Revert "Make HTTP headers use a growing buffer, not a fixed-size 8K one."

sdk/lib/io/http_impl.dart

Index: sdk/lib/io/http_impl.dart
diff --git a/sdk/lib/io/http_impl.dart b/sdk/lib/io/http_impl.dart
index ac7d67a7ef5361599a102a060c3b0d59b7cc95ab..a965afa43fe2f18dc4ce986a393e02a64429dd15 100644
--- a/sdk/lib/io/http_impl.dart
+++ b/sdk/lib/io/http_impl.dart
@@ -574,20 +574,29 @@ class _HttpResponse extends _HttpOutboundMessage<HttpResponse>
   }
 
   void _writeHeader() {
-    BytesBuilder buffer = new _CopyingBytesBuilder(_OUTGOING_BUFFER_SIZE);
+    Uint8List buffer = new Uint8List(_OUTGOING_BUFFER_SIZE);
+    int offset = 0;
+
+    void write(List<int> bytes) {
+      int len = bytes.length;
+      for (int i = 0; i < len; i++) {
+        buffer[offset + i] = bytes[i];
+      }
+      offset += len;
+    }
 
     // Write status line.
     if (headers.protocolVersion == "1.1") {
-      buffer.add(_Const.HTTP11);
+      write(_Const.HTTP11);
     } else {
-      buffer.add(_Const.HTTP10);
+      write(_Const.HTTP10);
     }
-    buffer.addByte(_CharCode.SP);
-    buffer.add(statusCode.toString().codeUnits);
-    buffer.addByte(_CharCode.SP);
-    buffer.add(reasonPhrase.codeUnits);
-    buffer.addByte(_CharCode.CR);
-    buffer.addByte(_CharCode.LF);
+    buffer[offset++] = _CharCode.SP;
+    write(statusCode.toString().codeUnits);
+    buffer[offset++] = _CharCode.SP;
+    write(reasonPhrase.codeUnits);
+    buffer[offset++] = _CharCode.CR;
+    buffer[offset++] = _CharCode.LF;
 
     var session = _httpRequest._session;
     if (session != null && !session._destroyed) {
@@ -621,11 +630,10 @@ class _HttpResponse extends _HttpOutboundMessage<HttpResponse>
     headers._finalize();
 
     // Write headers.
-    headers._build(buffer);
-    buffer.addByte(_CharCode.CR);
-    buffer.addByte(_CharCode.LF);
-    Uint8List headerBytes = buffer.takeBytes();
-    _outgoing.setHeader(headerBytes, headerBytes.length);
+    offset = headers._write(buffer, offset);
+    buffer[offset++] = _CharCode.CR;
+    buffer[offset++] = _CharCode.LF;
+    _outgoing.setHeader(buffer, offset);
   }
 
   String _findReasonPhrase(int statusCode) {
@@ -813,18 +821,27 @@ class _HttpClientRequest extends _HttpOutboundMessage<HttpClientResponse>
   }
 
   void _writeHeader() {
-    BytesBuilder buffer = new _CopyingBytesBuilder(_OUTGOING_BUFFER_SIZE);
+    Uint8List buffer = new Uint8List(_OUTGOING_BUFFER_SIZE);
+    int offset = 0;
+
+    void write(List<int> bytes) {
+      int len = bytes.length;
+      for (int i = 0; i < len; i++) {
+        buffer[offset + i] = bytes[i];
+      }
+      offset += len;
+    }
 
     // Write the request method.
-    buffer.add(method.codeUnits);
-    buffer.addByte(_CharCode.SP);
+    write(method.codeUnits);
+    buffer[offset++] = _CharCode.SP;
     // Write the request URI.
-    buffer.add(_requestUri().codeUnits);
-    buffer.addByte(_CharCode.SP);
+    write(_requestUri().codeUnits);
+    buffer[offset++] = _CharCode.SP;
     // Write HTTP/1.1.
-    buffer.add(_Const.HTTP11);
-    buffer.addByte(_CharCode.CR);
-    buffer.addByte(_CharCode.LF);
+    write(_Const.HTTP11);
+    buffer[offset++] = _CharCode.CR;
+    buffer[offset++] = _CharCode.LF;
 
     // Add the cookies to the headers.
     if (!cookies.isEmpty) {
@@ -839,11 +856,10 @@ class _HttpClientRequest extends _HttpOutboundMessage<HttpClientResponse>
     headers._finalize();
 
     // Write headers.
-    headers._build(buffer);
-    buffer.addByte(_CharCode.CR);
-    buffer.addByte(_CharCode.LF);
-    Uint8List headerBytes = buffer.takeBytes();
-    _outgoing.setHeader(headerBytes, headerBytes.length);
+    offset = headers._write(buffer, offset);
+    buffer[offset++] = _CharCode.CR;
+    buffer[offset++] = _CharCode.LF;
+    _outgoing.setHeader(buffer, offset);
   }
 }
 
@@ -919,6 +935,18 @@ class _HttpOutgoing implements StreamConsumer<List<int>> {
   // Returns either a future or 'null', if it was able to write headers
   // immediately.
   Future writeHeaders({bool drainRequest: true, bool setOutgoing: true}) {
+    Future write() {
+      try {
+        outbound._writeHeader();
+      } catch (_) {
+        // Headers too large.
+        return new Future.error(new HttpException(
+            "Headers size exceeded the of '$_OUTGOING_BUFFER_SIZE'"
+            " bytes"));
+      }
+      return null;
+    }
+
     if (headersWritten) return null;
     headersWritten = true;
     Future drainFuture;
@@ -947,22 +975,22 @@ class _HttpOutgoing implements StreamConsumer<List<int>> {
     } else {
       drainRequest = false;
     }
-    if (!ignoreBody) {
-      if (setOutgoing) {
-        int contentLength = outbound.headers.contentLength;
-        if (outbound.headers.chunkedTransferEncoding) {
-          chunked = true;
-          if (gzip) this.gzip = true;
-        } else if (contentLength >= 0) {
-          this.contentLength = contentLength;
-        }
-      }
-      if (drainFuture != null) {
-        return drainFuture.then((_) => outbound._writeHeader());
+    if (ignoreBody) {
+      return write();
+    }
+    if (setOutgoing) {
+      int contentLength = outbound.headers.contentLength;
+      if (outbound.headers.chunkedTransferEncoding) {
+        chunked = true;
+        if (gzip) this.gzip = true;
+      } else if (contentLength >= 0) {
+        this.contentLength = contentLength;
       }
     }
-    outbound._writeHeader();
-    return null;
+    if (drainFuture != null) {
+      return drainFuture.then((_) => write());
+    }
+    return write();
   }
 
 
@@ -1132,6 +1160,7 @@ class _HttpOutgoing implements StreamConsumer<List<int>> {
 
   void setHeader(List<int> data, int length) {
     assert(_length == 0);
+    assert(data.length == _OUTGOING_BUFFER_SIZE);
     _buffer = data;
     _length = length;
   }