Fix #255 blockchain should be exportable

bin/ucoind

@@ -30,8 +30,9 @@ function keys (val) {
   return val.split(',');
 }
 
-var INTERACTIVE_SYNC = true;
-var ERASE_IF_ALREADY_RECORDED = true;
+const INTERACTIVE_SYNC = true;
+const ERASE_IF_ALREADY_RECORDED = true;
+const NO_LOGS = true;
 
 program
   .version(pjson.version)
@@ -357,26 +358,44 @@ program
   .command('export-bc [upto]')
   .description('Exports the whole blockchain as JSON array, up to [upto] block number (excluded).')
   .action(service(function (upto, server) {
-    async.waterfall([
-      function (next){
-        server.dal.getBlocksUntil(upto).then(_.partial(next, null)).catch(next);
-      },
-      function (blocks, next){
-        var jsoned = [];
+    return co(function *() {
+      let CHUNK_SIZE = 500;
+      let jsoned = [];
+      let current = yield server.dal.getCurrentBlockOrNull();
+      let lastNumber = current ? current.number + 1 : -1;
+      if (upto !== undefined && upto.match(/\d+/)) {
+        lastNumber = Math.min(parseInt(upto), lastNumber);
+      }
+      let chunksCount = Math.floor(lastNumber / CHUNK_SIZE);
+      let chunks = [];
+      // Max-size chunks
+      for (let i = 0, len = chunksCount; i < len; i++) {
+        chunks.push({ start: i * CHUNK_SIZE, to: i * CHUNK_SIZE + CHUNK_SIZE });
+      }
+      // A last chunk
+      if (lastNumber > chunks * CHUNK_SIZE) {
+        chunks.push({ start: chunksCount * CHUNK_SIZE, to: lastNumber });
+      }
+      for (let j = 0, len = chunks.length; j < len; j++) {
+        let chunk = chunks[j];
+        let blocks = yield server.dal.getBlocksBetween(chunk.start, chunk.to);
         blocks.forEach(function (block) {
-          jsoned.push(_(block.json()).omit('raw'));
+          jsoned.push(_(new Block(block).json()).omit('raw'));
         });
-        console.log(JSON.stringify(jsoned, null, "  "));
-        next();
-      }
-    ], function (err) {
-      if (err) {
-        logger.error(err);
       }
-      server.disconnect();
+      console.log(JSON.stringify(jsoned, null, "  "));
+      yield server.disconnect();
       process.exit();
-    });
-  }));
+    })
+      .catch(function(err) {
+        logger.warn(err.message || err);
+        server.disconnect()
+          .catch(() => null)
+          .then(function(){
+            process.exit();
+          });
+      });
+  }, NO_LOGS));
 
 program
   .command('check-config')
@@ -769,7 +788,15 @@ function connect(callback, forConf, useDefaultConf) {
   };
 }
 
-function service(callback) {
+function service(callback, nologs) {
+
+  if (nologs) {
+    // Disable logs
+    require('log4js').configure({
+      "appenders": [
+      ]
+    });
+  }
   return function () {
     var cbArgs = arguments;
     var dbName = program.mdb || "ucoin_default";