1 files changed, 51 insertions, 0 deletions
diff --git a/plugins/temporal/workflow/id_registry.go b/plugins/temporal/workflow/id_registry.go
new file mode 100644
index 00000000..ac75cbda
--- /dev/null
+++ b/plugins/temporal/workflow/id_registry.go
@@ -0,0 +1,51 @@
+package workflow
+
+import (
+	"sync"
+
+	bindings "go.temporal.io/sdk/internalbindings"
+)
+
+// used to gain access to child workflow ids after they become available via callback result.
+type idRegistry struct {
+	mu        sync.Mutex
+	ids       map[uint64]entry
+	listeners map[uint64]listener
+}
+
+type listener func(w bindings.WorkflowExecution, err error)
+
+type entry struct {
+	w   bindings.WorkflowExecution
+	err error
+}
+
+func newIDRegistry() *idRegistry {
+	return &idRegistry{
+		ids:       map[uint64]entry{},
+		listeners: map[uint64]listener{},
+	}
+}
+
+func (c *idRegistry) listen(id uint64, cl listener) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	c.listeners[id] = cl
+
+	if e, ok := c.ids[id]; ok {
+		cl(e.w, e.err)
+	}
+}
+
+func (c *idRegistry) push(id uint64, w bindings.WorkflowExecution, err error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	e := entry{w: w, err: err}
+	c.ids[id] = e
+
+	if l, ok := c.listeners[id]; ok {
+		l(e.w, e.err)
+	}
+}