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// Copyright 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.
#ifndef COMPONENTS_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_
#define COMPONENTS_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_
#include <string>
#include "base/callback_forward.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/weak_ptr.h"
#include "components/web_resource/resource_request_allowed_notifier.h"
#include "net/url_request/url_fetcher_delegate.h"
#include "url/gurl.h"
class PrefService;
namespace base {
class DictionaryValue;
class Value;
}
namespace net {
class URLFetcher;
class URLRequestContextGetter;
}
namespace web_resource {
// A WebResourceService fetches JSON data from a web server and periodically
// refreshes it.
class WebResourceService
: public net::URLFetcherDelegate,
public ResourceRequestAllowedNotifier::Observer {
public:
// Callbacks for JSON parsing.
using SuccessCallback = base::Callback<void(scoped_ptr<base::Value>)>;
using ErrorCallback = base::Callback<void(const std::string&)>;
using ParseJSONCallback = base::Callback<
void(const std::string&, const SuccessCallback&, const ErrorCallback&)>;
// Creates a new WebResourceService.
// If |application_locale| is not empty, it will be appended as a locale
// parameter to the resource URL.
WebResourceService(PrefService* prefs,
const GURL& web_resource_server,
const std::string& application_locale, // May be empty
const char* last_update_time_pref_name,
int start_fetch_delay_ms,
int cache_update_delay_ms,
net::URLRequestContextGetter* request_context,
const char* disable_network_switch,
const ParseJSONCallback& parse_json_callback);
~WebResourceService() override;
// Sleep until cache needs to be updated, but always for at least
// |start_fetch_delay_ms| so we don't interfere with startup.
// Then begin updating resources.
void StartAfterDelay();
protected:
PrefService* prefs_;
private:
// For the subclasses to process the result of a fetch.
virtual void Unpack(const base::DictionaryValue& parsed_json) = 0;
// net::URLFetcherDelegate implementation:
void OnURLFetchComplete(const net::URLFetcher* source) override;
// Schedules a fetch after |delay_ms| milliseconds.
void ScheduleFetch(int64 delay_ms);
// Starts fetching data from the server.
void StartFetch();
// Set |in_fetch_| to false, clean up temp directories (in the future).
void EndFetch();
// Callbacks from the JSON parser.
void OnUnpackFinished(scoped_ptr<base::Value> value);
void OnUnpackError(const std::string& error_message);
// Implements ResourceRequestAllowedNotifier::Observer.
void OnResourceRequestsAllowed() override;
// Helper class used to tell this service if it's allowed to make network
// resource requests.
ResourceRequestAllowedNotifier resource_request_allowed_notifier_;
// The tool that fetches the url data from the server.
scoped_ptr<net::URLFetcher> url_fetcher_;
// True if we are currently fetching or unpacking data. If we are asked to
// start a fetch when we are still fetching resource data, schedule another
// one in |cache_update_delay_ms_| time, and silently exit.
bool in_fetch_;
// URL that hosts the web resource.
GURL web_resource_server_;
// Application locale, appended to the URL if not empty.
std::string application_locale_;
// Pref name to store the last update's time.
const char* last_update_time_pref_name_;
// Delay on first fetch so we don't interfere with startup.
int start_fetch_delay_ms_;
// Delay between calls to update the web resource cache. This delay may be
// different for different builds of Chrome.
int cache_update_delay_ms_;
// The request context for the resource fetch.
scoped_refptr<net::URLRequestContextGetter> request_context_;
// Callback used to parse JSON.
ParseJSONCallback parse_json_callback_;
// So that we can delay our start so as not to affect start-up time; also,
// so that we can schedule future cache updates.
base::WeakPtrFactory<WebResourceService> weak_ptr_factory_;
DISALLOW_COPY_AND_ASSIGN(WebResourceService);
};
} // namespace web_resource
#endif // COMPONENTS_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_