diff options
Diffstat (limited to 'src/Text/Pandoc/Readers')
| -rw-r--r-- | src/Text/Pandoc/Readers/Markdown.hs | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/src/Text/Pandoc/Readers/Markdown.hs b/src/Text/Pandoc/Readers/Markdown.hs index 607d0971a..31db51028 100644 --- a/src/Text/Pandoc/Readers/Markdown.hs +++ b/src/Text/Pandoc/Readers/Markdown.hs @@ -1041,8 +1041,20 @@ inlinesBetween start end = where inner = innerSpace <|> (notFollowedBy' whitespace >> inline) innerSpace = try $ whitespace >>~ notFollowedBy' end +-- This is used to prevent exponential blowups for things like: +-- a**a*a**a*a**a*a**a*a**a*a**a*a** +nested :: GenParser Char ParserState a + -> GenParser Char ParserState a +nested p = do + nestlevel <- stateMaxNestingLevel `fmap` getState + guard $ nestlevel > 0 + updateState $ \st -> st{ stateMaxNestingLevel = stateMaxNestingLevel st - 1 } + res <- p + updateState $ \st -> st{ stateMaxNestingLevel = nestlevel } + return res + emph :: GenParser Char ParserState Inline -emph = Emph `liftM` +emph = Emph `fmap` nested (inlinesBetween starStart starEnd <|> inlinesBetween ulStart ulEnd) where starStart = char '*' >> lookAhead nonspaceChar starEnd = notFollowedBy' strong >> char '*' @@ -1050,7 +1062,7 @@ emph = Emph `liftM` ulEnd = notFollowedBy' strong >> char '_' strong :: GenParser Char ParserState Inline -strong = Strong `liftM` +strong = Strong `liftM` nested (inlinesBetween starStart starEnd <|> inlinesBetween ulStart ulEnd) where starStart = string "**" >> lookAhead nonspaceChar starEnd = try $ string "**" |