diff options
| -rw-r--r-- | doc/lua-filters.md | 27 | ||||
| -rw-r--r-- | pandoc.cabal | 1 | ||||
| -rw-r--r-- | src/Text/Pandoc/Lua/Marshaling/MediaBag.hs | 75 | ||||
| -rw-r--r-- | src/Text/Pandoc/Lua/Module/MediaBag.hs | 8 | ||||
| -rw-r--r-- | src/Text/Pandoc/MediaBag.hs | 6 |
5 files changed, 116 insertions, 1 deletions
diff --git a/doc/lua-filters.md b/doc/lua-filters.md index 45abe8ac8..667a58bcc 100644 --- a/doc/lua-filters.md +++ b/doc/lua-filters.md @@ -2475,6 +2475,33 @@ Usage: local contents = "Hello, World!" pandoc.mediabag(fp, mt, contents) +### iter {#mediabag-iter} + +`items ()` + +Returns an iterator triple to be used with Lua's generic `for` +statement. The iterator returns the filepath, MIME type, and +content of a media bag item on each invocation. Items are +processed one-by-one to avoid excessive memory use. + +This function should be used only when full access to all items, +including their contents, is required. For all other cases, +[`list`](#mediabag-list) should be preferred. + +Returns: + + - The iterator function; must be called with the iterator state + and the current iterator value. + - Iterator state – an opaque value to be passed to the iterator + function. + - Initial iterator value. + +Usage: + + for fp, mt, contents in pandoc.mediabag.items() do + -- print(fp, mt, contents) + end + ### list {#mediabag-list} `list ()` diff --git a/pandoc.cabal b/pandoc.cabal index ab67b5697..af509b2fd 100644 --- a/pandoc.cabal +++ b/pandoc.cabal @@ -591,6 +591,7 @@ library Text.Pandoc.Lua.Marshaling.AST, Text.Pandoc.Lua.Marshaling.AnyValue, Text.Pandoc.Lua.Marshaling.CommonState, + Text.Pandoc.Lua.Marshaling.MediaBag, Text.Pandoc.Lua.Marshaling.ReaderOptions, Text.Pandoc.Lua.Marshaling.Version, Text.Pandoc.Lua.Module.MediaBag, diff --git a/src/Text/Pandoc/Lua/Marshaling/MediaBag.hs b/src/Text/Pandoc/Lua/Marshaling/MediaBag.hs new file mode 100644 index 000000000..816843c1d --- /dev/null +++ b/src/Text/Pandoc/Lua/Marshaling/MediaBag.hs @@ -0,0 +1,75 @@ +{-# LANGUAGE NoImplicitPrelude #-} +{- | + Module : Text.Pandoc.Lua.Marshaling.MediaBag + Copyright : © 2012-2019 John MacFarlane + © 2017-2019 Albert Krewinkel + License : GNU GPL, version 2 or above + Maintainer : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de> + Stability : alpha + +Instances to marshal (push) and unmarshal (peek) media data. +-} +module Text.Pandoc.Lua.Marshaling.MediaBag (pushIterator) where + +import Prelude +import Foreign.Ptr (Ptr) +import Foreign.StablePtr (StablePtr, deRefStablePtr, newStablePtr) +import Foreign.Lua (Lua, NumResults, Peekable, Pushable, StackIndex) +import Foreign.Lua.Types.Peekable (reportValueOnFailure) +import Foreign.Lua.Userdata (ensureUserdataMetatable, pushAnyWithMetatable, + toAnyWithName) +import Text.Pandoc.MediaBag (MediaBag, mediaItems) +import Text.Pandoc.MIME (MimeType) +import Text.Pandoc.Lua.Marshaling.AnyValue (AnyValue (..)) + +import qualified Data.ByteString.Lazy as BL +import qualified Foreign.Lua as Lua +import qualified Foreign.Storable as Storable + +-- | A list of 'MediaBag' items. +newtype MediaItems = MediaItems [(String, MimeType, BL.ByteString)] + +instance Pushable MediaItems where + push = pushMediaItems + +instance Peekable MediaItems where + peek = peekMediaItems + +-- | Push an iterator triple to be used with Lua's @for@ loop construct. +-- Each iterator invokation returns a tripple consisting of an item's +-- filename, MIME type, and content. +pushIterator :: MediaBag -> Lua NumResults +pushIterator mb = do + Lua.pushHaskellFunction nextItem + Lua.push (MediaItems $ mediaItems mb) + Lua.pushnil + return 3 + +-- | Lua type name for @'MediaItems'@. +mediaItemsTypeName :: String +mediaItemsTypeName = "pandoc MediaItems" + +-- | Push a @MediaItems@ element to the stack. +pushMediaItems :: MediaItems -> Lua () +pushMediaItems xs = pushAnyWithMetatable pushMT xs + where + pushMT = ensureUserdataMetatable mediaItemsTypeName (return ()) + +-- | Retrieve a @MediaItems@ element from the stack. +peekMediaItems :: StackIndex -> Lua MediaItems +peekMediaItems = reportValueOnFailure mediaItemsTypeName + (`toAnyWithName` mediaItemsTypeName) + +-- | Retrieve a list of items from an iterator state, return the first +-- item (if present), and advance the state. +nextItem :: Ptr (StablePtr MediaItems) -> AnyValue -> Lua NumResults +nextItem ptr _ = do + (MediaItems items) <- Lua.liftIO $ deRefStablePtr =<< Storable.peek ptr + case items of + [] -> 2 <$ (Lua.pushnil *> Lua.pushnil) + (key, mt, content):xs -> do + Lua.liftIO $ Storable.poke ptr =<< newStablePtr (MediaItems xs) + Lua.push key + Lua.push mt + Lua.push content + return 3 diff --git a/src/Text/Pandoc/Lua/Module/MediaBag.hs b/src/Text/Pandoc/Lua/Module/MediaBag.hs index 52aeaa1af..ce6303ec6 100644 --- a/src/Text/Pandoc/Lua/Module/MediaBag.hs +++ b/src/Text/Pandoc/Lua/Module/MediaBag.hs @@ -20,6 +20,7 @@ import Foreign.Lua (Lua, NumResults, Optional, liftIO) import Text.Pandoc.Class (CommonState (..), fetchItem, putCommonState, runIOorExplode, setMediaBag) import Text.Pandoc.Lua.Marshaling () +import Text.Pandoc.Lua.Marshaling.MediaBag (pushIterator) import Text.Pandoc.Lua.Util (addFunction) import Text.Pandoc.MIME (MimeType) @@ -34,6 +35,7 @@ pushModule :: Lua NumResults pushModule = do Lua.newtable addFunction "insert" insertMediaFn + addFunction "items" items addFunction "lookup" lookupMediaFn addFunction "list" mediaDirectoryFn addFunction "fetch" fetch @@ -66,9 +68,13 @@ insertMediaFn fp optionalMime contents = do modifyCommonState $ \st -> let mb = MB.insertMedia fp (Lua.fromOptional optionalMime) contents (stMediaBag st) - in st { stMediaBag = mb} + in st { stMediaBag = mb } return 0 +-- | Returns iterator values to be used with a Lua @for@ loop. +items :: Lua NumResults +items = stMediaBag <$> getCommonState >>= pushIterator + lookupMediaFn :: FilePath -> Lua NumResults lookupMediaFn fp = do diff --git a/src/Text/Pandoc/MediaBag.hs b/src/Text/Pandoc/MediaBag.hs index f1e811232..94512b71d 100644 --- a/src/Text/Pandoc/MediaBag.hs +++ b/src/Text/Pandoc/MediaBag.hs @@ -19,6 +19,7 @@ module Text.Pandoc.MediaBag ( lookupMedia, insertMedia, mediaDirectory, + mediaItems ) where import Prelude import qualified Data.ByteString.Lazy as BL @@ -66,3 +67,8 @@ mediaDirectory :: MediaBag -> [(String, MimeType, Int)] mediaDirectory (MediaBag mediamap) = M.foldrWithKey (\fp (mime,contents) -> ((Posix.joinPath fp, mime, fromIntegral $ BL.length contents):)) [] mediamap + +mediaItems :: MediaBag -> [(String, MimeType, BL.ByteString)] +mediaItems (MediaBag mediamap) = + M.foldrWithKey (\fp (mime,contents) -> + ((Posix.joinPath fp, mime, contents):)) [] mediamap |