Flow Control work.
This defines the counting semaphore type, processes WINDOW_UPDATE
frames, processes SETTINGS frames more, etc.
Untested, since we don't yet write DATA frames. That's next.
diff --git a/flow_test.go b/flow_test.go
new file mode 100644
index 0000000..cdf9697
--- /dev/null
+++ b/flow_test.go
@@ -0,0 +1,67 @@
+// Copyright 2014 The Go Authors.
+// See https://code.google.com/p/go/source/browse/CONTRIBUTORS
+// Licensed under the same terms as Go itself:
+// https://code.google.com/p/go/source/browse/LICENSE
+
+package http2
+
+import (
+ "testing"
+ "time"
+)
+
+func (f *flow) cur() int32 {
+ f.c.L.Lock()
+ defer f.c.L.Unlock()
+ return f.size
+}
+
+func TestFlow(t *testing.T) {
+ f := newFlow(10)
+ if got, want := f.cur(), int32(10); got != want {
+ t.Fatalf("size = %d; want %d", got, want)
+ }
+ if waits := f.acquire(1); waits != 0 {
+ t.Errorf("waits = %d; want 0", waits)
+ }
+ if got, want := f.cur(), int32(9); got != want {
+ t.Fatalf("size = %d; want %d", got, want)
+ }
+
+ // Wait for 10, which should block, so start a background goroutine
+ // to refill it.
+ go func() {
+ time.Sleep(50 * time.Millisecond)
+ f.add(50)
+ }()
+ if waits := f.acquire(10); waits != 1 {
+ t.Errorf("waits for 50 = %d; want 0", waits)
+ }
+
+ if got, want := f.cur(), int32(49); got != want {
+ t.Fatalf("size = %d; want %d", got, want)
+ }
+}
+
+func TestFlowAdd(t *testing.T) {
+ f := newFlow(0)
+ if !f.add(1) {
+ t.Fatal("failed to add 1")
+ }
+ if !f.add(-1) {
+ t.Fatal("failed to add -1")
+ }
+ if got, want := f.cur(), int32(0); got != want {
+ t.Fatalf("size = %d; want %d", got, want)
+ }
+ if !f.add(1<<31 - 1) {
+ t.Fatal("failed to add 2^31-1")
+ }
+ if got, want := f.cur(), int32(1<<31-1); got != want {
+ t.Fatalf("size = %d; want %d", got, want)
+ }
+ if f.add(1) {
+ t.Fatal("adding 1 to max shouldn't be allowed")
+ }
+
+}
