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// Copyright (C) 2019-2024 Algorand, Inc.
// This file is part of go-algorand
//
// go-algorand is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// go-algorand is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with go-algorand. If not, see <https://www.gnu.org/licenses/>.
package logging
import (
"bytes"
"io"
"github.com/algorand/go-deadlock"
)
type logBuffer struct {
buffer []string
maxDepth uint
lock deadlock.Mutex
first uint
used uint
}
func createLogBuffer(maxDepth uint) *logBuffer {
return &logBuffer{
maxDepth: maxDepth,
buffer: make([]string, maxDepth),
}
}
func (b *logBuffer) append(line string) {
// MaxDepth of 0 means no history is stored
if b.maxDepth == 0 {
return
}
b.lock.Lock()
defer b.lock.Unlock()
// once we reach maxDepth, we switch to cyclic buffer logic.
if b.used >= b.maxDepth {
// we've already reached capacity. overwrite the oldest message.
b.buffer[b.first] = line
b.first = (b.first + 1) % b.maxDepth
} else {
// we haven't reached capacity ( yet )
b.buffer[(b.first+b.used)%b.maxDepth] = line
b.used++
}
}
// trim() will delete the first half of the history; this allows us to reduce redundant log history
// sent when multiple events occur near each other.
func (b *logBuffer) trim() {
b.lock.Lock()
defer b.lock.Unlock()
// Keep only 1/2 of what we've got (rounded up)
keep := (b.used + 1) / 2
// Skip over the old entries so there are 'keep' left
b.first = (b.first + b.used - keep) % b.maxDepth
// And update used to reflect how many we're keeping
b.used = keep
}
func (b *logBuffer) string() string {
if b.maxDepth == 0 {
return ""
}
b.lock.Lock()
defer b.lock.Unlock()
var bytesBuffer bytes.Buffer
for i := uint(0); i < b.used; i++ {
bytesBuffer.WriteString(b.buffer[(b.first+i)%b.maxDepth])
}
return bytesBuffer.String()
}
func (b *logBuffer) wrapOutput(out io.Writer) io.Writer {
return &writerTee{
out,
b,
}
}
type writerTee struct {
out io.Writer
logBuffer *logBuffer
}
func (writer writerTee) Write(p []byte) (n int, err error) {
writer.logBuffer.append(string(p))
return writer.out.Write(p)
}
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