Moved ExtensionInfoMap and ExtensionsQuotaService to extensions/

In the move these classes became extensions::InfoMap and
extensions::QuotaService.

TBR=sky
BUG=162530

Review URL: https://codereview.chromium.org/63933003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234131 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 192 insertions, 0 deletions

diff --git a/extensions/browser/quota_service.cc b/extensions/browser/quota_service.cc
new file mode 100644
index 0000000..ce21b25
--- /dev/null
+++ b/extensions/browser/quota_service.cc
@@ -0,0 +1,192 @@
+// Copyright 2013 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.
+
+#include "extensions/browser/quota_service.h"
+
+#include "base/message_loop/message_loop.h"
+#include "base/stl_util.h"
+#include "chrome/browser/extensions/extension_function.h"
+#include "extensions/common/error_utils.h"
+
+namespace {
+
+// If the browser stays open long enough, we reset state once a day.
+// Whatever this value is, it should be an order of magnitude longer than
+// the longest interval in any of the QuotaLimitHeuristics in use.
+const int kPurgeIntervalInDays = 1;
+
+const char kOverQuotaError[] = "This request exceeds the * quota.";
+
+}  // namespace
+
+namespace extensions {
+
+QuotaService::QuotaService() {
+  if (base::MessageLoop::current() != NULL) {  // Null in unit tests.
+    purge_timer_.Start(FROM_HERE,
+                       base::TimeDelta::FromDays(kPurgeIntervalInDays),
+                       this,
+                       &QuotaService::Purge);
+  }
+}
+
+QuotaService::~QuotaService() {
+  DCHECK(CalledOnValidThread());
+  purge_timer_.Stop();
+  Purge();
+}
+
+std::string QuotaService::Assess(const std::string& extension_id,
+                                 ExtensionFunction* function,
+                                 const base::ListValue* args,
+                                 const base::TimeTicks& event_time) {
+  DCHECK(CalledOnValidThread());
+
+  if (function->ShouldSkipQuotaLimiting())
+    return std::string();
+
+  // Lookup function list for extension.
+  FunctionHeuristicsMap& functions = function_heuristics_[extension_id];
+
+  // Lookup heuristics for function, create if necessary.
+  QuotaLimitHeuristics& heuristics = functions[function->name()];
+  if (heuristics.empty())
+    function->GetQuotaLimitHeuristics(&heuristics);
+
+  if (heuristics.empty())
+    return std::string();  // No heuristic implies no limit.
+
+  ViolationErrorMap::iterator violation_error =
+      violation_errors_.find(extension_id);
+  if (violation_error != violation_errors_.end())
+    return violation_error->second;  // Repeat offender.
+
+  QuotaLimitHeuristic* failed_heuristic = NULL;
+  for (QuotaLimitHeuristics::iterator heuristic = heuristics.begin();
+       heuristic != heuristics.end();
+       ++heuristic) {
+    // Apply heuristic to each item (bucket).
+    if (!(*heuristic)->ApplyToArgs(args, event_time)) {
+      failed_heuristic = *heuristic;
+      break;
+    }
+  }
+
+  if (!failed_heuristic)
+    return std::string();
+
+  std::string error = failed_heuristic->GetError();
+  DCHECK_GT(error.length(), 0u);
+
+  PurgeFunctionHeuristicsMap(&functions);
+  function_heuristics_.erase(extension_id);
+  violation_errors_[extension_id] = error;
+  return error;
+}
+
+void QuotaService::PurgeFunctionHeuristicsMap(FunctionHeuristicsMap* map) {
+  FunctionHeuristicsMap::iterator heuristics = map->begin();
+  while (heuristics != map->end()) {
+    STLDeleteElements(&heuristics->second);
+    map->erase(heuristics++);
+  }
+}
+
+void QuotaService::Purge() {
+  DCHECK(CalledOnValidThread());
+  std::map<std::string, FunctionHeuristicsMap>::iterator it =
+      function_heuristics_.begin();
+  for (; it != function_heuristics_.end(); function_heuristics_.erase(it++))
+    PurgeFunctionHeuristicsMap(&it->second);
+}
+
+void QuotaLimitHeuristic::Bucket::Reset(const Config& config,
+                                        const base::TimeTicks& start) {
+  num_tokens_ = config.refill_token_count;
+  expiration_ = start + config.refill_interval;
+}
+
+void QuotaLimitHeuristic::SingletonBucketMapper::GetBucketsForArgs(
+    const base::ListValue* args,
+    BucketList* buckets) {
+  buckets->push_back(&bucket_);
+}
+
+QuotaLimitHeuristic::QuotaLimitHeuristic(const Config& config,
+                                         BucketMapper* map,
+                                         const std::string& name)
+    : config_(config), bucket_mapper_(map), name_(name) {}
+
+QuotaLimitHeuristic::~QuotaLimitHeuristic() {}
+
+bool QuotaLimitHeuristic::ApplyToArgs(const base::ListValue* args,
+                                      const base::TimeTicks& event_time) {
+  BucketList buckets;
+  bucket_mapper_->GetBucketsForArgs(args, &buckets);
+  for (BucketList::iterator i = buckets.begin(); i != buckets.end(); ++i) {
+    if ((*i)->expiration().is_null())  // A brand new bucket.
+      (*i)->Reset(config_, event_time);
+    if (!Apply(*i, event_time))
+      return false;  // It only takes one to spoil it for everyone.
+  }
+  return true;
+}
+
+std::string QuotaLimitHeuristic::GetError() const {
+  return extensions::ErrorUtils::FormatErrorMessage(kOverQuotaError, name_);
+}
+
+QuotaService::SustainedLimit::SustainedLimit(const base::TimeDelta& sustain,
+                                             const Config& config,
+                                             BucketMapper* map,
+                                             const std::string& name)
+    : QuotaLimitHeuristic(config, map, name),
+      repeat_exhaustion_allowance_(sustain.InSeconds() /
+                                   config.refill_interval.InSeconds()),
+      num_available_repeat_exhaustions_(repeat_exhaustion_allowance_) {}
+
+bool QuotaService::TimedLimit::Apply(Bucket* bucket,
+                                     const base::TimeTicks& event_time) {
+  if (event_time > bucket->expiration())
+    bucket->Reset(config(), event_time);
+
+  return bucket->DeductToken();
+}
+
+bool QuotaService::SustainedLimit::Apply(Bucket* bucket,
+                                         const base::TimeTicks& event_time) {
+  if (event_time > bucket->expiration()) {
+    // We reset state for this item and start over again if this request breaks
+    // the bad cycle that was previously being tracked.  This occurs if the
+    // state in the bucket expired recently (it has been long enough since the
+    // event that we don't care about the last event), but the bucket still has
+    // tokens (so pressure was not sustained over that time), OR we are more
+    // than 1 full refill interval away from the last event (so even if we used
+    // up all the tokens in the last bucket, nothing happened in the entire
+    // next refill interval, so it doesn't matter).
+    if (bucket->has_tokens() ||
+        event_time > bucket->expiration() + config().refill_interval) {
+      bucket->Reset(config(), event_time);
+      num_available_repeat_exhaustions_ = repeat_exhaustion_allowance_;
+    } else if (--num_available_repeat_exhaustions_ > 0) {
+      // The last interval was saturated with requests, and this is the first
+      // event in the next interval. If this happens
+      // repeat_exhaustion_allowance_ times, it's a violation. Reset the bucket
+      // state to start timing from the end of the last interval (and we'll
+      // deduct the token below) so we can detect this each time it happens.
+      bucket->Reset(config(), bucket->expiration());
+    } else {
+      // No allowances left; this request is a violation.
+      return false;
+    }
+  }
+
+  // We can go negative since we check has_tokens when we get to *next* bucket,
+  // and for the small interval all that matters is whether we used up all the
+  // tokens (which is true if num_tokens_ <= 0).
+  bucket->DeductToken();
+  return true;
+}
+
+}  // namespace extensions