92 lines
2.8 KiB
Go
92 lines
2.8 KiB
Go
// Copyright (c) 2014 Couchbase, Inc.
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package search
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import (
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"reflect"
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)
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var reflectStaticSizeDocumentMatchPool int
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func init() {
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var dmp DocumentMatchPool
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reflectStaticSizeDocumentMatchPool = int(reflect.TypeOf(dmp).Size())
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}
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// DocumentMatchPoolTooSmall is a callback function that can be executed
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// when the DocumentMatchPool does not have sufficient capacity
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// By default we just perform just-in-time allocation, but you could log
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// a message, or panic, etc.
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type DocumentMatchPoolTooSmall func(p *DocumentMatchPool) *DocumentMatch
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// DocumentMatchPool manages use/re-use of DocumentMatch instances
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// it pre-allocates space from a single large block with the expected
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// number of instances. It is not thread-safe as currently all
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// aspects of search take place in a single goroutine.
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type DocumentMatchPool struct {
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avail DocumentMatchCollection
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TooSmall DocumentMatchPoolTooSmall
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}
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func defaultDocumentMatchPoolTooSmall(p *DocumentMatchPool) *DocumentMatch {
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return &DocumentMatch{}
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}
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// NewDocumentMatchPool will build a DocumentMatchPool with memory
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// pre-allocated to accommodate the requested number of DocumentMatch
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// instances
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func NewDocumentMatchPool(size, sortsize int) *DocumentMatchPool {
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avail := make(DocumentMatchCollection, size)
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// pre-allocate the expected number of instances
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startBlock := make([]DocumentMatch, size)
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startSorts := make([]string, size*sortsize)
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// make these initial instances available
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i, j := 0, 0
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for i < size {
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avail[i] = &startBlock[i]
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avail[i].Sort = startSorts[j:j]
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i += 1
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j += sortsize
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}
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return &DocumentMatchPool{
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avail: avail,
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TooSmall: defaultDocumentMatchPoolTooSmall,
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}
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}
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// Get returns an available DocumentMatch from the pool
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// if the pool was not allocated with sufficient size, an allocation will
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// occur to satisfy this request. As a side-effect this will grow the size
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// of the pool.
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func (p *DocumentMatchPool) Get() *DocumentMatch {
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var rv *DocumentMatch
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if len(p.avail) > 0 {
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rv, p.avail = p.avail[len(p.avail)-1], p.avail[:len(p.avail)-1]
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} else {
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rv = p.TooSmall(p)
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}
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return rv
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}
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// Put returns a DocumentMatch to the pool
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func (p *DocumentMatchPool) Put(d *DocumentMatch) {
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if d == nil {
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return
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}
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// reset DocumentMatch before returning it to available pool
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d.Reset()
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p.avail = append(p.avail, d)
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}
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