logdiag/src/ld-lua.c

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/*
* ld-lua.c
*
* This file is a part of logdiag.
* Copyright Přemysl Janouch 2010. All rights reserved.
*
* See the file LICENSE for licensing information.
*
*/
#include <gtk/gtk.h>
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
#include "config.h"
#include "ld-symbol.h"
#include "ld-library.h"
#include "ld-lua.h"
#include "ld-lua-symbol.h"
#include "ld-lua-private.h"
#include "ld-lua-symbol-private.h"
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/**
* SECTION:ld-lua
* @short_description: Lua symbol engine.
* @see_also: #LdLuaSymbol
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*
* #LdLua is a symbol engine that uses Lua scripts to manage symbols.
*/
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/*
* LdLuaPrivate:
* @L: Lua state.
*
* The library contains the real function for rendering.
*/
struct _LdLuaPrivate
{
lua_State *L;
};
/* registry.logdiag_symbols
* -> table indexed by pointers to LdLuaSymbol objects
* registry.logdiag_symbols.object.render(cr)
* -> 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"
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/*
* 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;
};
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);
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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, LdSymbolArea *area);
static void push_cairo_object (lua_State *L, cairo_t *cr);
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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_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 luaL_Reg ld_lua_logdiag_lib[] =
{
{"register", ld_lua_logdiag_register},
{NULL, NULL}
};
static luaL_Reg ld_lua_cairo_table[] =
{
{"move_to", ld_lua_cairo_move_to},
{"line_to", ld_lua_cairo_line_to},
{"stroke", ld_lua_cairo_stroke},
{"stroke_preserve", ld_lua_cairo_stroke_preserve},
{"fill", ld_lua_cairo_fill},
{"fill_preserve", ld_lua_cairo_fill_preserve},
{NULL, NULL}
};
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/* ===== Generic =========================================================== */
G_DEFINE_TYPE (LdLua, ld_lua, G_TYPE_OBJECT);
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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;
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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 symbols table. */
lua_newtable (L);
lua_setfield (L, LUA_REGISTRYINDEX, LD_LUA_SYMBOLS_INDEX);
}
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static void
ld_lua_finalize (GObject *gobject)
{
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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.
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*/
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;
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);
}
}
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->cr);
lua_pcall (L, 1, 0, 0);
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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);
symbol = g_object_new (LD_TYPE_LUA_SYMBOL, NULL);
/* Use a protected environment, so script errors won't cause leaking
* of the symbol object. Only the failure of one of the following three
* function calls may cause the symbol to leak.
*/
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)
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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.");
/* TODO: Read and set the terminals. */
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);
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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, LdSymbolArea *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);
return TRUE;
}
/* ===== Cairo ============================================================= */
static void
push_cairo_object (lua_State *L, cairo_t *cr)
{
luaL_Reg *fn;
/* Create a table. */
lua_newtable (L);
/* Add methods. */
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/* 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 will go SIGSEGV.
*/
for (fn = ld_lua_cairo_table; fn->name; fn++)
{
lua_pushlightuserdata (L, cr);
lua_pushcclosure (L, fn->func, 1);
lua_setfield (L, -2, fn->name);
}
}
/* TODO: More functions. Possibly put it into another file
* and generate it automatically.
*/
static int
ld_lua_cairo_move_to (lua_State *L)
{
cairo_t *cr;
lua_Number x, y;
cr = lua_touserdata (L, lua_upvalueindex (1));
x = luaL_checknumber (L, 1);
y = luaL_checknumber (L, 2);
cairo_move_to (cr, x, y);
return 0;
}
static int
ld_lua_cairo_line_to (lua_State *L)
{
cairo_t *cr;
lua_Number x, y;
cr = lua_touserdata (L, lua_upvalueindex (1));
x = luaL_checknumber (L, 1);
y = luaL_checknumber (L, 2);
cairo_line_to (cr, x, y);
return 0;
}
static int
ld_lua_cairo_stroke (lua_State *L)
{
cairo_t *cr;
cr = lua_touserdata (L, lua_upvalueindex (1));
cairo_stroke (cr);
return 0;
}
static int
ld_lua_cairo_stroke_preserve (lua_State *L)
{
cairo_t *cr;
cr = lua_touserdata (L, lua_upvalueindex (1));
cairo_stroke_preserve (cr);
return 0;
}
static int
ld_lua_cairo_fill (lua_State *L)
{
cairo_t *cr;
cr = lua_touserdata (L, lua_upvalueindex (1));
cairo_fill (cr);
return 0;
}
static int
ld_lua_cairo_fill_preserve (lua_State *L)
{
cairo_t *cr;
cr = lua_touserdata (L, lua_upvalueindex (1));
cairo_fill_preserve (cr);
return 0;
}