Split File into File and RandomAccessFile.

samples/chat/chat_server_lib.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #library("chat_server");
 #import("http.dart");
 #import("../../client/json/dart_json.dart");
 
 typedef void RequestHandler(HTTPRequest request, HTTPResponse response);
 
@@ skipping 348 matching lines @@
 
   // Serve the content of a file.
   void fileHandler(
       HTTPRequest request, HTTPResponse response, [String fileName = null]) {
     final int BUFFER_SIZE = 4096;
     if (fileName == null) {
       fileName = request.path.substring(1);
     }
     File file = new File(fileName);
     if (file.existsSync()) {
-      file.openSync();
+      RandomAccessFile openedFile = file.openSync();
       int totalRead = 0;
       List<int> buffer = new List<int>(BUFFER_SIZE);
 
       String mimeType = "text/html; charset=UTF-8";
       int lastDot = fileName.lastIndexOf(".", fileName.length);
       if (lastDot != -1) {
         String extension = fileName.substring(lastDot);
         if (extension == ".css") { mimeType = "text/css"; }
         if (extension == ".js") { mimeType = "application/javascript"; }
         if (extension == ".ico") { mimeType = "image/vnd.microsoft.icon"; }
         if (extension == ".png") { mimeType = "image/png"; }
       }
       response.setHeader("Content-Type", mimeType);
-      response.contentLength = file.lengthSync();
+      response.contentLength = openedFile.lengthSync();
+
+      bool checkDone() {
+        if (totalRead == openedFile.lengthSync()) {
+          openedFile.closeSync();
+          response.writeDone();
+          return true;
+        }
+        return false;
+      }
 
       void writeFileData() {
-        while (totalRead < file.lengthSync()) {
-          var read = file.readListSync(buffer, 0, BUFFER_SIZE);
+        if (checkDone()) return;
+        while (totalRead < openedFile.lengthSync()) {
+          var read = openedFile.readListSync(buffer, 0, BUFFER_SIZE);
           totalRead += read;
 
           // Write this buffer and get a callback when it makes sense
           // to write more.
-          bool allWritten = response.writeList(buffer, 0, read, writeFileData);
-          if (!allWritten) break;
-        }
-
-        if (totalRead == file.lengthSync()) {
-          response.writeDone();
+          bool writeCompleted =
+              response.writeList(buffer, 0, read, writeFileData);
+          if (writeCompleted) {
+            if (checkDone()) return;
+          } else {
+            break;
+          }
         }
       }
 
       writeFileData();
     } else {
       print("File not found: $fileName");
       _notFoundHandler(request, response);
     }
   }
 
@@ skipping 319 matching lines @@
     }
   }
 
   int _timeRange;
   List<int> _buckets;
   int _currentBucket;
   int _currentBucketTime;
   num _bucketTimeRange;
   int _sum;
 }