Make a separate library.

This is required for gtkdoc-scangobj. So far it's much like it's been
before, the main differences are that source files are in two directories
from now on and the build process has two stages.

1 files changed, 808 insertions, 0 deletions

diff --git a/liblogdiag/ld-lua.c b/liblogdiag/ld-lua.c
new file mode 100644
index 0000000..47a41b5
--- /dev/null
+++ b/liblogdiag/ld-lua.c
@@ -0,0 +1,808 @@
+/*
+ * ld-lua.c
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2010 - 2011. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#include <lua.h>
+#include <lualib.h>
+#include <lauxlib.h>
+
+#include "liblogdiag.h"
+#include "config.h"
+
+#include "ld-lua-private.h"
+#include "ld-lua-symbol-private.h"
+
+
+/**
+ * SECTION:ld-lua
+ * @short_description: Lua symbol engine.
+ * @see_also: #LdLuaSymbol
+ *
+ * #LdLua is a symbol engine that uses Lua scripts to manage symbols.
+ */
+
+/*
+ * LdLuaPrivate:
+ * @L: Lua state.
+ *
+ * The library contains the real function for rendering.
+ */
+struct _LdLuaPrivate
+{
+	lua_State *L;
+};
+
+/* registry.logdiag_symbols
+ *   -> A table indexed by pointers to LdLuaSymbol objects
+ * registry.logdiag_symbols.object.render(cr)
+ *   -> The rendering function
+ */
+
+#define LD_LUA_LIBRARY_NAME "logdiag"
+#define LD_LUA_DATA_INDEX LD_LUA_LIBRARY_NAME "_data"
+#define LD_LUA_SYMBOLS_INDEX LD_LUA_LIBRARY_NAME "_symbols"
+
+/*
+ * LdLuaData:
+ * @self: A reference to self.
+ * @load_callback: A callback for newly registered symbols.
+ * @load_user_data: User data to be passed to the callback.
+ *
+ * Full user data to be stored in Lua registry.
+ */
+typedef struct _LdLuaData LdLuaData;
+
+struct _LdLuaData
+{
+	LdLua *self;
+	LdLuaLoadCallback load_callback;
+	gpointer load_user_data;
+};
+
+typedef struct _LdLuaDrawData LdLuaDrawData;
+
+struct _LdLuaDrawData
+{
+	LdLuaSymbol *symbol;
+	cairo_t *cr;
+	unsigned save_count;
+};
+
+static void ld_lua_finalize (GObject *gobject);
+
+static void *ld_lua_alloc (void *ud, void *ptr, size_t osize, size_t nsize);
+
+static int ld_lua_private_draw_cb (lua_State *L);
+static int ld_lua_private_unregister_cb (lua_State *L);
+
+static int ld_lua_logdiag_register (lua_State *L);
+static int process_registration (lua_State *L);
+static gchar *get_translation (lua_State *L, int index);
+static gboolean read_symbol_area (lua_State *L, int index, LdRectangle *area);
+static gboolean read_terminals (lua_State *L, int index,
+	LdPointArray **terminals);
+
+static void push_cairo_object (lua_State *L, LdLuaDrawData *draw_data);
+static gdouble get_cairo_scale (cairo_t *cr);
+static int ld_lua_cairo_save (lua_State *L);
+static int ld_lua_cairo_restore (lua_State *L);
+static int ld_lua_cairo_get_line_width (lua_State *L);
+static int ld_lua_cairo_set_line_width (lua_State *L);
+static int ld_lua_cairo_move_to (lua_State *L);
+static int ld_lua_cairo_line_to (lua_State *L);
+static int ld_lua_cairo_curve_to (lua_State *L);
+static int ld_lua_cairo_arc (lua_State *L);
+static int ld_lua_cairo_arc_negative (lua_State *L);
+static int ld_lua_cairo_new_path (lua_State *L);
+static int ld_lua_cairo_new_sub_path (lua_State *L);
+static int ld_lua_cairo_close_path (lua_State *L);
+static int ld_lua_cairo_stroke (lua_State *L);
+static int ld_lua_cairo_stroke_preserve (lua_State *L);
+static int ld_lua_cairo_fill (lua_State *L);
+static int ld_lua_cairo_fill_preserve (lua_State *L);
+static int ld_lua_cairo_clip (lua_State *L);
+static int ld_lua_cairo_clip_preserve (lua_State *L);
+
+
+static luaL_Reg ld_lua_logdiag_lib[] =
+{
+	{"register", ld_lua_logdiag_register},
+	{NULL, NULL}
+};
+
+static luaL_Reg ld_lua_cairo_table[] =
+{
+	{"save", ld_lua_cairo_save},
+	{"restore", ld_lua_cairo_restore},
+	{"get_line_width", ld_lua_cairo_get_line_width},
+	{"set_line_width", ld_lua_cairo_set_line_width},
+	{"move_to", ld_lua_cairo_move_to},
+	{"line_to", ld_lua_cairo_line_to},
+	{"curve_to", ld_lua_cairo_curve_to},
+	{"arc", ld_lua_cairo_arc},
+	{"arc_negative", ld_lua_cairo_arc_negative},
+	{"new_path", ld_lua_cairo_new_path},
+	{"new_sub_path", ld_lua_cairo_new_sub_path},
+	{"close_path", ld_lua_cairo_close_path},
+	{"stroke", ld_lua_cairo_stroke},
+	{"stroke_preserve", ld_lua_cairo_stroke_preserve},
+	{"fill", ld_lua_cairo_fill},
+	{"fill_preserve", ld_lua_cairo_fill_preserve},
+	{"clip", ld_lua_cairo_clip},
+	{"clip_preserve", ld_lua_cairo_clip_preserve},
+	{NULL, NULL}
+};
+
+
+/* ===== Generic =========================================================== */
+
+G_DEFINE_TYPE (LdLua, ld_lua, G_TYPE_OBJECT);
+
+static void
+ld_lua_class_init (LdLuaClass *klass)
+{
+	GObjectClass *object_class;
+
+	object_class = G_OBJECT_CLASS (klass);
+	object_class->finalize = ld_lua_finalize;
+
+	g_type_class_add_private (klass, sizeof (LdLuaPrivate));
+}
+
+static void
+ld_lua_init (LdLua *self)
+{
+	lua_State *L;
+	LdLuaData *ud;
+
+	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
+		(self, LD_TYPE_LUA, LdLuaPrivate);
+
+	L = self->priv->L = lua_newstate (ld_lua_alloc, NULL);
+	g_return_if_fail (L != NULL);
+
+	/* TODO: lua_atpanic () */
+
+	/* Load some safe libraries. */
+	lua_pushcfunction (L, luaopen_string);
+	lua_call (L, 0, 0);
+
+	lua_pushcfunction (L, luaopen_table);
+	lua_call (L, 0, 0);
+
+	lua_pushcfunction (L, luaopen_math);
+	lua_call (L, 0, 0);
+
+	/* Load the application library. */
+	luaL_register (L, LD_LUA_LIBRARY_NAME, ld_lua_logdiag_lib);
+
+	/* Store user data to the registry. */
+	ud = lua_newuserdata (L, sizeof (LdLuaData));
+	ud->self = self;
+	ud->load_callback = NULL;
+	ud->load_user_data = NULL;
+
+	lua_setfield (L, LUA_REGISTRYINDEX, LD_LUA_DATA_INDEX);
+
+	/* Create an empty symbol table. */
+	lua_newtable (L);
+	lua_setfield (L, LUA_REGISTRYINDEX, LD_LUA_SYMBOLS_INDEX);
+}
+
+static void
+ld_lua_finalize (GObject *gobject)
+{
+	LdLua *self;
+
+	self = LD_LUA (gobject);
+	lua_close (self->priv->L);
+
+	/* Chain up to the parent class. */
+	G_OBJECT_CLASS (ld_lua_parent_class)->finalize (gobject);
+}
+
+/**
+ * ld_lua_new:
+ *
+ * Create an instance of #LdLua.
+ */
+LdLua *
+ld_lua_new (void)
+{
+	return g_object_new (LD_TYPE_LUA, NULL);
+}
+
+static void *
+ld_lua_alloc (void *ud, void *ptr, size_t osize, size_t nsize)
+{
+	if (!nsize)
+	{
+		g_free (ptr);
+		return NULL;
+	}
+	else
+		return g_try_realloc (ptr, nsize);
+}
+
+/**
+ * ld_lua_check_file:
+ * @self: An #LdLua object.
+ * @filename: The file to be checked.
+ *
+ * Check if the given filename can be loaded by #LdLua.
+ */
+gboolean
+ld_lua_check_file (LdLua *self, const gchar *filename)
+{
+	g_return_val_if_fail (LD_IS_LUA (self), FALSE);
+	g_return_val_if_fail (filename != NULL, FALSE);
+
+	return g_str_has_suffix (filename, ".lua")
+		&& g_file_test (filename, G_FILE_TEST_IS_REGULAR);
+}
+
+/**
+ * ld_lua_load_file:
+ * @self: An #LdLua object.
+ * @filename: The file to be loaded.
+ * @callback: A callback for newly registered symbols.
+ * The callee is responsible for referencing the symbol.
+ * @user_data: User data to be passed to the callback.
+ *
+ * Loads a file and creates #LdLuaSymbol objects for contained symbols.
+ *
+ * Returns: TRUE if no error has occured, FALSE otherwise.
+ */
+gboolean
+ld_lua_load_file (LdLua *self, const gchar *filename,
+	LdLuaLoadCallback callback, gpointer user_data)
+{
+	gint retval;
+	LdLuaData *ud;
+
+	g_return_val_if_fail (LD_IS_LUA (self), FALSE);
+	g_return_val_if_fail (filename != NULL, FALSE);
+	g_return_val_if_fail (callback != NULL, FALSE);
+
+	/* XXX: If something from the following fails, Lua will call exit(). */
+	lua_getfield (self->priv->L, LUA_REGISTRYINDEX, LD_LUA_DATA_INDEX);
+	ud = lua_touserdata (self->priv->L, -1);
+	lua_pop (self->priv->L, 1);
+	g_return_val_if_fail (ud != NULL, FALSE);
+
+	ud->load_callback = callback;
+	ud->load_user_data = user_data;
+
+	retval = luaL_loadfile (self->priv->L, filename);
+	if (retval)
+		goto ld_lua_lftc_fail;
+
+	retval = lua_pcall (self->priv->L, 0, 0, 0);
+	if (retval)
+		goto ld_lua_lftc_fail;
+
+	ud->load_callback = NULL;
+	ud->load_user_data = NULL;
+	return TRUE;
+
+ld_lua_lftc_fail:
+	g_warning ("Lua error: %s", lua_tostring (self->priv->L, -1));
+	lua_remove (self->priv->L, -1);
+
+	ud->load_callback = NULL;
+	ud->load_user_data = NULL;
+	return FALSE;
+}
+
+/* ===== LdLuaSymbol callbacks ============================================= */
+
+/**
+ * ld_lua_private_draw:
+ * @self: An #LdLua object.
+ * @symbol: A symbol to be drawn.
+ * @cr: A Cairo context to be drawn onto.
+ *
+ * Draw a symbol onto a Cairo context.
+ */
+void
+ld_lua_private_draw (LdLua *self, LdLuaSymbol *symbol, cairo_t *cr)
+{
+	LdLuaDrawData data;
+
+	g_return_if_fail (LD_IS_LUA (self));
+	g_return_if_fail (LD_IS_LUA_SYMBOL (symbol));
+	g_return_if_fail (cr != NULL);
+
+	data.symbol = symbol;
+	data.cr = cr;
+	data.save_count = 0;
+
+	if (lua_cpcall (self->priv->L, ld_lua_private_draw_cb, &data))
+	{
+		g_warning ("Lua error: %s", lua_tostring (self->priv->L, -1));
+		lua_pop (self->priv->L, 1);
+	}
+
+	while (data.save_count--)
+		cairo_restore (cr);
+}
+
+static int
+ld_lua_private_draw_cb (lua_State *L)
+{
+	LdLuaDrawData *data;
+
+	data = lua_touserdata (L, -1);
+
+	/* Retrieve the function for rendering from the registry. */
+	lua_getfield (L, LUA_REGISTRYINDEX, LD_LUA_SYMBOLS_INDEX);
+	lua_pushlightuserdata (L, data->symbol);
+	lua_gettable (L, -2);
+
+	luaL_checktype (L, -1, LUA_TTABLE);
+	lua_getfield (L, -1, "render");
+	luaL_checktype (L, -1, LUA_TFUNCTION);
+
+	/* Call the function do draw the symbol. */
+	push_cairo_object (L, data);
+	lua_pcall (L, 1, 0, 0);
+	return 0;
+}
+
+/**
+ * ld_lua_private_unregister:
+ * @self: An #LdLua object.
+ * @symbol: A symbol to be unregistered.
+ *
+ * Unregister a symbol from the internal Lua state.
+ */
+void
+ld_lua_private_unregister (LdLua *self, LdLuaSymbol *symbol)
+{
+	g_return_if_fail (LD_IS_LUA (self));
+	g_return_if_fail (LD_IS_LUA_SYMBOL (symbol));
+
+	if (lua_cpcall (self->priv->L, ld_lua_private_unregister_cb, symbol))
+	{
+		g_warning ("Lua error: %s", lua_tostring (self->priv->L, -1));
+		lua_pop (self->priv->L, 1);
+	}
+}
+
+static int
+ld_lua_private_unregister_cb (lua_State *L)
+{
+	/* Set the entry in the symbol table to nil. */
+	lua_getfield (L, LUA_REGISTRYINDEX, LD_LUA_SYMBOLS_INDEX);
+	lua_insert (L, -2);
+	lua_pushnil (L);
+	lua_settable (L, -3);
+	return 0;
+}
+
+/* ===== Application library =============================================== */
+
+static int
+ld_lua_logdiag_register (lua_State *L)
+{
+	LdLuaData *ud;
+	LdLuaSymbol *symbol;
+
+	lua_getfield (L, LUA_REGISTRYINDEX, LD_LUA_DATA_INDEX);
+	ud = lua_touserdata (L, -1);
+	lua_pop (L, 1);
+	g_return_val_if_fail (ud != NULL, 0);
+
+	/* Use a protected environment, so script errors won't cause leaking
+	 * of the symbol object. Only a failure of the last three function calls
+	 * before lua_pcall() may cause the symbol to leak.
+	 */
+	lua_checkstack (L, 3);
+	symbol = g_object_new (LD_TYPE_LUA_SYMBOL, NULL);
+
+	lua_pushlightuserdata (L, symbol);
+	lua_pushcclosure (L, process_registration, 1);
+	lua_insert (L, 1);
+
+	/* On the stack, there are function arguments plus the function itself. */
+	if (lua_pcall (L, lua_gettop (L) - 1, 0, 0))
+	{
+		luaL_where (L, 1);
+		lua_insert (L, -2);
+		lua_concat (L, 2);
+
+		g_warning ("Lua symbol registration failed: %s",
+			lua_tostring (L, -1));
+		lua_pushboolean (L, FALSE);
+	}
+	else
+	{
+		/* We don't want an extra LdLua reference either. */
+		symbol->priv->lua = ud->self;
+		g_object_ref (ud->self);
+
+		ud->load_callback (LD_SYMBOL (symbol), ud->load_user_data);
+		lua_pushboolean (L, TRUE);
+	}
+	g_object_unref (symbol);
+
+	return 1;
+}
+
+/*
+ * process_registration:
+ * @L: A Lua state.
+ *
+ * Parse arguments, write them to a symbol object and register the object.
+ */
+static int
+process_registration (lua_State *L)
+{
+	LdLuaSymbol *symbol;
+	gchar *human_name;
+
+	int i, type, types[] =
+		{LUA_TSTRING, LUA_TTABLE, LUA_TTABLE, LUA_TTABLE, LUA_TFUNCTION};
+	int n_args_needed = sizeof (types) / sizeof (int);
+
+	if (lua_gettop (L) < n_args_needed)
+		return luaL_error (L, "Too few arguments.");
+
+	for (i = 0; i < n_args_needed; i++)
+		if ((type = lua_type (L, i + 1)) != types[i])
+			return luaL_error (L, "Bad type of argument #%d."
+				" Expected %s, got %s.", i + 1,
+				lua_typename (L, types[i]), lua_typename (L, type));
+
+	symbol = LD_LUA_SYMBOL (lua_touserdata (L, lua_upvalueindex (1)));
+	symbol->priv->name = g_strdup (lua_tostring (L, 1));
+
+	human_name = get_translation (L, 2);
+	if (!human_name)
+		human_name = g_strdup (symbol->priv->name);
+	symbol->priv->human_name = human_name;
+
+	if (!read_symbol_area (L, 3, &symbol->priv->area))
+		return luaL_error (L, "Malformed symbol area array.");
+	if (!read_terminals (L, 4, &symbol->priv->terminals))
+		return luaL_error (L, "Malformed terminals array.");
+
+	lua_getfield (L, LUA_REGISTRYINDEX, LD_LUA_SYMBOLS_INDEX);
+	lua_pushlightuserdata (L, symbol);
+
+	lua_newtable (L);
+	lua_pushvalue (L, 5);
+	lua_setfield (L, -2, "render");
+
+	lua_settable (L, -3);
+	return 0;
+}
+
+/*
+ * get_translation:
+ * @L: A Lua state.
+ * @index: Stack index of the table.
+ *
+ * Select an applicable translation from a table.
+ * The return value has to be freed with g_free().
+ *
+ * Return value: The translation, if found. If none was found, returns NULL.
+ */
+static gchar *
+get_translation (lua_State *L, int index)
+{
+	const gchar *const *lang;
+	gchar *result;
+
+	for (lang = g_get_language_names (); *lang; lang++)
+	{
+		lua_getfield (L, 2, *lang);
+		if (lua_isstring (L, -1))
+		{
+			result = g_strdup (lua_tostring (L, -1));
+			lua_pop (L, 1);
+			return result;
+		}
+		lua_pop (L, 1);
+	}
+	return NULL;
+}
+
+/*
+ * read_symbol_area:
+ * @L: A Lua state.
+ * @index: Stack index of the table.
+ * @area: Where the area will be returned.
+ *
+ * Read a symbol area from a Lua table.
+ *
+ * Return value: TRUE on success, FALSE on failure.
+ */
+static gboolean
+read_symbol_area (lua_State *L, int index, LdRectangle *area)
+{
+	lua_Number x1, x2, y1, y2;
+
+	if (lua_objlen (L, index) != 4)
+		return FALSE;
+
+	lua_rawgeti (L, index, 1);
+	if (!lua_isnumber (L, -1))
+		return FALSE;
+	x1 = lua_tonumber (L, -1);
+
+	lua_rawgeti (L, index, 2);
+	if (!lua_isnumber (L, -1))
+		return FALSE;
+	y1 = lua_tonumber (L, -1);
+
+	lua_rawgeti (L, index, 3);
+	if (!lua_isnumber (L, -1))
+		return FALSE;
+	x2 = lua_tonumber (L, -1);
+
+	lua_rawgeti (L, index, 4);
+	if (!lua_isnumber (L, -1))
+		return FALSE;
+	y2 = lua_tonumber (L, -1);
+
+	area->x = MIN (x1, x2);
+	area->y = MIN (y1, y2);
+	area->width = ABS (x2 - x1);
+	area->height = ABS (y2 - y1);
+
+	lua_pop (L, 4);
+	return TRUE;
+}
+
+/*
+ * read_terminals:
+ * @L: A Lua state.
+ * @index: Stack index of the table.
+ * @area: Where the point array will be returned.
+ *
+ * Read symbol terminals from a Lua table.
+ *
+ * Return value: TRUE on success, FALSE on failure.
+ */
+static gboolean
+read_terminals (lua_State *L, int index, LdPointArray **terminals)
+{
+	LdPointArray *points;
+	size_t num_points;
+	unsigned i = 0;
+
+	num_points = lua_objlen (L, index);
+	points = ld_point_array_new (num_points);
+
+	lua_pushnil (L);
+	while (lua_next (L, index) != 0)
+	{
+		g_assert (i < num_points);
+
+		if (!lua_istable (L, -1) || lua_objlen (L, -1) != 2)
+			goto read_terminals_fail;
+
+		lua_rawgeti (L, -1, 1);
+		if (!lua_isnumber (L, -1))
+			goto read_terminals_fail;
+		points->points[i].x = lua_tonumber (L, -1);
+		lua_pop (L, 1);
+
+		lua_rawgeti (L, -1, 2);
+		if (!lua_isnumber (L, -1))
+			goto read_terminals_fail;
+		points->points[i].y = lua_tonumber (L, -1);
+
+		lua_pop (L, 2);
+		i++;
+	}
+	*terminals = points;
+	return TRUE;
+
+read_terminals_fail:
+	ld_point_array_free (points);
+	*terminals = NULL;
+	return FALSE;
+}
+
+
+/* ===== Cairo ============================================================= */
+
+static void
+push_cairo_object (lua_State *L, LdLuaDrawData *draw_data)
+{
+	luaL_Reg *fn;
+
+	/* Create a table. */
+	lua_newtable (L);
+
+	/* Add methods. */
+	/* XXX: The light user data pointer gets invalid after the end of
+	 *      "render" function invocation. If the script stores the "cr" object
+	 *      in some global variable and then tries to reuse it the next time,
+	 *      the application may go SIGSEGV.
+	 *
+	 *      The solution is creating a full user data instead, referencing
+	 *      the cairo object and dereferencing it upon garbage collection
+	 *      of the user data object.
+	 */
+	for (fn = ld_lua_cairo_table; fn->name; fn++)
+	{
+		lua_pushlightuserdata (L, draw_data);
+		lua_pushcclosure (L, fn->func, 1);
+		lua_setfield (L, -2, fn->name);
+	}
+}
+
+static gdouble
+get_cairo_scale (cairo_t *cr)
+{
+	double dx = 1, dy = 0;
+
+	cairo_user_to_device_distance (cr, &dx, &dy);
+	return dx;
+}
+
+#define LD_LUA_CAIRO_TRIVIAL(name) \
+static int \
+ld_lua_cairo_ ## name (lua_State *L) \
+{ \
+	LdLuaDrawData *data; \
+	data = lua_touserdata (L, lua_upvalueindex (1)); \
+	cairo_ ## name (data->cr); \
+	return 0; \
+}
+
+LD_LUA_CAIRO_TRIVIAL (new_path)
+LD_LUA_CAIRO_TRIVIAL (new_sub_path)
+LD_LUA_CAIRO_TRIVIAL (close_path)
+
+LD_LUA_CAIRO_TRIVIAL (stroke)
+LD_LUA_CAIRO_TRIVIAL (stroke_preserve)
+LD_LUA_CAIRO_TRIVIAL (fill)
+LD_LUA_CAIRO_TRIVIAL (fill_preserve)
+LD_LUA_CAIRO_TRIVIAL (clip)
+LD_LUA_CAIRO_TRIVIAL (clip_preserve)
+
+static int
+ld_lua_cairo_save (lua_State *L)
+{
+	LdLuaDrawData *data;
+
+	data = lua_touserdata (L, lua_upvalueindex (1));
+	if (data->save_count + 1)
+	{
+		data->save_count++;
+		cairo_save (data->cr);
+	}
+	return 0;
+}
+
+static int
+ld_lua_cairo_restore (lua_State *L)
+{
+	LdLuaDrawData *data;
+
+	data = lua_touserdata (L, lua_upvalueindex (1));
+	if (data->save_count)
+	{
+		data->save_count--;
+		cairo_restore (data->cr);
+	}
+	return 0;
+}
+
+static int
+ld_lua_cairo_get_line_width (lua_State *L)
+{
+	LdLuaDrawData *data;
+
+	data = lua_touserdata (L, lua_upvalueindex (1));
+	lua_pushnumber (L, cairo_get_line_width (data->cr)
+		* get_cairo_scale (data->cr));
+	return 1;
+}
+
+static int
+ld_lua_cairo_set_line_width (lua_State *L)
+{
+	LdLuaDrawData *data;
+
+	data = lua_touserdata (L, lua_upvalueindex (1));
+	cairo_set_line_width (data->cr, luaL_checknumber (L, 1)
+		/ get_cairo_scale (data->cr));
+	return 0;
+}
+
+static int
+ld_lua_cairo_move_to (lua_State *L)
+{
+	LdLuaDrawData *data;
+	lua_Number x, y;
+
+	data = lua_touserdata (L, lua_upvalueindex (1));
+
+	x = luaL_checknumber (L, 1);
+	y = luaL_checknumber (L, 2);
+
+	cairo_move_to (data->cr, x, y);
+	return 0;
+}
+
+static int
+ld_lua_cairo_line_to (lua_State *L)
+{
+	LdLuaDrawData *data;
+	lua_Number x, y;
+
+	data = lua_touserdata (L, lua_upvalueindex (1));
+
+	x = luaL_checknumber (L, 1);
+	y = luaL_checknumber (L, 2);
+
+	cairo_line_to (data->cr, x, y);
+	return 0;
+}
+
+static int
+ld_lua_cairo_curve_to (lua_State *L)
+{
+	LdLuaDrawData *data;
+	lua_Number x1, y1, x2, y2, x3, y3;
+
+	data = lua_touserdata (L, lua_upvalueindex (1));
+
+	x1 = luaL_checknumber (L, 1);
+	y1 = luaL_checknumber (L, 2);
+	x2 = luaL_checknumber (L, 3);
+	y2 = luaL_checknumber (L, 4);
+	x3 = luaL_checknumber (L, 5);
+	y3 = luaL_checknumber (L, 6);
+
+	cairo_curve_to (data->cr, x1, y1, x2, y2, x3, y3);
+	return 0;
+}
+
+static int
+ld_lua_cairo_arc (lua_State *L)
+{
+	LdLuaDrawData *data;
+	lua_Number xc, yc, radius, angle1, angle2;
+
+	data = lua_touserdata (L, lua_upvalueindex (1));
+
+	xc = luaL_checknumber (L, 1);
+	yc = luaL_checknumber (L, 2);
+	radius = luaL_checknumber (L, 3);
+	angle1 = luaL_checknumber (L, 4);
+	angle2 = luaL_checknumber (L, 5);
+
+	cairo_arc (data->cr, xc, yc, radius, angle1, angle2);
+	return 0;
+}
+
+static int
+ld_lua_cairo_arc_negative (lua_State *L)
+{
+	LdLuaDrawData *data;
+	lua_Number xc, yc, radius, angle1, angle2;
+
+	data = lua_touserdata (L, lua_upvalueindex (1));
+
+	xc = luaL_checknumber (L, 1);
+	yc = luaL_checknumber (L, 2);
+	radius = luaL_checknumber (L, 3);
+	angle1 = luaL_checknumber (L, 4);
+	angle2 = luaL_checknumber (L, 5);
+
+	cairo_arc_negative (data->cr, xc, yc, radius, angle1, angle2);
+	return 0;
+}
+