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

     1  // Copyright 2022 Steven Stern
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  // http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package counters
    16  
    17  import (
    18  	"fmt"
    19  )
    20  
    21  // Aeron.NullValue, but using it directly creates a circular dependency
    22  const nullValue = -1
    23  
    24  type ReadableCounter struct {
    25  	Reader         *Reader
    26  	RegistrationId int64
    27  	CounterId      int32
    28  	metaDataOffset int32
    29  	valueOffset    int32
    30  	isClosed       bool
    31  }
    32  
    33  func NewReadableRegisteredCounter(reader *Reader, registrationId int64, counterId int32) (*ReadableCounter, error) {
    34  	if counterId < 0 || counterId >= int32(reader.maxCounterID) {
    35  		return nil, fmt.Errorf("counterId=%d maxCounterId=%d", counterId, reader.maxCounterID)
    36  	}
    37  	metaDataOffset := counterId * MetadataLength
    38  	valueOffset := counterId * CounterLength
    39  	return &ReadableCounter{reader, registrationId, counterId, metaDataOffset, valueOffset, false}, nil
    40  }
    41  
    42  func NewReadableCounter(reader *Reader, counterId int32) (*ReadableCounter, error) {
    43  	return NewReadableRegisteredCounter(reader, nullValue, counterId)
    44  }
    45  
    46  func (rc *ReadableCounter) State() int32 {
    47  	return rc.Reader.metaData.GetInt32Volatile(rc.metaDataOffset)
    48  }
    49  
    50  func (rc *ReadableCounter) Label() string {
    51  	return rc.Reader.labelValue(rc.metaDataOffset)
    52  }
    53  
    54  func (rc *ReadableCounter) Get() int64 {
    55  	return rc.Reader.values.GetInt64Volatile(rc.valueOffset)
    56  }
    57  
    58  func (rc *ReadableCounter) GetWeak() int64 {
    59  	return rc.Reader.values.GetInt64(rc.valueOffset)
    60  }
    61  
    62  func (rc *ReadableCounter) Close() {
    63  	rc.isClosed = true
    64  }
    65  
    66  func (rc *ReadableCounter) IsClosed() bool {
    67  	return rc.isClosed
    68  }