Pull cacheinvalidations code directory into chromium repo.

third_party/cacheinvalidation/src/google/cacheinvalidation/impl/throttle.h

Index: third_party/cacheinvalidation/src/google/cacheinvalidation/impl/throttle.h
diff --git a/third_party/cacheinvalidation/src/google/cacheinvalidation/impl/throttle.h b/third_party/cacheinvalidation/src/google/cacheinvalidation/impl/throttle.h
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+// Copyright 2012 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.
+
+// Throttles calls to a function.
+
+#ifndef GOOGLE_CACHEINVALIDATION_IMPL_THROTTLE_H_
+#define GOOGLE_CACHEINVALIDATION_IMPL_THROTTLE_H_
+
+#include <cstddef>
+#include <deque>
+#include <vector>
+
+#include "google/cacheinvalidation/deps/callback.h"
+#include "google/cacheinvalidation/deps/logging.h"
+#include "google/cacheinvalidation/deps/scoped_ptr.h"
+#include "google/cacheinvalidation/deps/stl-namespace.h"
+#include "google/cacheinvalidation/deps/time.h"
+#include "google/cacheinvalidation/impl/client-protocol-namespace-fix.h"
+
+namespace invalidation {
+
+class Scheduler;
+
+using INVALIDATION_STL_NAMESPACE::deque;
+using INVALIDATION_STL_NAMESPACE::vector;
+
+// Provides an abstraction for multi-level rate-limiting.  For example, the
+// default limits state that no more than one message should be sent per second,
+// or six per minute.  Rate-limiting is implemented by maintaining a buffer of
+// recent messages, which is as large as the highest 'count' property.  Note:
+// this means the object consumes space proportional to the _largest_ 'count'.
+class Throttle {
+ public:
+  // Constructs a throttler to enforce the given rate limits for the given
+  // listener, using the given system resources.  Ownership of scheduler is
+  // retained by the caller, but the throttle takes ownership of the listener.
+  Throttle(const RepeatedPtrField<RateLimitP>& rate_limits,
+           Scheduler* scheduler, Closure* listener);
+
+  // If calling the listener would not violate the rate limits, does so.
+  // Otherwise, schedules a timer to do so as soon as doing so would not violate
+  // the rate limits, unless such a timer is already set, in which case does
+  // nothing.  I.e., once the rate limit is reached, additional calls are not
+  // queued.
+  void Fire();
+
+ private:
+  // Retries a call to Fire() after some delay.
+  void RetryFire() {
+    timer_scheduled_ = false;
+    Fire();
+  }
+
+  // Rate limits to be enforced by this object.
+  RepeatedPtrField<RateLimitP> rate_limits_;
+
+  // Scheduler for reading the current time and scheduling tasks that need to be
+  // delayed.
+  Scheduler* scheduler_;
+
+  // The closure whose calls are throttled.
+  scoped_ptr<Closure> listener_;
+
+  // Whether we've already scheduled a deferred call.
+  bool timer_scheduled_;
+
+  // A buffer of recent events, so we can determine the length of the interval
+  // in which we made the most recent K events.
+  deque<Time> recent_event_times_;
+
+  // The maximum size of the recent_event_times_ buffer.
+  size_t max_recent_events_;
+};
+
+}  // namespace invalidation
+
+#endif  // GOOGLE_CACHEINVALIDATION_IMPL_THROTTLE_H_