Data.Conduit.ByteString.Builder

conduit-extra-1.1.16: Batteries included conduit: adapters for common libraries.

Safe Haskell | None
Language | Haskell98

Data.Conduit.ByteString.Builder

Contents

- Conduits from builders to bytestrings
  - Flush
- Buffers
  - Status information
  - Creation and modification
  - Conversion to bytestings
- Buffer allocation strategies

Description

Convert a stream of blaze-builder `Builder`s into a stream of `ByteString`s.

Works with both blaze-builder < 0.4's `Builder`s and `Builder`.

Adapted from blaze-builder-enumerator, written by myself and Simon Meier.

Note that the functions here can work in any monad built on top of `IO` or `ST`.

Since 1.1.7.0

Synopsis

- builderToByteString :: (MonadBase base m, PrimMonad base, StreamingBuilder b) => Conduit b m ByteString
- unsafeBuilderToByteString :: (MonadBase base m, PrimMonad base, StreamingBuilder b) => IO Buffer -> Conduit b m ByteString
- builderToByteStringWith :: (MonadBase base m, PrimMonad base, StreamingBuilder b) => BufferAllocStrategy -> Conduit b m ByteString
- builderToByteStringFlush :: (MonadBase base m, PrimMonad base, StreamingBuilder b) => Conduit (Flush b) m (Flush ByteString)
- builderToByteStringWithFlush :: (MonadBase base m, PrimMonad base, StreamingBuilder b) => BufferAllocStrategy -> Conduit (Flush b) m (Flush ByteString)
- data Buffer :: *
- freeSize :: Buffer -> Int
- sliceSize :: Buffer -> Int
- bufferSize :: Buffer -> Int
- allocBuffer :: Int -> IO Buffer
- reuseBuffer :: Buffer -> Buffer
- nextSlice :: Int -> Buffer -> Maybe Buffer
- unsafeFreezeBuffer :: Buffer -> ByteString
- unsafeFreezeNonEmptyBuffer :: Buffer -> Maybe ByteString
- type BufferAllocStrategy = (IO Buffer, Int -> Buffer -> IO (IO Buffer))
- allNewBuffersStrategy :: Int -> BufferAllocStrategy
- reuseBufferStrategy :: IO Buffer -> BufferAllocStrategy

# Conduits from builders to bytestrings

builderToByteString :: (MonadBase base m, PrimMonad base, StreamingBuilder b) => Conduit b m ByteString #

Incrementally execute builders and pass on the filled chunks as bytestrings.

unsafeBuilderToByteString :: (MonadBase base m, PrimMonad base, StreamingBuilder b) => IO Buffer -> Conduit b m ByteString #

Incrementally execute builders on the given buffer and pass on the filled chunks as bytestrings. Note that, if the given buffer is too small for the execution of a build step, a larger one will be allocated.

WARNING: This conduit yields bytestrings that are NOT referentially transparent. Their content will be overwritten as soon as control is returned from the inner sink!

builderToByteStringWith :: (MonadBase base m, PrimMonad base, StreamingBuilder b) => BufferAllocStrategy -> Conduit b m ByteString #

A conduit that incrementally executes builders and passes on the filled chunks as bytestrings to an inner sink.

INV: All bytestrings passed to the inner sink are non-empty.

## Flush

builderToByteStringFlush :: (MonadBase base m, PrimMonad base, StreamingBuilder b) => Conduit (Flush b) m (Flush ByteString) #

Since 0.0.2

builderToByteStringWithFlush :: (MonadBase base m, PrimMonad base, StreamingBuilder b) => BufferAllocStrategy -> Conduit (Flush b) m (Flush ByteString) #

Since 0.0.2

# Buffers

data Buffer :: * #

A buffer `Buffer fpbuf p0 op ope` describes a buffer with the underlying byte array `fpbuf..ope`, the currently written slice `p0..op` and the free space `op..ope`.

Since 0.1.10.0

## Status information

freeSize :: Buffer -> Int #

The size of the free space of the buffer.

Since 0.1.10.0

sliceSize :: Buffer -> Int #

The size of the written slice in the buffer.

Since 0.1.10.0

bufferSize :: Buffer -> Int #

The size of the whole byte array underlying the buffer.

Since 0.1.10.0

## Creation and modification

allocBuffer :: Int -> IO Buffer #

`allocBuffer size` allocates a new buffer of size `size`.

Since 0.1.10.0

reuseBuffer :: Buffer -> Buffer #

Resets the beginning of the next slice and the next free byte such that the whole buffer can be filled again.

Since 0.1.10.0

nextSlice :: Int -> Buffer -> Maybe Buffer #

Move the beginning of the slice to the next free byte such that the remaining free space of the buffer can be filled further. This operation is safe and can be used to fill the remaining part of the buffer after a direct insertion of a bytestring or a flush.

Since 0.1.10.0

## Conversion to bytestings

unsafeFreezeBuffer :: Buffer -> ByteString #

Convert the buffer to a bytestring. This operation is unsafe in the sense that created bytestring shares the underlying byte array with the buffer. Hence, depending on the later use of this buffer (e.g., if it gets reset and filled again) referential transparency may be lost.

Since 0.1.10.0

unsafeFreezeNonEmptyBuffer :: Buffer -> Maybe ByteString #

Convert a buffer to a non-empty bytestring. See `unsafeFreezeBuffer` for the explanation of why this operation may be unsafe.

Since 0.1.10.0

# Buffer allocation strategies

type BufferAllocStrategy = (IO Buffer, Int -> Buffer -> IO (IO Buffer)) #

A buffer allocation strategy `(buf0, nextBuf)` specifies the initial buffer to use and how to compute a new buffer `nextBuf minSize buf` with at least size `minSize` from a filled buffer `buf`. The double nesting of the `IO` monad helps to ensure that the reference to the filled buffer `buf` is lost as soon as possible, but the new buffer doesn't have to be allocated too early.

Since 0.1.10.0

allNewBuffersStrategy :: Int -> BufferAllocStrategy #

The simplest buffer allocation strategy: whenever a buffer is requested, allocate a new one that is big enough for the next build step to execute.

NOTE that this allocation strategy may spill quite some memory upon direct insertion of a bytestring by the builder. Thats no problem for garbage collection, but it may lead to unreasonably high memory consumption in special circumstances.

Since 0.1.10.0

reuseBufferStrategy :: IO Buffer -> BufferAllocStrategy #

An unsafe, but possibly more efficient buffer allocation strategy: reuse the buffer, if it is big enough for the next build step to execute.

Since 0.1.10.0