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>

4 files changed, 64 insertions, 53 deletions

diff --git a/adapter/adapter.go b/adapter/adapter.go
index bc3a573..7d3d1e4 100644
--- a/adapter/adapter.go
+++ b/adapter/adapter.go
@@ -14,6 +14,16 @@
 
 package adapter
 
+import (
+	"errors"
+)
+
+// ErrNotImplemented is an error returned when missing implementation.
+var ErrNotImplemented = errors.New("not implemented for this OS")
+
+// MsgCallback defines func signature for message callback.
+type MsgCallback func(msgID uint16, context uint32, data []byte)
+
 // VppAdapter provides connection to VPP. It is responsible for sending and receiving of binary-encoded messages to/from VPP.
 type VppAdapter interface {
 	// Connect connects the process to VPP.
@@ -29,7 +39,7 @@ type VppAdapter interface {
 	SendMsg(context uint32, data []byte) error
 
 	// SetMsgCallback sets a callback function that will be called by the adapter whenever a message comes from VPP.
-	SetMsgCallback(func(context uint32, msgId uint16, data []byte))
+	SetMsgCallback(cb MsgCallback)
 
 	// WaitReady waits until adapter is ready.
 	WaitReady() error
diff --git a/adapter/mock/mock_adapter.go b/adapter/mock/mock_adapter.go
index a5cb62d..3f5686f 100644
--- a/adapter/mock/mock_adapter.go
+++ b/adapter/mock/mock_adapter.go
@@ -25,7 +25,6 @@ import (
 	"git.fd.io/govpp.git/adapter"
 	"git.fd.io/govpp.git/adapter/mock/binapi"
 	"git.fd.io/govpp.git/api"
-
 	"git.fd.io/govpp.git/codec"
 	"github.com/lunixbochs/struc"
 )
@@ -33,24 +32,24 @@ import (
 type replyMode int
 
 const (
-	_                replyMode = 0
-	useRepliesQueue            = 1 // use replies in the queue
-	useReplyHandlers           = 2 // use reply handler
+	_                replyMode = iota
+	useRepliesQueue            // use replies in the queue
+	useReplyHandlers           // use reply handler
 )
 
 // VppAdapter represents a mock VPP adapter that can be used for unit/integration testing instead of the vppapiclient adapter.
 type VppAdapter struct {
-	callback func(context uint32, msgId uint16, data []byte)
+	callback adapter.MsgCallback
 
+	msgIDSeq     uint16
+	access       sync.RWMutex
 	msgNameToIds map[string]uint16
 	msgIDsToName map[uint16]string
-	msgIDSeq     uint16
 	binAPITypes  map[string]reflect.Type
-	access       sync.RWMutex
 
+	repliesLock   sync.Mutex     // mutex for the queue
 	replies       []reply        // FIFO queue of messages
 	replyHandlers []ReplyHandler // callbacks that are able to calculate mock responses
-	repliesLock   sync.Mutex     // mutex for the queue
 	mode          replyMode      // mode in which the mock operates
 }
 
@@ -211,8 +210,6 @@ func (a *VppAdapter) GetMsgID(msgName string, msgCrc string) (uint16, error) {
 	a.msgNameToIds[msgName] = msgID
 	a.msgIDsToName[msgID] = msgName
 
-	log.Println("VPP GetMessageId ", msgID, " name:", msgName, " crc:", msgCrc)
-
 	return msgID, nil
 }
 
@@ -252,11 +249,12 @@ func (a *VppAdapter) SendMsg(clientID uint32, data []byte) error {
 				Data:     data,
 			})
 			if finished {
-				a.callback(clientID, msgID, reply)
+				a.callback(msgID, clientID, reply)
 				return nil
 			}
 		}
 		fallthrough
+
 	case useRepliesQueue:
 		a.repliesLock.Lock()
 		defer a.repliesLock.Unlock()
@@ -274,15 +272,15 @@ func (a *VppAdapter) SendMsg(clientID uint32, data []byte) error {
 				}
 				if msg.Msg.GetMessageType() == api.ReplyMessage {
 					struc.Pack(buf, &codec.VppReplyHeader{VlMsgID: msgID, Context: context})
-				} else if msg.Msg.GetMessageType() == api.EventMessage {
-					struc.Pack(buf, &codec.VppEventHeader{VlMsgID: msgID, Context: context})
 				} else if msg.Msg.GetMessageType() == api.RequestMessage {
 					struc.Pack(buf, &codec.VppRequestHeader{VlMsgID: msgID, Context: context})
+				} else if msg.Msg.GetMessageType() == api.EventMessage {
+					struc.Pack(buf, &codec.VppEventHeader{VlMsgID: msgID})
 				} else {
 					struc.Pack(buf, &codec.VppOtherHeader{VlMsgID: msgID})
 				}
 				struc.Pack(buf, msg.Msg)
-				a.callback(context, msgID, buf.Bytes())
+				a.callback(msgID, context, buf.Bytes())
 			}
 
 			a.replies = a.replies[1:]
@@ -301,13 +299,13 @@ func (a *VppAdapter) SendMsg(clientID uint32, data []byte) error {
 		msgID := uint16(defaultReplyMsgID)
 		struc.Pack(buf, &codec.VppReplyHeader{VlMsgID: msgID, Context: clientID})
 		struc.Pack(buf, &defaultReply{})
-		a.callback(clientID, msgID, buf.Bytes())
+		a.callback(msgID, clientID, buf.Bytes())
 	}
 	return nil
 }
 
 // SetMsgCallback sets a callback function that will be called by the adapter whenever a message comes from the mock.
-func (a *VppAdapter) SetMsgCallback(cb func(context uint32, msgID uint16, data []byte)) {
+func (a *VppAdapter) SetMsgCallback(cb adapter.MsgCallback) {
 	a.callback = cb
 }
 
diff --git a/adapter/vppapiclient/empty_adapter.go b/adapter/vppapiclient/empty_adapter.go
index c3010a0..7514048 100644
--- a/adapter/vppapiclient/empty_adapter.go
+++ b/adapter/vppapiclient/empty_adapter.go
@@ -32,7 +32,7 @@ func NewVppAdapter(string) adapter.VppAdapter {
 }
 
 func (a *vppAPIClientAdapter) Connect() error {
-	return nil
+	return adapter.ErrNotImplemented
 }
 
 func (a *vppAPIClientAdapter) Disconnect() {
@@ -47,7 +47,7 @@ func (a *vppAPIClientAdapter) SendMsg(clientID uint32, data []byte) error {
 	return nil
 }
 
-func (a *vppAPIClientAdapter) SetMsgCallback(cb func(context uint32, msgID uint16, data []byte)) {
+func (a *vppAPIClientAdapter) SetMsgCallback(cb adapter.MsgCallback) {
 	// no op
 }
 
diff --git a/adapter/vppapiclient/vppapiclient_adapter.go b/adapter/vppapiclient/vppapiclient_adapter.go
index c77d7f1..7aafa55 100644
--- a/adapter/vppapiclient/vppapiclient_adapter.go
+++ b/adapter/vppapiclient/vppapiclient_adapter.go
@@ -28,7 +28,7 @@ package vppapiclient
 #include <arpa/inet.h>
 #include <vpp-api/client/vppapiclient.h>
 
-extern void go_msg_callback(uint16_t, uint32_t, void*, size_t);
+extern void go_msg_callback(uint16_t msg_id, uint32_t context, void* data, size_t size);
 
 typedef struct __attribute__((__packed__)) _req_header {
     uint16_t msg_id;
@@ -38,7 +38,7 @@ typedef struct __attribute__((__packed__)) _req_header {
 
 typedef struct __attribute__((__packed__)) _reply_header {
     uint16_t msg_id;
-    uint32_t context;
+    uint32_t context; // currently not all reply messages contain context field
 } reply_header_t;
 
 static void
@@ -49,23 +49,23 @@ govpp_msg_callback (unsigned char *data, int size)
 }
 
 static int
-govpp_connect (char *shm)
+govpp_send(uint32_t context, void *data, size_t size)
 {
-    return vac_connect("govpp", shm, govpp_msg_callback, 32);
+	req_header_t *header = ((req_header_t *)data);
+	header->context = htonl(context);
+    return vac_write(data, size);
 }
 
 static int
-govvp_disconnect()
+govpp_connect (char *shm)
 {
-    return vac_disconnect();
+    return vac_connect("govpp", shm, govpp_msg_callback, 32);
 }
 
 static int
-govpp_send(uint32_t context, void *data, size_t size)
+govvp_disconnect()
 {
-	req_header_t *header = ((req_header_t *)data);
-	header->context = htonl(context);
-    return vac_write(data, size);
+    return vac_disconnect();
 }
 
 static uint32_t
@@ -79,6 +79,7 @@ import "C"
 import (
 	"fmt"
 	"os"
+	"path/filepath"
 	"reflect"
 	"unsafe"
 
@@ -98,7 +99,7 @@ const (
 // vppAPIClientAdapter is the opaque context of the adapter.
 type vppAPIClientAdapter struct {
 	shmPrefix string
-	callback  func(context uint32, msgId uint16, data []byte)
+	callback  adapter.MsgCallback
 }
 
 var vppClient *vppAPIClientAdapter // global vpp API client adapter context
@@ -138,6 +139,7 @@ func (a *vppAPIClientAdapter) GetMsgID(msgName string, msgCrc string) (uint16, e
 
 	msgID := uint16(C.govpp_get_msg_index(nameAndCrc))
 	if msgID == ^uint16(0) {
+		// VPP does not know this message
 		return msgID, fmt.Errorf("unknown message: %v (crc: %v)", msgName, msgCrc)
 	}
 
@@ -154,40 +156,41 @@ func (a *vppAPIClientAdapter) SendMsg(context uint32, data []byte) error {
 }
 
 // SetMsgCallback sets a callback function that will be called by the adapter whenever a message comes from VPP.
-func (a *vppAPIClientAdapter) SetMsgCallback(cb func(context uint32, msgID uint16, data []byte)) {
+func (a *vppAPIClientAdapter) SetMsgCallback(cb adapter.MsgCallback) {
 	a.callback = cb
 }
 
 // WaitReady blocks until shared memory for sending
 // binary api calls is present on the file system.
 func (a *vppAPIClientAdapter) WaitReady() error {
-	watcher, err := fsnotify.NewWatcher()
-	if err != nil {
-		return err
-	}
-	defer watcher.Close()
-
-	err = watcher.Add(watchedFolder)
-	if err != nil {
-		return err
-	}
-	// Path to the shared memory segment with prefix, if set
+	// Path to the shared memory segment
 	var path string
 	if a.shmPrefix == "" {
-		path = watchedFolder + watchedFile
+		path = filepath.Join(watchedFolder, watchedFile)
 	} else {
-		path = watchedFolder + a.shmPrefix + "-" + watchedFile
-	}
-	if fileExists(path) {
-		return nil
+		path = filepath.Join(watchedFolder, a.shmPrefix+"-"+watchedFile)
 	}
 
-	for {
-		ev := <-watcher.Events
-		if ev.Name == path && (ev.Op&fsnotify.Create) == fsnotify.Create {
-			break
+	// Watch folder if file does not exist yet
+	if !fileExists(path) {
+		watcher, err := fsnotify.NewWatcher()
+		if err != nil {
+			return err
+		}
+		defer watcher.Close()
+
+		if err := watcher.Add(watchedFolder); err != nil {
+			return err
+		}
+
+		for {
+			ev := <-watcher.Events
+			if ev.Name == path && (ev.Op&fsnotify.Create) == fsnotify.Create {
+				break
+			}
 		}
 	}
+
 	return nil
 }
 
@@ -206,5 +209,5 @@ func go_msg_callback(msgID C.uint16_t, context C.uint32_t, data unsafe.Pointer,
 	slice := &reflect.SliceHeader{Data: uintptr(data), Len: int(size), Cap: int(size)}
 	byteArr := *(*[]byte)(unsafe.Pointer(slice))
 
-	vppClient.callback(uint32(context), uint16(msgID), byteArr)
-}
\ No newline at end of file
+	vppClient.callback(uint16(msgID), uint32(context), byteArr)
+}