mirror of https://github.com/tidwall/tile38.git
152 lines
3.0 KiB
Go
152 lines
3.0 KiB
Go
// Copyright 2014 Gary Burd
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//
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// Licensed under the Apache License, Version 2.0 (the "License"): you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations
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// under the License.
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package redisx
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import (
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"errors"
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"sync"
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"github.com/gomodule/redigo/redis"
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)
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// ConnMux multiplexes one or more connections to a single underlying
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// connection. The ConnMux connections do not support concurrency, commands
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// that associate server side state with the connection or commands that put
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// the connection in a special mode.
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type ConnMux struct {
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c redis.Conn
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sendMu sync.Mutex
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sendID uint
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recvMu sync.Mutex
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recvID uint
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recvWait map[uint]chan struct{}
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}
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func NewConnMux(c redis.Conn) *ConnMux {
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return &ConnMux{c: c, recvWait: make(map[uint]chan struct{})}
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}
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// Get gets a connection. The application must close the returned connection.
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func (p *ConnMux) Get() redis.Conn {
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c := &muxConn{p: p}
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c.ids = c.buf[:0]
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return c
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}
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// Close closes the underlying connection.
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func (p *ConnMux) Close() error {
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return p.c.Close()
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}
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type muxConn struct {
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p *ConnMux
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ids []uint
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buf [8]uint
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}
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func (c *muxConn) send(flush bool, cmd string, args ...interface{}) error {
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if lookupCommandInfo(cmd).notMuxable {
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return errors.New("command not supported by mux pool")
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}
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p := c.p
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p.sendMu.Lock()
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id := p.sendID
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c.ids = append(c.ids, id)
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p.sendID++
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err := p.c.Send(cmd, args...)
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if flush {
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err = p.c.Flush()
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}
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p.sendMu.Unlock()
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return err
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}
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func (c *muxConn) Send(cmd string, args ...interface{}) error {
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return c.send(false, cmd, args...)
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}
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func (c *muxConn) Flush() error {
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p := c.p
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p.sendMu.Lock()
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err := p.c.Flush()
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p.sendMu.Unlock()
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return err
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}
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func (c *muxConn) Receive() (interface{}, error) {
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if len(c.ids) == 0 {
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return nil, errors.New("mux pool underflow")
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}
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id := c.ids[0]
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c.ids = c.ids[1:]
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if len(c.ids) == 0 {
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c.ids = c.buf[:0]
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}
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p := c.p
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p.recvMu.Lock()
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if p.recvID != id {
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ch := make(chan struct{})
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p.recvWait[id] = ch
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p.recvMu.Unlock()
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<-ch
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p.recvMu.Lock()
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if p.recvID != id {
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panic("out of sync")
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}
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}
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v, err := p.c.Receive()
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id++
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p.recvID = id
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ch, ok := p.recvWait[id]
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if ok {
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delete(p.recvWait, id)
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}
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p.recvMu.Unlock()
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if ok {
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ch <- struct{}{}
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}
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return v, err
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}
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func (c *muxConn) Close() error {
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var err error
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if len(c.ids) == 0 {
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return nil
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}
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c.Flush()
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for _ = range c.ids {
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_, err = c.Receive()
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}
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return err
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}
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func (c *muxConn) Do(cmd string, args ...interface{}) (interface{}, error) {
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if err := c.send(true, cmd, args...); err != nil {
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return nil, err
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}
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return c.Receive()
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}
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func (c *muxConn) Err() error {
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return c.p.c.Err()
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}
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