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|
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE FlexibleContexts #-}
{-
Copyright © 2017 Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-}
{-# LANGUAGE CPP #-}
{- |
Module : Text.Pandoc.Lua.PandocModule
Copyright : Copyright © 2017 Albert Krewinkel
License : GNU GPL, version 2 or above
Maintainer : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
Stability : alpha
Pandoc module for lua.
-}
module Text.Pandoc.Lua.PandocModule
( pushPandocModule
, pushMediaBagModule
) where
import Control.Monad (unless, zipWithM_)
import Data.ByteString.Char8 (unpack)
import Data.Default (Default (..))
import Data.Digest.Pure.SHA (sha1, showDigest)
import Data.IORef
import Data.Maybe (fromMaybe)
import Data.Text (pack)
import Foreign.Lua (ToLuaStack, FromLuaStack, Lua, NumResults, liftIO)
import Foreign.Lua.FunctionCalling (ToHaskellFunction)
import System.Exit (ExitCode (..))
import Text.Pandoc.Class (CommonState (..), fetchItem, putCommonState,
readDataFile, runIO, runIOorExplode, setMediaBag,
setUserDataDir)
import Text.Pandoc.Lua.StackInstances ()
import Text.Pandoc.Definition (Block, Inline)
import Text.Pandoc.Walk (Walkable)
import Text.Pandoc.MIME (MimeType)
import Text.Pandoc.Options (ReaderOptions (readerExtensions))
import Text.Pandoc.Process (pipeProcess)
import Text.Pandoc.Readers (Reader (..), getReader)
import qualified Data.ByteString.Lazy as BL
import qualified Foreign.Lua as Lua
import qualified Text.Pandoc.MediaBag as MB
import Text.Pandoc.Lua.Filter (walkInlines, walkBlocks, LuaFilter)
-- | Push the "pandoc" on the lua stack. Requires the `list` module to be
-- loaded.
pushPandocModule :: Maybe FilePath -> Lua ()
pushPandocModule datadir = do
loadListModule datadir
script <- liftIO (moduleScript datadir "pandoc.lua")
status <- Lua.loadstring script
unless (status /= Lua.OK) $ Lua.call 0 1
addFunction "_pipe" pipeFn
addFunction "_read" readDoc
addFunction "sha1" sha1HashFn
addFunction "walk_block" walkBlock
addFunction "walk_inline" walkInline
-- | Get the string representation of the pandoc module
moduleScript :: Maybe FilePath -> FilePath -> IO String
moduleScript datadir moduleFile = unpack <$>
runIOorExplode (setUserDataDir datadir >> readDataFile moduleFile)
-- Loads pandoc's list module without assigning it to a variable.
pushListModule :: Maybe FilePath -> Lua ()
pushListModule datadir = do
script <- liftIO (moduleScript datadir "List.lua")
status <- Lua.loadstring script
if status == Lua.OK
then Lua.call 0 1
else Lua.throwTopMessageAsError' ("Error while loading module `list`\n" ++)
loadListModule :: Maybe FilePath -> Lua ()
loadListModule datadir = do
Lua.getglobal' "package.loaded"
pushListModule datadir
Lua.setfield (-2) "pandoc.List"
Lua.pop 1
walkElement :: (ToLuaStack a, Walkable [Inline] a, Walkable [Block] a)
=> a -> LuaFilter -> Lua NumResults
walkElement x f = do
x' <- walkInlines f x >>= walkBlocks f
Lua.push x'
return 1
walkInline :: Inline -> LuaFilter -> Lua NumResults
walkInline = walkElement
walkBlock :: Block -> LuaFilter -> Lua NumResults
walkBlock = walkElement
readDoc :: String -> String -> Lua NumResults
readDoc formatSpec content = do
case getReader formatSpec of
Left s -> Lua.push s -- Unknown reader
Right (reader, es) ->
case reader of
TextReader r -> do
res <- liftIO $ runIO $ r def{ readerExtensions = es } (pack content)
case res of
Left s -> Lua.push $ show s -- error while reading
Right pd -> Lua.push pd -- success, push Pandoc
_ -> Lua.push "Only string formats are supported at the moment."
return 1
--
-- MediaBag submodule
--
pushMediaBagModule :: CommonState -> IORef MB.MediaBag -> Lua ()
pushMediaBagModule commonState mediaBagRef = do
Lua.newtable
addFunction "insert" (insertMediaFn mediaBagRef)
addFunction "lookup" (lookupMediaFn mediaBagRef)
addFunction "list" (mediaDirectoryFn mediaBagRef)
addFunction "fetch" (fetch commonState mediaBagRef)
return ()
addFunction :: ToHaskellFunction a => String -> a -> Lua ()
addFunction name fn = do
Lua.push name
Lua.pushHaskellFunction fn
Lua.rawset (-3)
sha1HashFn :: BL.ByteString
-> Lua NumResults
sha1HashFn contents = do
Lua.push $ showDigest (sha1 contents)
return 1
pipeFn :: String
-> [String]
-> BL.ByteString
-> Lua NumResults
pipeFn command args input = do
(ec, output) <- liftIO $ pipeProcess Nothing command args input
Lua.push $ case ec of
ExitSuccess -> 0
ExitFailure n -> n
Lua.push output
return 2
insertMediaFn :: IORef MB.MediaBag
-> FilePath
-> OrNil MimeType
-> BL.ByteString
-> Lua NumResults
insertMediaFn mbRef fp nilOrMime contents = do
liftIO . modifyIORef' mbRef $
MB.insertMedia fp (toMaybe nilOrMime) contents
return 0
lookupMediaFn :: IORef MB.MediaBag
-> FilePath
-> Lua NumResults
lookupMediaFn mbRef fp = do
res <- MB.lookupMedia fp <$> liftIO (readIORef mbRef)
case res of
Nothing -> Lua.pushnil *> return 1
Just (mimeType, contents) -> do
Lua.push mimeType
Lua.push contents
return 2
mediaDirectoryFn :: IORef MB.MediaBag
-> Lua NumResults
mediaDirectoryFn mbRef = do
dirContents <- MB.mediaDirectory <$> liftIO (readIORef mbRef)
Lua.newtable
zipWithM_ addEntry [1..] dirContents
return 1
where
addEntry :: Int -> (FilePath, MimeType, Int) -> Lua ()
addEntry idx (fp, mimeType, contentLength) = do
Lua.newtable
Lua.push "path" *> Lua.push fp *> Lua.rawset (-3)
Lua.push "type" *> Lua.push mimeType *> Lua.rawset (-3)
Lua.push "length" *> Lua.push contentLength *> Lua.rawset (-3)
Lua.rawseti (-2) idx
fetch :: CommonState
-> IORef MB.MediaBag
-> String
-> Lua NumResults
fetch commonState mbRef src = do
mediaBag <- liftIO $ readIORef mbRef
(bs, mimeType) <- liftIO . runIOorExplode $ do
putCommonState commonState
setMediaBag mediaBag
fetchItem src
Lua.push $ fromMaybe "" mimeType
Lua.push bs
return 2 -- returns 2 values: contents, mimetype
--
-- Helper types and orphan instances
--
newtype OrNil a = OrNil { toMaybe :: Maybe a }
instance FromLuaStack a => FromLuaStack (OrNil a) where
peek idx = do
noValue <- Lua.isnil idx
if noValue
then return (OrNil Nothing)
else OrNil . Just <$> Lua.peek idx
|
