44 lines
1.4 KiB
Go
44 lines
1.4 KiB
Go
// Copyright The OpenTelemetry Authors
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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 trace // import "go.opentelemetry.io/otel/sdk/trace"
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// evictedQueue is a FIFO queue with a configurable capacity.
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type evictedQueue struct {
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queue []interface{}
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capacity int
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droppedCount int
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}
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func newEvictedQueue(capacity int) evictedQueue {
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// Do not pre-allocate queue, do this lazily.
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return evictedQueue{capacity: capacity}
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}
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// add adds value to the evictedQueue eq. If eq is at capacity, the oldest
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// queued value will be discarded and the drop count incremented.
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func (eq *evictedQueue) add(value interface{}) {
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if eq.capacity == 0 {
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eq.droppedCount++
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return
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}
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if eq.capacity > 0 && len(eq.queue) == eq.capacity {
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// Drop first-in while avoiding allocating more capacity to eq.queue.
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copy(eq.queue[:eq.capacity-1], eq.queue[1:])
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eq.queue = eq.queue[:eq.capacity-1]
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eq.droppedCount++
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}
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eq.queue = append(eq.queue, value)
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}
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