blob: f70d56a5ccb03f894fe3f1f34da025c88448fda9 [file] [log] [blame]
// Copyright 2014 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.
// TODO(rdsmith): This class needs to be moved out to the net/ embedder and
// hooked into whatever mechanisms the embedder uses for authentication.
// Specifically, this class needs methods overriding
// URLRequest::Delegate::{OnAuthRequired,OnCertificateRequested} and can't
// implement them at the net/ layer.
#include <queue>
#include <set>
#include <string>
#include "base/memory/scoped_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/threading/non_thread_safe.h"
#include "net/base/sdch_manager.h"
#include "net/url_request/url_fetcher_delegate.h"
#include "net/url_request/url_request.h"
namespace net {
class URLRequest;
class URLRequestThrottlerEntryInterface;
// This class implements the SdchFetcher interface. It queues requests
// for dictionaries and dispatches them serially, implementing
// the URLRequest::Delegate interface to handle callbacks (but see above
// TODO). It tracks all requests, only attempting to fetch each dictionary
// once.
class NET_EXPORT SdchDictionaryFetcher
: public SdchFetcher,
public URLRequest::Delegate,
public base::NonThreadSafe {
// The consumer must guarantee that |*consumer| and |*context| outlive
// this object.
SdchDictionaryFetcher(SdchFetcher::Delegate* consumer,
URLRequestContext* context);
virtual ~SdchDictionaryFetcher();
// Implementation of SdchFetcher methods.
virtual void Schedule(const GURL& dictionary_url) OVERRIDE;
virtual void Cancel() OVERRIDE;
// Implementation of URLRequest::Delegate methods.
virtual void OnResponseStarted(URLRequest* request) OVERRIDE;
virtual void OnReadCompleted(URLRequest* request, int bytes_read) OVERRIDE;
enum State {
// State machine implementation.
int DoLoop(int rv);
int DoDispatchRequest(int rv);
int DoRequestStarted(int rv);
int DoRead(int rv);
int DoCompleteRequest(int rv);
State next_state_;
bool in_loop_;
SdchFetcher::Delegate* const consumer_;
// A queue of URLs that are being used to download dictionaries.
std::queue<GURL> fetch_queue_;
// The request and buffer used for getting the current dictionary
// Both are null when a fetch is not in progress.
scoped_ptr<URLRequest> current_request_;
scoped_refptr<IOBuffer> buffer_;
// The currently accumulating dictionary.
std::string dictionary_;
// Althought the SDCH spec does not preclude a server from using a single URL
// to load several distinct dictionaries (by telling a client to load a
// dictionary from an URL several times), current implementations seem to have
// that 1-1 relationship (i.e., each URL points at a single dictionary, and
// the dictionary content does not change over time, and hence is not worth
// trying to load more than once). In addition, some dictionaries prove
// unloadable only after downloading them (because they are too large? ...or
// malformed?). As a protective element, Chromium will *only* load a
// dictionary at most once from a given URL (so that it doesn't waste
// bandwidth trying repeatedly).
// The following set lists all the dictionary URLs that we've tried to load,
// so that we won't try to load from an URL more than once.
// TODO(jar): Try to augment the SDCH proposal to include this restiction.
std::set<GURL> attempted_load_;
// Store the URLRequestContext associated with the owning SdchManager for
// use while fetching.
URLRequestContext* context_;
base::WeakPtrFactory<SdchDictionaryFetcher> weak_factory_;
} // namespace net