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author | Ben Johnson <benbjohnson@yahoo.com> | 2016-01-02 22:34:41 -0700 |
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committer | Ben Johnson <benbjohnson@yahoo.com> | 2016-01-02 22:34:41 -0700 |
commit | 34a0fa5307f7562980fb8e7ff4723f7987edf49b (patch) | |
tree | 26a01c0d5a3da53f45c7f54062c3af11479c4a2f /batch.go | |
parent | Merge pull request #474 from elithrar/patch-1 (diff) | |
parent | test suite refactoring (diff) | |
download | dedo-34a0fa5307f7562980fb8e7ff4723f7987edf49b.tar.gz dedo-34a0fa5307f7562980fb8e7ff4723f7987edf49b.tar.xz |
Merge pull request #477 from benbjohnson/testing
Test suite refactoring
Diffstat (limited to 'batch.go')
-rw-r--r-- | batch.go | 138 |
1 files changed, 0 insertions, 138 deletions
diff --git a/batch.go b/batch.go deleted file mode 100644 index 84acae6..0000000 --- a/batch.go +++ /dev/null @@ -1,138 +0,0 @@ -package bolt - -import ( - "errors" - "fmt" - "sync" - "time" -) - -// Batch calls fn as part of a batch. It behaves similar to Update, -// except: -// -// 1. concurrent Batch calls can be combined into a single Bolt -// transaction. -// -// 2. the function passed to Batch may be called multiple times, -// regardless of whether it returns error or not. -// -// This means that Batch function side effects must be idempotent and -// take permanent effect only after a successful return is seen in -// caller. -// -// The maximum batch size and delay can be adjusted with DB.MaxBatchSize -// and DB.MaxBatchDelay, respectively. -// -// Batch is only useful when there are multiple goroutines calling it. -func (db *DB) Batch(fn func(*Tx) error) error { - errCh := make(chan error, 1) - - db.batchMu.Lock() - if (db.batch == nil) || (db.batch != nil && len(db.batch.calls) >= db.MaxBatchSize) { - // There is no existing batch, or the existing batch is full; start a new one. - db.batch = &batch{ - db: db, - } - db.batch.timer = time.AfterFunc(db.MaxBatchDelay, db.batch.trigger) - } - db.batch.calls = append(db.batch.calls, call{fn: fn, err: errCh}) - if len(db.batch.calls) >= db.MaxBatchSize { - // wake up batch, it's ready to run - go db.batch.trigger() - } - db.batchMu.Unlock() - - err := <-errCh - if err == trySolo { - err = db.Update(fn) - } - return err -} - -type call struct { - fn func(*Tx) error - err chan<- error -} - -type batch struct { - db *DB - timer *time.Timer - start sync.Once - calls []call -} - -// trigger runs the batch if it hasn't already been run. -func (b *batch) trigger() { - b.start.Do(b.run) -} - -// run performs the transactions in the batch and communicates results -// back to DB.Batch. -func (b *batch) run() { - b.db.batchMu.Lock() - b.timer.Stop() - // Make sure no new work is added to this batch, but don't break - // other batches. - if b.db.batch == b { - b.db.batch = nil - } - b.db.batchMu.Unlock() - -retry: - for len(b.calls) > 0 { - var failIdx = -1 - err := b.db.Update(func(tx *Tx) error { - for i, c := range b.calls { - if err := safelyCall(c.fn, tx); err != nil { - failIdx = i - return err - } - } - return nil - }) - - if failIdx >= 0 { - // take the failing transaction out of the batch. it's - // safe to shorten b.calls here because db.batch no longer - // points to us, and we hold the mutex anyway. - c := b.calls[failIdx] - b.calls[failIdx], b.calls = b.calls[len(b.calls)-1], b.calls[:len(b.calls)-1] - // tell the submitter re-run it solo, continue with the rest of the batch - c.err <- trySolo - continue retry - } - - // pass success, or bolt internal errors, to all callers - for _, c := range b.calls { - if c.err != nil { - c.err <- err - } - } - break retry - } -} - -// trySolo is a special sentinel error value used for signaling that a -// transaction function should be re-run. It should never be seen by -// callers. -var trySolo = errors.New("batch function returned an error and should be re-run solo") - -type panicked struct { - reason interface{} -} - -func (p panicked) Error() string { - if err, ok := p.reason.(error); ok { - return err.Error() - } - return fmt.Sprintf("panic: %v", p.reason) -} - -func safelyCall(fn func(*Tx) error, tx *Tx) (err error) { - defer func() { - if p := recover(); p != nil { - err = panicked{p} - } - }() - return fn(tx) -} |