1 files changed, 62 insertions, 0 deletions
diff --git a/vendor/github.com/oklog/run/group.go b/vendor/github.com/oklog/run/group.go
new file mode 100644
index 000000000..832d47dd1
--- /dev/null
+++ b/vendor/github.com/oklog/run/group.go
@@ -0,0 +1,62 @@
+// Package run implements an actor-runner with deterministic teardown. It is
+// somewhat similar to package errgroup, except it does not require actor
+// goroutines to understand context semantics. This makes it suitable for use in
+// more circumstances; for example, goroutines which are handling connections
+// from net.Listeners, or scanning input from a closable io.Reader.
+package run
+
+// Group collects actors (functions) and runs them concurrently.
+// When one actor (function) returns, all actors are interrupted.
+// The zero value of a Group is useful.
+type Group struct {
+	actors []actor
+}
+
+// Add an actor (function) to the group. Each actor must be pre-emptable by an
+// interrupt function. That is, if interrupt is invoked, execute should return.
+// Also, it must be safe to call interrupt even after execute has returned.
+//
+// The first actor (function) to return interrupts all running actors.
+// The error is passed to the interrupt functions, and is returned by Run.
+func (g *Group) Add(execute func() error, interrupt func(error)) {
+	g.actors = append(g.actors, actor{execute, interrupt})
+}
+
+// Run all actors (functions) concurrently.
+// When the first actor returns, all others are interrupted.
+// Run only returns when all actors have exited.
+// Run returns the error returned by the first exiting actor.
+func (g *Group) Run() error {
+	if len(g.actors) == 0 {
+		return nil
+	}
+
+	// Run each actor.
+	errors := make(chan error, len(g.actors))
+	for _, a := range g.actors {
+		go func(a actor) {
+			errors <- a.execute()
+		}(a)
+	}
+
+	// Wait for the first actor to stop.
+	err := <-errors
+
+	// Signal all actors to stop.
+	for _, a := range g.actors {
+		a.interrupt(err)
+	}
+
+	// Wait for all actors to stop.
+	for i := 1; i < cap(errors); i++ {
+		<-errors
+	}
+
+	// Return the original error.
+	return err
+}
+
+type actor struct {
+	execute   func() error
+	interrupt func(error)
+}