New cache function for bulk-inserts in single txn to avoid excessive disk writes and blocking by worker.

Adding new getBlockByID function for future tool functionality.

lib/local_comms.js

@@ -218,6 +218,21 @@ function Database(){
         return highestBlock;
     };
 
+    this.getBlockByID = function(blockID){
+        this.refreshEnv();
+        debug("Getting the data for blockID: " + blockID);
+        let txn = this.env.beginTxn({readOnly: true});
+        let data = txn.getBinary(blockID);
+        if (data === null){
+            debug("Unable to get block at height: "+ blockID);
+            return false;
+        }
+        let blockData = global.protos.Block.decode(data);
+        txn.commit();
+        debug("Done getting the last block for: "+ blockData.poolType + " height of: "+ blockID);
+        return blockData;
+    };
+
     this.calculateShares = function(blockData, blockHeight){
         debug("Calculating shares for "+ blockData.hash);
         this.refreshEnv();
@@ -376,6 +391,16 @@ function Database(){
         txn.commit();
     };
 
+    this.bulkSetCache = function(cacheUpdates){
+        let txn = this.env.beginTxn();
+        for (let key in cacheUpdates){
+            if (cacheUpdates.hasOwnProperty(key)){
+                txn.putString(this.cacheDB, key, JSON.stringify(cacheUpdates[key]));
+            }
+        }
+        txn.commit();
+    };
+
     this.cleanShareDB = function() {
         /*
         This function takes the difficulty of the current block, and the last PPS block.  If it's 0, save everything,