X-Git-Url: http://gitweb.michael.orlitzky.com/?p=dead%2Fharbl.git;a=blobdiff_plain;f=harbl%2Fsrc%2FNetwork%2FDNS%2FRBL%2FDomain.hs;h=7adc1a99f6d67422deabb4f99441484d26820939;hp=4dd5d1d43fd0548c23e7c073b4e0e3ae41deba13;hb=4dd314687c806419fac1fc88c96df6541e1dff4b;hpb=7decace098b98d7f19b7af43e9d0c641f445640f diff --git a/harbl/src/Network/DNS/RBL/Domain.hs b/harbl/src/Network/DNS/RBL/Domain.hs index 4dd5d1d..7adc1a9 100644 --- a/harbl/src/Network/DNS/RBL/Domain.hs +++ b/harbl/src/Network/DNS/RBL/Domain.hs @@ -19,281 +19,23 @@ module Network.DNS.RBL.Domain ( domain ) where -import Data.Char ( toLower ) import Text.Parsec ( (<|>), char, optionMaybe, string, try ) -import qualified Text.Parsec as Parsec ( digit, letter) import Text.Parsec.String ( Parser ) +import Network.DNS.RBL.Domain.LdhStr ( + LdhStr(..), + ldh_str, + ldh_str_length ) +import Network.DNS.RBL.Domain.LetDig ( LetDig, let_dig ) +import Network.DNS.RBL.Domain.LetDigHyp ( LetDigHyp(..) ) import Network.DNS.RBL.Pretty ( Pretty(..) ) import Network.DNS.RBL.Reversible ( Reversible(..) ) --- * Digits - --- | A wrapper around a digit character. --- -newtype Digit = Digit Char deriving (Eq, Show) -instance Pretty Digit where pretty_show (Digit d) = [d] - --- | Parse a single digit, but wrap it in our 'Digit' type. --- -digit :: Parser Digit -digit = fmap Digit Parsec.digit - - --- * Letters - --- | A wrapper around a letter character. --- -newtype Letter = Letter Char deriving (Show) -instance Pretty Letter where pretty_show (Letter l) = [l] - - --- | Parse a single letter, but wrap it in our 'Letter' type. --- -letter :: Parser Letter -letter = fmap Letter Parsec.letter - --- | The derived instance of 'Eq' for letters is incorrect. All --- comparisons should be made case-insensitively. The following --- is an excerpt from RFC1035: --- --- 2.3.3. Character Case --- --- For all parts of the DNS that are part of the official --- protocol, all comparisons between character strings (e.g., --- labels, domain names, etc.) are done in a case-insensitive --- manner... --- --- Since each part of DNS name is composed of our custom types, it --- suffices to munge the equality for 'Letter'. RFC4343 --- clarifies the --- case-insensitivity rules, but the fact that we're treating DNS --- names as strings makes most of those problems go away (in --- exchange for new ones). --- -instance Eq Letter where - (Letter l1) == (Letter l2) = (toLower l1) == (toLower l2) - --- * Letters/Digits - --- | A sum type representing either a letter or a digit. --- -data LetDig = - LetDigLetter Letter | - LetDigDigit Digit - deriving (Eq, Show) - -instance Pretty LetDig where - pretty_show (LetDigLetter l) = pretty_show l - pretty_show (LetDigDigit d) = pretty_show d - --- | Parse a letter or a digit and wrap it in our 'LetDig' type. --- -let_dig :: Parser LetDig -let_dig = (fmap LetDigLetter letter) <|> (fmap LetDigDigit digit) - - --- * Hyphens - --- | A wrapper around a single hyphen character. --- -newtype Hyphen = Hyphen Char deriving (Eq, Show) -instance Pretty Hyphen where pretty_show (Hyphen h) = [h] - --- | Parse a single hyphen and wrap it in our 'Hyphen' type. --- -hyphen :: Parser Hyphen -hyphen = fmap Hyphen (char '-') - - --- * Letter, Digit, or Hyphen. - --- | A sum type representing a letter, digit, or hyphen. --- -data LetDigHyp = - LetDigHypLetDig LetDig | - LetDigHypHyphen Hyphen - deriving (Eq, Show) - -instance Pretty LetDigHyp where - pretty_show (LetDigHypLetDig ld) = pretty_show ld - pretty_show (LetDigHypHyphen h) = pretty_show h - - --- | The following is the simplest type in the domain grammar that --- isn't already implemented for us. --- --- ::= | --- --- ==== _Examples_ --- --- >>> import Text.Parsec ( parseTest ) --- --- Letters, digits, and hyphens are all parsed: --- --- >>> parseTest let_dig_hyp "a" --- LetDigHypLetDig (LetDigLetter (Letter 'a')) --- --- >>> parseTest let_dig_hyp "7" --- LetDigHypLetDig (LetDigDigit (Digit '7')) --- --- >>> parseTest let_dig_hyp "-" --- LetDigHypHyphen (Hyphen '-') --- --- However, an underscore (for example) is not: --- --- >>> parseTest let_dig_hyp "_" --- parse error at (line 1, column 1): --- unexpected "_" --- expecting letter, digit or "-" --- -let_dig_hyp :: Parser LetDigHyp -let_dig_hyp = - parse_letdig <|> parse_hyphen - where - parse_letdig :: Parser LetDigHyp - parse_letdig = fmap LetDigHypLetDig let_dig - - parse_hyphen :: Parser LetDigHyp - parse_hyphen = fmap LetDigHypHyphen hyphen - - --- * Letter/Digit/Hyphen strings - --- | A string of letters, digits, and hyphens from the RFC1035 grammar: --- --- ::= | --- --- These are represented as either a single instance of a --- 'LetDigHyp', or a string of them (recursive). --- -data LdhStr = - LdhStrSingleLdh LetDigHyp | - LdhStrMultipleLdh LetDigHyp LdhStr - deriving (Eq, Show) - -instance Pretty LdhStr where - pretty_show (LdhStrSingleLdh ldh) = pretty_show ldh - pretty_show (LdhStrMultipleLdh ldh s) = (pretty_show ldh) ++ (pretty_show s) - --- | Parse a string of letters, digits, and hyphens (an 'LdhStr'). --- --- ==== _Examples_ --- --- >>> import Text.Parsec ( parseTest ) --- --- Single letters, digits, and hyphens are parsed: --- --- >>> parseTest ldh_str "a" --- LdhStrSingleLdh (LetDigHypLetDig (LetDigLetter (Letter 'a'))) --- --- >>> parseTest ldh_str "0" --- LdhStrSingleLdh (LetDigHypLetDig (LetDigDigit (Digit '0'))) --- --- >>> parseTest ldh_str "-" --- LdhStrSingleLdh (LetDigHypHyphen (Hyphen '-')) --- --- As well as strings of them: --- --- >>> import Text.Parsec ( parse ) --- >>> pretty_print $ parse ldh_str "" "a0-b" --- a0-b --- -ldh_str :: Parser LdhStr -ldh_str = try both <|> just_one - where - both :: Parser LdhStr - both = do - ldh1 <- let_dig_hyp - ldh_tail <- ldh_str - return $ LdhStrMultipleLdh ldh1 ldh_tail - - just_one :: Parser LdhStr - just_one = fmap LdhStrSingleLdh let_dig_hyp - - - --- | A version of 'last' that works on a 'LdhStr' rather than a --- list. That is, it returns the last 'LetDigHyp' in the --- string. Since 'LdhStr' contains at least one character, there's --- no \"nil\" case here. --- --- ==== _Examples_ --- --- >>> import Text.Parsec ( parse ) --- --- >>> let (Right r) = parse ldh_str "" "a" --- >>> last_ldh_str r --- LetDigHypLetDig (LetDigLetter (Letter 'a')) --- --- >>> let (Right r) = parse ldh_str "" "abc-def" --- >>> last_ldh_str r --- LetDigHypLetDig (LetDigLetter (Letter 'f')) --- -last_ldh_str :: LdhStr -> LetDigHyp -last_ldh_str (LdhStrSingleLdh x) = x -last_ldh_str (LdhStrMultipleLdh _ x) = last_ldh_str x - - --- | A version of 'init' that works on a 'LdhStr' rather than a --- list. That is, it returns everything /except/ the last character in --- the string. --- --- Since an 'LdhStr' must contain at least one character, this might --- not be opssible (when the input is of length one). So, we return --- a 'Maybe' value. --- --- ==== _Examples_ --- --- >>> import Text.Parsec ( parse ) --- --- >>> let (Right r) = parse ldh_str "" "a" --- >>> init_ldh_str r --- Nothing --- --- >>> let (Right r) = parse ldh_str "" "ab" --- >>> init_ldh_str r --- Just (LdhStrSingleLdh (LetDigHypLetDig (LetDigLetter (Letter 'a')))) --- --- >>> let (Right r) = parse ldh_str "" "abc-def" --- >>> init_ldh_str r --- Just (LdhStrMultipleLdh (LetDigHypLetDig (LetDigLetter (Letter 'a'))) (LdhStrMultipleLdh (LetDigHypLetDig (LetDigLetter (Letter 'b'))) (LdhStrMultipleLdh (LetDigHypLetDig (LetDigLetter (Letter 'c'))) (LdhStrMultipleLdh (LetDigHypHyphen (Hyphen '-')) (LdhStrMultipleLdh (LetDigHypLetDig (LetDigLetter (Letter 'd'))) (LdhStrSingleLdh (LetDigHypLetDig (LetDigLetter (Letter 'e'))))))))) --- -init_ldh_str :: LdhStr -> Maybe LdhStr -init_ldh_str (LdhStrSingleLdh _) = Nothing -init_ldh_str (LdhStrMultipleLdh h t) = - Just $ case (init_ldh_str t) of - -- We just got the second-to-last character, we're done. - Nothing -> LdhStrSingleLdh h - - -- There's still more stuff. Recurse. - Just rest -> LdhStrMultipleLdh h rest - - --- | Compute the length of an 'LdhStr'. It will be at least one, since --- 'LdhStr's are non-empty. And if there's something other than the --- first character present, we simply recurse. --- --- ==== _Examples_ --- --- >>> import Text.Parsec ( parse ) --- --- >>> let (Right r) = parse ldh_str "" "a" --- >>> length_ldh_str r --- 1 --- --- >>> let (Right r) = parse ldh_str "" "abc-def" --- >>> length_ldh_str r --- 7 --- -length_ldh_str :: LdhStr -> Int -length_ldh_str (LdhStrSingleLdh _) = 1 -length_ldh_str (LdhStrMultipleLdh _ t) = 1 + (length_ldh_str t) -- * Letter/Digit/Hyphen string followed by a trailing Letter/Digit @@ -314,6 +56,8 @@ instance Pretty LdhStrLetDig where pretty_show (LdhStrLetDig Nothing ld) = pretty_show ld pretty_show (LdhStrLetDig (Just s) ld) = (pretty_show s) ++ (pretty_show ld) + + -- | Parse an 'LdhStrLetDig'. This isn't in the grammar, but we might -- as well define the parser for it independently since we gave it -- its own data type. @@ -345,23 +89,24 @@ ldh_str_let_dig = do full_ldh <- ldh_str -- So we have to go back and see what happened. - case (last_ldh_str full_ldh) of - (LetDigHypHyphen _) -> fail "label cannot end with a hyphen" - (LetDigHypLetDig ld) -> - -- Ok, the label didn't end with a hyphen; now we need to split - -- off the last letter/digit so we can pack it into our return - -- type separately. - return $ case (init_ldh_str full_ldh) of - -- We only parsed one letter/digit. This can happen - -- if the label contains two characters. For example, - -- if we try to parse the label "ab", then the "a" - -- will be eaten by the label parser, and this - -- function will be left with only "b". - Nothing -> LdhStrLetDig Nothing ld - - -- Usual case: there's was some leading let-dig-hyp junk, - -- return it too. - leading_ldhs -> LdhStrLetDig leading_ldhs ld + case (backwards full_ldh) of + + -- Fail on a single hyphen. + (LdhStrSingleLdh (LetDigHypHyphen _)) -> + fail "label cannot end with a hyphen" + + -- Fail for a hyphen followed by other stuff. + (LdhStrMultipleLdh (LetDigHypHyphen _) _) -> + fail "label cannot end with a hyphen" + + -- Simply return the thing if it's a single non-hyphen. + (LdhStrSingleLdh (LetDigHypLetDig ld)) -> return $ LdhStrLetDig Nothing ld + + -- And peel off the last character for a non-hyphen followed by + -- other stuff. We wind up reversing things twice, but whatever. + (LdhStrMultipleLdh (LetDigHypLetDig ld) init_ldh_rev) -> + let init_ldh = backwards init_ldh_rev + in return $ LdhStrLetDig (Just init_ldh) ld @@ -384,7 +129,7 @@ ldh_str_let_dig = do length_ldh_str_let_dig :: LdhStrLetDig -> Int length_ldh_str_let_dig (LdhStrLetDig Nothing _) = 1 length_ldh_str_let_dig (LdhStrLetDig (Just ldhstring) _) = - 1 + (length_ldh_str ldhstring) + 1 + (ldh_str_length ldhstring) -- * Labels @@ -532,30 +277,17 @@ instance Reversible Subdomain where backwards (SubdomainMultipleLabel l (SubdomainSingleLabel m)) = SubdomainMultipleLabel m (SubdomainSingleLabel l) - -- And now the hard case. If we reversed @s@, then the "head" of - -- the result (@last_s@) should be the last label in the entire - -- subdomain. Stick @last_s@ on the front of the result. That makes - -- enough sense. - -- - -- But what to do about the rest? We need to get \"init s\" - -- somehow. Well, we have the reverse of it... why not waste a bunch - -- of time and reverse that, too? With @init s@ in hand, we can - -- prepend @l@ to that, and THEN reverse the entire thing. What we'll - -- wind up with looks like @[last_s, init_s_rev, l]@ which you can - -- pretend you recognize as the subdomain in reverse. + -- And now the hard case. See the 'LdhStr' implementation for an + -- explanation. -- - backwards (SubdomainMultipleLabel l s) = - case (backwards s) of - SubdomainMultipleLabel last_s init_s_rev -> - let init_s = backwards init_s_rev - in - SubdomainMultipleLabel - last_s - (backwards (SubdomainMultipleLabel l init_s)) - - -- Reversing a multiple label thing gives you back a multiple - -- label thing but there's no way to promise that. - impossible -> impossible + backwards (SubdomainMultipleLabel l s) = build (SubdomainSingleLabel l) s + where + -- Build up the first Subdomain on the left by peeling off the + -- leading elements of the second Subdomain. + build :: Subdomain -> Subdomain -> Subdomain + build dst (SubdomainSingleLabel final) = SubdomainMultipleLabel final dst + build dst (SubdomainMultipleLabel leading rest) = + build (SubdomainMultipleLabel leading dst) rest