Petitions

app_petition.go

@@ -0,0 +1,128 @@
+package lazyledger
+
+import (
+    "encoding/binary"
+
+    "github.com/golang/protobuf/proto"
+    "github.com/libp2p/go-libp2p-crypto"
+)
+
+type PetitionApp struct {
+    state MapStore
+}
+
+func NewPetitionApp(state MapStore) Application {
+    return &PetitionApp{
+        state: state,
+    }
+}
+
+func (app *PetitionApp) ProcessMessage(message Message) {
+    transaction := &PetitionAppTransaction{}
+    err := proto.Unmarshal(message.Data(), transaction)
+    if err != nil {
+        return
+    }
+    apm := transaction.GetApm()
+    if apm != nil {
+        app.ProcessAddPetitionMessage(apm)
+    }
+    spm := transaction.GetSpm()
+    if spm != nil {
+        app.ProcessSignPetitionMessage(spm)
+    }
+}
+
+func (app *PetitionApp) ProcessAddPetitionMessage(apm *AddPetitionMessage) {
+    app.addPetition(*apm.Text)
+}
+
+func (app *PetitionApp) ProcessSignPetitionMessage(spm *SignPetitionMessage) {
+    key, _ := crypto.UnmarshalPublicKey(spm.Signer)
+    signedData := make([]byte, binary.MaxVarintLen64)
+    binary.BigEndian.PutUint64(signedData, *spm.Id)
+    ok, err := key.Verify(signedData, spm.Signature)
+    if !ok || err != nil {
+        return
+    }
+    app.incrementPetition(*spm.Id)
+}
+
+func (app *PetitionApp) Namespace() [namespaceSize]byte {
+    var namespace [namespaceSize]byte
+    copy(namespace[:], []byte("pet"))
+    return namespace
+}
+
+func (app *PetitionApp) SetBlockHead(hash []byte) {
+    app.state.Put([]byte("__head__"), hash)
+}
+
+func (app *PetitionApp) BlockHead() []byte {
+    head, _ := app.state.Get([]byte("__head__"))
+    return head
+}
+
+func (app *PetitionApp) Petition(petition uint64) uint64 {
+    id := make([]byte, binary.MaxVarintLen64)
+    binary.BigEndian.PutUint64(id, petition)
+    c, err := app.state.Get(id)
+    if err != nil {
+        return 0
+    }
+    return binary.BigEndian.Uint64(c)
+}
+
+func (app *PetitionApp) incrementPetition(petition uint64) {
+    v := app.Petition(petition)
+    newValue := make([]byte, binary.MaxVarintLen64)
+    binary.BigEndian.PutUint64(newValue, v + 1)
+
+    id := make([]byte, binary.MaxVarintLen64)
+    binary.BigEndian.PutUint64(id, petition)
+    app.state.Put(id, newValue)
+}
+
+func (app *PetitionApp) addPetition(text string) {
+    latestIdBytes, err := app.state.Get([]byte("__last__"))
+    var latestId uint64
+    if err != nil {
+        latestId = 0
+    } else {
+        latestId = binary.BigEndian.Uint64(latestIdBytes)
+    }
+    newValue := make([]byte, binary.MaxVarintLen64)
+    binary.BigEndian.PutUint64(newValue, latestId + 1)
+    app.state.Put([]byte("__last__"), newValue)
+    app.state.Put(append([]byte("text__"), newValue...), []byte(text))
+}
+
+func (app *PetitionApp) GenerateSignPetitionTransaction(key crypto.PrivKey, petition uint64) Message {
+    signedData := make([]byte, binary.MaxVarintLen64)
+    binary.BigEndian.PutUint64(signedData, petition)
+    sig, _ := key.Sign(signedData)
+    kb, _ := key.GetPublic().Bytes()
+    spm := &SignPetitionMessage{
+        Id: &petition,
+        Signature: sig,
+        Signer: kb,
+    }
+    pspm := PetitionAppTransaction_Spm{Spm: spm}
+    t := &PetitionAppTransaction{
+        Message: &pspm,
+    }
+    d, _ := proto.Marshal(t)
+    return *NewMessage(app.Namespace(), d)
+}
+
+func (app *PetitionApp) GenerateAddPetitionTransaction(text string) Message {
+    apm := &AddPetitionMessage{
+        Text: &text,
+    }
+    papm := PetitionAppTransaction_Apm{Apm: apm}
+    t := &PetitionAppTransaction{
+        Message: &papm,
+    }
+    d, _ := proto.Marshal(t)
+    return *NewMessage(app.Namespace(), d)
+}

app_petition.proto

@@ -0,0 +1,19 @@
+syntax = "proto2";
+package lazyledger;
+
+message PetitionAppTransaction {
+    oneof message {
+        AddPetitionMessage apm = 1;
+        SignPetitionMessage spm = 2;
+    }
+}
+
+message AddPetitionMessage {
+    required string text = 1;
+}
+
+message SignPetitionMessage {
+    required uint64 id = 1;
+    required bytes signature = 2;
+    required bytes signer = 3;
+}