Usishchev Yury
65 lines
1.3 KiB
Go
65 lines
1.3 KiB
Go
package quota
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import (
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"encoding/json"
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"os"
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"sync"
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)
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// fileStore persists all records into one JSON file. A single instance is shared
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// per path so concurrent per-name saves merge instead of clobbering each other.
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type fileStore struct {
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path string
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mu sync.Mutex
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data map[string]Record
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}
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var fileStores sync.Map // path -> *fileStore
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func NewFileStore(path string) Store {
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if v, ok := fileStores.Load(path); ok {
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return v.(*fileStore)
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}
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fs := &fileStore{path: path, data: make(map[string]Record)}
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fs.load()
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actual, _ := fileStores.LoadOrStore(path, fs)
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return actual.(*fileStore)
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}
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func (fs *fileStore) load() {
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b, err := os.ReadFile(fs.path)
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if err != nil {
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return
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}
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data := make(map[string]Record)
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if json.Unmarshal(b, &data) == nil {
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fs.data = data
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}
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}
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func (fs *fileStore) Load(name string) (Record, bool, error) {
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fs.mu.Lock()
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defer fs.mu.Unlock()
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rec, ok := fs.data[name]
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return rec, ok, nil
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}
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func (fs *fileStore) Save(name string, rec Record) error {
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fs.mu.Lock()
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defer fs.mu.Unlock()
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fs.data[name] = rec
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return fs.writeLocked()
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}
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func (fs *fileStore) writeLocked() error {
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b, err := json.MarshalIndent(fs.data, "", " ")
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if err != nil {
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return err
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}
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tmp := fs.path + ".tmp"
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if err := os.WriteFile(tmp, b, 0o644); err != nil {
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return err
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}
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return os.Rename(tmp, fs.path)
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}
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