1 files changed, 80 insertions, 0 deletions
diff --git a/funcs.go b/funcs.go
new file mode 100644
index 0000000..f87efb8
--- /dev/null
+++ b/funcs.go
@@ -0,0 +1,80 @@
+package stm
+
+// Atomically executes the atomic function fn.
+func Atomically(fn func(*Tx)) {
+retry:
+	// run the transaction
+	tx := &Tx{
+		reads:  make(map[*Var]uint64),
+		writes: make(map[*Var]interface{}),
+	}
+	if catchRetry(fn, tx) {
+		// wait for one of the variables we read to change before retrying
+		tx.wait()
+		goto retry
+	}
+	// verify the read log
+	globalLock.Lock()
+	if !tx.verify() {
+		globalLock.Unlock()
+		goto retry
+	}
+	// commit the write log and broadcast that variables have changed
+	if len(tx.writes) > 0 {
+		tx.commit()
+		globalCond.Broadcast()
+	}
+	globalLock.Unlock()
+}
+
+// AtomicGet is a helper function that atomically reads a value.
+func AtomicGet(v *Var) interface{} {
+	// since we're only doing one operation, we don't need a full transaction
+	globalLock.Lock()
+	v.mu.Lock()
+	val := v.val
+	v.mu.Unlock()
+	globalLock.Unlock()
+	return val
+}
+
+// AtomicSet is a helper function that atomically writes a value.
+func AtomicSet(v *Var, val interface{}) {
+	// since we're only doing one operation, we don't need a full transaction
+	globalLock.Lock()
+	v.mu.Lock()
+	v.val = val
+	v.version++
+	v.mu.Unlock()
+	globalCond.Broadcast()
+	globalLock.Unlock()
+}
+
+// Compose is a helper function that composes multiple transactions into a
+// single transaction.
+func Compose(fns ...func(*Tx)) func(*Tx) {
+	return func(tx *Tx) {
+		for _, f := range fns {
+			f(tx)
+		}
+	}
+}
+
+// Select runs the supplied functions in order. Execution stops when a
+// function succeeds without calling Retry. If no functions succeed, the
+// entire selection will be retried.
+func Select(fns ...func(*Tx)) func(*Tx) {
+	return func(tx *Tx) {
+		switch len(fns) {
+		case 0:
+			// empty Select blocks forever
+			tx.Retry()
+		case 1:
+			fns[0](tx)
+		default:
+			if catchRetry(fns[0], tx) {
+				Select(fns[1:]...)(tx)
+			}
+		}
+	}
+}