github.com/m3db/m3@v1.5.0/src/query/executor/transform/cache.go (about)

     1  // Copyright (c) 2018 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package transform
    22  
    23  import (
    24  	"sync"
    25  
    26  	"github.com/m3db/m3/src/query/block"
    27  	"github.com/m3db/m3/src/query/parser"
    28  
    29  	"github.com/pkg/errors"
    30  )
    31  
    32  // BlockCache is used to cache blocks
    33  type BlockCache struct {
    34  	blocks map[parser.NodeID]block.Block
    35  	mu     sync.Mutex
    36  }
    37  
    38  // NewBlockCache creates a new BlockCache
    39  func NewBlockCache() *BlockCache {
    40  	return &BlockCache{
    41  		blocks: make(map[parser.NodeID]block.Block),
    42  	}
    43  }
    44  
    45  // Add the block to the cache, errors out if block already exists
    46  func (c *BlockCache) Add(key parser.NodeID, b block.Block) error {
    47  	c.mu.Lock()
    48  	defer c.mu.Unlock()
    49  	_, ok := c.blocks[key]
    50  	if ok {
    51  		return errors.New("block already exists")
    52  	}
    53  
    54  	c.blocks[key] = b
    55  	return nil
    56  }
    57  
    58  // Remove the block from the cache
    59  func (c *BlockCache) Remove(key parser.NodeID) {
    60  	c.mu.Lock()
    61  	defer c.mu.Unlock()
    62  	delete(c.blocks, key)
    63  }
    64  
    65  // Get the block from the cache
    66  // TODO: Evaluate only a single process getting a block at a time
    67  func (c *BlockCache) Get(key parser.NodeID) (block.Block, bool) {
    68  	c.mu.Lock()
    69  	defer c.mu.Unlock()
    70  	b, ok := c.blocks[key]
    71  	return b, ok
    72  }