{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}

module Network.HTTP2.Frame.Decode (
  -- * Decoding
    decodeFrame
  , decodeFrameHeader
  , checkFrameHeader
  , FrameDecodeError(..)
  -- * Decoding payload
  , decodeFramePayload
  , FramePayloadDecoder
  , decodeDataFrame
  , decodeHeadersFrame
  , decodePriorityFrame
  , decoderstStreamFrame
  , decodeSettingsFrame
  , decodePushPromiseFrame
  , decodePingFrame
  , decodeGoAwayFrame
  , decodeWindowUpdateFrame
  , decodeContinuationFrame
  ) where

import Data.Array (Array, listArray, (!))
import qualified Data.ByteString as BS
import Foreign.Ptr (Ptr, plusPtr)
import qualified Network.ByteOrder as N
import System.IO.Unsafe (unsafeDupablePerformIO)

import Imports
import Network.HTTP2.Frame.Types

----------------------------------------------------------------

data FrameDecodeError = FrameDecodeError ErrorCode StreamId ShortByteString
                        deriving (FrameDecodeError -> FrameDecodeError -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: FrameDecodeError -> FrameDecodeError -> Bool
$c/= :: FrameDecodeError -> FrameDecodeError -> Bool
== :: FrameDecodeError -> FrameDecodeError -> Bool
$c== :: FrameDecodeError -> FrameDecodeError -> Bool
Eq, Int -> FrameDecodeError -> ShowS
[FrameDecodeError] -> ShowS
FrameDecodeError -> String
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [FrameDecodeError] -> ShowS
$cshowList :: [FrameDecodeError] -> ShowS
show :: FrameDecodeError -> String
$cshow :: FrameDecodeError -> String
showsPrec :: Int -> FrameDecodeError -> ShowS
$cshowsPrec :: Int -> FrameDecodeError -> ShowS
Show)

----------------------------------------------------------------

-- | Decoding an HTTP/2 frame to 'ByteString'.
-- The second argument must be include the entire of frame.
-- So, this function is not useful for real applications
-- but useful for testing.
decodeFrame :: Settings    -- ^ HTTP/2 settings
            -> ByteString  -- ^ Input byte-stream
            -> Either FrameDecodeError Frame -- ^ Decoded frame
decodeFrame :: Settings -> ByteString -> Either FrameDecodeError Frame
decodeFrame Settings
settings ByteString
bs = Settings
-> (FrameType, FrameHeader)
-> Either FrameDecodeError (FrameType, FrameHeader)
checkFrameHeader Settings
settings (ByteString -> (FrameType, FrameHeader)
decodeFrameHeader ByteString
bs0)
                      forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \(FrameType
typ,FrameHeader
header) -> FrameType -> FramePayloadDecoder
decodeFramePayload FrameType
typ FrameHeader
header ByteString
bs1
                      forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \FramePayload
payload -> forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ FrameHeader -> FramePayload -> Frame
Frame FrameHeader
header FramePayload
payload
  where
    (ByteString
bs0,ByteString
bs1) = Int -> ByteString -> (ByteString, ByteString)
BS.splitAt Int
9 ByteString
bs

----------------------------------------------------------------

-- | Decoding an HTTP/2 frame header.
--   Must supply 9 bytes.
decodeFrameHeader :: ByteString -> (FrameType, FrameHeader)
decodeFrameHeader :: ByteString -> (FrameType, FrameHeader)
decodeFrameHeader (PS ForeignPtr Word8
fptr Int
off Int
_) = forall a. IO a -> a
unsafeDupablePerformIO forall a b. (a -> b) -> a -> b
$ forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
withForeignPtr ForeignPtr Word8
fptr forall a b. (a -> b) -> a -> b
$ \Ptr Word8
ptr -> do
    let p :: Ptr Word8
p = Ptr Word8
ptr Ptr Word8 -> Int -> Ptr Word8
+. Int
off
    Int
len <- forall a b. (Integral a, Num b) => a -> b
fromIntegral forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Ptr Word8 -> Int -> IO Word32
N.peek24 Ptr Word8
p Int
0
    FrameType
typ <- Word8 -> FrameType
toFrameType  forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Ptr Word8 -> Int -> IO Word8
N.peek8  Ptr Word8
p Int
3
    Word8
flg <-                  Ptr Word8 -> Int -> IO Word8
N.peek8  Ptr Word8
p Int
4
    Word32
w32 <-                  Ptr Word8 -> Int -> IO Word32
N.peek32 Ptr Word8
p Int
5
    let sid :: Int
sid = Word32 -> Int
streamIdentifier Word32
w32
    forall (m :: * -> *) a. Monad m => a -> m a
return (FrameType
typ, Int -> Word8 -> Int -> FrameHeader
FrameHeader Int
len Word8
flg Int
sid)

(+.) :: Ptr Word8 -> Int -> Ptr Word8
+. :: Ptr Word8 -> Int -> Ptr Word8
(+.) = forall a b. Ptr a -> Int -> Ptr b
plusPtr

----------------------------------------------------------------

-- | Checking a frame header and reporting an error if any.
--
-- >>> checkFrameHeader defaultSettings (FrameData,(FrameHeader 100 0 0))
-- Left (FrameDecodeError ProtocolError 0 "cannot used in control stream")
checkFrameHeader :: Settings
                 -> (FrameType, FrameHeader)
                 -> Either FrameDecodeError (FrameType, FrameHeader)
checkFrameHeader :: Settings
-> (FrameType, FrameHeader)
-> Either FrameDecodeError (FrameType, FrameHeader)
checkFrameHeader Settings {Bool
Int
Maybe Int
maxHeaderBlockSize :: Settings -> Maybe Int
maxFrameSize :: Settings -> Int
initialWindowSize :: Settings -> Int
maxConcurrentStreams :: Settings -> Maybe Int
enablePush :: Settings -> Bool
headerTableSize :: Settings -> Int
maxHeaderBlockSize :: Maybe Int
maxFrameSize :: Int
initialWindowSize :: Int
maxConcurrentStreams :: Maybe Int
enablePush :: Bool
headerTableSize :: Int
..} typfrm :: (FrameType, FrameHeader)
typfrm@(FrameType
typ,FrameHeader{Int
Word8
streamId :: FrameHeader -> Int
flags :: FrameHeader -> Word8
payloadLength :: FrameHeader -> Int
streamId :: Int
flags :: Word8
payloadLength :: Int
..})
  | Int
payloadLength forall a. Ord a => a -> a -> Bool
> Int
maxFrameSize =
      forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"exceeds maximum frame size"
  | FrameType
typ forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [FrameType]
nonZeroFrameTypes Bool -> Bool -> Bool
&& Int -> Bool
isControl Int
streamId =
      forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
ProtocolError Int
streamId ShortByteString
"cannot used in control stream"
  | FrameType
typ forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [FrameType]
zeroFrameTypes Bool -> Bool -> Bool
&& Bool -> Bool
not (Int -> Bool
isControl Int
streamId) =
      forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
ProtocolError Int
streamId ShortByteString
"cannot used in non-zero stream"
  | Bool
otherwise = FrameType -> Either FrameDecodeError (FrameType, FrameHeader)
checkType FrameType
typ
  where
    checkType :: FrameType -> Either FrameDecodeError (FrameType, FrameHeader)
checkType FrameType
FrameHeaders
      | Word8 -> Bool
testPadded Word8
flags Bool -> Bool -> Bool
&& Int
payloadLength forall a. Ord a => a -> a -> Bool
< Int
1 =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"insufficient payload for Pad Length"
      | Word8 -> Bool
testPriority Word8
flags Bool -> Bool -> Bool
&& Int
payloadLength forall a. Ord a => a -> a -> Bool
< Int
5 =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"insufficient payload for priority fields"
      | Word8 -> Bool
testPadded Word8
flags Bool -> Bool -> Bool
&& Word8 -> Bool
testPriority Word8
flags Bool -> Bool -> Bool
&& Int
payloadLength forall a. Ord a => a -> a -> Bool
< Int
6 =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"insufficient payload for Pad Length and priority fields"
    checkType FrameType
FramePriority | Int
payloadLength forall a. Eq a => a -> a -> Bool
/= Int
5 =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"payload length is not 5 in priority frame"
    checkType FrameType
FrameRSTStream | Int
payloadLength forall a. Eq a => a -> a -> Bool
/= Int
4 =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"payload length is not 4 in rst stream frame"
    checkType FrameType
FrameSettings
      | Int
payloadLength forall a. Integral a => a -> a -> a
`mod` Int
6 forall a. Eq a => a -> a -> Bool
/= Int
0 =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"payload length is not multiple of 6 in settings frame"
      | Word8 -> Bool
testAck Word8
flags Bool -> Bool -> Bool
&& Int
payloadLength forall a. Eq a => a -> a -> Bool
/= Int
0 =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"payload length must be 0 if ack flag is set"
    checkType FrameType
FramePushPromise
      | Bool -> Bool
not Bool
enablePush =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
ProtocolError Int
streamId ShortByteString
"push not enabled" -- checkme
      | Int -> Bool
isClientInitiated Int
streamId =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
ProtocolError Int
streamId ShortByteString
"push promise must be used with even stream identifier"
    checkType FrameType
FramePing | Int
payloadLength forall a. Eq a => a -> a -> Bool
/= Int
8 =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"payload length is 8 in ping frame"
    checkType FrameType
FrameGoAway | Int
payloadLength forall a. Ord a => a -> a -> Bool
< Int
8 =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"goaway body must be 8 bytes or larger"
    checkType FrameType
FrameWindowUpdate | Int
payloadLength forall a. Eq a => a -> a -> Bool
/= Int
4 =
        forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"payload length is 4 in window update frame"
    checkType FrameType
_ = forall a b. b -> Either a b
Right (FrameType, FrameHeader)
typfrm

zeroFrameTypes :: [FrameType]
zeroFrameTypes :: [FrameType]
zeroFrameTypes = [
    FrameType
FrameSettings
  , FrameType
FramePing
  , FrameType
FrameGoAway
  ]

nonZeroFrameTypes :: [FrameType]
nonZeroFrameTypes :: [FrameType]
nonZeroFrameTypes = [
    FrameType
FrameData
  , FrameType
FrameHeaders
  , FrameType
FramePriority
  , FrameType
FrameRSTStream
  , FrameType
FramePushPromise
  , FrameType
FrameContinuation
  ]

----------------------------------------------------------------

-- | The type for frame payload decoder.
type FramePayloadDecoder = FrameHeader -> ByteString
                        -> Either FrameDecodeError FramePayload

payloadDecoders :: Array FrameType FramePayloadDecoder
payloadDecoders :: Array FrameType FramePayloadDecoder
payloadDecoders = forall i e. Ix i => (i, i) -> [e] -> Array i e
listArray (FrameType
minFrameType, FrameType
maxFrameType)
    [ FramePayloadDecoder
decodeDataFrame
    , FramePayloadDecoder
decodeHeadersFrame
    , FramePayloadDecoder
decodePriorityFrame
    , FramePayloadDecoder
decoderstStreamFrame
    , FramePayloadDecoder
decodeSettingsFrame
    , FramePayloadDecoder
decodePushPromiseFrame
    , FramePayloadDecoder
decodePingFrame
    , FramePayloadDecoder
decodeGoAwayFrame
    , FramePayloadDecoder
decodeWindowUpdateFrame
    , FramePayloadDecoder
decodeContinuationFrame
    ]

-- | Decoding an HTTP/2 frame payload.
--   This function is considered to return a frame payload decoder
--   according to a frame type.
decodeFramePayload :: FrameType -> FramePayloadDecoder
decodeFramePayload :: FrameType -> FramePayloadDecoder
decodeFramePayload FrameType
ftyp
    | FrameType
ftyp forall a. Ord a => a -> a -> Bool
> FrameType
maxFrameType = FramePayloadDecoder -> FramePayloadDecoder
checkFrameSize forall a b. (a -> b) -> a -> b
$ FrameType -> FramePayloadDecoder
decodeUnknownFrame FrameType
ftyp
decodeFramePayload FrameType
ftyp   = FramePayloadDecoder -> FramePayloadDecoder
checkFrameSize FramePayloadDecoder
decoder
  where
    decoder :: FramePayloadDecoder
decoder = Array FrameType FramePayloadDecoder
payloadDecoders forall i e. Ix i => Array i e -> i -> e
! FrameType
ftyp

----------------------------------------------------------------

-- | Frame payload decoder for DATA frame.
decodeDataFrame :: FramePayloadDecoder
decodeDataFrame :: FramePayloadDecoder
decodeDataFrame FrameHeader
header ByteString
bs = FrameHeader
-> ByteString
-> (ByteString -> FramePayload)
-> Either FrameDecodeError FramePayload
decodeWithPadding FrameHeader
header ByteString
bs ByteString -> FramePayload
DataFrame

-- | Frame payload decoder for HEADERS frame.
decodeHeadersFrame :: FramePayloadDecoder
decodeHeadersFrame :: FramePayloadDecoder
decodeHeadersFrame FrameHeader
header ByteString
bs = FrameHeader
-> ByteString
-> (ByteString -> FramePayload)
-> Either FrameDecodeError FramePayload
decodeWithPadding FrameHeader
header ByteString
bs forall a b. (a -> b) -> a -> b
$ \ByteString
bs' ->
    if Bool
hasPriority then
        let (ByteString
bs0,ByteString
bs1) = Int -> ByteString -> (ByteString, ByteString)
BS.splitAt Int
5 ByteString
bs'
            p :: Priority
p = ByteString -> Priority
priority ByteString
bs0
        in Maybe Priority -> ByteString -> FramePayload
HeadersFrame (forall a. a -> Maybe a
Just Priority
p) ByteString
bs1
    else
        Maybe Priority -> ByteString -> FramePayload
HeadersFrame forall a. Maybe a
Nothing ByteString
bs'
  where
    hasPriority :: Bool
hasPriority = Word8 -> Bool
testPriority forall a b. (a -> b) -> a -> b
$ FrameHeader -> Word8
flags FrameHeader
header

-- | Frame payload decoder for PRIORITY frame.
decodePriorityFrame :: FramePayloadDecoder
decodePriorityFrame :: FramePayloadDecoder
decodePriorityFrame FrameHeader
_ ByteString
bs = forall a b. b -> Either a b
Right forall a b. (a -> b) -> a -> b
$ Priority -> FramePayload
PriorityFrame forall a b. (a -> b) -> a -> b
$ ByteString -> Priority
priority ByteString
bs

-- | Frame payload decoder for RST_STREAM frame.
decoderstStreamFrame :: FramePayloadDecoder
decoderstStreamFrame :: FramePayloadDecoder
decoderstStreamFrame FrameHeader
_ ByteString
bs = forall a b. b -> Either a b
Right forall a b. (a -> b) -> a -> b
$ ErrorCode -> FramePayload
RSTStreamFrame forall a b. (a -> b) -> a -> b
$ Word32 -> ErrorCode
toErrorCode (ByteString -> Word32
N.word32 ByteString
bs)

-- | Frame payload decoder for SETTINGS frame.
decodeSettingsFrame :: FramePayloadDecoder
decodeSettingsFrame :: FramePayloadDecoder
decodeSettingsFrame FrameHeader{Int
Word8
streamId :: Int
flags :: Word8
payloadLength :: Int
streamId :: FrameHeader -> Int
flags :: FrameHeader -> Word8
payloadLength :: FrameHeader -> Int
..} (PS ForeignPtr Word8
fptr Int
off Int
_)
  | Int
num forall a. Ord a => a -> a -> Bool
> Int
10  = forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
EnhanceYourCalm Int
streamId ShortByteString
"Settings is too large"
  | Bool
otherwise = forall a b. b -> Either a b
Right forall a b. (a -> b) -> a -> b
$ SettingsList -> FramePayload
SettingsFrame SettingsList
alist
  where
    num :: Int
num = Int
payloadLength forall a. Integral a => a -> a -> a
`div` Int
6
    alist :: SettingsList
alist = forall a. IO a -> a
unsafeDupablePerformIO forall a b. (a -> b) -> a -> b
$ forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
withForeignPtr ForeignPtr Word8
fptr forall a b. (a -> b) -> a -> b
$ \Ptr Word8
ptr -> do
        let p :: Ptr Word8
p = Ptr Word8
ptr Ptr Word8 -> Int -> Ptr Word8
+. Int
off
        forall {t} {b} {a}.
(Eq t, Num t, Num b) =>
t -> Ptr Word8 -> ([(SettingsKey, b)] -> a) -> IO a
settings Int
num Ptr Word8
p forall a. a -> a
id
    settings :: t -> Ptr Word8 -> ([(SettingsKey, b)] -> a) -> IO a
settings t
0 Ptr Word8
_ [(SettingsKey, b)] -> a
builder = forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ [(SettingsKey, b)] -> a
builder []
    settings t
n Ptr Word8
p [(SettingsKey, b)] -> a
builder = do
        Word16
rawSetting <- Ptr Word8 -> Int -> IO Word16
N.peek16 Ptr Word8
p Int
0
        let k :: SettingsKey
k = Word16 -> SettingsKey
toSettingsKey Word16
rawSetting
            n' :: t
n' = t
n forall a. Num a => a -> a -> a
- t
1
        if SettingsKey
k forall a. Ord a => a -> a -> Bool
< SettingsKey
minSettingsKey Bool -> Bool -> Bool
|| SettingsKey
k forall a. Ord a => a -> a -> Bool
> SettingsKey
maxSettingsKey then
            t -> Ptr Word8 -> ([(SettingsKey, b)] -> a) -> IO a
settings t
n' (Ptr Word8
p Ptr Word8 -> Int -> Ptr Word8
+. Int
6) [(SettingsKey, b)] -> a
builder -- ignoring unknown one (Section 6.5.2)
          else do
            Word32
w32 <- Ptr Word8 -> Int -> IO Word32
N.peek32 Ptr Word8
p Int
2
            let v :: b
v = forall a b. (Integral a, Num b) => a -> b
fromIntegral Word32
w32
            t -> Ptr Word8 -> ([(SettingsKey, b)] -> a) -> IO a
settings t
n' (Ptr Word8
p Ptr Word8 -> Int -> Ptr Word8
+. Int
6) ([(SettingsKey, b)] -> a
builderforall b c a. (b -> c) -> (a -> b) -> a -> c
. ((SettingsKey
k,b
v)forall a. a -> [a] -> [a]
:))

-- | Frame payload decoder for PUSH_PROMISE frame.
decodePushPromiseFrame :: FramePayloadDecoder
decodePushPromiseFrame :: FramePayloadDecoder
decodePushPromiseFrame FrameHeader
header ByteString
bs = FrameHeader
-> ByteString
-> (ByteString -> FramePayload)
-> Either FrameDecodeError FramePayload
decodeWithPadding FrameHeader
header ByteString
bs forall a b. (a -> b) -> a -> b
$ \ByteString
bs' ->
    let (ByteString
bs0,ByteString
bs1) = Int -> ByteString -> (ByteString, ByteString)
BS.splitAt Int
4 ByteString
bs'
        sid :: Int
sid = Word32 -> Int
streamIdentifier (ByteString -> Word32
N.word32 ByteString
bs0)
    in Int -> ByteString -> FramePayload
PushPromiseFrame Int
sid ByteString
bs1

-- | Frame payload decoder for PING frame.
decodePingFrame :: FramePayloadDecoder
decodePingFrame :: FramePayloadDecoder
decodePingFrame FrameHeader
_ ByteString
bs = forall a b. b -> Either a b
Right forall a b. (a -> b) -> a -> b
$ ByteString -> FramePayload
PingFrame ByteString
bs

-- | Frame payload decoder for GOAWAY frame.
decodeGoAwayFrame :: FramePayloadDecoder
decodeGoAwayFrame :: FramePayloadDecoder
decodeGoAwayFrame FrameHeader
_ ByteString
bs = forall a b. b -> Either a b
Right forall a b. (a -> b) -> a -> b
$ Int -> ErrorCode -> ByteString -> FramePayload
GoAwayFrame Int
sid ErrorCode
ecid ByteString
bs2
  where
    (ByteString
bs0,ByteString
bs1') = Int -> ByteString -> (ByteString, ByteString)
BS.splitAt Int
4 ByteString
bs
    (ByteString
bs1,ByteString
bs2)  = Int -> ByteString -> (ByteString, ByteString)
BS.splitAt Int
4 ByteString
bs1'
    sid :: Int
sid = Word32 -> Int
streamIdentifier (ByteString -> Word32
N.word32 ByteString
bs0)
    ecid :: ErrorCode
ecid = Word32 -> ErrorCode
toErrorCode (ByteString -> Word32
N.word32 ByteString
bs1)

-- | Frame payload decoder for WINDOW_UPDATE frame.
decodeWindowUpdateFrame :: FramePayloadDecoder
decodeWindowUpdateFrame :: FramePayloadDecoder
decodeWindowUpdateFrame FrameHeader{Int
Word8
streamId :: Int
flags :: Word8
payloadLength :: Int
streamId :: FrameHeader -> Int
flags :: FrameHeader -> Word8
payloadLength :: FrameHeader -> Int
..} ByteString
bs
  | Int
wsi forall a. Eq a => a -> a -> Bool
== Int
0  = forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
ProtocolError Int
streamId ShortByteString
"window update must not be 0"
  | Bool
otherwise = forall a b. b -> Either a b
Right forall a b. (a -> b) -> a -> b
$ Int -> FramePayload
WindowUpdateFrame Int
wsi
  where
    wsi :: Int
wsi = forall a b. (Integral a, Num b) => a -> b
fromIntegral (ByteString -> Word32
N.word32 ByteString
bs forall a. Bits a => a -> Int -> a
`clearBit` Int
31)

-- | Frame payload decoder for CONTINUATION frame.
decodeContinuationFrame :: FramePayloadDecoder
decodeContinuationFrame :: FramePayloadDecoder
decodeContinuationFrame FrameHeader
_ ByteString
bs = forall a b. b -> Either a b
Right forall a b. (a -> b) -> a -> b
$ ByteString -> FramePayload
ContinuationFrame ByteString
bs

decodeUnknownFrame :: FrameType -> FramePayloadDecoder
decodeUnknownFrame :: FrameType -> FramePayloadDecoder
decodeUnknownFrame FrameType
typ FrameHeader
_ ByteString
bs = forall a b. b -> Either a b
Right forall a b. (a -> b) -> a -> b
$ FrameType -> ByteString -> FramePayload
UnknownFrame FrameType
typ ByteString
bs

----------------------------------------------------------------

checkFrameSize :: FramePayloadDecoder -> FramePayloadDecoder
checkFrameSize :: FramePayloadDecoder -> FramePayloadDecoder
checkFrameSize FramePayloadDecoder
func header :: FrameHeader
header@FrameHeader{Int
Word8
streamId :: Int
flags :: Word8
payloadLength :: Int
streamId :: FrameHeader -> Int
flags :: FrameHeader -> Word8
payloadLength :: FrameHeader -> Int
..} ByteString
body
  | Int
payloadLength forall a. Ord a => a -> a -> Bool
> ByteString -> Int
BS.length ByteString
body =
      forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
FrameSizeError Int
streamId ShortByteString
"payload is too short"
  | Bool
otherwise = FramePayloadDecoder
func FrameHeader
header ByteString
body

-- | Helper function to pull off the padding if its there, and will
-- eat up the trailing padding automatically. Calls the decoder func
-- passed in with the length of the unpadded portion between the
-- padding octet and the actual padding
decodeWithPadding :: FrameHeader -> ByteString -> (ByteString -> FramePayload) -> Either FrameDecodeError FramePayload
decodeWithPadding :: FrameHeader
-> ByteString
-> (ByteString -> FramePayload)
-> Either FrameDecodeError FramePayload
decodeWithPadding FrameHeader{Int
Word8
streamId :: Int
flags :: Word8
payloadLength :: Int
streamId :: FrameHeader -> Int
flags :: FrameHeader -> Word8
payloadLength :: FrameHeader -> Int
..} ByteString
bs ByteString -> FramePayload
body
  | Bool
padded = let (Word8
w8,ByteString
rest) = forall a. a -> Maybe a -> a
fromMaybe (forall a. HasCallStack => String -> a
error String
"decodeWithPadding") forall a b. (a -> b) -> a -> b
$ ByteString -> Maybe (Word8, ByteString)
BS.uncons ByteString
bs
                 padlen :: Int
padlen = Word8 -> Int
intFromWord8 Word8
w8
                 bodylen :: Int
bodylen = Int
payloadLength forall a. Num a => a -> a -> a
- Int
padlen forall a. Num a => a -> a -> a
- Int
1
             in if Int
bodylen forall a. Ord a => a -> a -> Bool
< Int
0 then
                    forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ ErrorCode -> Int -> ShortByteString -> FrameDecodeError
FrameDecodeError ErrorCode
ProtocolError Int
streamId ShortByteString
"padding is not enough"
                  else
                    forall a b. b -> Either a b
Right forall b c a. (b -> c) -> (a -> b) -> a -> c
. ByteString -> FramePayload
body forall a b. (a -> b) -> a -> b
$ Int -> ByteString -> ByteString
BS.take Int
bodylen ByteString
rest
  | Bool
otherwise = forall a b. b -> Either a b
Right forall a b. (a -> b) -> a -> b
$ ByteString -> FramePayload
body ByteString
bs
  where
    padded :: Bool
padded = Word8 -> Bool
testPadded Word8
flags

streamIdentifier :: Word32 -> StreamId
streamIdentifier :: Word32 -> Int
streamIdentifier Word32
w32 = Int -> Int
clearExclusive forall a b. (a -> b) -> a -> b
$ forall a b. (Integral a, Num b) => a -> b
fromIntegral Word32
w32

priority :: ByteString -> Priority
priority :: ByteString -> Priority
priority (PS ForeignPtr Word8
fptr Int
off Int
_) = forall a. IO a -> a
unsafeDupablePerformIO forall a b. (a -> b) -> a -> b
$ forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
withForeignPtr ForeignPtr Word8
fptr forall a b. (a -> b) -> a -> b
$ \Ptr Word8
ptr -> do
    let p :: Ptr Word8
p = Ptr Word8
ptr Ptr Word8 -> Int -> Ptr Word8
+. Int
off
    Word32
w32 <- Ptr Word8 -> Int -> IO Word32
N.peek32 Ptr Word8
p Int
0
    let streamdId :: Int
streamdId = Word32 -> Int
streamIdentifier Word32
w32
        exclusive :: Bool
exclusive = Int -> Bool
testExclusive (forall a b. (Integral a, Num b) => a -> b
fromIntegral Word32
w32) -- fixme
    Word8
w8 <- Ptr Word8 -> Int -> IO Word8
N.peek8 Ptr Word8
p Int
4
    let weight :: Int
weight = Word8 -> Int
intFromWord8 Word8
w8 forall a. Num a => a -> a -> a
+ Int
1
    forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ Bool -> Int -> Int -> Priority
Priority Bool
exclusive Int
streamdId Int
weight

intFromWord8 :: Word8 -> Int
intFromWord8 :: Word8 -> Int
intFromWord8 = forall a b. (Integral a, Num b) => a -> b
fromIntegral