github.com/matrixorigin/matrixone@v0.7.0/pkg/fileservice/rc.go (about)

     1  // Copyright 2022 Matrix Origin
     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 fileservice
    16  
    17  import "sync/atomic"
    18  
    19  // RC represents a reference counted value that will not evict in LRU if refs is greater than 0
    20  type RC[T any] struct {
    21  	refs  int64
    22  	Value T
    23  }
    24  
    25  // NewRC creates an RC value with 0 reference
    26  func NewRC[T any](value T) *RC[T] {
    27  	return &RC[T]{
    28  		Value: value,
    29  		refs:  0,
    30  	}
    31  }
    32  
    33  // IncRef increases reference count
    34  func (r *RC[T]) IncRef() {
    35  	atomic.AddInt64(&r.refs, 1)
    36  }
    37  
    38  // DecRef decreases reference count
    39  func (r *RC[T]) DecRef() {
    40  	atomic.AddInt64(&r.refs, -1)
    41  }
    42  
    43  // RefCount returns reference count
    44  func (r *RC[T]) RefCount() int64 {
    45  	return atomic.LoadInt64(&r.refs)
    46  }