super-graph/serv/prepare.go

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2019-07-29 07:13:33 +02:00
package serv
import (
"bytes"
"fmt"
"io"
"github.com/dosco/super-graph/qcode"
"github.com/go-pg/pg"
"github.com/valyala/fasttemplate"
)
type preparedItem struct {
stmt *pg.Stmt
args []string
skipped uint32
qc *qcode.QCode
}
var (
_preparedList map[string]*preparedItem
)
func initPreparedList() {
_preparedList = make(map[string]*preparedItem)
for k, v := range _allowList.list {
err := prepareStmt(k, v.gql)
if err != nil {
panic(err)
}
}
}
func prepareStmt(key, gql string) error {
if len(gql) == 0 || len(key) == 0 {
return nil
}
qc, err := qcompile.CompileQuery([]byte(gql))
if err != nil {
return err
}
buf := &bytes.Buffer{}
skipped, err := pcompile.Compile(qc, buf)
if err != nil {
return err
}
t := fasttemplate.New(buf.String(), `('{{`, `}}')`)
am := make([]string, 0, 5)
i := 0
finalSQL := t.ExecuteFuncString(func(w io.Writer, tag string) (int, error) {
am = append(am, tag)
i++
return w.Write([]byte(fmt.Sprintf("$%d", i)))
})
if err != nil {
return err
}
pstmt, err := db.Prepare(finalSQL)
if err != nil {
return err
}
_preparedList[key] = &preparedItem{
stmt: pstmt,
args: am,
skipped: skipped,
qc: qc,
}
return nil
}