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gitea/modules/indexer/code/wrapped.go
zeripath 30181d459d Wrap the code indexer (#9476)
* Wrap the code indexer

In order to prevent a data race in the code indexer it must be wrapped
with a holder otherwise it is possible to Search/Index on an
incompletely initialised indexer, and search will fail with a nil
pointer until the repository indexer is initialised.

Further a completely initialised repository indexer should not be closed
until Termination otherwise actions in Hammer/Shutdown phases could
block or be lost.

Finally, there is a complex dance of shutdown etiquette should the index
initialisation fail. This PR restores that.

* Always return err if closed whilst waiting

Co-authored-by: techknowlogick <matti@mdranta.net>
2019-12-24 15:26:34 +08:00

95 lines
1.8 KiB
Go

// Copyright 2019 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package code
import (
"fmt"
"sync"
)
var (
indexer = newWrappedIndexer()
)
// ErrWrappedIndexerClosed is the error returned if the indexer was closed before it was ready
var ErrWrappedIndexerClosed = fmt.Errorf("Indexer closed before ready")
type wrappedIndexer struct {
internal Indexer
lock sync.RWMutex
cond *sync.Cond
closed bool
}
func newWrappedIndexer() *wrappedIndexer {
w := &wrappedIndexer{}
w.cond = sync.NewCond(w.lock.RLocker())
return w
}
func (w *wrappedIndexer) set(indexer Indexer) {
w.lock.Lock()
defer w.lock.Unlock()
if w.closed {
// Too late!
indexer.Close()
}
w.internal = indexer
w.cond.Broadcast()
}
func (w *wrappedIndexer) get() (Indexer, error) {
w.lock.RLock()
defer w.lock.RUnlock()
if w.internal == nil {
if w.closed {
return nil, ErrWrappedIndexerClosed
}
w.cond.Wait()
if w.closed {
return nil, ErrWrappedIndexerClosed
}
}
return w.internal, nil
}
func (w *wrappedIndexer) Index(repoID int64) error {
indexer, err := w.get()
if err != nil {
return err
}
return indexer.Index(repoID)
}
func (w *wrappedIndexer) Delete(repoID int64) error {
indexer, err := w.get()
if err != nil {
return err
}
return indexer.Delete(repoID)
}
func (w *wrappedIndexer) Search(repoIDs []int64, keyword string, page, pageSize int) (int64, []*SearchResult, error) {
indexer, err := w.get()
if err != nil {
return 0, nil, err
}
return indexer.Search(repoIDs, keyword, page, pageSize)
}
func (w *wrappedIndexer) Close() {
w.lock.Lock()
defer w.lock.Unlock()
if w.closed {
return
}
w.closed = true
w.cond.Broadcast()
if w.internal != nil {
w.internal.Close()
}
}