searcher pool impl

binding/golang/service/searcher_pool.go

@@ -10,5 +10,86 @@
 
 package service
 
+import (
+	"context"
+	"fmt"
+	"sync/atomic"
+
+	"github.com/lionsoul2014/ip2region/binding/golang/xdb"
+)
+
 type SearcherPool struct {
+	// config
+	config *Config
+
+	// searcher pool
+	pool chan *xdb.Searcher
+
+	// for pool close
+	closing chan struct{}
+
+	// searcher number that was loaned out
+	loanCount int32
+}
+
+func NewSearcherPool(config *Config) (*SearcherPool, error) {
+	if config.searchers < 1 {
+		return nil, fmt.Errorf("config.searchers must > 0")
+	}
+
+	pool := make(chan *xdb.Searcher, config.searchers+1)
+	// check and create all the searchers
+	for i := 0; i < config.searchers; i++ {
+		searcher, err := xdb.NewSearcher(config.ipVersion, config.xdbPath, config.vIndex, config.cBuffer)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create the %dth searcher: %w", i+1, err)
+		}
+
+		// push the search to the pool
+		pool <- searcher
+	}
+
+	return &SearcherPool{
+		config: config,
+		pool:   pool,
+
+		closing:   make(chan struct{}, 1),
+		loanCount: 0,
+	}, nil
+}
+
+// Stat return the stat {loanCount, leftCount} info of the pool
+func (sp *SearcherPool) Stat() (int, int) {
+	loanCount := int(atomic.LoadInt32(&sp.loanCount))
+	return loanCount, len(sp.pool) - loanCount
+}
+
+func (sp *SearcherPool) BorrowSearcher() *xdb.Searcher {
+	select {
+	case <-sp.closing:
+		// stop searcher borrow while closing
+		return nil
+	case s := <-sp.pool:
+		atomic.AddInt32(&sp.loanCount, 1)
+		return s
+	}
+}
+
+func (sp *SearcherPool) ReturnSearcher(searcher *xdb.Searcher) {
+	select {
+	case <-sp.closing:
+		// manually close the searcher
+		searcher.Close()
+	default:
+		// return the searcher
+		sp.pool <- searcher
+		atomic.AddInt32(&sp.loanCount, -1)
+	}
+}
+
+func (sp *SearcherPool) Close(ctx context.Context) {
+	close(sp.closing)
+	for s := range sp.pool {
+		s.Close()
+	}
 }