media/mtransport/simpletokenbucket.cpp@97036ab72558 (annotated)
media/mtransport/simpletokenbucket.cpp
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | /* vim: set ts=2 et sw=2 tw=80: */ |
| michael@0 | 3 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 4 | * License, v. 2.0. If a copy of the MPL was not distributed with this file, |
| michael@0 | 5 | * You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 6 | |
| michael@0 | 7 | /* Original author: bcampen@mozilla.com */ |
| michael@0 | 8 | |
| michael@0 | 9 | #include "simpletokenbucket.h" |
| michael@0 | 10 | |
| michael@0 | 11 | #include <stdint.h> |
| michael@0 | 12 | |
| michael@0 | 13 | #include "prinrval.h" |
| michael@0 | 14 | |
| michael@0 | 15 | namespace mozilla { |
| michael@0 | 16 | |
| michael@0 | 17 | SimpleTokenBucket::SimpleTokenBucket(size_t bucket_size, |
| michael@0 | 18 | size_t tokens_per_second) : |
| michael@0 | 19 | max_tokens_(bucket_size), |
| michael@0 | 20 | num_tokens_(bucket_size), |
| michael@0 | 21 | tokens_per_second_(tokens_per_second), |
| michael@0 | 22 | last_time_tokens_added_(PR_IntervalNow()) { |
| michael@0 | 23 | } |
| michael@0 | 24 | |
| michael@0 | 25 | size_t SimpleTokenBucket::getTokens(size_t num_requested_tokens) { |
| michael@0 | 26 | // Only fill if there isn't enough to satisfy the request. |
| michael@0 | 27 | // If we get tokens so seldomly that we are able to roll the timer all |
| michael@0 | 28 | // the way around its range, then we lose that entire range of time |
| michael@0 | 29 | // for token accumulation. Probably not the end of the world. |
| michael@0 | 30 | if (num_requested_tokens > num_tokens_) { |
| michael@0 | 31 | PRIntervalTime now = PR_IntervalNow(); |
| michael@0 | 32 | |
| michael@0 | 33 | // If we roll over the max, since everything in this calculation is the same |
| michael@0 | 34 | // unsigned type, this will still yield the elapsed time (unless we've |
| michael@0 | 35 | // wrapped more than once). |
| michael@0 | 36 | PRIntervalTime elapsed_ticks = now - last_time_tokens_added_; |
| michael@0 | 37 | |
| michael@0 | 38 | uint32_t elapsed_milli_sec = PR_IntervalToMilliseconds(elapsed_ticks); |
| michael@0 | 39 | size_t tokens_to_add = (elapsed_milli_sec * tokens_per_second_)/1000; |
| michael@0 | 40 | |
| michael@0 | 41 | // Only update our timestamp if we added some tokens |
| michael@0 | 42 | // TODO:(bcampen@mozilla.com) Should we attempt to "save" leftover time? |
| michael@0 | 43 | if (tokens_to_add) { |
| michael@0 | 44 | num_tokens_ += tokens_to_add; |
| michael@0 | 45 | if (num_tokens_ > max_tokens_) { |
| michael@0 | 46 | num_tokens_ = max_tokens_; |
| michael@0 | 47 | } |
| michael@0 | 48 | |
| michael@0 | 49 | last_time_tokens_added_ = now; |
| michael@0 | 50 | } |
| michael@0 | 51 | |
| michael@0 | 52 | if (num_requested_tokens > num_tokens_) { |
| michael@0 | 53 | return num_tokens_; |
| michael@0 | 54 | } |
| michael@0 | 55 | } |
| michael@0 | 56 | |
| michael@0 | 57 | num_tokens_ -= num_requested_tokens; |
| michael@0 | 58 | return num_requested_tokens; |
| michael@0 | 59 | } |
| michael@0 | 60 | |
| michael@0 | 61 | } // namespace mozilla |
| michael@0 | 62 |
