dbb93b75a4
this lays the foundation for supporting the new firestorm indexing scheme. i'm merging these changes ahead of the rest of the firestorm branch so i can continue to make changes to the analysis pipeline in parallel
71 lines
1.9 KiB
Go
71 lines
1.9 KiB
Go
// Copyright (c) 2015 Couchbase, Inc.
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
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// except in compliance with the License. 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 distributed under the
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// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
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// either express or implied. See the License for the specific language governing permissions
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// and limitations under the License.
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package index
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import (
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"sync"
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)
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type FieldCache struct {
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fieldIndexes map[string]uint16
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lastFieldIndex int
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mutex sync.RWMutex
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}
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func NewFieldCache() *FieldCache {
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return &FieldCache{
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fieldIndexes: make(map[string]uint16),
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lastFieldIndex: -1,
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}
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}
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func (f *FieldCache) AddExisting(field string, index uint16) {
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f.mutex.Lock()
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defer f.mutex.Unlock()
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f.fieldIndexes[field] = index
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if int(index) > f.lastFieldIndex {
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f.lastFieldIndex = int(index)
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}
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}
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// FieldNamed returns the index of the field, and whether or not it existed
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// before this call. if createIfMissing is true, and new field index is assigned
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// but the second return value will still be false
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func (f *FieldCache) FieldNamed(field string, createIfMissing bool) (uint16, bool) {
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f.mutex.RLock()
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if index, ok := f.fieldIndexes[field]; ok {
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f.mutex.RUnlock()
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return index, true
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} else if !createIfMissing {
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f.mutex.RUnlock()
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return 0, false
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}
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// trade read lock for write lock
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f.mutex.RUnlock()
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f.mutex.Lock()
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// assign next field id
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index := uint16(f.lastFieldIndex + 1)
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f.fieldIndexes[field] = index
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f.lastFieldIndex = int(index)
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f.mutex.Unlock()
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return index, false
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}
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func (f *FieldCache) FieldIndexed(index uint16) string {
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f.mutex.RLock()
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defer f.mutex.RUnlock()
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for fieldName, fieldIndex := range f.fieldIndexes {
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if index == fieldIndex {
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return fieldName
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}
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}
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return ""
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}
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