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Add field highlighting using Lua plugins

This commit is contained in:
Přemysl Eric Janouch 2017-01-17 14:45:10 +01:00
parent 101c58a136
commit bf7eae8bf6
Signed by: p
GPG Key ID: B715679E3A361BE6
1 changed files with 547 additions and 0 deletions
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hex.c
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@ -68,6 +68,14 @@ enum
#include "tui.c"
#include "termo.h"
#ifdef HAVE_LUA
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
#include <dirent.h>
#endif // HAVE_LUA
#define APP_TITLE PROGRAM_NAME ///< Left top corner
// --- Utilities ---------------------------------------------------------------
@ -157,6 +165,12 @@ static struct app_context
struct poller_fd tty_event; ///< Terminal input event
struct poller_fd signal_event; ///< Signal FD event
#ifdef HAVE_LUA
lua_State *L; ///< Lua state
int ref_format; ///< Reference to "string.format"
struct str_map coders; ///< Map of coders by name
#endif // HAVE_LUA
// Data:
char *message; ///< Last logged message
@ -777,6 +791,492 @@ app_on_refresh (void *user_data)
refresh ();
}
// --- Lua ---------------------------------------------------------------------
#ifdef HAVE_LUA
static void *
app_lua_alloc (void *ud, void *ptr, size_t o_size, size_t n_size)
{
(void) ud;
(void) o_size;
if (n_size)
return realloc (ptr, n_size);
free (ptr);
return NULL;
}
static int
app_lua_panic (lua_State *L)
{
// XXX: we might be able to do something better
print_fatal ("Lua panicked: %s", lua_tostring (L, -1));
lua_close (L);
exit (EXIT_FAILURE);
return 0;
}
static bool
app_lua_getfield (lua_State *L, int idx, const char *name,
int expected, bool optional)
{
int found = lua_getfield (L, idx, name);
if (found == expected)
return true;
if (optional && found == LUA_TNIL)
return false;
const char *message = optional
? "invalid field \"%s\" (found: %s, expected: %s or nil)"
: "invalid or missing field \"%s\" (found: %s, expected: %s)";
return luaL_error (L, message, name,
lua_typename (L, found), lua_typename (L, expected));
}
static int
app_lua_error_handler (lua_State *L)
{
luaL_traceback (L, L, luaL_checkstring (L, 1), 1);
return 1;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
struct app_lua_coder
{
int ref_detect; ///< Reference to the "detect" method
int ref_decode; ///< Reference to the "decode" method
};
static void
app_lua_coder_free (void *coder)
{
struct app_lua_coder *self = coder;
luaL_unref (g_ctx.L, LUA_REGISTRYINDEX, self->ref_decode);
luaL_unref (g_ctx.L, LUA_REGISTRYINDEX, self->ref_detect);
}
static int
app_lua_register (lua_State *L)
{
luaL_checktype (L, 1, LUA_TTABLE);
(void) app_lua_getfield (L, 1, "type", LUA_TSTRING, false);
const char *type = lua_tostring (L, -1);
if (str_map_find (&g_ctx.coders, type))
luaL_error (L, "a coder has already been registered for `%s'", type);
(void) app_lua_getfield (L, 1, "detect", LUA_TFUNCTION, true);
(void) app_lua_getfield (L, 1, "decode", LUA_TFUNCTION, false);
struct app_lua_coder *coder = xcalloc (1, sizeof *coder);
coder->ref_decode = luaL_ref (L, LUA_REGISTRYINDEX);
coder->ref_detect = luaL_ref (L, LUA_REGISTRYINDEX);
str_map_set (&g_ctx.coders, type, coder);
return 0;
}
static luaL_Reg app_lua_library[] =
{
{ "register", app_lua_register },
{ NULL, NULL }
};
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
#define XLUA_CHUNK_METATABLE "chunk"
struct app_lua_chunk
{
int64_t offset; ///< Offset from start of file
int64_t len; ///< Length of the sequence
int64_t position; ///< Read position in the sequence
enum endianity endianity; ///< Read endianity
};
static struct app_lua_chunk *
app_lua_chunk_new (lua_State *L)
{
struct app_lua_chunk *chunk = lua_newuserdata (L, sizeof *chunk);
luaL_setmetatable (L, XLUA_CHUNK_METATABLE);
memset (chunk, 0, sizeof *chunk);
return chunk;
}
static int
app_lua_chunk_len (lua_State *L)
{
struct app_lua_chunk *self = luaL_checkudata (L, 1, XLUA_CHUNK_METATABLE);
lua_pushinteger (L, self->len);
return 0;
}
/// Create a new subchunk following Lua's string.sub() semantics.
/// An implication is that it is not possible to go extend a chunk's bounds.
static int
app_lua_chunk_call (lua_State *L)
{
struct app_lua_chunk *self = luaL_checkudata (L, 1, XLUA_CHUNK_METATABLE);
lua_Integer start = luaL_optinteger (L, 2, 1);
lua_Integer end = luaL_optinteger (L, 3, -1);
if (start < 0) start += self->len + 1;
if (end < 0) end += self->len + 1;
start = MAX (start, 1);
end = MIN (end, self->len);
struct app_lua_chunk *clone = app_lua_chunk_new (L);
clone->position = 0;
clone->endianity = self->endianity;
if (start > end)
{
// "start" can be too high and "end" can be too low;
// the length is zero, so the offset doesn't matter much anyway
clone->offset = self->offset;
clone->len = 0;
}
else
{
clone->offset = self->offset + start - 1;
clone->len = end - start + 1;
}
return 1;
}
static int
app_lua_chunk_index (lua_State *L)
{
struct app_lua_chunk *self = luaL_checkudata (L, 1, XLUA_CHUNK_METATABLE);
const char *key = luaL_checkstring (L, 2);
if (luaL_getmetafield (L, 1, key))
return 1;
if (!strcmp (key, "offset"))
lua_pushinteger (L, self->offset);
else if (!strcmp (key, "endianity"))
lua_pushstring (L, self->endianity == ENDIANITY_LE ? "le" : "be");
else if (!strcmp (key, "position"))
lua_pushinteger (L, self->position + 1);
else if (!strcmp (key, "eof"))
lua_pushboolean (L, self->position >= self->len);
else
return luaL_argerror (L, 2, "not a readable property");
return 1;
}
static int
app_lua_chunk_newindex (lua_State *L)
{
struct app_lua_chunk *self = luaL_checkudata (L, 1, XLUA_CHUNK_METATABLE);
const char *key = luaL_checkstring (L, 2);
if (!strcmp (key, "endianity"))
{
// Needs to be in the enum order
const char *options[] = { "le", "be" };
self->endianity = luaL_checkoption (L, 3, options[0], options);
}
else if (!strcmp (key, "position"))
{
lua_Integer position = luaL_checkinteger (L, 3) - 1;
if (position < 1 || position > self->len + 1)
return luaL_error (L, "position out of range: %" PRId64, position);
self->position = position - 1;
}
else
return luaL_argerror (L, 2, "not a writable property");
return 0;
}
static void
app_lua_mark (int64_t offset, int64_t len, const char *desc)
{
ARRAY_RESERVE (g_ctx.marks, 1);
g_ctx.marks[g_ctx.marks_len++] =
(struct mark) { offset, len, g_ctx.mark_strings.len };
str_append (&g_ctx.mark_strings, desc);
str_append_c (&g_ctx.mark_strings, 0);
}
static int
app_lua_chunk_mark (lua_State *L)
{
struct app_lua_chunk *self = luaL_checkudata (L, 1, XLUA_CHUNK_METATABLE);
app_lua_mark (self->offset, self->len, luaL_checkstring (L, 2));
return 0;
}
/// Try to detect any registered type in the data and return its name
static int
app_lua_chunk_identify (lua_State *L)
{
(void) luaL_checkudata (L, 1, XLUA_CHUNK_METATABLE);
struct str_map_iter iter;
str_map_iter_init (&iter, &g_ctx.coders);
struct app_lua_coder *coder;
while ((coder = str_map_iter_next (&iter)))
{
lua_rawgeti (L, LUA_REGISTRYINDEX, coder->ref_detect);
// Clone the chunk first to reset its read position
lua_pushcfunction (L, app_lua_chunk_call);
lua_pushvalue (L, 1);
lua_call (L, 1, 1);
lua_call (L, 1, 1);
if (lua_toboolean (L, -1))
{
lua_pushstring (L, iter.link->key);
return 1;
}
lua_pop (L, 1);
}
return 0;
}
static int
app_lua_chunk_decode (lua_State *L)
{
(void) luaL_checkudata (L, 1, XLUA_CHUNK_METATABLE);
const char *type = luaL_optstring (L, 2, NULL);
// TODO: further arguments should be passed to the decoding function
if (!type)
{
lua_pushcfunction (L, app_lua_chunk_identify);
lua_pushvalue (L, 1);
lua_call (L, 1, 1);
type = lua_tostring (L, -1);
}
// Can't identify -> can't decode, nothing to do here
if (!type)
return 0;
// While we could call "detect" here, just to be sure, some kinds may not
// even be detectable and it's better to leave it up to the plugin
struct app_lua_coder *coder = str_map_find (&g_ctx.coders, type);
if (!coder)
return luaL_error (L, "unknown type: %s", type);
lua_rawgeti (L, LUA_REGISTRYINDEX, coder->ref_decode);
lua_pushvalue (L, 1);
// TODO: the chunk could remember the name of the coder and prepend it
// to all marks set from the callback; then reset it back to NULL
lua_call (L, 1, 0);
return 0;
}
static int
app_lua_chunk_read (lua_State *L)
{
struct app_lua_chunk *self = luaL_checkudata (L, 1, XLUA_CHUNK_METATABLE);
lua_Integer len = luaL_checkinteger (L, 2);
if (len < 0)
return luaL_argerror (L, 2, "invalid read length");
int64_t start = self->offset + self->position;
// XXX: or just return a shorter string in this case?
if (start + len > g_ctx.data_offset + g_ctx.data_len)
return luaL_argerror (L, 2, "chunk is too short");
lua_pushlstring (L, (char *) g_ctx.data + (start - g_ctx.data_offset), len);
self->position += len;
return 1;
}
/// Mark a field that has just been read from the chunk and advance position:
/// - the second argument, if present, is a simple format string for marking;
/// - the third argument, if present, is a filtering function.
///
/// I am aware of how ugly the implicit "string.format" is. Convenience wins.
static void
app_lua_chunk_finish_read
(lua_State *L, struct app_lua_chunk *self, int64_t len)
{
int n_args = lua_gettop (L) - 1;
if (n_args < 2)
return;
// Prepare <string.format>, <format>, <value>
lua_rawgeti (L, LUA_REGISTRYINDEX, g_ctx.ref_format);
lua_pushvalue (L, 2);
int pre_filter_top = lua_gettop (L);
lua_pushvalue (L, -3);
// Transform the value if a filtering function is provided
if (n_args >= 3)
{
lua_pushvalue (L, 3);
lua_insert (L, -2);
lua_call (L, 1, LUA_MULTRET);
int n_ret = lua_gettop (L) - pre_filter_top;
// When no value has been returned, keep the old one
if (n_ret < 1)
lua_pushvalue (L, pre_filter_top - 2);
// Forward multiple return values to "string.format"
if (n_ret > 1)
{
lua_pushvalue (L, pre_filter_top - 1);
lua_insert (L, -n_ret - 1);
lua_call (L, n_ret, 1);
}
}
lua_call (L, 2, 1);
app_lua_mark (self->offset + self->position, len, lua_tostring (L, -1));
self->position += len;
lua_pop (L, 1);
}
static int
app_lua_chunk_cstring (lua_State *L)
{
struct app_lua_chunk *self = luaL_checkudata (L, 1, XLUA_CHUNK_METATABLE);
void *s = g_ctx.data + (self->offset - g_ctx.data_offset) + self->position;
void *nil;
if (!(nil = memchr (s, '\0', self->len - self->position)))
return luaL_error (L, "unexpected EOF");
lua_pushlstring (L, s, nil - s);
app_lua_chunk_finish_read (L, self, nil - s + 1);
return 1;
}
/// Decode "len" bytes as a number starting at the current position in "self"
static uint64_t
app_lua_chunk_decode_int (lua_State *L, struct app_lua_chunk *self, size_t len)
{
if (self->position + (int64_t) len > self->len)
return luaL_error (L, "unexpected EOF");
void *s = g_ctx.data + (self->offset - g_ctx.data_offset) + self->position;
return app_decode (s, len, self->endianity);
}
#define APP_LUA_CHUNK_INT(name, type) \
static int \
app_lua_chunk_ ## name (lua_State *L) \
{ \
struct app_lua_chunk *self = \
luaL_checkudata (L, 1, XLUA_CHUNK_METATABLE); \
type v = app_lua_chunk_decode_int (L, self, sizeof v); \
lua_pushinteger (L, v); \
app_lua_chunk_finish_read (L, self, sizeof v); \
return 1; \
}
APP_LUA_CHUNK_INT (u8, uint8_t) APP_LUA_CHUNK_INT (s8, int8_t)
APP_LUA_CHUNK_INT (u16, uint16_t) APP_LUA_CHUNK_INT (s16, int16_t)
APP_LUA_CHUNK_INT (u32, uint32_t) APP_LUA_CHUNK_INT (s32, int32_t)
APP_LUA_CHUNK_INT (u64, uint64_t) APP_LUA_CHUNK_INT (s64, int64_t)
static luaL_Reg app_lua_chunk_table[] =
{
{ "__len", app_lua_chunk_len },
{ "__call", app_lua_chunk_call },
{ "__index", app_lua_chunk_index },
{ "__newindex", app_lua_chunk_newindex },
{ "mark", app_lua_chunk_mark },
{ "identify", app_lua_chunk_identify },
{ "decode", app_lua_chunk_decode },
{ "read", app_lua_chunk_read },
{ "cstring", app_lua_chunk_cstring },
{ "u8", app_lua_chunk_u8 },
{ "s8", app_lua_chunk_s8 },
{ "u16", app_lua_chunk_u16 },
{ "s16", app_lua_chunk_s16 },
{ "u32", app_lua_chunk_u32 },
{ "s32", app_lua_chunk_s32 },
{ "u64", app_lua_chunk_u64 },
{ "s64", app_lua_chunk_s64 },
{ NULL, NULL }
};
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
static void
app_lua_load_plugins (const char *plugin_dir)
{
DIR *dir;
if (!(dir = opendir (plugin_dir)))
{
if (errno != ENOENT)
print_error ("cannot open directory `%s': %s",
plugin_dir, strerror (errno));
return;
}
struct dirent *iter;
while ((errno = 0, iter = readdir (dir)))
{
const char *dot = strrchr (iter->d_name, '.');
if (!dot || strcmp (dot, ".lua"))
continue;
char *path = xstrdup_printf ("%s/%s", plugin_dir, iter->d_name);
lua_pushcfunction (g_ctx.L, app_lua_error_handler);
if (luaL_loadfile (g_ctx.L, path)
|| lua_pcall (g_ctx.L, 0, 0, -2))
exit_fatal ("Lua: %s", lua_tostring (g_ctx.L, -1));
lua_pop (g_ctx.L, 1);
free (path);
}
if (errno)
exit_fatal ("readdir: %s", strerror (errno));
closedir (dir);
}
static void
app_lua_init (void)
{
if (!(g_ctx.L = lua_newstate (app_lua_alloc, NULL)))
exit_fatal ("Lua initialization failed");
str_map_init (&g_ctx.coders);
g_ctx.coders.free = app_lua_coder_free;
lua_atpanic (g_ctx.L, app_lua_panic);
luaL_openlibs (g_ctx.L);
luaL_checkversion (g_ctx.L);
// I don't want to reimplement this and the C function is not exported
hard_assert (lua_getglobal (g_ctx.L, LUA_STRLIBNAME));
hard_assert (lua_getfield (g_ctx.L, -1, "format"));
g_ctx.ref_format = luaL_ref (g_ctx.L, LUA_REGISTRYINDEX);
luaL_newlib (g_ctx.L, app_lua_library);
lua_setglobal (g_ctx.L, PROGRAM_NAME);
luaL_newmetatable (g_ctx.L, XLUA_CHUNK_METATABLE);
luaL_setfuncs (g_ctx.L, app_lua_chunk_table, 0);
lua_pop (g_ctx.L, 1);
struct str_vector v;
str_vector_init (&v);
get_xdg_data_dirs (&v);
for (size_t i = 0; i < v.len; i++)
{
char *path = xstrdup_printf
("%s/%s", v.vector[i], PROGRAM_NAME "/plugins");
app_lua_load_plugins (path);
free (path);
}
str_vector_free (&v);
}
#endif // HAVE_LUA
// --- Actions -----------------------------------------------------------------
/// Checks what items are visible and returns if fixes were needed
@ -1299,12 +1799,16 @@ main (int argc, char *argv[])
{ 'o', "offset", NULL, 0, "offset within the file" },
{ 's', "size", NULL, 0, "size limit (1G by default)" },
#ifdef HAVE_LUA
{ 't', "type", NULL, 0, "force interpretation as the given type" },
#endif // HAVE_LUA
{ 0, NULL, NULL, 0, NULL }
};
struct opt_handler oh;
opt_handler_init (&oh, argc, argv, opts, "[FILE]", "Hex viewer.");
int64_t size_limit = 1 << 30;
const char *forced_type = NULL;
int c;
while ((c = opt_handler_get (&oh)) != -1)
@ -1328,6 +1832,9 @@ main (int argc, char *argv[])
if (!decode_size (optarg, &size_limit))
exit_fatal ("invalid size limit specified");
break;
case 't':
forced_type = optarg;
break;
default:
print_error ("wrong options");
opt_handler_usage (&oh, stderr);
@ -1337,6 +1844,21 @@ main (int argc, char *argv[])
argc -= optind;
argv += optind;
#ifdef HAVE_LUA
// We do it at this questionable location to catch plugin failure before
// we read potentially hundreds of megabytes of data in
app_lua_init ();
if (forced_type && !strcmp (forced_type, "list"))
{
struct str_map_iter iter;
str_map_iter_init (&iter, &g_ctx.coders);
while (str_map_iter_next (&iter))
puts (iter.link->key);
exit (EXIT_SUCCESS);
}
#endif // HAVE_LUA
// When no filename is given, read from stdin and replace it with the tty
int input_fd;
if (argc == 0)
@ -1399,6 +1921,26 @@ main (int argc, char *argv[])
print_warning ("failed to set the locale");
app_init_context ();
#ifdef HAVE_LUA
// TODO: eventually we should do this in a separate thread after load
// as it may take a long time (-> responsivity) and once we allow the user
// to edit the file, each change will need a background rescan
lua_pushcfunction (g_ctx.L, app_lua_error_handler);
lua_pushcfunction (g_ctx.L, app_lua_chunk_decode);
struct app_lua_chunk *chunk = app_lua_chunk_new (g_ctx.L);
chunk->offset = g_ctx.data_offset;
chunk->len = g_ctx.data_len;
if (forced_type)
lua_pushstring (g_ctx.L, forced_type);
else
lua_pushnil (g_ctx.L);
if (lua_pcall (g_ctx.L, 2, 0, -4))
exit_fatal ("Lua: decoding failed: %s", lua_tostring (g_ctx.L, -1));
lua_pop (g_ctx.L, 1);
#endif // HAVE_LUA
app_flatten_marks ();
app_load_configuration ();
@ -1418,5 +1960,10 @@ main (int argc, char *argv[])
endwin ();
g_log_message_real = log_message_stdio;
app_free_context ();
#ifdef HAVE_LUA
str_map_free (&g_ctx.coders);
#endif // HAVE_LUA
return 0;
}