blob: 5251bfe69e65d0e552c0a1c0993d2e3c899c64a2 [file] [log] [blame]
// Copyright (c) 2010 The Chromium OS 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 <deque>
#include <utility>
#include <vector>
#include <base/memory/scoped_ptr.h>
#include "update_engine/http_fetcher.h"
// This class is a simple wrapper around an HttpFetcher. The client
// specifies a vector of byte ranges. MultiRangeHttpFetcher will fetch bytes
// from those offsets, using the same bash fetcher for all ranges. Thus, the
// fetcher must support beginning a transfter after one has stopped. Pass -1
// as a length to specify unlimited length. It really only would make sense
// for the last range specified to have unlimited length, tho it is legal for
// other entries to have unlimited length.
// There are three states a MultiRangeHttpFetcher object will be in:
// - Stopped (start state)
// - Downloading
// - Pending transfer ended
// Various functions below that might change state indicate possible
// state changes.
namespace chromeos_update_engine {
class MultiRangeHttpFetcher : public HttpFetcher, public HttpFetcherDelegate {
// Takes ownership of the passed in fetcher.
explicit MultiRangeHttpFetcher(HttpFetcher* base_fetcher)
: HttpFetcher(base_fetcher->proxy_resolver(),
bytes_received_this_range_(0) {}
~MultiRangeHttpFetcher() {}
void ClearRanges() { ranges_.clear(); }
void AddRange(off_t offset, size_t size) {
CHECK_GT(size, static_cast<size_t>(0));
ranges_.push_back(Range(offset, size));
void AddRange(off_t offset) {
virtual void SetOffset(off_t offset) {} // for now, doesn't support this
virtual void SetLength(size_t length) {} // unsupported
virtual void UnsetLength() {}
// Begins the transfer to the specified URL.
// State change: Stopped -> Downloading
// (corner case: Stopped -> Stopped for an empty request)
virtual void BeginTransfer(const std::string& url);
// State change: Downloading -> Pending transfer ended
virtual void TerminateTransfer();
virtual void Pause() { base_fetcher_->Pause(); }
virtual void Unpause() { base_fetcher_->Unpause(); }
// These functions are overloaded in LibcurlHttp fetcher for testing purposes.
virtual void set_idle_seconds(int seconds) {
virtual void set_retry_seconds(int seconds) {
virtual void SetBuildType(bool is_official) {
virtual void SetProxies(const std::deque<std::string>& proxies) {
inline virtual size_t GetBytesDownloaded() {
return base_fetcher_->GetBytesDownloaded();
// A range object defining the offset and length of a download chunk. Zero
// length indicates an unspecified end offset (note that it is impossible to
// request a zero-length range in HTTP).
class Range {
Range(off_t offset, size_t length) : offset_(offset), length_(length) {}
Range(off_t offset) : offset_(offset), length_(0) {}
inline off_t offset() const { return offset_; }
inline size_t length() const { return length_; }
inline bool HasLength() const { return (length_ > 0); }
std::string ToString() const;
off_t offset_;
size_t length_;
typedef std::vector<Range> RangesVect;
// State change: Stopped or Downloading -> Downloading
void StartTransfer();
// State change: Downloading -> Downloading or Pending transfer ended
virtual void ReceivedBytes(HttpFetcher* fetcher,
const char* bytes,
int length);
// State change: Pending transfer ended -> Stopped
void TransferEnded(HttpFetcher* fetcher, bool successful);
// These two call TransferEnded():
virtual void TransferComplete(HttpFetcher* fetcher, bool successful);
virtual void TransferTerminated(HttpFetcher* fetcher);
void Reset();
scoped_ptr<HttpFetcher> base_fetcher_;
// If true, do not send any more data or TransferComplete to the delegate.
bool base_fetcher_active_;
// If true, the next fetcher needs to be started when TransferTerminated is
// received from the current fetcher.
bool pending_transfer_ended_;
// True if we are waiting for base fetcher to terminate b/c we are
// ourselves terminating.
bool terminating_;
RangesVect ranges_;
RangesVect::size_type current_index_; // index into ranges_
size_t bytes_received_this_range_;
} // namespace chromeos_update_engine