46 lines
965 B
Go
46 lines
965 B
Go
package server
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import (
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"errors"
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"sync"
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)
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// Log represents a commit log.
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type Log struct {
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mu sync.Mutex
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records []Record
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}
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// NewLog returns a new ready to use Log.
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func NewLog() *Log {
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return &Log{}
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}
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// Append adds a new record to a log.
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func (c *Log) Append(record Record) (uint64, error) {
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c.mu.Lock()
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defer c.mu.Unlock()
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record.Offset = uint64(len(c.records))
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c.records = append(c.records, record)
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return record.Offset, nil
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}
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// Read returns an individual record from the log given its offset.
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// Returns an error if the offset does not exist.
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func (c *Log) Read(offset uint64) (Record, error) {
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c.mu.Lock()
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defer c.mu.Unlock()
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if offset >= uint64(len(c.records)) {
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return Record{}, ErrOffsetNotFound
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}
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return c.records[offset], nil
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}
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// Record represents a single record in a commit log.
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type Record struct {
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Value []byte `json:"value"`
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Offset uint64 `json:"offset"`
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}
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var ErrOffsetNotFound = errors.New("offset not found")
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