add term description, packetdata abstraction in 2/3

docs/spec/ibc/ibc.md

@@ -2,6 +2,16 @@
 
 IBC(Inter-Blockchain Communication) protocol is used by multiple zones on Cosmos. Using IBC, the zones can send coins or arbitrary data to other zones.
 
+## Terms
+
+How IBC module treats incoming IBC packets is simillar with how BaseApp treats incoming transactions. Therefore, the components of IBC module have their corresponding pair in BaseApp.
+
+| BaseApp Terms | IBC Terms  |
+| ------------- | ---------- |
+| Router        | Dispatcher |
+| Tx            | Packet     |
+| Msg           | PacketData |
+
 ## MVP Specifications
 
 ### [MVP1](./mvp1.md)
@@ -18,4 +28,4 @@ Light client verification is added to verify the message from the other chain. R
 
 ### [MVP4](./mvp4.md)
 
-ACK verification and messaging queue is implemented to make it failsafe. Modules will register callback to handle failure when they register handlers.
+ACK verification / timeout handler helper functions and messaging queue are implemented to make it failsafe. Callbacks will be registered to the dispatcher to handle failure when they register handlers.

docs/spec/ibc/mvp2.md

@@ -11,25 +11,43 @@ IBC module will store its own router for handling custom incoming msgs. `IBCPush
 ```golang
 // User facing API
 
-type IBCPacket struct {
+type Packet struct {
+    Data      PacketData
+    SrcChain  string
+    DestChain string
+}
+
+type PacketData interface {
+    Type() string
+    ValidateBasic() sdk.Error
+}
+
+type TransferPacketData struct {
     DestAddr sdk.Address
     Coins    sdk.Coins
-    SrcChain string
-    DestChain string
 }
 
 // Implements sdk.Msg
 type IBCTransferMsg struct {
-    IBCPacket
+    Packet
 }
 
 // Implements sdk.Msg
 type IBCReceiveMsg struct {
-    IBCPacket
+    Packet
 }
 
 // Internal API
 
+type rule struct {
+    r string
+    f func(sdk.Context, IBCPacket) sdk.Result
+}
+
+type Dispatcher struct {
+    rules []rule
+}
+
 func NewHandler(dispatcher Dispatcher, ibcm IBCMapper) sdk.Handler
 
 type IBCMapper struct {

docs/spec/ibc/mvp3.md

@@ -6,29 +6,52 @@
 
 ### IBC Module
 
+
+// Implements sdk.Msg
+type IBCTransferMsg struct {
+    Packet
+}
+
+// Implements sdk.Msg
+type IBCReceiveMsg struct {
+    Packet
+}
+
+// Internal API
+
+
+
 ```golang
 // User facing API
 
-type IBCTransferData struct {
+type Packet struct {
+    Data      PacketData
+    SrcChain  string
+    DestChain string
+}
+
+type PacketData interface {
+    Type() string
+    ValidateBasic() sdk.Error
+}
+
+type TransferPacketData struct {
     SrcAddr  sdk.Address
     DestAddr sdk.Address
     Coins    sdk.Coins
 }
 
-// Implements ibc.PacketData
+// Implements sdk.Msg
-type IBCPacket struct {
+type IBCTransferMsg struct {
-    IBCData
+    Packet
 }
 
-// Implements ibc.PacketData
+// Implements sdk.Msg
-type IBCReceivePacket struct {
+type IBCReceiveMsg struct {
-    IBCData    
+    Packet
-}
+    Proof           iavl.Proof
-
+    FromChainID     string
-type Packet struct {
+    FromChainHeight uint64
-    Data      PacketData
-    SrcChain  string    
-    DestChain string
 }
 
 type RootOfTrust struct {
@@ -49,6 +72,15 @@ type IBCUpdateMsg struct {
 
 // Internal API
 
+type rule struct {
+    r string
+    f func(sdk.Context, IBCPacket) sdk.Result
+}
+
+type Dispatcher struct {
+    rules []rule
+}
+
 func NewHandler(dispatcher Dispatcher, ibcm IBCMapper) sdk.Handler
 
 type IBCMapper struct {