critical_finder_support_util.h

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/*
 * Copyright 2013 Google Inc.
 *
 * 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.
 */


#ifndef NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_FINDER_SUPPORT_UTIL_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_FINDER_SUPPORT_UTIL_H_

#include "net/instaweb/rewriter/critical_keys.pb.h"
#include "net/instaweb/util/public/property_cache.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/base/timer.h"

namespace net_instaweb {

const int64 kBeaconTimeoutIntervalMs = Timer::kMinuteMs;

const int64 kHighFreqBeaconCount = 3;

const int64 kLowFreqBeaconMult = 100;

const int64 kNonceExpirationLimit = 5;

class MessageHandler;
class NonceGenerator;
class RewriteDriver;

enum BeaconStatus {
  kDoNotBeacon,
  kBeaconNoNonce,
  kBeaconWithNonce
};

struct BeaconMetadata {
  BeaconMetadata() : status(kDoNotBeacon) { }
  BeaconStatus status;
  GoogleString nonce;
};

bool ValidateAndExpireNonce(int64 now_ms, StringPiece nonce,
                            CriticalKeys* critical_keys);

void GetCriticalKeysFromProto(int64 support_percentage,
                              const CriticalKeys& critical_keys,
                              StringSet* keys);

void UpdateCriticalKeys(bool require_prior_support,
                        const StringSet& new_set, int support_value,
                        CriticalKeys* critical_keys);

bool ShouldBeacon(int64 next_beacon_timestamp_ms, const RewriteDriver& driver);

enum CriticalKeysWriteFlags {
  kNoRequirementsOnPriorResult = 0,  
  kReplacePriorResult = 1,
  kRequirePriorSupport = 2,
  kSkipNonceCheck = 4
};

void WriteCriticalKeysToPropertyCache(
    const StringSet& new_keys, StringPiece nonce, int support_interval,
    CriticalKeysWriteFlags flags,
    StringPiece property_name, const PropertyCache* cache,
    const PropertyCache::Cohort* cohort, AbstractPropertyPage* page,
    MessageHandler* message_handler, Timer* timer);

void PrepareForBeaconInsertionHelper(CriticalKeys* proto,
                                     NonceGenerator* nonce_generator,
                                     RewriteDriver* driver,
                                     bool using_candidate_key_detection,
                                     BeaconMetadata* result);

bool UpdateCandidateKeys(const StringSet& keys, CriticalKeys* proto,
                         bool clear_rebeacon_timestamp);

inline bool IsBeaconDataAvailable(const CriticalKeys& proto) {
  return (proto.valid_beacons_received() > 0);
}

}  

#endif