зеркало из https://github.com/mozilla/gecko-dev.git
63 строки
2.0 KiB
C++
63 строки
2.0 KiB
C++
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* Original author: bcampen@mozilla.com */
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#include "simpletokenbucket.h"
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#include <stdint.h>
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#include "prinrval.h"
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namespace mozilla {
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SimpleTokenBucket::SimpleTokenBucket(size_t bucket_size,
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size_t tokens_per_second) :
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max_tokens_(bucket_size),
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num_tokens_(bucket_size),
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tokens_per_second_(tokens_per_second),
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last_time_tokens_added_(PR_IntervalNow()) {
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}
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size_t SimpleTokenBucket::getTokens(size_t num_requested_tokens) {
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// Only fill if there isn't enough to satisfy the request.
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// If we get tokens so seldomly that we are able to roll the timer all
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// the way around its range, then we lose that entire range of time
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// for token accumulation. Probably not the end of the world.
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if (num_requested_tokens > num_tokens_) {
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PRIntervalTime now = PR_IntervalNow();
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// If we roll over the max, since everything in this calculation is the same
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// unsigned type, this will still yield the elapsed time (unless we've
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// wrapped more than once).
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PRIntervalTime elapsed_ticks = now - last_time_tokens_added_;
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uint32_t elapsed_milli_sec = PR_IntervalToMilliseconds(elapsed_ticks);
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size_t tokens_to_add = (elapsed_milli_sec * tokens_per_second_)/1000;
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// Only update our timestamp if we added some tokens
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// TODO:(bcampen@mozilla.com) Should we attempt to "save" leftover time?
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if (tokens_to_add) {
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num_tokens_ += tokens_to_add;
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if (num_tokens_ > max_tokens_) {
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num_tokens_ = max_tokens_;
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}
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last_time_tokens_added_ = now;
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}
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if (num_requested_tokens > num_tokens_) {
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return num_tokens_;
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}
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}
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num_tokens_ -= num_requested_tokens;
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return num_requested_tokens;
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}
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} // namespace mozilla
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