net: Move data reading functionalities from UploadElement to UploadElementReader

net/base/upload_bytes_element_reader.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/base/upload_bytes_element_reader.h"
+
+#include "base/logging.h"
+#include "net/base/net_errors.h"
+
+namespace net {
+
+UploadBytesElementReader::UploadBytesElementReader(const char* bytes,
+                                                   int bytes_length)
+    : bytes_(bytes),
+      bytes_length_(bytes_length),
+      offset_(0) {
+}
+
+UploadBytesElementReader::~UploadBytesElementReader() {
+}
+
+int UploadBytesElementReader::InitSync() {
+  return OK;
+}
+
+uint64 UploadBytesElementReader::GetContentLength() const {
+  return bytes_length_;
+}
+
+uint64 UploadBytesElementReader::BytesRemaining() const {
+  return bytes_length_ - offset_;
+}
+
+int UploadBytesElementReader::ReadSync(char* buf, int buf_length) {
+  DCHECK_LT(0, buf_length);
+
+  const size_t num_bytes_to_read =
+      std::min(BytesRemaining(), static_cast<uint64>(buf_length));
+
+  // Check if we have anything to copy first, because we are getting
+  // the address of an element in |bytes_| and that will throw an
+  // exception if |bytes_| is an empty vector.
+  if (num_bytes_to_read > 0)
+    memcpy(buf, bytes_ + offset_, num_bytes_to_read);
+
+  offset_ += num_bytes_to_read;
+  return num_bytes_to_read;
+}
+
+bool UploadBytesElementReader::IsInMemory() const {
+  return true;
+}
+
+}  // namespace net