Start writing a new configuration system

For degesch but in the long term for the rest as well.
This commit is contained in:
Přemysl Eric Janouch 2015-05-01 15:24:42 +02:00
parent 452f42d96e
commit 6bf57d3450
2 changed files with 596 additions and 12 deletions

596
common.c
View File

@ -31,6 +31,7 @@
#endif // WANT_SYSLOG_LOGGING
#include "liberty/liberty.c"
#include <setjmp.h>
#include <arpa/inet.h>
// --- Logging -----------------------------------------------------------------
@ -458,3 +459,598 @@ socks_connect (const char *socks_host, const char *socks_port,
fail:
return result;
}
// --- To be moved to liberty --------------------------------------------------
static bool
isalpha_ascii (int c)
{
c &= ~32;
return c >= 'A' && c <= 'Z';
}
static bool
isdigit_ascii (int c)
{
return c >= '0' && c <= '9';
}
static bool
isalnum_ascii (int c)
{
return isalpha_ascii (c) || isdigit_ascii (c);
}
static int
toupper_ascii (int c)
{
return c >= 'A' && c <= 'Z' ? c : c - ('a' - 'A');
}
// --- Advanced configuration --------------------------------------------------
// This is a new configuration format, superseding the one currently present
// in liberty. It's just a lot more complicated and allows key-value maps.
// We need it in degesch to provide non-sucking user experience.
enum config_item_type
{
CONFIG_ITEM_NULL, ///< No value
CONFIG_ITEM_OBJECT, ///< Key-value map
CONFIG_ITEM_BOOLEAN, ///< Truth value
CONFIG_ITEM_INTEGER, ///< Integer
CONFIG_ITEM_STRING, ///< Arbitrary string of characters
CONFIG_ITEM_STRING_ARRAY ///< Comma-separated list of strings
};
struct config_item_
{
enum config_item_type type; ///< Type of the item
union
{
struct str_map object; ///< Key-value data
bool boolean; ///< Boolean data
int64_t integer; ///< Integer data
struct str string; ///< String data
}
value; ///< The value of this item
struct config_schema *schema; ///< Schema describing this value
void *user_data; ///< User value attached by schema owner
};
struct config_schema
{
const char *name; ///< Name of the item
const char *comment; ///< User-readable description
enum config_item_type type; ///< Required type
bool is_nullable; ///< Can be null?
const char *default_; ///< Default as a configuration snippet
/// Check if the new value can be accepted.
/// If this is not defined, only "type" and "is_nullable" is considered.
bool (*validate) (struct config_item_ *, const struct config_item_ *);
/// The value has changed. Only appliable to objects.
bool (*on_changed) (struct config_item_ *);
/// Free any resources located in "item->user_data"
void (*on_destroy) (struct config_item_ *item);
};
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
static void
config_item_destroy (struct config_item_ *self)
{
if (self->schema && self->schema->on_destroy)
self->schema->on_destroy (self);
switch (self->type)
{
case CONFIG_ITEM_STRING:
case CONFIG_ITEM_STRING_ARRAY:
str_free (&self->value.string);
break;
case CONFIG_ITEM_OBJECT:
str_map_free (&self->value.object);
default:
break;
}
free (self);
}
static struct config_item_ *
config_item_new (enum config_item_type type)
{
struct config_item_ *self = xcalloc (1, sizeof *self);
self->type = type;
return self;
}
static struct config_item_ *
config_item_null (void)
{
return config_item_new (CONFIG_ITEM_NULL);
}
static struct config_item_ *
config_item_boolean (bool b)
{
struct config_item_ *self = config_item_new (CONFIG_ITEM_BOOLEAN);
self->value.boolean = b;
return self;
}
static struct config_item_ *
config_item_integer (int64_t i)
{
struct config_item_ *self = config_item_new (CONFIG_ITEM_INTEGER);
self->value.integer = i;
return self;
}
static struct config_item_ *
config_item_string (const struct str *s)
{
struct config_item_ *self = config_item_new (CONFIG_ITEM_STRING);
str_init (&self->value.string);
if (s) str_append_str (&self->value.string, s);
return self;
}
static struct config_item_ *
config_item_string_array (const struct str *s)
{
struct config_item_ *self = config_item_string (s);
self->type = CONFIG_ITEM_STRING_ARRAY;
return self;
}
static struct config_item_ *
config_item_object (void)
{
struct config_item_ *self = config_item_new (CONFIG_ITEM_BOOLEAN);
str_map_init (&self->value.object);
self->value.object.free = (void (*)(void *)) config_item_destroy;
return self;
}
/// Doesn't do any validations or such, only moves source data to the item
static void
config_item_move (struct config_item_ *self, struct config_item_ *source)
{
// TODO
}
static bool
config_item_set_from (struct config_item_ *self,
struct config_item_ *source, struct error **e)
{
hard_assert (self->type == CONFIG_ITEM_OBJECT);
// TODO
}
static struct config_item_ *
config_item_get (struct config_item_ *self, const char *path)
{
hard_assert (self->type == CONFIG_ITEM_OBJECT);
// TODO
}
static void
config_item_write (struct config_item_ *root, struct str *output)
{
// TODO
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
static void
config_schema_apply_to_object
(struct config_schema *schema_array, struct config_item_ *object)
{
hard_assert (object->type == CONFIG_ITEM_OBJECT);
// TODO
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
enum config_token
{
CONFIG_T_ABORT, ///< EOF or error
CONFIG_T_WORD, ///< [a-zA-Z0-9_]+
CONFIG_T_EQUALS, ///< Equal sign
CONFIG_T_LBRACE, ///< Left curly bracket
CONFIG_T_RBRACE, ///< Right curly bracket
CONFIG_T_NEWLINE, ///< New line
CONFIG_T_NULL, ///< CONFIG_ITEM_NULL
CONFIG_T_BOOLEAN, ///< CONFIG_ITEM_BOOLEAN
CONFIG_T_INTEGER, ///< CONFIG_ITEM_INTEGER
CONFIG_T_STRING ///< CONFIG_ITEM_STRING{,_LIST}
};
struct config_tokenizer
{
const char *p;
size_t len;
unsigned line;
unsigned column;
int64_t integer;
struct str string;
};
/// Input has to be null-terminated anyway
static void
config_tokenizer_init (struct config_tokenizer *self, const char *p, size_t len)
{
memset (self, 0, sizeof *self);
self->p = p;
self->len = len;
str_init (&self->string);
}
static void
config_tokenizer_free (struct config_tokenizer *self)
{
str_free (&self->string);
}
static bool
config_tokenizer_is_word_char (int c)
{
return isalnum_ascii (c) || c == '_';
}
static int
config_tokenizer_advance (struct config_tokenizer *self)
{
int c = *self->p++;
if (c == '\n')
{
self->column = 0;
self->line++;
}
else
self->column++;
self->len--;
return c;
}
static void
config_tokenizer_error (struct config_tokenizer *self,
struct error **e, const char *description)
{
// FIXME: we don't always want to specify the line
error_set (e, "near line %u, column %u: %s",
self->line + 1, self->column + 1, description);
}
static enum config_token
config_tokenizer_next (struct config_tokenizer *self, struct error **e)
{
// Skip over any whitespace between tokens
while (self->len && isspace_ascii (*self->p) && *self->p != '\n')
config_tokenizer_advance (self);
if (!self->len)
return CONFIG_T_ABORT;
switch (*self->p)
{
case '\n': config_tokenizer_advance (self); return CONFIG_T_NEWLINE;
case '=': config_tokenizer_advance (self); return CONFIG_T_EQUALS;
case '{': config_tokenizer_advance (self); return CONFIG_T_LBRACE;
case '}': config_tokenizer_advance (self); return CONFIG_T_RBRACE;
case '#':
// Comments go until newline
while (self->len)
if (config_tokenizer_advance (self) == '\n')
return CONFIG_T_NEWLINE;
return CONFIG_T_ABORT;
case '"':
// TODO: string, validate as UTF-8
break;
}
bool is_word = false;
while (config_tokenizer_is_word_char (*self->p))
{
is_word = true;
str_reset (&self->string);
str_append_c (&self->string, config_tokenizer_advance (self));
}
if (is_word)
{
if (!strcmp (self->string.str, "null"))
return CONFIG_T_NULL;
bool boolean;
if (!set_boolean_if_valid (&boolean, self->string.str))
return CONFIG_T_WORD;
self->integer = boolean;
return CONFIG_T_BOOLEAN;
}
char *end;
errno = 0;
self->integer = strtoll (self->p, &end, 10);
if (errno == ERANGE)
{
config_tokenizer_error (self, e, "integer out of range");
return CONFIG_T_ABORT;
}
if (end != self->p)
{
self->len -= end - self->p;
self->p = end;
return CONFIG_T_INTEGER;
}
config_tokenizer_error (self, e, "invalid input");
return CONFIG_T_ABORT;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
struct config_parser
{
struct config_tokenizer tokenizer; ///< Tokenizer
struct error *error; ///< Tokenizer error
enum config_token token; ///< Current token in the tokenizer
bool replace_token; ///< Replace the token
};
static void
config_parser_init (struct config_parser *self, const char *script, size_t len)
{
memset (self, 0, sizeof *self);
config_tokenizer_init (&self->tokenizer, script, len);
// As reading in tokens may cause exceptions, we wait for the first peek()
// to replace the initial CONFIG_T_ABORT.
self->replace_token = true;
}
static void
config_parser_free (struct config_parser *self)
{
config_tokenizer_free (&self->tokenizer);
if (self->error)
error_free (self->error);
}
static enum config_token
config_parser_peek (struct config_parser *self, jmp_buf out)
{
if (self->replace_token)
{
self->token = config_tokenizer_next (&self->tokenizer, &self->error);
if (self->error)
longjmp (out, 1);
self->replace_token = false;
}
return self->token;
}
static bool
config_parser_accept
(struct config_parser *self, enum config_token token, jmp_buf out)
{
return self->replace_token = (config_parser_peek (self, out) == token);
}
static void
config_parser_expect
(struct config_parser *self, enum config_token token, jmp_buf out)
{
if (config_parser_accept (self, token, out))
return;
// TODO: fill in "X" and "Y"
config_tokenizer_error (&self->tokenizer, &self->error,
"unexpected X, expected Y");
longjmp (out, 1);
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// We don't need no generator, but a few macros will come in handy.
// From time to time C just doesn't have the right features.
#define PEEK() config_parser_peek (self, err)
#define ACCEPT(token) config_parser_accept (self, token, err)
#define EXPECT(token) config_parser_expect (self, token, err)
#define SKIP_NL() do {} while (ACCEPT (CONFIG_T_NEWLINE))
static struct config_item_ *config_parser_parse_object
(struct config_parser *self, jmp_buf out);
static struct config_item_ *
config_parser_parse_value (struct config_parser *self, jmp_buf out)
{
struct config_item_ *volatile result = NULL;
jmp_buf err;
if (setjmp (err))
{
if (result)
config_item_destroy (result);
longjmp (out, 1);
}
if (ACCEPT (CONFIG_T_LBRACE))
{
result = config_parser_parse_object (self, out);
EXPECT (CONFIG_T_RBRACE);
return result;
}
if (ACCEPT (CONFIG_T_NULL))
return config_item_null ();
if (ACCEPT (CONFIG_T_BOOLEAN))
return config_item_boolean (self->tokenizer.integer);
if (ACCEPT (CONFIG_T_INTEGER))
return config_item_integer (self->tokenizer.integer);
if (ACCEPT (CONFIG_T_STRING))
return config_item_string (&self->tokenizer.string);
// TODO: fill in "X" as the token name
config_tokenizer_error (&self->tokenizer, &self->error,
"unexpected X, expected a value");
longjmp (out, 1);
}
/// Parse a single "key = value" assignment into @a object
static bool
config_parser_parse_kv_pair (struct config_parser *self,
struct config_item_ *object, jmp_buf out)
{
char *volatile key = NULL;
jmp_buf err;
if (setjmp (err))
{
free (key);
longjmp (out, 1);
}
SKIP_NL ();
// Either this object's closing right brace if called recursively,
// or end of file when called on a whole configuration file
if (PEEK () == CONFIG_T_RBRACE
|| PEEK () == CONFIG_T_ABORT)
return false;
EXPECT (CONFIG_T_WORD);
key = xstrdup (self->tokenizer.string.str);
SKIP_NL ();
EXPECT (CONFIG_T_EQUALS);
SKIP_NL ();
str_map_set (&object->value.object, key,
config_parser_parse_value (self, err));
free (key);
key = NULL;
if (PEEK () == CONFIG_T_RBRACE
|| PEEK () == CONFIG_T_ABORT)
return false;
EXPECT (CONFIG_T_NEWLINE);
return true;
}
/// Parse the inside of an object definition
static struct config_item_ *
config_parser_parse_object (struct config_parser *self, jmp_buf out)
{
struct config_item_ *volatile object = config_item_object ();
jmp_buf err;
if (setjmp (err))
{
config_item_destroy (object);
longjmp (out, 1);
}
while (config_parser_parse_kv_pair (self, object, err))
;
return object;
}
#undef PEEK
#undef ACCEPT
#undef EXPECT
#undef SKIP_NL
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/// Parse a configuration snippet either as an object or a bare value.
/// If it's the latter (@a single_value_only), no newlines may follow.
static struct config_item_ *
config_item_parse (const char *script, size_t len,
bool single_value_only, struct error **e)
{
struct config_parser parser;
config_parser_init (&parser, script, len);
struct config_item_ *volatile object = NULL;
jmp_buf err;
if (setjmp (err))
{
if (object)
{
config_item_destroy (object);
object = NULL;
}
error_propagate (e, parser.error);
parser.error = NULL;
goto end;
}
if (single_value_only)
object = config_parser_parse_value (&parser, err);
else
object = config_parser_parse_object (&parser, err);
config_parser_expect (&parser, CONFIG_T_ABORT, err);
end:
config_parser_free (&parser);
return object;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
typedef void (*config_module_load_fn)
(struct config_item_ *subtree, void *user_data);
struct config_module
{
char *name; ///< Name of the subtree
config_module_load_fn loader; ///< Module config subtree loader
void *user_data; ///< User data
};
struct config
{
struct str_map modules; ///< Toplevel modules
struct config_item_ *root; ///< CONFIG_ITEM_OBJECT
};
static void
config_init (struct config *self)
{
// TODO
}
static void
config_free (struct config *self)
{
// TODO
}
static bool
config_register_module (const char *name,
config_module_load_fn loader, void *user_data)
{
// TODO
}
static bool
config_load (struct config_item_ *root, struct error **e)
{
// TODO
}

View File

@ -108,18 +108,6 @@ static struct config_item g_config_table[] =
// All text stored in our data structures is encoded in UTF-8.
// Or at least should be. The exception is IRC identifiers.
static bool
isdigit_ascii (int c)
{
return c >= '0' && c <= '9';
}
static int
toupper_ascii (int c)
{
return c >= 'A' && c <= 'Z' ? c : c - ('a' - 'A');
}
/// Shorthand to set an error and return failure from the function
#define FAIL(...) \
BLOCK_START \