From 6d8f122a5160f6d9e4c51579f2429dfaa62c7271 Mon Sep 17 00:00:00 2001 From: Christopher Speller Date: Fri, 16 Feb 2018 06:47:51 -0800 Subject: Upgrading server dependancies (#8308) --- vendor/golang.org/x/time/rate/rate.go | 380 ---------------------------------- 1 file changed, 380 deletions(-) delete mode 100644 vendor/golang.org/x/time/rate/rate.go (limited to 'vendor/golang.org/x/time/rate/rate.go') diff --git a/vendor/golang.org/x/time/rate/rate.go b/vendor/golang.org/x/time/rate/rate.go deleted file mode 100644 index eabcd1147..000000000 --- a/vendor/golang.org/x/time/rate/rate.go +++ /dev/null @@ -1,380 +0,0 @@ -// Copyright 2015 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -// Package rate provides a rate limiter. -package rate - -import ( - "fmt" - "math" - "sync" - "time" -) - -// Limit defines the maximum frequency of some events. -// Limit is represented as number of events per second. -// A zero Limit allows no events. -type Limit float64 - -// Inf is the infinite rate limit; it allows all events (even if burst is zero). -const Inf = Limit(math.MaxFloat64) - -// Every converts a minimum time interval between events to a Limit. -func Every(interval time.Duration) Limit { - if interval <= 0 { - return Inf - } - return 1 / Limit(interval.Seconds()) -} - -// A Limiter controls how frequently events are allowed to happen. -// It implements a "token bucket" of size b, initially full and refilled -// at rate r tokens per second. -// Informally, in any large enough time interval, the Limiter limits the -// rate to r tokens per second, with a maximum burst size of b events. -// As a special case, if r == Inf (the infinite rate), b is ignored. -// See https://en.wikipedia.org/wiki/Token_bucket for more about token buckets. -// -// The zero value is a valid Limiter, but it will reject all events. -// Use NewLimiter to create non-zero Limiters. -// -// Limiter has three main methods, Allow, Reserve, and Wait. -// Most callers should use Wait. -// -// Each of the three methods consumes a single token. -// They differ in their behavior when no token is available. -// If no token is available, Allow returns false. -// If no token is available, Reserve returns a reservation for a future token -// and the amount of time the caller must wait before using it. -// If no token is available, Wait blocks until one can be obtained -// or its associated context.Context is canceled. -// -// The methods AllowN, ReserveN, and WaitN consume n tokens. -type Limiter struct { - limit Limit - burst int - - mu sync.Mutex - tokens float64 - // last is the last time the limiter's tokens field was updated - last time.Time - // lastEvent is the latest time of a rate-limited event (past or future) - lastEvent time.Time -} - -// Limit returns the maximum overall event rate. -func (lim *Limiter) Limit() Limit { - lim.mu.Lock() - defer lim.mu.Unlock() - return lim.limit -} - -// Burst returns the maximum burst size. Burst is the maximum number of tokens -// that can be consumed in a single call to Allow, Reserve, or Wait, so higher -// Burst values allow more events to happen at once. -// A zero Burst allows no events, unless limit == Inf. -func (lim *Limiter) Burst() int { - return lim.burst -} - -// NewLimiter returns a new Limiter that allows events up to rate r and permits -// bursts of at most b tokens. -func NewLimiter(r Limit, b int) *Limiter { - return &Limiter{ - limit: r, - burst: b, - } -} - -// Allow is shorthand for AllowN(time.Now(), 1). -func (lim *Limiter) Allow() bool { - return lim.AllowN(time.Now(), 1) -} - -// AllowN reports whether n events may happen at time now. -// Use this method if you intend to drop / skip events that exceed the rate limit. -// Otherwise use Reserve or Wait. -func (lim *Limiter) AllowN(now time.Time, n int) bool { - return lim.reserveN(now, n, 0).ok -} - -// A Reservation holds information about events that are permitted by a Limiter to happen after a delay. -// A Reservation may be canceled, which may enable the Limiter to permit additional events. -type Reservation struct { - ok bool - lim *Limiter - tokens int - timeToAct time.Time - // This is the Limit at reservation time, it can change later. - limit Limit -} - -// OK returns whether the limiter can provide the requested number of tokens -// within the maximum wait time. If OK is false, Delay returns InfDuration, and -// Cancel does nothing. -func (r *Reservation) OK() bool { - return r.ok -} - -// Delay is shorthand for DelayFrom(time.Now()). -func (r *Reservation) Delay() time.Duration { - return r.DelayFrom(time.Now()) -} - -// InfDuration is the duration returned by Delay when a Reservation is not OK. -const InfDuration = time.Duration(1<<63 - 1) - -// DelayFrom returns the duration for which the reservation holder must wait -// before taking the reserved action. Zero duration means act immediately. -// InfDuration means the limiter cannot grant the tokens requested in this -// Reservation within the maximum wait time. -func (r *Reservation) DelayFrom(now time.Time) time.Duration { - if !r.ok { - return InfDuration - } - delay := r.timeToAct.Sub(now) - if delay < 0 { - return 0 - } - return delay -} - -// Cancel is shorthand for CancelAt(time.Now()). -func (r *Reservation) Cancel() { - r.CancelAt(time.Now()) - return -} - -// CancelAt indicates that the reservation holder will not perform the reserved action -// and reverses the effects of this Reservation on the rate limit as much as possible, -// considering that other reservations may have already been made. -func (r *Reservation) CancelAt(now time.Time) { - if !r.ok { - return - } - - r.lim.mu.Lock() - defer r.lim.mu.Unlock() - - if r.lim.limit == Inf || r.tokens == 0 || r.timeToAct.Before(now) { - return - } - - // calculate tokens to restore - // The duration between lim.lastEvent and r.timeToAct tells us how many tokens were reserved - // after r was obtained. These tokens should not be restored. - restoreTokens := float64(r.tokens) - r.limit.tokensFromDuration(r.lim.lastEvent.Sub(r.timeToAct)) - if restoreTokens <= 0 { - return - } - // advance time to now - now, _, tokens := r.lim.advance(now) - // calculate new number of tokens - tokens += restoreTokens - if burst := float64(r.lim.burst); tokens > burst { - tokens = burst - } - // update state - r.lim.last = now - r.lim.tokens = tokens - if r.timeToAct == r.lim.lastEvent { - prevEvent := r.timeToAct.Add(r.limit.durationFromTokens(float64(-r.tokens))) - if !prevEvent.Before(now) { - r.lim.lastEvent = prevEvent - } - } - - return -} - -// Reserve is shorthand for ReserveN(time.Now(), 1). -func (lim *Limiter) Reserve() *Reservation { - return lim.ReserveN(time.Now(), 1) -} - -// ReserveN returns a Reservation that indicates how long the caller must wait before n events happen. -// The Limiter takes this Reservation into account when allowing future events. -// ReserveN returns false if n exceeds the Limiter's burst size. -// Usage example: -// r := lim.ReserveN(time.Now(), 1) -// if !r.OK() { -// // Not allowed to act! Did you remember to set lim.burst to be > 0 ? -// return -// } -// time.Sleep(r.Delay()) -// Act() -// Use this method if you wish to wait and slow down in accordance with the rate limit without dropping events. -// If you need to respect a deadline or cancel the delay, use Wait instead. -// To drop or skip events exceeding rate limit, use Allow instead. -func (lim *Limiter) ReserveN(now time.Time, n int) *Reservation { - r := lim.reserveN(now, n, InfDuration) - return &r -} - -// contextContext is a temporary(?) copy of the context.Context type -// to support both Go 1.6 using golang.org/x/net/context and Go 1.7+ -// with the built-in context package. If people ever stop using Go 1.6 -// we can remove this. -type contextContext interface { - Deadline() (deadline time.Time, ok bool) - Done() <-chan struct{} - Err() error - Value(key interface{}) interface{} -} - -// Wait is shorthand for WaitN(ctx, 1). -func (lim *Limiter) wait(ctx contextContext) (err error) { - return lim.WaitN(ctx, 1) -} - -// WaitN blocks until lim permits n events to happen. -// It returns an error if n exceeds the Limiter's burst size, the Context is -// canceled, or the expected wait time exceeds the Context's Deadline. -// The burst limit is ignored if the rate limit is Inf. -func (lim *Limiter) waitN(ctx contextContext, n int) (err error) { - if n > lim.burst && lim.limit != Inf { - return fmt.Errorf("rate: Wait(n=%d) exceeds limiter's burst %d", n, lim.burst) - } - // Check if ctx is already cancelled - select { - case <-ctx.Done(): - return ctx.Err() - default: - } - // Determine wait limit - now := time.Now() - waitLimit := InfDuration - if deadline, ok := ctx.Deadline(); ok { - waitLimit = deadline.Sub(now) - } - // Reserve - r := lim.reserveN(now, n, waitLimit) - if !r.ok { - return fmt.Errorf("rate: Wait(n=%d) would exceed context deadline", n) - } - // Wait - t := time.NewTimer(r.DelayFrom(now)) - defer t.Stop() - select { - case <-t.C: - // We can proceed. - return nil - case <-ctx.Done(): - // Context was canceled before we could proceed. Cancel the - // reservation, which may permit other events to proceed sooner. - r.Cancel() - return ctx.Err() - } -} - -// SetLimit is shorthand for SetLimitAt(time.Now(), newLimit). -func (lim *Limiter) SetLimit(newLimit Limit) { - lim.SetLimitAt(time.Now(), newLimit) -} - -// SetLimitAt sets a new Limit for the limiter. The new Limit, and Burst, may be violated -// or underutilized by those which reserved (using Reserve or Wait) but did not yet act -// before SetLimitAt was called. -func (lim *Limiter) SetLimitAt(now time.Time, newLimit Limit) { - lim.mu.Lock() - defer lim.mu.Unlock() - - now, _, tokens := lim.advance(now) - - lim.last = now - lim.tokens = tokens - lim.limit = newLimit -} - -// reserveN is a helper method for AllowN, ReserveN, and WaitN. -// maxFutureReserve specifies the maximum reservation wait duration allowed. -// reserveN returns Reservation, not *Reservation, to avoid allocation in AllowN and WaitN. -func (lim *Limiter) reserveN(now time.Time, n int, maxFutureReserve time.Duration) Reservation { - lim.mu.Lock() - - if lim.limit == Inf { - lim.mu.Unlock() - return Reservation{ - ok: true, - lim: lim, - tokens: n, - timeToAct: now, - } - } - - now, last, tokens := lim.advance(now) - - // Calculate the remaining number of tokens resulting from the request. - tokens -= float64(n) - - // Calculate the wait duration - var waitDuration time.Duration - if tokens < 0 { - waitDuration = lim.limit.durationFromTokens(-tokens) - } - - // Decide result - ok := n <= lim.burst && waitDuration <= maxFutureReserve - - // Prepare reservation - r := Reservation{ - ok: ok, - lim: lim, - limit: lim.limit, - } - if ok { - r.tokens = n - r.timeToAct = now.Add(waitDuration) - } - - // Update state - if ok { - lim.last = now - lim.tokens = tokens - lim.lastEvent = r.timeToAct - } else { - lim.last = last - } - - lim.mu.Unlock() - return r -} - -// advance calculates and returns an updated state for lim resulting from the passage of time. -// lim is not changed. -func (lim *Limiter) advance(now time.Time) (newNow time.Time, newLast time.Time, newTokens float64) { - last := lim.last - if now.Before(last) { - last = now - } - - // Avoid making delta overflow below when last is very old. - maxElapsed := lim.limit.durationFromTokens(float64(lim.burst) - lim.tokens) - elapsed := now.Sub(last) - if elapsed > maxElapsed { - elapsed = maxElapsed - } - - // Calculate the new number of tokens, due to time that passed. - delta := lim.limit.tokensFromDuration(elapsed) - tokens := lim.tokens + delta - if burst := float64(lim.burst); tokens > burst { - tokens = burst - } - - return now, last, tokens -} - -// durationFromTokens is a unit conversion function from the number of tokens to the duration -// of time it takes to accumulate them at a rate of limit tokens per second. -func (limit Limit) durationFromTokens(tokens float64) time.Duration { - seconds := tokens / float64(limit) - return time.Nanosecond * time.Duration(1e9*seconds) -} - -// tokensFromDuration is a unit conversion function from a time duration to the number of tokens -// which could be accumulated during that duration at a rate of limit tokens per second. -func (limit Limit) tokensFromDuration(d time.Duration) float64 { - return d.Seconds() * float64(limit) -} -- cgit v1.2.3-1-g7c22