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buffered_connection.go
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buffered_connection.go
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// Copyright 2014-2019 Aerospike, Inbc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package aerospike
import (
"fmt"
"github.com/aerospike/aerospike-client-go/logger"
"github.com/aerospike/aerospike-client-go/types"
)
type bufferedConn struct {
conn *Connection
remaining int
head, tail int
}
func newBufferedConn(conn *Connection, total int) bufferedConn {
return bufferedConn{
conn: conn,
remaining: total,
}
}
// emptyCap returns the empty capacity in the buffer.
func (bc *bufferedConn) emptyCap() int {
return len(bc.buf()) - bc.len()
}
// len returns the number of unread bytes in the buffer.
func (bc *bufferedConn) len() int {
return bc.tail - bc.head
}
// buf returns the connection's byte buffer.
func (bc *bufferedConn) buf() []byte {
return bc.conn.dataBuffer
}
// shiftContentToHead will move the unread bytes to the head of the buffer.
// It will also resize the buffer if there is not enough empty capacity to read
// the minimum number of bytes that are requested.
// If the buffer is empty, head and tail will be reset to the beginning of the buffer.
func (bc *bufferedConn) shiftContentToHead(length int) {
// shift data to the head of the byte slice
if length > bc.emptyCap() {
buf := make([]byte, bc.len()+length)
copy(buf, bc.buf()[bc.head:bc.tail])
bc.conn.dataBuffer = buf
bc.tail -= bc.head
bc.head = 0
} else if bc.len() > 0 {
copy(bc.buf(), bc.buf()[bc.head:bc.tail])
bc.tail -= bc.head
bc.head = 0
} else {
bc.tail = 0
bc.head = 0
}
}
// readConn will read the minimum minLength number of bytes from the connection.
// It will read more if it has extra empty capacity in the buffer.
func (bc *bufferedConn) readConn(minLength int) error {
// Corrupted data streams can result in a huge minLength.
// Do a sanity check here.
if minLength > MaxBufferSize || minLength <= 0 || minLength > bc.remaining {
return types.NewAerospikeError(types.PARSE_ERROR, fmt.Sprintf("Invalid readBytes length: %d", minLength))
}
bc.shiftContentToHead(minLength)
toRead := bc.remaining
if ec := bc.emptyCap(); toRead > ec {
toRead = ec
}
n, err := bc.conn.Read(bc.buf()[bc.tail:], toRead)
bc.tail += n
bc.remaining -= n
if err != nil {
logger.Logger.Debug("Requested to read %d bytes, but %d was read. (%v)", minLength, n, err)
return err
}
return nil
}
func (bc *bufferedConn) read(length int) ([]byte, error) {
if cl := bc.len(); length > cl {
if err := bc.readConn(length - cl); err != nil {
return nil, err
}
}
buf := bc.buf()[bc.head : bc.head+length]
bc.head += length
return buf, nil
}
func (bc *bufferedConn) drainConn() error {
if !bc.conn.IsConnected() {
return nil
}
toRead := 0
for bc.remaining > 0 {
toRead = bc.remaining
if toRead > len(bc.buf()) {
toRead = len(bc.buf())
}
n, err := bc.conn.Read(bc.conn.dataBuffer, toRead)
bc.remaining -= n
if err != nil {
return err
}
}
return nil
}
func (bc *bufferedConn) reset(total int) error {
bc.remaining = total
bc.head = 0
bc.tail = 0
return nil
}