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//
// Copyright (C) 2010 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#include "update_engine/multi_range_http_fetcher.h"
#include <base/strings/stringprintf.h>
#include <algorithm>
#include <string>
#include "update_engine/utils.h"
namespace chromeos_update_engine {
// Begins the transfer to the specified URL.
// State change: Stopped -> Downloading
// (corner case: Stopped -> Stopped for an empty request)
void MultiRangeHttpFetcher::BeginTransfer(const std::string& url) {
CHECK(!base_fetcher_active_) << "BeginTransfer but already active.";
CHECK(!pending_transfer_ended_) << "BeginTransfer but pending.";
CHECK(!terminating_) << "BeginTransfer but terminating.";
if (ranges_.empty()) {
// Note that after the callback returns this object may be destroyed.
if (delegate_)
delegate_->TransferComplete(this, true);
return;
}
url_ = url;
current_index_ = 0;
bytes_received_this_range_ = 0;
LOG(INFO) << "starting first transfer";
base_fetcher_->set_delegate(this);
StartTransfer();
}
// State change: Downloading -> Pending transfer ended
void MultiRangeHttpFetcher::TerminateTransfer() {
if (!base_fetcher_active_) {
LOG(INFO) << "Called TerminateTransfer but not active.";
// Note that after the callback returns this object may be destroyed.
if (delegate_)
delegate_->TransferTerminated(this);
return;
}
terminating_ = true;
if (!pending_transfer_ended_) {
base_fetcher_->TerminateTransfer();
}
}
// State change: Stopped or Downloading -> Downloading
void MultiRangeHttpFetcher::StartTransfer() {
if (current_index_ >= ranges_.size()) {
return;
}
Range range = ranges_[current_index_];
LOG(INFO) << "starting transfer of range " << range.ToString();
bytes_received_this_range_ = 0;
base_fetcher_->SetOffset(range.offset());
if (range.HasLength())
base_fetcher_->SetLength(range.length());
else
base_fetcher_->UnsetLength();
if (delegate_)
delegate_->SeekToOffset(range.offset());
base_fetcher_active_ = true;
base_fetcher_->BeginTransfer(url_);
}
// State change: Downloading -> Downloading or Pending transfer ended
void MultiRangeHttpFetcher::ReceivedBytes(HttpFetcher* fetcher,
const void* bytes,
size_t length) {
CHECK_LT(current_index_, ranges_.size());
CHECK_EQ(fetcher, base_fetcher_.get());
CHECK(!pending_transfer_ended_);
size_t next_size = length;
Range range = ranges_[current_index_];
if (range.HasLength()) {
next_size = std::min(next_size,
range.length() - bytes_received_this_range_);
}
LOG_IF(WARNING, next_size <= 0) << "Asked to write length <= 0";
if (delegate_) {
delegate_->ReceivedBytes(this, bytes, next_size);
}
bytes_received_this_range_ += length;
if (range.HasLength() && bytes_received_this_range_ >= range.length()) {
// Terminates the current fetcher. Waits for its TransferTerminated
// callback before starting the next range so that we don't end up
// signalling the delegate that the whole multi-transfer is complete
// before all fetchers are really done and cleaned up.
pending_transfer_ended_ = true;
LOG(INFO) << "terminating transfer";
fetcher->TerminateTransfer();
}
}
// State change: Downloading or Pending transfer ended -> Stopped
void MultiRangeHttpFetcher::TransferEnded(HttpFetcher* fetcher,
bool successful) {
CHECK(base_fetcher_active_) << "Transfer ended unexpectedly.";
CHECK_EQ(fetcher, base_fetcher_.get());
pending_transfer_ended_ = false;
http_response_code_ = fetcher->http_response_code();
LOG(INFO) << "TransferEnded w/ code " << http_response_code_;
if (terminating_) {
LOG(INFO) << "Terminating.";
Reset();
// Note that after the callback returns this object may be destroyed.
if (delegate_)
delegate_->TransferTerminated(this);
return;
}
// If we didn't get enough bytes, it's failure
Range range = ranges_[current_index_];
if (range.HasLength()) {
if (bytes_received_this_range_ < range.length()) {
// Failure
LOG(INFO) << "Didn't get enough bytes. Ending w/ failure.";
Reset();
// Note that after the callback returns this object may be destroyed.
if (delegate_)
delegate_->TransferComplete(this, false);
return;
}
// We got enough bytes and there were bytes specified, so this is success.
successful = true;
}
// If we have another transfer, do that.
if (current_index_ + 1 < ranges_.size()) {
current_index_++;
LOG(INFO) << "Starting next transfer (" << current_index_ << ").";
StartTransfer();
return;
}
LOG(INFO) << "Done w/ all transfers";
Reset();
// Note that after the callback returns this object may be destroyed.
if (delegate_)
delegate_->TransferComplete(this, successful);
}
void MultiRangeHttpFetcher::TransferComplete(HttpFetcher* fetcher,
bool successful) {
LOG(INFO) << "Received transfer complete.";
TransferEnded(fetcher, successful);
}
void MultiRangeHttpFetcher::TransferTerminated(HttpFetcher* fetcher) {
LOG(INFO) << "Received transfer terminated.";
TransferEnded(fetcher, false);
}
void MultiRangeHttpFetcher::Reset() {
base_fetcher_active_ = pending_transfer_ended_ = terminating_ = false;
current_index_ = 0;
bytes_received_this_range_ = 0;
}
std::string MultiRangeHttpFetcher::Range::ToString() const {
std::string range_str = base::StringPrintf("%jd+", offset());
if (HasLength())
range_str += std::to_string(length());
else
range_str += "?";
return range_str;
}
} // namespace chromeos_update_engine