case GTK_SOURCE_LANGUAGE_VERSION_2_0:
					success = _gtk_source_language_file_parse_version2 (language, ctx_data);
					break;

				default:
					g_assert_not_reached ();
			}

			if (!success)
				_gtk_source_context_data_unref (ctx_data);
			else
				language->priv->ctx_data = ctx_data;
		}
	}
	else
	{
		_gtk_source_context_data_ref (language->priv->ctx_data);
	}

	return language->priv->ctx_data;
}

GtkSourceEngine *
_gtk_source_language_create_engine (GtkSourceLanguage *language)
{
	GtkSourceContextEngine *ce = NULL;
	GtkSourceContextData *ctx_data;

	ctx_data = gtk_source_language_parse_file (language);

	if (ctx_data != NULL)
	{
		ce = _gtk_source_context_engine_new (ctx_data);
		_gtk_source_context_data_unref (ctx_data);
	}

	return ce ? GTK_SOURCE_ENGINE (ce) : NULL;
}

typedef struct _AddStyleIdData AddStyleIdData;

struct _AddStyleIdData
{
	gchar             *language_id;
	GPtrArray         *ids_array;
};

static void
add_style_id (gchar *id, G_GNUC_UNUSED gpointer value, AddStyleIdData *data)
{
	if (g_str_has_prefix (id, data->language_id))
		g_ptr_array_add (data->ids_array, g_strdup (id));
}

static gchar **
get_style_ids (GtkSourceLanguage *language)
{
	GPtrArray *ids_array;
	AddStyleIdData data;

	g_return_val_if_fail (language->priv->styles != NULL, NULL);

	ids_array = g_ptr_array_new ();

	data.language_id = g_strdup_printf ("%s:", language->priv->id);
	data.ids_array = ids_array;

	g_hash_table_foreach (language->priv->styles,
			      (GHFunc) add_style_id,
			      &data);

	g_free (data.language_id);

	if (ids_array->len == 0)
	{
		/* No style defined in this language */
		g_ptr_array_free (ids_array, TRUE);

		return NULL;
	}
	else
	{
		/* Terminate the array with NULL */
		g_ptr_array_add (ids_array, NULL);

		return (gchar **)g_ptr_array_free (ids_array, FALSE);
	}
}

static gboolean
force_styles (GtkSourceLanguage *language)
{
	/* To be sure to have the list of styles we need to parse lang file
	 * as if we were to create an engine. In the future we can improve
	 * this by parsing styles only.
	 */
	if (!language->priv->styles_loaded && language->priv->ctx_data == NULL)
	{
		GtkSourceContextData *ctx_data;

		ctx_data = gtk_source_language_parse_file (language);
		if (ctx_data == NULL)
			return FALSE;

		language->priv->styles_loaded = TRUE;
		_gtk_source_context_data_unref (ctx_data);
	}

	return TRUE;
}

/**
 * gtk_source_language_get_style_ids:
 * @language: a #GtkSourceLanguage.
 *
 * Returns the ids of the styles defined by this @language.
 *
 * Returns: (nullable) (array zero-terminated=1) (transfer full):
 * a newly-allocated %NULL terminated array containing ids of the
 * styles defined by this @language or %NULL if no style is defined.
 * The returned array must be freed with g_strfreev().
*/
gchar **
gtk_source_language_get_style_ids (GtkSourceLanguage *language)
{
	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), NULL);
	g_return_val_if_fail (language->priv->id != NULL, NULL);

	if (!force_styles (language))
		return NULL;

	return get_style_ids (language);
}

static GtkSourceStyleInfo *
get_style_info (GtkSourceLanguage *language, const char *style_id)
{
	GtkSourceStyleInfo *info;

	if (!force_styles (language))
		return NULL;

	g_return_val_if_fail (language->priv->styles != NULL, NULL);

	info = g_hash_table_lookup (language->priv->styles, style_id);

	return info;
}

/**
 * gtk_source_language_get_style_name:
 * @language: a #GtkSourceLanguage.
 * @style_id: a style ID.
 *
 * Returns the name of the style with ID @style_id defined by this @language.
 *
 * Returns: (nullable) (transfer none): the name of the style with ID @style_id
 * defined by this @language or %NULL if the style has no name or there is no
 * style with ID @style_id defined by this @language.
 * The returned string is owned by the @language and must not be modified.
 */
const gchar *
gtk_source_language_get_style_name (GtkSourceLanguage *language,
				    const gchar       *style_id)
{
	GtkSourceStyleInfo *info;

	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), NULL);
	g_return_val_if_fail (language->priv->id != NULL, NULL);
	g_return_val_if_fail (style_id != NULL, NULL);

	info = get_style_info (language, style_id);

	return info ? info->name : NULL;
}

/**
 * gtk_source_language_get_style_fallback:
 * @language: a #GtkSourceLanguage.
 * @style_id: a style ID.
 *
 * Returns the ID of the style to use if the specified @style_id
 * is not present in the current style scheme.
 *
 * Returns: (nullable) (transfer none): the ID of the style to use if the
 * specified @style_id is not present in the current style scheme or %NULL
 * if the style has no fallback defined.
 * The returned string is owned by the @language and must not be modified.
 *
 * Since: 3.4
 */
const gchar *
gtk_source_language_get_style_fallback (GtkSourceLanguage *language,
					const gchar       *style_id)
{
	GtkSourceStyleInfo *info;

	g_return_val_if_fail (GTK_SOURCE_IS_LANGUAGE (language), NULL);
	g_return_val_if_fail (language->priv->id != NULL, NULL);
	g_return_val_if_fail (style_id != NULL, NULL);

	info = get_style_info (language, style_id);

	return info ? info->map_to : NULL;
}

/* Utility functions for GtkSourceStyleInfo */

GtkSourceStyleInfo *
_gtk_source_style_info_new (const gchar *name, const gchar *map_to)
{
	GtkSourceStyleInfo *info = g_new0 (GtkSourceStyleInfo, 1);

	info->name = g_strdup (name);
	info->map_to = g_strdup (map_to);

	return info;
}

GtkSourceStyleInfo *
_gtk_source_style_info_copy (GtkSourceStyleInfo *info)
{
	g_return_val_if_fail (info != NULL, NULL);
	return _gtk_source_style_info_new (info->name, info->map_to);
}

void
_gtk_source_style_info_free (GtkSourceStyleInfo *info)
{
	if (info == NULL)
		return;

	g_free (info->name);
	g_free (info->map_to);

	g_free (info);
}