github.com/lirm/aeron-go@v0.0.0-20230415210743-920325491dc4/aeron/broadcast/copyreceiver.go (about)

     1  /*
     2  Copyright 2016 Stanislav Liberman
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8  http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package broadcast
    18  
    19  import (
    20  	"fmt"
    21  
    22  	"github.com/lirm/aeron-go/aeron/atomic"
    23  )
    24  
    25  type Handler func(int32, *atomic.Buffer, int32, int32)
    26  
    27  type CopyReceiver struct {
    28  	receiver      *Receiver
    29  	scratchBuffer *atomic.Buffer
    30  }
    31  
    32  func NewCopyReceiver(receiver *Receiver) *CopyReceiver {
    33  	bcast := new(CopyReceiver)
    34  	bcast.receiver = receiver
    35  	bcast.scratchBuffer = atomic.MakeBuffer(make([]byte, 4096))
    36  
    37  	// Scroll to the latest unprocessed
    38  	for bcast.receiver.receiveNext() {
    39  	}
    40  	return bcast
    41  }
    42  
    43  func (bcast *CopyReceiver) Receive(handler Handler) int {
    44  	messagesReceived := 0
    45  	lastSeenLappedCount := bcast.receiver.GetLappedCount()
    46  
    47  	if bcast.receiver.receiveNext() {
    48  		if lastSeenLappedCount != bcast.receiver.GetLappedCount() {
    49  			panic("Unable to keep up with broadcast buffer")
    50  		}
    51  
    52  		length := bcast.receiver.length()
    53  		if length > bcast.scratchBuffer.Capacity() {
    54  			panic(fmt.Sprintf("Buffer required size %d but only has %d", length, bcast.scratchBuffer.Capacity()))
    55  		}
    56  
    57  		msgTypeID := bcast.receiver.typeID()
    58  		bcast.scratchBuffer.PutBytes(0, bcast.receiver.buffer, bcast.receiver.offset(), length)
    59  
    60  		if !bcast.receiver.Validate() {
    61  			panic("Unable to keep up with broadcast buffer")
    62  		}
    63  
    64  		handler(msgTypeID, bcast.scratchBuffer, 0, length)
    65  
    66  		messagesReceived = 1
    67  	}
    68  
    69  	return messagesReceived
    70  }