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{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{- |
Module : Text.Pandoc.MediaBag
Copyright : Copyright (C) 2014-2015, 2017-2021 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Definition of a MediaBag object to hold binary resources, and an
interface for interacting with it.
-}
module Text.Pandoc.MediaBag (
MediaItem(..),
MediaBag,
deleteMedia,
lookupMedia,
insertMedia,
mediaDirectory,
mediaItems
) where
import qualified Data.ByteString.Lazy as BL
import Data.Data (Data)
import qualified Data.Map as M
import Data.Maybe (fromMaybe)
import Data.Typeable (Typeable)
import System.FilePath
import Text.Pandoc.MIME (MimeType, getMimeTypeDef, extensionFromMimeType)
import Data.Text (Text)
import qualified Data.Text as T
import Data.Digest.Pure.SHA (sha1, showDigest)
data MediaItem =
MediaItem
{ mediaMimeType :: MimeType
, mediaPath :: FilePath
, mediaContents :: BL.ByteString
} deriving (Eq, Ord, Show, Data, Typeable)
-- | A container for a collection of binary resources, with names and
-- mime types. Note that a 'MediaBag' is a Monoid, so 'mempty'
-- can be used for an empty 'MediaBag', and '<>' can be used to append
-- two 'MediaBag's.
newtype MediaBag = MediaBag (M.Map Text MediaItem)
deriving (Semigroup, Monoid, Data, Typeable)
instance Show MediaBag where
show bag = "MediaBag " ++ show (mediaDirectory bag)
-- | We represent paths with /, in normalized form.
canonicalize :: FilePath -> Text
canonicalize = T.replace "\\" "/" . T.pack . normalise
-- | Delete a media item from a 'MediaBag', or do nothing if no item corresponds
-- to the given path.
deleteMedia :: FilePath -- ^ relative path and canonical name of resource
-> MediaBag
-> MediaBag
deleteMedia fp (MediaBag mediamap) =
MediaBag $ M.delete (canonicalize fp) mediamap
-- | Insert a media item into a 'MediaBag', replacing any existing
-- value with the same name.
insertMedia :: FilePath -- ^ relative path and canonical name of resource
-> Maybe MimeType -- ^ mime type (Nothing = determine from extension)
-> BL.ByteString -- ^ contents of resource
-> MediaBag
-> MediaBag
insertMedia fp mbMime contents (MediaBag mediamap) =
MediaBag (M.insert fp' mediaItem mediamap)
where mediaItem = MediaItem{ mediaPath = newpath
, mediaContents = contents
, mediaMimeType = mt }
fp' = canonicalize fp
newpath = if isRelative fp && ".." `notElem` splitPath fp
then T.unpack fp'
else showDigest (sha1 contents) <> "." <> ext
fallback = case takeExtension fp of
".gz" -> getMimeTypeDef $ dropExtension fp
_ -> getMimeTypeDef fp
mt = fromMaybe fallback mbMime
ext = case takeExtension fp of
'.':e -> e
_ -> maybe "" T.unpack $ extensionFromMimeType mt
-- | Lookup a media item in a 'MediaBag', returning mime type and contents.
lookupMedia :: FilePath
-> MediaBag
-> Maybe MediaItem
lookupMedia fp (MediaBag mediamap) = M.lookup (canonicalize fp) mediamap
-- | Get a list of the file paths stored in a 'MediaBag', with
-- their corresponding mime types and the lengths in bytes of the contents.
mediaDirectory :: MediaBag -> [(FilePath, MimeType, Int)]
mediaDirectory mediabag =
map (\(fp, mt, bs) -> (fp, mt, fromIntegral (BL.length bs)))
(mediaItems mediabag)
mediaItems :: MediaBag -> [(FilePath, MimeType, BL.ByteString)]
mediaItems (MediaBag mediamap) =
map (\item -> (mediaPath item, mediaMimeType item, mediaContents item))
(M.elems mediamap)
|
