rtmp: clarify C_RTMPSockBuf_Fill

The while loop in the C is only there to allow sigint to be caught and
ignored when user interupts are not allowed.

rtmp/rtmp.go

@@ -54,6 +54,7 @@ import (
 	"math/rand"
 	"strconv"
 	"strings"
+	"syscall"
 	"time"
 	"unsafe"
 
@@ -1795,29 +1796,27 @@ func C_CloseInternal(r *C_RTMP, reconnect int32) {
 // int RTMPSockBuf_Fill(RTMPSockBuf* sb);
 // rtmp.c +4253
 func C_RTMPSockBuf_Fill(sb *C_RTMPSockBuf) int {
-	var nBytes int
-
 	if sb.sb_size == 0 {
 		sb.sb_start = &sb.sb_buf[0]
 	}
 
-	for {
-		nBytes = int(unsafe.Sizeof(sb.sb_buf)) - 1 - int(sb.sb_size) -
-			int(uintptr(unsafe.Pointer(sb.sb_start))-uintptr(unsafe.Pointer(
+	nBytes := C.long(unsafe.Sizeof(sb.sb_buf)) - 1 - C.long(sb.sb_size) -
+		C.long(uintptr(unsafe.Pointer(sb.sb_start))-uintptr(unsafe.Pointer(
 			&sb.sb_buf[0])))
 
-		// TODO: figure out what to do with recv
-		nBytes = int(C.recv(C.int(sb.sb_socket), unsafe.Pointer(uintptr(unsafe.Pointer(
-			sb.sb_start))+uintptr(int(sb.sb_size))), C.size_t(nBytes), 0))
-
-		if nBytes != -1 {
-			sb.sb_size += int32(nBytes)
+	nBytes, err := C.recv(C.int(sb.sb_socket), unsafe.Pointer(uintptr(unsafe.Pointer(
+		sb.sb_start))+uintptr(int(sb.sb_size))), C.size_t(nBytes), 0)
+	if nBytes == -1 {
+		log.Printf("C_RTMPSockBuf_Fill: recv error: %v", err)
+		if err == syscall.EWOULDBLOCK || err == syscall.EAGAIN {
+			sb.sb_timedout = 1
+			nBytes = 0
+		}
 	} else {
-			log.Println("C_RTMPSockBuf_Fill: recv error!")
+		sb.sb_size += int32(nBytes)
 	}
-		break
-	}
-	return nBytes
+
+	return int(nBytes)
 }
 
 // int RTMPSockBuf_Send(RTMPSockBuf* sb, const char* buf, int len);