From 13d89969ef61b71b6fee9e26796c76137823da9b Mon Sep 17 00:00:00 2001
From: Jae Kwon <jkwon.work@gmail.com>
Date: Sat, 19 Jul 2014 16:47:00 -0700
Subject: [PATCH] implementing BlockManager

---
 blocks/block_manager.go | 118 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 106 insertions(+), 12 deletions(-)

diff --git a/blocks/block_manager.go b/blocks/block_manager.go
index 5c0825b3a..2654645fb 100644
--- a/blocks/block_manager.go
+++ b/blocks/block_manager.go
@@ -1,43 +1,57 @@
 package blocks
 
 import (
+	db_ "github.com/tendermint/tendermint/db"
 	"github.com/tendermint/tendermint/p2p"
 )
 
 const (
-	BlocksCh = "block"
+	blocksCh = "block"
 
 	msgTypeUnknown = Byte(0x00)
 	msgTypeState   = Byte(0x01)
 	msgTypeRequest = Byte(0x02)
 	msgTypeData    = Byte(0x03)
 
-	dataTypeAll        = byte(0x00)
-	dataTypeValidation = byte(0x01)
-	dataTypeTxs        = byte(0x02)
+	DataTypeFullBlock  = byte(0x00)
+	DataTypeValidation = byte(0x01)
+	DataTypeTxs        = byte(0x02)
 	// dataTypeCheckpoint = byte(0x04)
+
+	dbKeyState = "state"
 )
 
 /*
  */
 type BlockManager struct {
-	quit    chan struct{}
-	started uint32
-	stopped uint32
+	db         *db_.LevelDB
+	sw         *p2p.Switch
+	swEvents   chan interface{}
+	state      blockManagerState
+	peerStates map[string]*blockManagerState
+	quit       chan struct{}
+	started    uint32
+	stopped    uint32
 }
 
-func NewBlockManager() *BlockManager {
+func NewBlockManager(sw *p2p.Switch, db *db_.LevelDB) *BlockManager {
+	swEvents := make(chan interface{})
+	sw.AddEventListener("BlockManager.swEvents", swEvents)
 	bm := &BlockManager{
-		sw:   sw,
-		quit: make(chan struct{}),
+		db:         db,
+		sw:         sw,
+		swEvents:   swEvents,
+		peerStates: make(map[string]*blockManagerState),
+		quit:       make(chan struct{}),
 	}
+	bm.loadState()
 	return bm
 }
 
 func (bm *BlockManager) Start() {
 	if atomic.CompareAndSwapUint32(&bm.started, 0, 1) {
 		log.Info("Starting BlockManager")
-		go bm.XXX()
+		go bm.switchEventsHandler()
 	}
 }
 
@@ -45,10 +59,90 @@ func (bm *BlockManager) Stop() {
 	if atomic.CompareAndSwapUint32(&bm.stopped, 0, 1) {
 		log.Info("Stopping BlockManager")
 		close(bm.quit)
+		close(bm.swEvents)
 	}
 }
 
-func (bm *BlockManager) XXX() {
+func (bm *BlockManager) StoreData(dataType byte, dataObj interface{}) {
+	// Validate data if possible.
+	// If we have new data that extends our contiguous range, then announce it.
+}
+
+func (bm *BlockManager) LoadData(dataType byte) interface{} {
+	// NOTE: who's calling?
+}
+
+func (bm *BlockManager) loadState() {
+	// Load the state
+	stateBytes := bm.db.Get(dbKeyState)
+	if stateBytes == nil {
+		log.Info("New BlockManager with no state")
+	} else {
+		err := json.Unmarshal(stateBytes, &bm.state)
+		if err != nil {
+			panic("Could not unmarshal state bytes: %X", stateBytes)
+		}
+	}
+}
+
+func (bm *BlockManager) saveState() {
+	stateBytes, err := json.Marshal(&bm.state)
+	if err != nil {
+		panic("Could not marshal state bytes")
+	}
+	bm.db.Set(dbKeyState, stateBytes)
+}
+
+func (bm *BlockManager) switchEventsHandler() {
+	for {
+		swEvent, ok := <-bm.swEvents
+		if !ok {
+			break
+		}
+		switch swEvent.(type) {
+		case p2p.SwitchEventNewPeer:
+			event := swEvent.(p2p.SwitchEventNewPeer)
+			// Create entry in .peerStates
+			// Share our state with event.Peer
+			event.Peer
+		case p2p.SwitchEventDonePeer:
+			// Remove entry from .peerStates
+		}
+	}
+}
+
+//-----------------------------------------------------------------------------
+
+/* This is just to persist the block manager state in the db. */
+type blockManagerState struct {
+	LastHeaderHeight       uint64 // Last contiguous header height
+	OtherHeaderHeights     []uint64
+	LastValidationHeight   uint64 // Last contiguous validation height
+	OtherValidationHeights []uint64
+	LastTxsHeight          uint64 // Last contiguous txs height
+	OtherTxsHeights        []uint64
+}
+
+//-----------------------------------------------------------------------------
+
+/*
+Each part of a block are stored separately in the db.
+*/
+
+func headerKey(height int) {
+	return fmt.Sprintf("B%v", height)
+}
+
+func validationKey(height int) {
+	return fmt.Sprintf("V%v", height)
+}
+
+func txsKey(height int) {
+	return fmt.Sprintf("T%v", height)
+}
+
+func checkpointKey(height int) {
+	return fmt.Sprintf("C%v", height)
 }
 
 //-----------------------------------------------------------------------------