mirror of https://github.com/etcd-io/dbtester.git
vendor: add 'time/rate'
This commit is contained in:
parent
9547011c87
commit
5ac7466be5
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@ -1,5 +1,5 @@
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hash: 7e56e2b0795ce80b8d55b4ed02cea643952ce670b7f5d6cd09fbc5817b88db86
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updated: 2016-12-19T11:51:16.093755958-08:00
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hash: d4a1ceef843a6f16e969081a50aeb9117cdca088ddee1f652b847f1bf322a03d
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updated: 2016-12-20T12:42:08.836209288-08:00
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imports:
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- name: bitbucket.org/zombiezen/gopdf
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version: 1c63dc69751bc45441c2ce1f56b631c55294b4d5
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@ -133,7 +133,7 @@ imports:
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subpackages:
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- go
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- name: github.com/prometheus/common
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version: 195bde7883f7c39ea62b0d92ab7359b5327065cb
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version: 6d76b79f239843a04e8ad8dfd8fcadfa3920236f
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subpackages:
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- expfmt
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- internal/bitbucket.org/ww/goautoneg
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@ -153,7 +153,7 @@ imports:
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subpackages:
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- codec
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- name: golang.org/x/image
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version: ed90ab82a880d9b63d5adecdc23c5cd5020addc1
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version: f1b1ff53e10e288d0ab6f161067c0a69b72cee28
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subpackages:
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- draw
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- font
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@ -178,6 +178,10 @@ imports:
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- internal
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- jws
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- jwt
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- name: golang.org/x/time
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version: a4bde12657593d5e90d0533a3e4fd95e635124cb
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subpackages:
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- rate
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- name: google.golang.org/api
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version: a53f28dc539c26b08a77fc5ae954e02917686ef4
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subpackages:
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@ -103,3 +103,7 @@ import:
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version: 53feefa2559fb8dfa8d81baad31be332c97d6c77
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- package: github.com/spf13/pflag
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version: 5ccb023bc27df288a957c5e994cd44fd19619465
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- package: golang.org/x/time
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version: a4bde12657593d5e90d0533a3e4fd95e635124cb
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subpackages:
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- rate
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@ -44,7 +44,7 @@ func (m Metric) Before(o Metric) bool {
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// Clone returns a copy of the Metric.
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func (m Metric) Clone() Metric {
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clone := Metric{}
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clone := make(Metric, len(m))
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for k, v := range m {
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clone[k] = v
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}
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|
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@ -169,6 +169,26 @@ func (d *Drawer) DrawString(s string) {
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}
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}
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// BoundBytes returns the bounding box of s, drawn at the drawer dot, as well as
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// the advance.
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//
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// It is equivalent to BoundBytes(string(s)) but may be more efficient.
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func (d *Drawer) BoundBytes(s []byte) (bounds fixed.Rectangle26_6, advance fixed.Int26_6) {
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bounds, advance = BoundBytes(d.Face, s)
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bounds.Min = bounds.Min.Add(d.Dot)
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bounds.Max = bounds.Max.Add(d.Dot)
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return
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}
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// BoundString returns the bounding box of s, drawn at the drawer dot, as well
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// as the advance.
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func (d *Drawer) BoundString(s string) (bounds fixed.Rectangle26_6, advance fixed.Int26_6) {
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bounds, advance = BoundString(d.Face, s)
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bounds.Min = bounds.Min.Add(d.Dot)
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bounds.Max = bounds.Max.Add(d.Dot)
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return
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}
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// MeasureBytes returns how far dot would advance by drawing s.
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//
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// It is equivalent to MeasureString(string(s)) but may be more efficient.
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@ -181,6 +201,73 @@ func (d *Drawer) MeasureString(s string) (advance fixed.Int26_6) {
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return MeasureString(d.Face, s)
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}
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// BoundBytes returns the bounding box of s with f, drawn at a dot equal to the
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// origin, as well as the advance.
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//
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// It is equivalent to BoundString(string(s)) but may be more efficient.
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func BoundBytes(f Face, s []byte) (bounds fixed.Rectangle26_6, advance fixed.Int26_6) {
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prevC := rune(-1)
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for len(s) > 0 {
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c, size := utf8.DecodeRune(s)
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s = s[size:]
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if prevC >= 0 {
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advance += f.Kern(prevC, c)
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}
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b, a, ok := f.GlyphBounds(c)
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if !ok {
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// TODO: is falling back on the U+FFFD glyph the responsibility of
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// the Drawer or the Face?
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// TODO: set prevC = '\ufffd'?
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continue
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}
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bounds = grow(bounds, b, advance)
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advance += a
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prevC = c
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}
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return
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}
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// BoundString returns the bounding box of s with f, drawn at a dot equal to the
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// origin, as well as the advance.
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func BoundString(f Face, s string) (bounds fixed.Rectangle26_6, advance fixed.Int26_6) {
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prevC := rune(-1)
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for _, c := range s {
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if prevC >= 0 {
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advance += f.Kern(prevC, c)
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}
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b, a, ok := f.GlyphBounds(c)
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if !ok {
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// TODO: is falling back on the U+FFFD glyph the responsibility of
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// the Drawer or the Face?
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// TODO: set prevC = '\ufffd'?
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continue
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}
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bounds = grow(bounds, b, advance)
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advance += a
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prevC = c
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}
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return
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}
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// grow returns the smallest rectangle containing both b and b2+shift.
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func grow(b, b2 fixed.Rectangle26_6, shift fixed.Int26_6) fixed.Rectangle26_6 {
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x := b2.Min.X + shift
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if b.Min.X > x {
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b.Min.X = x
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}
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if b.Min.Y > b2.Min.Y {
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b.Min.Y = b2.Min.Y
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}
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x = b2.Max.X + shift
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if b.Max.X < x {
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b.Max.X = x
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}
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if b.Max.Y < b2.Max.Y {
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b.Max.Y = b2.Max.Y
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}
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return b
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}
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// MeasureBytes returns how far dot would advance by drawing s with f.
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//
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// It is equivalent to MeasureString(string(s)) but may be more efficient.
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|
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@ -0,0 +1,27 @@
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Copyright (c) 2009 The Go Authors. All rights reserved.
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Redistribution and use in source and binary forms, with or without
|
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modification, are permitted provided that the following conditions are
|
||||
met:
|
||||
|
||||
* Redistributions of source code must retain the above copyright
|
||||
notice, this list of conditions and the following disclaimer.
|
||||
* Redistributions in binary form must reproduce the above
|
||||
copyright notice, this list of conditions and the following disclaimer
|
||||
in the documentation and/or other materials provided with the
|
||||
distribution.
|
||||
* Neither the name of Google Inc. nor the names of its
|
||||
contributors may be used to endorse or promote products derived from
|
||||
this software without specific prior written permission.
|
||||
|
||||
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
||||
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
||||
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
||||
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
||||
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
||||
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
||||
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
||||
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
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@ -0,0 +1,22 @@
|
|||
Additional IP Rights Grant (Patents)
|
||||
|
||||
"This implementation" means the copyrightable works distributed by
|
||||
Google as part of the Go project.
|
||||
|
||||
Google hereby grants to You a perpetual, worldwide, non-exclusive,
|
||||
no-charge, royalty-free, irrevocable (except as stated in this section)
|
||||
patent license to make, have made, use, offer to sell, sell, import,
|
||||
transfer and otherwise run, modify and propagate the contents of this
|
||||
implementation of Go, where such license applies only to those patent
|
||||
claims, both currently owned or controlled by Google and acquired in
|
||||
the future, licensable by Google that are necessarily infringed by this
|
||||
implementation of Go. This grant does not include claims that would be
|
||||
infringed only as a consequence of further modification of this
|
||||
implementation. If you or your agent or exclusive licensee institute or
|
||||
order or agree to the institution of patent litigation against any
|
||||
entity (including a cross-claim or counterclaim in a lawsuit) alleging
|
||||
that this implementation of Go or any code incorporated within this
|
||||
implementation of Go constitutes direct or contributory patent
|
||||
infringement, or inducement of patent infringement, then any patent
|
||||
rights granted to you under this License for this implementation of Go
|
||||
shall terminate as of the date such litigation is filed.
|
||||
|
|
@ -0,0 +1,368 @@
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|||
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package rate provides a rate limiter.
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package rate
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import (
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"fmt"
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"math"
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"sync"
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"time"
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"golang.org/x/net/context"
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)
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// Limit defines the maximum frequency of some events.
|
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// Limit is represented as number of events per second.
|
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// A zero Limit allows no events.
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type Limit float64
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|
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// Inf is the infinite rate limit; it allows all events (even if burst is zero).
|
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const Inf = Limit(math.MaxFloat64)
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|
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// 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
|
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|
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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, ok := lim.ReserveN(time.Now(), 1)
|
||||
// if !ok {
|
||||
// // Not allowed to act! Did you remember to set lim.burst to be > 0 ?
|
||||
// }
|
||||
// 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
|
||||
}
|
||||
|
||||
// Wait is shorthand for WaitN(ctx, 1).
|
||||
func (lim *Limiter) Wait(ctx context.Context) (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.
|
||||
func (lim *Limiter) WaitN(ctx context.Context, n int) (err error) {
|
||||
if n > lim.burst {
|
||||
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()
|
||||
defer lim.mu.Unlock()
|
||||
|
||||
if lim.limit == Inf {
|
||||
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
|
||||
}
|
||||
|
||||
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)
|
||||
}
|
||||
Loading…
Reference in New Issue