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Change how Cairo is presented to Lua scripts.

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Makes the whole thing a bit more stable and less weird.
This commit is contained in:
Přemysl Eric Janouch
2012-08-12 06:10:27 +02:00
parent 9366c42026
commit a1b79a55d2
20 changed files with 385 additions and 374 deletions
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185
liblogdiag/ld-lua.c
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@@ -2,7 +2,7 @@
* ld-lua.c
*
* This file is a part of logdiag.
* Copyright Přemysl Janouch 2010 - 2011. All rights reserved.
* Copyright Přemysl Janouch 2010, 2011, 2012. All rights reserved.
*
* See the file LICENSE for licensing information.
*
@@ -44,9 +44,10 @@ struct _LdLuaPrivate
* -> 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"
#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"
#define LD_LUA_META_INDEX LD_LUA_LIBRARY_NAME "_meta"
/*
* LdLuaData:
@@ -88,7 +89,6 @@ 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);
@@ -163,6 +163,24 @@ ld_lua_class_init (LdLuaClass *klass)
g_type_class_add_private (klass, sizeof (LdLuaPrivate));
}
static void
push_cairo_metatable (lua_State *L)
{
luaL_Reg *fn;
luaL_newmetatable (L, LD_LUA_META_INDEX);
/* Create a method table. */
lua_newtable (L);
for (fn = ld_lua_cairo_table; fn->name; fn++)
{
lua_pushcfunction (L, fn->func);
lua_setfield (L, -2, fn->name);
}
lua_setfield (L, -2, "__index");
}
static void
ld_lua_init (LdLua *self)
{
@@ -175,7 +193,7 @@ ld_lua_init (LdLua *self)
L = self->priv->L = lua_newstate (ld_lua_alloc, NULL);
g_return_if_fail (L != NULL);
/* TODO: lua_atpanic () */
/* XXX: Might not be a bad idea to use lua_atpanic(). */
/* Load some safe libraries. */
lua_pushcfunction (L, luaopen_string);
@@ -191,7 +209,7 @@ ld_lua_init (LdLua *self)
luaL_register (L, LD_LUA_LIBRARY_NAME, ld_lua_logdiag_lib);
/* Store user data to the registry. */
ud = lua_newuserdata (L, sizeof (LdLuaData));
ud = lua_newuserdata (L, sizeof *ud);
ud->self = self;
ud->load_callback = NULL;
ud->load_user_data = NULL;
@@ -201,6 +219,8 @@ ld_lua_init (LdLua *self)
/* Create an empty symbol table. */
lua_newtable (L);
lua_setfield (L, LUA_REGISTRYINDEX, LD_LUA_SYMBOLS_INDEX);
push_cairo_metatable (L);
}
static void
@@ -278,7 +298,7 @@ ld_lua_load_file (LdLua *self, const gchar *filename,
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(). */
/* XXX: If something from the following fails, Lua will panic. */
lua_getfield (self->priv->L, LUA_REGISTRYINDEX, LD_LUA_DATA_INDEX);
ud = lua_touserdata (self->priv->L, -1);
lua_pop (self->priv->L, 1);
@@ -344,7 +364,7 @@ ld_lua_private_draw (LdLua *self, LdLuaSymbol *symbol, cairo_t *cr)
static int
ld_lua_private_draw_cb (lua_State *L)
{
LdLuaDrawData *data;
LdLuaDrawData *data, *luadata;
data = lua_touserdata (L, -1);
@@ -357,9 +377,28 @@ ld_lua_private_draw_cb (lua_State *L)
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);
/* Create a Cairo wrapper object. */
luadata = lua_newuserdata (L, sizeof *data);
memcpy (luadata, data, sizeof *data);
lua_getfield (L, LUA_REGISTRYINDEX, LD_LUA_META_INDEX);
lua_setmetatable (L, -2);
/* Force it to stay alive for a bit longer. */
lua_pushvalue (L, -1);
lua_insert (L, 1);
/* Draw the symbol. */
if (lua_pcall (L, 1, 0, 0))
{
g_warning ("Lua error: %s", lua_tostring (L, -1));
lua_pop (L, 1);
}
/* Copy the userdata back and invalidate it, so that malicious Lua
* scripts won't succeed at drawing onto a long invalid Cairo context.
*/
memcpy (data, luadata, sizeof *data);
memset (luadata, 0, sizeof *data);
return 0;
}
@@ -562,7 +601,7 @@ read_symbol_area (lua_State *L, int index, LdRectangle *area)
area->x = MIN (x1, x2);
area->y = MIN (y1, y2);
area->width = ABS (x2 - x1);
area->width = ABS (x2 - x1);
area->height = ABS (y2 - y1);
lua_pop (L, 4);
@@ -622,32 +661,6 @@ read_terminals_fail:
/* ===== 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)
{
@@ -657,6 +670,11 @@ get_cairo_scale (cairo_t *cr)
return dx;
}
#define LD_LUA_CAIRO_GET_DATA \
data = luaL_checkudata (L, 1, LD_LUA_META_INDEX); \
if (!data->cr) \
return luaL_error (L, "Tried to use an invalid Cairo object");
#define LD_LUA_CAIRO_BEGIN(name) \
static int \
ld_lua_cairo_ ## name (lua_State *L) \
@@ -669,7 +687,7 @@ ld_lua_cairo_ ## name (lua_State *L) \
#define LD_LUA_CAIRO_TRIVIAL(name) \
LD_LUA_CAIRO_BEGIN (name) \
data = lua_touserdata (L, lua_upvalueindex (1)); \
LD_LUA_CAIRO_GET_DATA \
cairo_ ## name (data->cr); \
LD_LUA_CAIRO_END (0)
@@ -685,7 +703,7 @@ LD_LUA_CAIRO_TRIVIAL (clip)
LD_LUA_CAIRO_TRIVIAL (clip_preserve)
LD_LUA_CAIRO_BEGIN (save)
data = lua_touserdata (L, lua_upvalueindex (1));
LD_LUA_CAIRO_GET_DATA
if (data->save_count + 1)
{
data->save_count++;
@@ -694,7 +712,7 @@ LD_LUA_CAIRO_BEGIN (save)
LD_LUA_CAIRO_END (0)
LD_LUA_CAIRO_BEGIN (restore)
data = lua_touserdata (L, lua_upvalueindex (1));
LD_LUA_CAIRO_GET_DATA
if (data->save_count)
{
data->save_count--;
@@ -703,24 +721,23 @@ LD_LUA_CAIRO_BEGIN (restore)
LD_LUA_CAIRO_END (0)
LD_LUA_CAIRO_BEGIN (get_line_width)
data = lua_touserdata (L, lua_upvalueindex (1));
LD_LUA_CAIRO_GET_DATA
lua_pushnumber (L, cairo_get_line_width (data->cr)
* get_cairo_scale (data->cr));
LD_LUA_CAIRO_END (1)
LD_LUA_CAIRO_BEGIN (set_line_width)
data = lua_touserdata (L, lua_upvalueindex (1));
cairo_set_line_width (data->cr, luaL_checknumber (L, 1)
LD_LUA_CAIRO_GET_DATA
cairo_set_line_width (data->cr, luaL_checknumber (L, 2)
/ get_cairo_scale (data->cr));
LD_LUA_CAIRO_END (0)
LD_LUA_CAIRO_BEGIN (translate)
lua_Number x, y;
data = lua_touserdata (L, lua_upvalueindex (1));
x = luaL_checknumber (L, 1);
y = luaL_checknumber (L, 2);
LD_LUA_CAIRO_GET_DATA
x = luaL_checknumber (L, 2);
y = luaL_checknumber (L, 3);
cairo_translate (data->cr, x, y);
LD_LUA_CAIRO_END (0)
@@ -728,10 +745,9 @@ LD_LUA_CAIRO_END (0)
LD_LUA_CAIRO_BEGIN (scale)
lua_Number sx, sy;
data = lua_touserdata (L, lua_upvalueindex (1));
sx = luaL_checknumber (L, 1);
sy = luaL_checknumber (L, 2);
LD_LUA_CAIRO_GET_DATA
sx = luaL_checknumber (L, 2);
sy = luaL_checknumber (L, 3);
cairo_scale (data->cr, sx, sy);
LD_LUA_CAIRO_END (0)
@@ -739,18 +755,17 @@ LD_LUA_CAIRO_END (0)
LD_LUA_CAIRO_BEGIN (rotate)
lua_Number angle;
data = lua_touserdata (L, lua_upvalueindex (1));
angle = luaL_checknumber (L, 1);
LD_LUA_CAIRO_GET_DATA
angle = luaL_checknumber (L, 2);
cairo_rotate (data->cr, angle);
LD_LUA_CAIRO_END (0)
LD_LUA_CAIRO_BEGIN (move_to)
lua_Number x, y;
data = lua_touserdata (L, lua_upvalueindex (1));
x = luaL_checknumber (L, 1);
y = luaL_checknumber (L, 2);
LD_LUA_CAIRO_GET_DATA
x = luaL_checknumber (L, 2);
y = luaL_checknumber (L, 3);
cairo_move_to (data->cr, x, y);
LD_LUA_CAIRO_END (0)
@@ -758,10 +773,9 @@ LD_LUA_CAIRO_END (0)
LD_LUA_CAIRO_BEGIN (line_to)
lua_Number x, y;
data = lua_touserdata (L, lua_upvalueindex (1));
x = luaL_checknumber (L, 1);
y = luaL_checknumber (L, 2);
LD_LUA_CAIRO_GET_DATA
x = luaL_checknumber (L, 2);
y = luaL_checknumber (L, 3);
cairo_line_to (data->cr, x, y);
LD_LUA_CAIRO_END (0)
@@ -769,14 +783,13 @@ LD_LUA_CAIRO_END (0)
LD_LUA_CAIRO_BEGIN (curve_to)
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);
LD_LUA_CAIRO_GET_DATA
x1 = luaL_checknumber (L, 2);
y1 = luaL_checknumber (L, 3);
x2 = luaL_checknumber (L, 4);
y2 = luaL_checknumber (L, 5);
x3 = luaL_checknumber (L, 6);
y3 = luaL_checknumber (L, 7);
cairo_curve_to (data->cr, x1, y1, x2, y2, x3, y3);
LD_LUA_CAIRO_END (0)
@@ -784,13 +797,12 @@ LD_LUA_CAIRO_END (0)
LD_LUA_CAIRO_BEGIN (arc)
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);
LD_LUA_CAIRO_GET_DATA
xc = luaL_checknumber (L, 2);
yc = luaL_checknumber (L, 3);
radius = luaL_checknumber (L, 4);
angle1 = luaL_checknumber (L, 5);
angle2 = luaL_checknumber (L, 6);
cairo_arc (data->cr, xc, yc, radius, angle1, angle2);
LD_LUA_CAIRO_END (0)
@@ -798,13 +810,12 @@ LD_LUA_CAIRO_END (0)
LD_LUA_CAIRO_BEGIN (arc_negative)
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);
LD_LUA_CAIRO_GET_DATA
xc = luaL_checknumber (L, 2);
yc = luaL_checknumber (L, 3);
radius = luaL_checknumber (L, 4);
angle1 = luaL_checknumber (L, 5);
angle2 = luaL_checknumber (L, 6);
cairo_arc_negative (data->cr, xc, yc, radius, angle1, angle2);
LD_LUA_CAIRO_END (0)
@@ -816,8 +827,8 @@ LD_LUA_CAIRO_BEGIN (show_text)
int width, height;
double x, y;
data = lua_touserdata (L, lua_upvalueindex (1));
text = luaL_checkstring (L, 1);
LD_LUA_CAIRO_GET_DATA
text = luaL_checkstring (L, 2);
layout = pango_cairo_create_layout (data->cr);
pango_layout_set_text (layout, text, -1);