mirror of https://github.com/dapr/kit.git
86 lines
2.5 KiB
Go
86 lines
2.5 KiB
Go
/*
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Copyright 2021 The Dapr Authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package byteslicepool
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import (
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"sync"
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)
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/*
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Originally based on https://github.com/xdg-go/zzz-slice-recycling
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Copyright (C) 2019 by David A. Golden
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License (Apache2): https://github.com/xdg-go/zzz-slice-recycling/blob/master/LICENSE
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*/
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// ByteSlicePool is a wrapper around sync.Pool to get []byte objects with a given capacity.
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type ByteSlicePool struct {
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MinCap int
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pool *sync.Pool
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}
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// NewByteSlicePool returns a new ByteSlicePool object.
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func NewByteSlicePool(minCap int) *ByteSlicePool {
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return &ByteSlicePool{
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MinCap: minCap,
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pool: &sync.Pool{},
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}
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}
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// Get a slice from the pool.
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// The capacity parameter is used only if we need to allocate a new byte slice; there's no guarantee a slice retrieved from the pool will have enough capacity for that.
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func (sp ByteSlicePool) Get(capacity int) []byte {
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bp := sp.pool.Get()
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if bp == nil {
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if capacity < sp.MinCap {
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capacity = sp.MinCap
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}
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return make([]byte, 0, capacity)
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}
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buf := bp.([]byte)
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// This will be optimized by the compiler
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for i := range buf {
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buf[i] = 0
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}
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return buf[:0]
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}
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// Put a slice back in the pool.
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func (sp ByteSlicePool) Put(bs []byte) {
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// The linter here complains because we're putting a slice rather than a pointer in the pool.
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// The complain is valid, because doing so does cause an allocation for the local copy of the slice header.
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// However, this is ok for us because given how we use ByteSlicePool, we can't keep around the pointer we took out.
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// See this thread for some discussion: https://github.com/dominikh/go-tools/issues/1336
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//nolint:staticcheck
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sp.pool.Put(bs)
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}
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// Resize a byte slice, making sure that it has enough capacity for a given size.
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func (sp ByteSlicePool) Resize(orig []byte, size int) []byte {
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if size < cap(orig) {
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return orig[0:size]
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}
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// Allocate a new byte slice and then discard the old one, too small, so it can be garbage collected
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temp := make([]byte, size, max(size, cap(orig)*2))
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copy(temp, orig)
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return temp
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}
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func max(x, y int) int {
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if x < y {
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return y
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}
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return x
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}
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