net: Move data reading functionalities from UploadElement to UploadElementReader

net/base/upload_file_element_reader.cc

Index: net/base/upload_file_element_reader.cc
diff --git a/net/base/upload_file_element_reader.cc b/net/base/upload_file_element_reader.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b71c0225b8acb32b3c96a8cd81fc350866e74434
--- /dev/null
+++ b/net/base/upload_file_element_reader.cc
@@ -0,0 +1,142 @@
+// 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_file_element_reader.h"
+
+#include "base/file_util.h"
+#include "base/threading/thread_restrictions.h"
+#include "net/base/file_stream.h"
+#include "net/base/net_errors.h"
+
+namespace net {
+
+namespace {
+
+// In tests, this value is used to override the return value of
+// UploadFileElementReader::GetContentLength() when set to non-zero.
+uint64 overriding_content_length = 0;
+
+}  // namespace
+
+UploadFileElementReader::UploadFileElementReader(
+    const FilePath& path,
+    uint64 range_offset,
+    uint64 range_length,
+    const base::Time& expected_modification_time)
+    : path_(path),
+      range_offset_(range_offset),
+      range_length_(range_length),
+      expected_modification_time_(expected_modification_time),
+      content_length_(0),
+      bytes_remaining_(0) {
+}
+
+UploadFileElementReader::~UploadFileElementReader() {
+  // Temporarily allow until fix: http://crbug.com/72001.
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
+  if (file_stream_.get())
+    file_stream_->CloseSync();
+}
+
+int UploadFileElementReader::InitSync() {
+  // Temporarily allow until fix: http://crbug.com/72001.
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
+
+  scoped_ptr<FileStream> file_stream(new FileStream(NULL));
+  int64 rv = file_stream->OpenSync(
+      path_, base::PLATFORM_FILE_OPEN | base::PLATFORM_FILE_READ);
+  if (rv != OK) {
+    // If the file can't be opened, we'll just upload an empty file.
+    DLOG(WARNING) << "Failed to open \"" << path_.value()
+                  << "\" for reading: " << rv;
+    file_stream.reset();
+  }
+  if (file_stream.get() && range_offset_) {
+    rv = file_stream->SeekSync(FROM_BEGIN, range_offset_);
+    if (rv < 0) {
+      DLOG(WARNING) << "Failed to seek \"" << path_.value()
+                    << "\" to offset: " << range_offset_ << " (" << rv
+                    << ")";
+      file_stream->CloseSync();
+      file_stream.reset();
+    }
+  }
+  file_stream_.reset(file_stream.release());
+
+  int64 length = 0;
+  if (file_stream_.get() &&
+      file_util::GetFileSize(path_, &length) &&
+      range_offset_ < static_cast<uint64>(length)) {
+    // Compensate for the offset.
+    length = std::min(length - range_offset_, range_length_);
+  }
+  content_length_ = length;
+  bytes_remaining_ = GetContentLength();
+
+  // If the underlying file has been changed and the expected file
+  // modification time is set, treat it as error. Note that the expected
+  // modification time from WebKit is based on time_t precision. So we

[willchan no longer on Chromium, 2012/09/06 01:06:01]

I don't fully understand this comment. Is this moved from somewhere else, or is
it new? If it's new, I sort of object, because it looks like a layering
violation.

[hashimoto, 2012/09/06 01:55:39]

This comment is moved from UploadDataStream::Init().
Agree, this part is really ugly.

+  // have to convert both to time_t to compare. This check is used for
+  // sliced files.
+  if (!expected_modification_time_.is_null()) {
+    base::PlatformFileInfo info;
+    if (file_util::GetFileInfo(path_, &info) &&
+        expected_modification_time_.ToTimeT() !=
+        info.last_modified.ToTimeT()) {
+      return ERR_UPLOAD_FILE_CHANGED;
+    }
+  }
+
+  return OK;
+}
+
+uint64 UploadFileElementReader::GetContentLength() const {
+  if (overriding_content_length)
+    return overriding_content_length;
+  return content_length_;
+}
+
+uint64 UploadFileElementReader::BytesRemaining() const {
+  return bytes_remaining_;
+}
+
+int UploadFileElementReader::ReadSync(char* buf, int buf_length) {
+  // Temporarily allow until fix: http://crbug.com/72001.
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
+  DCHECK_LT(0, buf_length);
+
+  const uint64 num_bytes_to_read =
+      static_cast<int>(std::min(BytesRemaining(),
+                                static_cast<uint64>(buf_length)));
+  if (num_bytes_to_read > 0) {
+    int num_bytes_consumed = 0;
+    // file_stream_ is NULL if the target file is
+    // missing or not readable.
+    if (file_stream_.get()) {
+      num_bytes_consumed =
+          file_stream_->ReadSync(buf, num_bytes_to_read);
+    }
+    if (num_bytes_consumed <= 0) {
+      // If there's less data to read than we initially observed, then
+      // pad with zero.  Otherwise the server will hang waiting for the
+      // rest of the data.
+      memset(buf, 0, num_bytes_to_read);
+    }
+  }
+  DCHECK_GE(bytes_remaining_, num_bytes_to_read);
+  bytes_remaining_ -= num_bytes_to_read;
+  return num_bytes_to_read;
+}
+
+UploadFileElementReader::ScopedOverridingContentLengthForTests::
+ScopedOverridingContentLengthForTests(uint64 value) {
+  overriding_content_length = value;
+}
+
+UploadFileElementReader::ScopedOverridingContentLengthForTests::
+~ScopedOverridingContentLengthForTests() {
+  overriding_content_length = 0;
+}
+
+}  // namespace net