Add Listen, Must, PipeListener, and T

1 files changed, 88 insertions, 0 deletions

diff --git a/net.go b/net.go
new file mode 100644
index 0000000..b1331e9
--- /dev/null
+++ b/net.go
@@ -0,0 +1,88 @@
+package core
+
+import (
+	"context"
+	"net"
+	"strings"
+	"sync"
+	"syscall"
+)
+
+// Listen is a wrapper around net.Listen. If addr cannot be split in two
+// parts around the first colon found, Listen will try to create a UNIX
+// or TCP net.Listener depending on whether addr contains a slash.
+func Listen(addr string) (net.Listener, error) {
+	if fields := strings.SplitN(addr, ":", 2); len(fields) == 2 {
+		return net.Listen(fields[0], fields[1])
+	}
+	if strings.ContainsRune(addr, '/') {
+		return net.Listen("unix", addr)
+	}
+	return net.Listen("tcp", addr)
+}
+
+// PipeListener is a net.Listener that works over a pipe. It provides
+// dialer functions that can be used in an HTTP client or gRPC options.
+//
+// Its zero value is safe to use. PipeListener must not be copied after
+// its first use.
+type PipeListener struct {
+	conns chan net.Conn
+	done  chan struct{}
+
+	closeOnce sync.Once
+	initOnce  sync.Once
+}
+
+var _ net.Listener = &PipeListener{}
+
+func (p *PipeListener) Accept() (net.Conn, error) {
+	p.initOnce.Do(p.init)
+
+	select {
+	case conn := <-p.conns:
+		return conn, nil
+	case <-p.done:
+		return nil, syscall.EINVAL
+	}
+}
+
+func (p *PipeListener) Addr() net.Addr { return pipeListenerAddr{} }
+
+func (p *PipeListener) Close() error {
+	p.initOnce.Do(p.init)
+	p.closeOnce.Do(func() { close(p.done) })
+	return nil
+}
+
+func (p *PipeListener) Dial(_, _ string) (net.Conn, error) {
+	return p.DialContext(context.Background(), "", "")
+}
+
+func (p *PipeListener) DialContext(ctx context.Context, _, _ string) (net.Conn, error) {
+	p.initOnce.Do(p.init)
+
+	s, c := net.Pipe()
+	select {
+	case p.conns <- s:
+		return c, nil
+	case <-p.done:
+		return nil, syscall.ECONNREFUSED
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+}
+
+func (p *PipeListener) DialContextGRPC(ctx context.Context, _ string) (net.Conn, error) {
+	return p.DialContext(ctx, "", "")
+}
+
+func (p *PipeListener) init() {
+	p.conns = make(chan net.Conn)
+	p.done = make(chan struct{})
+}
+
+type pipeListenerAddr struct{}
+
+func (pipeListenerAddr) Network() string { return "pipe" }
+func (pipeListenerAddr) String() string  { return "pipe" }