mirror of
https://github.com/ncruces/go-sqlite3.git
synced 2026-01-12 05:59:14 +00:00
71 lines
1.7 KiB
Go
71 lines
1.7 KiB
Go
// Package blob provides an alternative interface to incremental BLOB I/O.
|
|
package blob
|
|
|
|
import (
|
|
"errors"
|
|
|
|
"github.com/ncruces/go-sqlite3"
|
|
"github.com/ncruces/go-sqlite3/internal/util"
|
|
)
|
|
|
|
// Register registers the blob_open SQL function:
|
|
//
|
|
// blob_open(schema, table, column, rowid, flags, callback, args...)
|
|
//
|
|
// The callback must be an [sqlite3.Pointer] to an [OpenCallback].
|
|
// Any optional args will be passed to the callback,
|
|
// along with the [sqlite3.Blob] handle.
|
|
//
|
|
// https://sqlite.org/c3ref/blob.html
|
|
func Register(db *sqlite3.Conn) {
|
|
db.CreateFunction("blob_open", -1,
|
|
sqlite3.DETERMINISTIC|sqlite3.DIRECTONLY, openBlob)
|
|
}
|
|
|
|
func openBlob(ctx sqlite3.Context, arg ...sqlite3.Value) {
|
|
if len(arg) < 6 {
|
|
ctx.ResultError(util.ErrorString("blob_open: wrong number of arguments"))
|
|
return
|
|
}
|
|
|
|
row := arg[3].Int64()
|
|
|
|
var err error
|
|
blob, ok := ctx.GetAuxData(0).(*sqlite3.Blob)
|
|
if ok {
|
|
err = blob.Reopen(row)
|
|
if errors.Is(err, sqlite3.MISUSE) {
|
|
// Blob was closed (db, table, column or write changed).
|
|
ok = false
|
|
}
|
|
}
|
|
|
|
if !ok {
|
|
db := arg[0].Text()
|
|
table := arg[1].Text()
|
|
column := arg[2].Text()
|
|
write := arg[4].Bool()
|
|
blob, err = ctx.Conn().OpenBlob(db, table, column, row, write)
|
|
}
|
|
if err != nil {
|
|
ctx.ResultError(err)
|
|
return
|
|
}
|
|
|
|
fn := arg[5].Pointer().(OpenCallback)
|
|
err = fn(blob, arg[6:]...)
|
|
if err != nil {
|
|
ctx.ResultError(err)
|
|
return
|
|
}
|
|
|
|
// This ensures the blob is closed if db, table, column or write change.
|
|
ctx.SetAuxData(0, blob) // db
|
|
ctx.SetAuxData(1, blob) // table
|
|
ctx.SetAuxData(2, blob) // column
|
|
ctx.SetAuxData(4, blob) // write
|
|
}
|
|
|
|
// OpenCallback is the type for the blob_open callback.
|
|
type OpenCallback func(*sqlite3.Blob, ...sqlite3.Value) error
|