/
fibonacci.go
79 lines (66 loc) · 1.4 KB
/
fibonacci.go
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package fibonacci
import (
"database/sql"
"os"
"path"
_ "github.com/lib/pq"
)
type Fibonacci interface {
GetFib(n int) (result string, err error)
GetCacheSize() (size int, err error)
GetCacheSizeLT(end int) (size int, err error)
ClearCache() error
}
type PgFib struct {
db *sql.DB
}
func New(db *sql.DB, initFilePath string) (fib Fibonacci, err error) {
err = db.Ping()
if err != nil {
return
}
err = initDb(db, initFilePath)
if err != nil {
return
}
fib = &PgFib{db: db}
return
}
func (f *PgFib) GetFib(n int) (result string, err error) {
row := f.db.QueryRow(`SELECT get_fib($1);`, n)
result = ""
err = row.Scan(&result)
return
}
func (f *PgFib) GetCacheSize() (size int, err error) {
row := f.db.QueryRow(`SELECT get_cache_size();`)
size = 0
err = row.Scan(&size)
return
}
// Returns the number of cache entries in the exclusive range from 0 to `end`
func (f *PgFib) GetCacheSizeLT(end int) (size int, err error) {
row := f.db.QueryRow(`SELECT get_cache_size_lt($1);`, end)
size = 0
err = row.Scan(&size)
return
}
func (f *PgFib) ClearCache() error {
_, err := f.db.Exec(`TRUNCATE TABLE fibonacci;`)
return err
}
func initDb(db *sql.DB, initFilePath string) error {
cwd, err := os.Getwd()
if err != nil {
return err
}
s, err := os.ReadFile(path.Join(cwd, initFilePath))
if err != nil {
return err
}
_, err = db.Exec(string(s))
if err != nil {
return err
}
return nil
}