src/extensions/browser/quota_service.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "extensions/browser/quota_service.h"
   6
   7 #include "base/message_loop/message_loop.h"
   8 #include "base/stl_util.h"
   9 #include "extensions/browser/extension_function.h"
  10 #include "extensions/common/error_utils.h"
  11
  12 namespace {
  13
  14 // If the browser stays open long enough, we reset state once a day.
  15 // Whatever this value is, it should be an order of magnitude longer than
  16 // the longest interval in any of the QuotaLimitHeuristics in use.
  17 const int kPurgeIntervalInDays = 1;
  18
  19 const char kOverQuotaError[] = "This request exceeds the * quota.";
  20
  21 }  // namespace
  22
  23 namespace extensions {
  24
  25 QuotaService::QuotaService() {
  26   if (base::MessageLoop::current() != NULL) {  // Null in unit tests.
  27     purge_timer_.Start(FROM_HERE,
  28                        base::TimeDelta::FromDays(kPurgeIntervalInDays),
  29                        this,
  30                        &QuotaService::Purge);
  31   }
  32 }
  33
  34 QuotaService::~QuotaService() {
  35   DCHECK(CalledOnValidThread());
  36   purge_timer_.Stop();
  37   Purge();
  38 }
  39
  40 std::string QuotaService::Assess(const std::string& extension_id,
  41                                  ExtensionFunction* function,
  42                                  const base::ListValue* args,
  43                                  const base::TimeTicks& event_time) {
  44   DCHECK(CalledOnValidThread());
  45
  46   if (function->ShouldSkipQuotaLimiting())
  47     return std::string();
  48
  49   // Lookup function list for extension.
  50   FunctionHeuristicsMap& functions = function_heuristics_[extension_id];
  51
  52   // Lookup heuristics for function, create if necessary.
  53   QuotaLimitHeuristics& heuristics = functions[function->name()];
  54   if (heuristics.empty())
  55     function->GetQuotaLimitHeuristics(&heuristics);
  56
  57   if (heuristics.empty())
  58     return std::string();  // No heuristic implies no limit.
  59
  60   QuotaLimitHeuristic* failed_heuristic = NULL;
  61   for (QuotaLimitHeuristics::iterator heuristic = heuristics.begin();
  62        heuristic != heuristics.end();
  63        ++heuristic) {
  64     // Apply heuristic to each item (bucket).
  65     if (!(*heuristic)->ApplyToArgs(args, event_time)) {
  66       failed_heuristic = *heuristic;
  67       break;
  68     }
  69   }
  70
  71   if (!failed_heuristic)
  72     return std::string();
  73
  74   std::string error = failed_heuristic->GetError();
  75   DCHECK_GT(error.length(), 0u);
  76   return error;
  77 }
  78
  79 void QuotaService::PurgeFunctionHeuristicsMap(FunctionHeuristicsMap* map) {
  80   FunctionHeuristicsMap::iterator heuristics = map->begin();
  81   while (heuristics != map->end()) {
  82     STLDeleteElements(&heuristics->second);
  83     map->erase(heuristics++);
  84   }
  85 }
  86
  87 void QuotaService::Purge() {
  88   DCHECK(CalledOnValidThread());
  89   std::map<std::string, FunctionHeuristicsMap>::iterator it =
  90       function_heuristics_.begin();
  91   for (; it != function_heuristics_.end(); function_heuristics_.erase(it++))
  92     PurgeFunctionHeuristicsMap(&it->second);
  93 }
  94
  95 void QuotaLimitHeuristic::Bucket::Reset(const Config& config,
  96                                         const base::TimeTicks& start) {
  97   num_tokens_ = config.refill_token_count;
  98   expiration_ = start + config.refill_interval;
  99 }
 100
 101 void QuotaLimitHeuristic::SingletonBucketMapper::GetBucketsForArgs(
 102     const base::ListValue* args,
 103     BucketList* buckets) {
 104   buckets->push_back(&bucket_);
 105 }
 106
 107 QuotaLimitHeuristic::QuotaLimitHeuristic(const Config& config,
 108                                          BucketMapper* map,
 109                                          const std::string& name)
 110     : config_(config), bucket_mapper_(map), name_(name) {}
 111
 112 QuotaLimitHeuristic::~QuotaLimitHeuristic() {}
 113
 114 bool QuotaLimitHeuristic::ApplyToArgs(const base::ListValue* args,
 115                                       const base::TimeTicks& event_time) {
 116   BucketList buckets;
 117   bucket_mapper_->GetBucketsForArgs(args, &buckets);
 118   for (BucketList::iterator i = buckets.begin(); i != buckets.end(); ++i) {
 119     if ((*i)->expiration().is_null())  // A brand new bucket.
 120       (*i)->Reset(config_, event_time);
 121     if (!Apply(*i, event_time))
 122       return false;  // It only takes one to spoil it for everyone.
 123   }
 124   return true;
 125 }
 126
 127 std::string QuotaLimitHeuristic::GetError() const {
 128   return extensions::ErrorUtils::FormatErrorMessage(kOverQuotaError, name_);
 129 }
 130
 131 bool QuotaService::TimedLimit::Apply(Bucket* bucket,
 132                                      const base::TimeTicks& event_time) {
 133   if (event_time > bucket->expiration())
 134     bucket->Reset(config(), event_time);
 135
 136   return bucket->DeductToken();
 137 }
 138
 139 }  // namespace extensions