112 lines
2.4 KiB
Go
112 lines
2.4 KiB
Go
package buffer
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import (
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"bytes"
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"encoding/binary"
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"encoding/gob"
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"io/ioutil"
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"os"
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"sync"
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)
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// Pool provides a way to Allocate and Release Buffer objects
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// Pools mut be concurrent-safe for calls to Get() and Put().
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type Pool interface {
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Get() (Buffer, error) // Allocate a Buffer
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Put(buf Buffer) error // Release or Reuse a Buffer
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}
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type pool struct {
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pool sync.Pool
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}
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// NewPool returns a Pool(), it's backed by a sync.Pool so its safe for concurrent use.
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// Get() and Put() errors will always be nil.
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// It will not work with gob.
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func NewPool(New func() Buffer) Pool {
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return &pool{
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pool: sync.Pool{
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New: func() interface{} {
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return New()
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},
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},
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}
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}
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func (p *pool) Get() (Buffer, error) {
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return p.pool.Get().(Buffer), nil
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}
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func (p *pool) Put(buf Buffer) error {
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buf.Reset()
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p.pool.Put(buf)
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return nil
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}
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type memPool struct {
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N int64
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Pool
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}
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// NewMemPool returns a Pool, Get() returns an in memory buffer of max size N.
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// Put() returns the buffer to the pool after resetting it.
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// Get() and Put() errors will always be nil.
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func NewMemPool(N int64) Pool {
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return &memPool{
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N: N,
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Pool: NewPool(func() Buffer {
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return New(N)
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}),
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}
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}
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func (m *memPool) MarshalBinary() ([]byte, error) {
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buf := bytes.NewBuffer(nil)
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err := binary.Write(buf, binary.LittleEndian, m.N)
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return buf.Bytes(), err
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}
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func (m *memPool) UnmarshalBinary(data []byte) error {
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buf := bytes.NewReader(data)
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err := binary.Read(buf, binary.LittleEndian, &m.N)
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m.Pool = NewPool(func() Buffer {
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return New(m.N)
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})
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return err
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}
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type filePool struct {
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N int64
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Directory string
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}
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// NewFilePool returns a Pool, Get() returns a file-based buffer of max size N.
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// Put() closes and deletes the underlying file for the buffer.
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// Get() may return an error if it fails to create a file for the buffer.
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// Put() may return an error if it fails to delete the file.
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func NewFilePool(N int64, dir string) Pool {
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return &filePool{N: N, Directory: dir}
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}
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func (p *filePool) Get() (Buffer, error) {
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file, err := ioutil.TempFile(p.Directory, "buffer")
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if err != nil {
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return nil, err
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}
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return NewFile(p.N, file), nil
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}
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func (p *filePool) Put(buf Buffer) (err error) {
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buf.Reset()
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if fileBuf, ok := buf.(*fileBuffer); ok {
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fileBuf.file.Close()
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err = os.Remove(fileBuf.file.Name())
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}
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return err
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}
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func init() {
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gob.Register(&memPool{})
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gob.Register(&filePool{})
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}
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