diff --git a/include/Desktop/mimehandler.h b/include/Desktop/mimehandler.h
index a8bf691..d8ff6d7 100644
--- a/include/Desktop/mimehandler.h
+++ b/include/Desktop/mimehandler.h
@@ -37,7 +37,7 @@
 
 /* MimeHandler */
 /* types */
-typedef struct _Hash MimeHandler;
+typedef struct _MimeHandler MimeHandler;
 
 typedef enum _MimeHandlerType
 {
@@ -59,19 +59,23 @@ int mimehandler_can_display(MimeHandler * handler);
 int mimehandler_can_execute(MimeHandler * handler);
 int mimehandler_can_open(MimeHandler * handler);
 
+String const ** mimehandler_get_categories(MimeHandler * handler);
 String const * mimehandler_get_comment(MimeHandler * handler);
+String const * mimehandler_get_filename(MimeHandler * handler);
 String const * mimehandler_get_generic_name(MimeHandler * handler);
 String const * mimehandler_get_icon(MimeHandler * handler);
 String const * mimehandler_get_name(MimeHandler * handler);
 String const * mimehandler_get_path(MimeHandler * handler);
 String const * mimehandler_get_program(MimeHandler * handler);
 MimeHandlerType mimehandler_get_type(MimeHandler * handler);
-String ** mimehandler_get_types(MimeHandler * handler);
+String const ** mimehandler_get_types(MimeHandler * handler);
 String const * mimehandler_get_url(MimeHandler * handler);
 
 int mimehandler_is_hidden(MimeHandler * handler);
 
 /* useful */
+int mimehandler_execute(MimeHandler * handler, String const * filename);
+
 int mimehandler_load(MimeHandler * handler, String const * filename);
 int mimehandler_load_by_name(MimeHandler * handler, String const * name);
 int mimehandler_save(MimeHandler * handler);
diff --git a/src/mimehandler.c b/src/mimehandler.c
index 8c9e688..0a156a8 100644
--- a/src/mimehandler.c
+++ b/src/mimehandler.c
@@ -31,6 +31,8 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
+#include <System.h>
 #include "Desktop.h"
 
 #ifndef PREFIX
@@ -42,17 +44,44 @@
 
 
 /* private */
+/* types */
+struct _MimeHandler
+{
+	Config * config;
+	String * filename;
+	String ** categories;
+	String ** types;
+};
+
+
 /* constants */
 #define EXTENSION	".desktop"
 #define SECTION		"Desktop Entry"
 
 
+/* prototypes */
+static void _mimehandler_cache_invalidate(MimeHandler * handler);
+
+
 /* public */
 /* functions */
 /* mimehandler_new */
 MimeHandler * mimehandler_new(void)
 {
-	return config_new();
+	MimeHandler * handler;
+
+	if((handler = object_new(sizeof(*handler))) == NULL)
+		return NULL;
+	handler->config = config_new();
+	handler->filename = NULL;
+	handler->categories = NULL;
+	handler->types = NULL;
+	if(handler->config == NULL)
+	{
+		mimehandler_delete(handler);
+		return NULL;
+	}
+	return handler;
 }
 
 
@@ -91,7 +120,10 @@ MimeHandler * mimehandler_new_open(String const * filename)
 /* mimehandler_delete */
 void mimehandler_delete(MimeHandler * handler)
 {
-	config_delete(handler);
+	_mimehandler_cache_invalidate(handler);
+	config_delete(handler->config);
+	string_delete(handler->filename);
+	object_delete(handler);
 }
 
 
@@ -101,7 +133,7 @@ int mimehandler_can_display(MimeHandler * handler)
 {
 	String const * p;
 
-	if((p = config_get(handler, SECTION, "NoDisplay")) == NULL)
+	if((p = config_get(handler->config, SECTION, "NoDisplay")) == NULL)
 		return 1;
 	return (string_compare(p, "true") == 0) ? 1 : 0;
 }
@@ -118,10 +150,10 @@ int mimehandler_can_execute(MimeHandler * handler)
 
 	if(mimehandler_get_type(handler) != MIMEHANDLER_TYPE_APPLICATION)
 		return 0;
-	if((p = config_get(handler, SECTION, "TryExec")) != NULL
+	if((p = config_get(handler->config, SECTION, "TryExec")) != NULL
 			&& _can_execute_access(p, X_OK) == 0)
 		return 0;
-	return (config_get(handler, SECTION, "Exec") != NULL) ? 1 : 0;
+	return (config_get(handler->config, SECTION, "Exec") != NULL) ? 1 : 0;
 }
 
 static int _can_execute_access(String const * path, int mode)
@@ -178,92 +210,8 @@ int mimehandler_can_open(MimeHandler * handler)
 }
 
 
-/* mimehandler_get_comment */
-String const * mimehandler_get_comment(MimeHandler * handler)
-{
-	return config_get(handler, SECTION, "Comment");
-}
-
-
-/* mimehandler_get_generic_name */
-String const * mimehandler_get_generic_name(MimeHandler * handler)
-{
-	return config_get(handler, SECTION, "GenericName");
-}
-
-
-/* mimehandler_get_icon */
-String const * mimehandler_get_icon(MimeHandler * handler)
-{
-	return config_get(handler, SECTION, "Icon");
-}
-
-
-/* mimehandler_get_name */
-String const * mimehandler_get_name(MimeHandler * handler)
-{
-	return config_get(handler, SECTION, "Name");
-}
-
-
-/* mimehandler_get_path */
-String const * mimehandler_get_path(MimeHandler * handler)
-{
-	switch(mimehandler_get_type(handler))
-	{
-		case MIMEHANDLER_TYPE_APPLICATION:
-		case MIMEHANDLER_TYPE_DIRECTORY:
-			return config_get(handler, SECTION, "Path");
-		default:
-			return NULL;
-	}
-}
-
-
-/* mimehandler_get_program */
-String const * mimehandler_get_program(MimeHandler * handler)
-{
-	switch(mimehandler_get_type(handler))
-	{
-		case MIMEHANDLER_TYPE_APPLICATION:
-			/* XXX may be a format string */
-			return config_get(handler, SECTION, "Exec");
-		case MIMEHANDLER_TYPE_DIRECTORY:
-		case MIMEHANDLER_TYPE_UNKNOWN:
-		case MIMEHANDLER_TYPE_URL:
-			return NULL;
-	}
-	return NULL;
-}
-
-
-/* mimehandler_get_type */
-MimeHandlerType mimehandler_get_type(MimeHandler * handler)
-{
-	String const * type;
-	struct
-	{
-		String const * name;
-		MimeHandlerType type;
-	} types[] =
-	{
-		{ "Application",MIMEHANDLER_TYPE_APPLICATION	},
-		{ "Directory",	MIMEHANDLER_TYPE_DIRECTORY	},
-		{ "URL",	MIMEHANDLER_TYPE_URL		}
-	};
-	size_t i;
-
-	if((type = config_get(handler, SECTION, "Type")) == NULL)
-		return MIMEHANDLER_TYPE_UNKNOWN;
-	for(i = 0; i < sizeof(types) / sizeof(*types); i++)
-		if(string_compare(types[i].name, type) == 0)
-			return types[i].type;
-	return MIMEHANDLER_TYPE_UNKNOWN;
-}
-
-
-/* mimehandler_get_types */
-String ** mimehandler_get_types(MimeHandler * handler)
+/* mimehandler_get_categories */
+String const ** mimehandler_get_categories(MimeHandler * handler)
 {
 	String ** ret = NULL;
 	size_t cnt = 0;
@@ -273,13 +221,14 @@ String ** mimehandler_get_types(MimeHandler * handler)
 	String * last;
 	String ** r;
 
-	if(mimehandler_get_type(handler) != MIMEHANDLER_TYPE_APPLICATION)
-		return NULL;
-	if((p = config_get(handler, SECTION, "MimeType")) == NULL)
+	if(handler->categories != NULL)
+		return (String const **)handler->categories;
+	if((p = config_get(handler->config, SECTION, "Categories")) == NULL)
 	{
 		if((ret = malloc(sizeof(String *))) == NULL)
 			return NULL;
 		ret[0] = NULL;
+		handler->categories = ret;
 		return ret;
 	}
 	if((q = string_new(p)) == NULL)
@@ -305,6 +254,149 @@ String ** mimehandler_get_types(MimeHandler * handler)
 	}
 	if(ret != NULL)
 		ret[cnt] = NULL;
+	handler->categories = ret;
+	return ret;
+}
+
+
+/* mimehandler_get_comment */
+String const * mimehandler_get_comment(MimeHandler * handler)
+{
+	return config_get(handler->config, SECTION, "Comment");
+}
+
+
+/* mimehandler_get_filename */
+String const * mimehandler_get_filename(MimeHandler * handler)
+{
+	return handler->filename;
+}
+
+
+/* mimehandler_get_generic_name */
+String const * mimehandler_get_generic_name(MimeHandler * handler)
+{
+	return config_get(handler->config, SECTION, "GenericName");
+}
+
+
+/* mimehandler_get_icon */
+String const * mimehandler_get_icon(MimeHandler * handler)
+{
+	return config_get(handler->config, SECTION, "Icon");
+}
+
+
+/* mimehandler_get_name */
+String const * mimehandler_get_name(MimeHandler * handler)
+{
+	return config_get(handler->config, SECTION, "Name");
+}
+
+
+/* mimehandler_get_path */
+String const * mimehandler_get_path(MimeHandler * handler)
+{
+	switch(mimehandler_get_type(handler))
+	{
+		case MIMEHANDLER_TYPE_APPLICATION:
+		case MIMEHANDLER_TYPE_DIRECTORY:
+			return config_get(handler->config, SECTION, "Path");
+		default:
+			return NULL;
+	}
+}
+
+
+/* mimehandler_get_program */
+String const * mimehandler_get_program(MimeHandler * handler)
+{
+	switch(mimehandler_get_type(handler))
+	{
+		case MIMEHANDLER_TYPE_APPLICATION:
+			/* XXX may be a format string */
+			return config_get(handler->config, SECTION, "Exec");
+		case MIMEHANDLER_TYPE_DIRECTORY:
+		case MIMEHANDLER_TYPE_UNKNOWN:
+		case MIMEHANDLER_TYPE_URL:
+			return NULL;
+	}
+	return NULL;
+}
+
+
+/* mimehandler_get_type */
+MimeHandlerType mimehandler_get_type(MimeHandler * handler)
+{
+	String const * type;
+	struct
+	{
+		String const * name;
+		MimeHandlerType type;
+	} types[] =
+	{
+		{ "Application",MIMEHANDLER_TYPE_APPLICATION	},
+		{ "Directory",	MIMEHANDLER_TYPE_DIRECTORY	},
+		{ "URL",	MIMEHANDLER_TYPE_URL		}
+	};
+	size_t i;
+
+	if((type = config_get(handler->config, SECTION, "Type")) == NULL)
+		return MIMEHANDLER_TYPE_UNKNOWN;
+	for(i = 0; i < sizeof(types) / sizeof(*types); i++)
+		if(string_compare(types[i].name, type) == 0)
+			return types[i].type;
+	return MIMEHANDLER_TYPE_UNKNOWN;
+}
+
+
+/* mimehandler_get_types */
+String const ** mimehandler_get_types(MimeHandler * handler)
+{
+	String ** ret = NULL;
+	size_t cnt = 0;
+	size_t i;
+	String const * p;
+	String * q;
+	String * last;
+	String ** r;
+
+	if(handler->types != NULL)
+		return handler->types;
+	if(mimehandler_get_type(handler) != MIMEHANDLER_TYPE_APPLICATION)
+		return NULL;
+	if((p = config_get(handler->config, SECTION, "MimeType")) == NULL)
+	{
+		if((ret = malloc(sizeof(String *))) == NULL)
+			return NULL;
+		ret[0] = NULL;
+		handler->types = ret;
+		return ret;
+	}
+	if((q = string_new(p)) == NULL)
+		return NULL;
+	for(p = strtok_r(q, ":", &last); p != NULL;
+			p = strtok_r(NULL, ":", &last))
+	{
+		if(strlen(p) == 0)
+			continue;
+		if((r = realloc(ret, sizeof(*ret) * (cnt + 1))) != NULL)
+		{
+			ret = r;
+			ret[cnt] = string_new(p);
+		}
+		if(r == NULL || ret[cnt] == NULL)
+		{
+			for(i = 0; i < cnt; i++)
+				string_delete(ret[i]);
+			free(ret);
+			return NULL;
+		}
+		cnt++;
+	}
+	if(ret != NULL)
+		ret[cnt] = NULL;
+	handler->types = ret;
 	return ret;
 }
 
@@ -313,7 +405,7 @@ String ** mimehandler_get_types(MimeHandler * handler)
 String const * mimehandler_get_url(MimeHandler * handler)
 {
 	if(mimehandler_get_type(handler) == MIMEHANDLER_TYPE_URL)
-		return config_get(handler, SECTION, "URL");
+		return config_get(handler->config, SECTION, "URL");
 	return NULL;
 }
 
@@ -323,23 +415,86 @@ int mimehandler_is_hidden(MimeHandler * handler)
 {
 	String const * p;
 
-	if((p = config_get(handler, SECTION, "Hidden")) == NULL)
+	if((p = config_get(handler->config, SECTION, "Hidden")) == NULL)
 		return 0;
 	return (string_compare(p, "true") == 0) ? 1 : 0;
 }
 
 
 /* useful */
+/* mimehandler_execute */
+int mimehandler_execute(MimeHandler * handler, String const * filename)
+{
+	/* FIXME implement filename */
+	int ret = 0;
+        String * program;
+        String * p;
+        String const * q;
+        pid_t pid;
+        GError * error = NULL;
+
+        if((q = config_get(handler->config, SECTION, "Exec")) == NULL)
+                return -1;
+        if((program = string_new(q)) == NULL)
+                return -1;
+        /* XXX crude way to ignore %f, %F, %u and %U */
+        if((p = strchr(program, '%')) != NULL)
+                *p = '\0';
+#ifdef DEBUG
+        fprintf(stderr, "DEBUG: %s() \"%s\"", __func__, program);
+#endif
+        if((q = mimehandler_get_path(handler)) == NULL)
+        {
+                /* execute the program directly */
+                if(g_spawn_command_line_async(program, &error) != TRUE)
+                {
+			error_set_code(1, "%s: %s", program, error->message);
+                        g_error_free(error);
+                }
+        }
+        else if((pid = fork()) == 0)
+        {
+                /* change the current working directory */
+                if(chdir(q) != 0)
+			error_set_code(-errno, "%s: %s: %s", program, q,
+					strerror(errno));
+                else if(g_spawn_command_line_async(program, &error) != TRUE)
+                {
+			error_set_code(1, "%s: %s", program, error->message);
+                        g_error_free(error);
+                }
+                exit(125);
+        }
+        else if(pid < 0)
+	{
+                error_set_code(-errno, "%s: %s", program, strerror(errno));
+		ret = -1;
+	}
+        string_delete(program);
+	return ret;
+}
+
+
 /* mimehandler_load */
 int mimehandler_load(MimeHandler * handler, String const * filename)
 {
-	return (config_reset(handler) == 0
-			&& config_load(handler, filename) == 0
-			&& mimehandler_get_type(handler)
-				!= MIMEHANDLER_TYPE_UNKNOWN
-			&& mimehandler_get_name(handler) != NULL
-			&& mimehandler_is_hidden(handler) == 0)
-		? 0 : -1;
+	Config * config;
+	String * p;
+
+	if((config = config_new()) == NULL)
+		return -1;
+	if(config_load(config, filename) != 0
+			|| (p = string_new(filename)) == NULL)
+	{
+		config_delete(config);
+		return -1;
+	}
+	config_delete(handler->config);
+	handler->config = config;
+	string_delete(handler->filename);
+	handler->filename = p;
+	_mimehandler_cache_invalidate(handler);
+	return 0;
 }
 
 
@@ -397,3 +552,22 @@ static int _load_by_name_path(MimeHandler * handler, String const * name,
 	string_delete(filename);
 	return ret;
 }
+
+
+/* private */
+/* mimehandler_cache_invalidate */
+static void _mimehandler_cache_invalidate(MimeHandler * handler)
+{
+	size_t i;
+
+	if(handler->categories != NULL)
+		for(i = 0; handler->categories[i] != NULL; i++)
+			string_delete(handler->categories[i]);
+	free(handler->categories);
+	handler->categories = NULL;
+	if(handler->types != NULL)
+		for(i = 0; handler->types[i] != NULL; i++)
+			string_delete(handler->types[i]);
+	free(handler->types);
+	handler->types = NULL;
+}