mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-10-31 22:25:30 +00:00
63 lines
2.0 KiB
C++
63 lines
2.0 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* vim: set ts=2 et sw=2 tw=80: */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
|
|
* You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
/* Original author: bcampen@mozilla.com */
|
|
|
|
#include "simpletokenbucket.h"
|
|
|
|
#include <stdint.h>
|
|
|
|
#include "prinrval.h"
|
|
|
|
namespace mozilla {
|
|
|
|
SimpleTokenBucket::SimpleTokenBucket(size_t bucket_size,
|
|
size_t tokens_per_second) :
|
|
max_tokens_(bucket_size),
|
|
num_tokens_(bucket_size),
|
|
tokens_per_second_(tokens_per_second),
|
|
last_time_tokens_added_(PR_IntervalNow()) {
|
|
}
|
|
|
|
size_t SimpleTokenBucket::getTokens(size_t num_requested_tokens) {
|
|
// Only fill if there isn't enough to satisfy the request.
|
|
// If we get tokens so seldomly that we are able to roll the timer all
|
|
// the way around its range, then we lose that entire range of time
|
|
// for token accumulation. Probably not the end of the world.
|
|
if (num_requested_tokens > num_tokens_) {
|
|
PRIntervalTime now = PR_IntervalNow();
|
|
|
|
// If we roll over the max, since everything in this calculation is the same
|
|
// unsigned type, this will still yield the elapsed time (unless we've
|
|
// wrapped more than once).
|
|
PRIntervalTime elapsed_ticks = now - last_time_tokens_added_;
|
|
|
|
uint32_t elapsed_milli_sec = PR_IntervalToMilliseconds(elapsed_ticks);
|
|
size_t tokens_to_add = (elapsed_milli_sec * tokens_per_second_)/1000;
|
|
|
|
// Only update our timestamp if we added some tokens
|
|
// TODO:(bcampen@mozilla.com) Should we attempt to "save" leftover time?
|
|
if (tokens_to_add) {
|
|
num_tokens_ += tokens_to_add;
|
|
if (num_tokens_ > max_tokens_) {
|
|
num_tokens_ = max_tokens_;
|
|
}
|
|
|
|
last_time_tokens_added_ = now;
|
|
}
|
|
|
|
if (num_requested_tokens > num_tokens_) {
|
|
return num_tokens_;
|
|
}
|
|
}
|
|
|
|
num_tokens_ -= num_requested_tokens;
|
|
return num_requested_tokens;
|
|
}
|
|
|
|
} // namespace mozilla
|
|
|