Refactor GoVPP

Squashed commit of the following:

commit 348930db31575e9f59b3834d9fec07411f011e05
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Wed Aug 15 11:30:13 2018 +0200

    Use debug level for log about different context

commit 9fc963c559cea67a41b85c6cdadc322fb3b1fc7c
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Wed Aug 15 11:22:03 2018 +0200

    Remove annoying logs and add env vars for debugging

commit fdc9fd624d13feadb602e0d03d58f8a44b7a565f
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Wed Aug 15 11:18:47 2018 +0200

    Fix printing unknown VPPApiError

commit 8f968be36a91de4d4a8ea17593ba314f82aa9583
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Tue Aug 14 17:25:10 2018 +0200

    Refactor entire GoVPP

    - fix some cases with inconsistent VPP messages, causing messages
      to be incorrectly identified as event or request
    - simplify API, remove direct access to internal Go channels
    - add module name with message to registration of messages
    - start watching filesystem only when vpe-api file does not exist
    - simplify code in message codec and remove unneeded parts
    - retrieve IDs of all registered messages after connect to VPP
    - define fallback for control ping in core to avoid duplicate registration
    - add SetLogLevel function to set logger level more easily
    - remove lot of unused code

commit 34dd1b7e10ef0324aa8c4e4cc42375bd6021c6cb
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Mon Aug 13 11:29:54 2018 +0200

    Rename VnetError to VPPApiError

commit c6549d6f77847a1367a12ff47fb716e2955e973a
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Mon Aug 13 10:23:43 2018 +0200

    Fix examples and regenerate binapi

commit 4612e36b416779771f5efab4fc654c2766d2cb1c
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Mon Aug 13 09:51:22 2018 +0200

    Add parsing and generation for services

commit ac9c5280c5aa27e325f327609e2364cc66f3723f
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Fri Aug 10 14:30:15 2018 +0200

    Fix exit status on error and add continue-onerror flag

commit 9b3f4ef9fc7c8c62037fa107085eae18a8725314
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 15:20:56 2018 +0200

    Return VnetError when Retval != 0

commit 8fd21a907b5e628ec4d2026215b83d15da96c297
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 14:59:05 2018 +0200

    Add all missing errors from api_errno.h

commit 08450f288d3046ebaecf40203174ae342a07f1eb
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 14:29:27 2018 +0200

    Update README

commit d8dced0728dd62243539be741868fb7d9b8de4cc
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 13:59:59 2018 +0200

    Regenerate vpe in core

commit 254da7592cdbf634cf7aa46ae36ce7bb6d4ee555
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 13:37:00 2018 +0200

    Add VnetError type for Retvals

commit 4475c1087fb53ab4c788e530bc7fef7cfc89d2cd
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 13:36:07 2018 +0200

    Add registration API

commit 892a3ea5a2c703e2f7c29331663f6a6fa706bff5
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 13:30:43 2018 +0200

    Generate registration for messages and check all IDs on connect

commit 389ed03b6e7082260281866c3449d72d72347c99
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 11:32:41 2018 +0200

    Show error for empty adapter (on Darwin/Windows)

commit ef1ea040d656ade64242432dc5f06810ed8dcde6
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 11:31:37 2018 +0200

    Improve logged info

commit d4adae3b14ed54c8d693060dd857fa9ba5ec8e06
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 11:27:48 2018 +0200

    Update examples

commit 63921e1346014701a22639a2611129563bb1eb78
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 11:02:56 2018 +0200

    Generate unions and fix some issues

    - add comments between sections
    - define structs on single line if it has no fields
    - generate unions with setters/getters for each field
    - fix detection of message type

commit 6ab3e3fa590b245898306a6ffaf32c7721eab60c
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Wed Aug 8 15:37:10 2018 +0200

    Refactor binapi-generator

    - split JSON parsing from code generation
    - parse and generate enums
    - parse unions (no generation yet)
    - change output file suffix to '.ba.go'
    - cleanup and simplify code
    - split code into files
    - add flag for debug mode

Change-Id: I58f685e0d4c7a38e9a7b6ea0a1f47792d95d7399
Signed-off-by: Ondrej Fabry <ofabry@cisco.com>

1 files changed, 61 insertions, 49 deletions

diff --git a/codec/msg_codec.go b/codec/msg_codec.go
index 7ba8771..572e672 100644
--- a/codec/msg_codec.go
+++ b/codec/msg_codec.go
@@ -43,8 +43,8 @@ type VppReplyHeader struct {
 
 // VppEventHeader struct contains header fields implemented by all VPP events.
 type VppEventHeader struct {
-	VlMsgID uint16
-	Context uint32
+	VlMsgID     uint16
+	ClientIndex uint32
 }
 
 // VppOtherHeader struct contains header fields implemented by other VPP messages (not requests nor replies).
@@ -52,42 +52,36 @@ type VppOtherHeader struct {
 	VlMsgID uint16
 }
 
-const (
-	vppRequestHeaderSize = 10 // size of a VPP request header
-	vppReplyHeaderSize   = 6  // size of a VPP reply header
-	vppEventHeaderSize   = 6  // size of a VPP event header
-	vppOtherHeaderSize   = 2  // size of the header of other VPP messages
-)
-
 // EncodeMsg encodes provided `Message` structure into its binary-encoded data representation.
 func (*MsgCodec) EncodeMsg(msg api.Message, msgID uint16) ([]byte, error) {
 	if msg == nil {
 		return nil, errors.New("nil message passed in")
 	}
 
-	buf := new(bytes.Buffer)
-
 	// encode message header
 	var header interface{}
-	if msg.GetMessageType() == api.RequestMessage {
+	switch msg.GetMessageType() {
+	case api.RequestMessage:
 		header = &VppRequestHeader{VlMsgID: msgID}
-	} else if msg.GetMessageType() == api.ReplyMessage {
+	case api.ReplyMessage:
 		header = &VppReplyHeader{VlMsgID: msgID}
-	} else if msg.GetMessageType() == api.EventMessage {
+	case api.EventMessage:
 		header = &VppEventHeader{VlMsgID: msgID}
-	} else {
+	default:
 		header = &VppOtherHeader{VlMsgID: msgID}
 	}
-	err := struc.Pack(buf, header)
-	if err != nil {
-		return nil, fmt.Errorf("unable to encode message: header: %v, error %v", header, err)
+
+	buf := new(bytes.Buffer)
+
+	// encode message header
+	if err := struc.Pack(buf, header); err != nil {
+		return nil, fmt.Errorf("unable to encode message header: %v, error %v", header, err)
 	}
 
 	// encode message content
-	if reflect.Indirect(reflect.ValueOf(msg)).NumField() > 0 {
-		err := struc.Pack(buf, msg)
-		if err != nil {
-			return nil, fmt.Errorf("unable to encode message: header %v, error %v", header, err)
+	if reflect.TypeOf(msg).Elem().NumField() > 0 {
+		if err := struc.Pack(buf, msg); err != nil {
+			return nil, fmt.Errorf("unable to encode message data: %v, error %v", header, err)
 		}
 	}
 
@@ -100,42 +94,60 @@ func (*MsgCodec) DecodeMsg(data []byte, msg api.Message) error {
 		return errors.New("nil message passed in")
 	}
 
-	buf := bytes.NewReader(data)
-
 	// check which header is expected
 	var header interface{}
-	if msg.GetMessageType() == api.RequestMessage {
-		header = &VppRequestHeader{}
-	} else if msg.GetMessageType() == api.ReplyMessage {
-		header = &VppReplyHeader{}
-	} else if msg.GetMessageType() == api.EventMessage {
-		header = &VppEventHeader{}
-	} else {
-		header = &VppOtherHeader{}
+	switch msg.GetMessageType() {
+	case api.RequestMessage:
+		header = new(VppRequestHeader)
+	case api.ReplyMessage:
+		header = new(VppReplyHeader)
+	case api.EventMessage:
+		header = new(VppEventHeader)
+	default:
+		header = new(VppOtherHeader)
 	}
 
-	// decode message header
-	err := struc.Unpack(buf, header)
-	if err != nil {
-		return fmt.Errorf("unable to decode message: data %v, error %v", data, err)
-	}
+	buf := bytes.NewReader(data)
 
-	// get rid of the message header
-	if msg.GetMessageType() == api.RequestMessage {
-		buf = bytes.NewReader(data[vppRequestHeaderSize:])
-	} else if msg.GetMessageType() == api.ReplyMessage {
-		buf = bytes.NewReader(data[vppReplyHeaderSize:])
-	} else if msg.GetMessageType() == api.EventMessage {
-		buf = bytes.NewReader(data[vppEventHeaderSize:])
-	} else {
-		buf = bytes.NewReader(data[vppOtherHeaderSize:])
+	// decode message header
+	if err := struc.Unpack(buf, header); err != nil {
+		return fmt.Errorf("unable to decode message header: %+v, error %v", data, err)
 	}
 
 	// decode message content
-	err = struc.Unpack(buf, msg)
-	if err != nil {
-		return fmt.Errorf("unable to decode message: data %v, error %v", data, err)
+	if err := struc.Unpack(buf, msg); err != nil {
+		return fmt.Errorf("unable to decode message data: %+v, error %v", data, err)
 	}
 
 	return nil
 }
+
+func (*MsgCodec) DecodeMsgContext(data []byte, msg api.Message) (uint32, error) {
+	if msg == nil {
+		return 0, errors.New("nil message passed in")
+	}
+
+	var getContext func() uint32
+
+	// check which header is expected
+	var header interface{}
+	switch msg.GetMessageType() {
+	case api.RequestMessage:
+		header = new(VppRequestHeader)
+		getContext = func() uint32 { return header.(*VppRequestHeader).Context }
+	case api.ReplyMessage:
+		header = new(VppReplyHeader)
+		getContext = func() uint32 { return header.(*VppReplyHeader).Context }
+	default:
+		return 0, nil
+	}
+
+	buf := bytes.NewReader(data)
+
+	// decode message header
+	if err := struc.Unpack(buf, header); err != nil {
+		return 0, fmt.Errorf("decoding message header failed: %v", err)
+	}
+
+	return getContext(), nil
+}