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Diffstat (limited to 'vendor/github.com/jmoiron/sqlx/sqlx.go')
| -rw-r--r-- | vendor/github.com/jmoiron/sqlx/sqlx.go | 1028 |
1 files changed, 1028 insertions, 0 deletions
diff --git a/vendor/github.com/jmoiron/sqlx/sqlx.go b/vendor/github.com/jmoiron/sqlx/sqlx.go new file mode 100644 index 0000000..c7a0bf3 --- /dev/null +++ b/vendor/github.com/jmoiron/sqlx/sqlx.go @@ -0,0 +1,1028 @@ +package sqlx + +import ( + "database/sql" + "database/sql/driver" + "errors" + "fmt" + + "io/ioutil" + "path/filepath" + "reflect" + "strings" + + "github.com/jmoiron/sqlx/reflectx" +) + +// Although the NameMapper is convenient, in practice it should not +// be relied on except for application code. If you are writing a library +// that uses sqlx, you should be aware that the name mappings you expect +// can be overridden by your user's application. + +// NameMapper is used to map column names to struct field names. By default, +// it uses strings.ToLower to lowercase struct field names. It can be set +// to whatever you want, but it is encouraged to be set before sqlx is used +// as name-to-field mappings are cached after first use on a type. +var NameMapper = strings.ToLower +var origMapper = reflect.ValueOf(NameMapper) + +// Rather than creating on init, this is created when necessary so that +// importers have time to customize the NameMapper. +var mpr *reflectx.Mapper + +// mapper returns a valid mapper using the configured NameMapper func. +func mapper() *reflectx.Mapper { + if mpr == nil { + mpr = reflectx.NewMapperFunc("db", NameMapper) + } else if origMapper != reflect.ValueOf(NameMapper) { + // if NameMapper has changed, create a new mapper + mpr = reflectx.NewMapperFunc("db", NameMapper) + origMapper = reflect.ValueOf(NameMapper) + } + return mpr +} + +// isScannable takes the reflect.Type and the actual dest value and returns +// whether or not it's Scannable. Something is scannable if: +// * it is not a struct +// * it implements sql.Scanner +// * it has no exported fields +func isScannable(t reflect.Type) bool { + if reflect.PtrTo(t).Implements(_scannerInterface) { + return true + } + if t.Kind() != reflect.Struct { + return true + } + + // it's not important that we use the right mapper for this particular object, + // we're only concerned on how many exported fields this struct has + m := mapper() + if len(m.TypeMap(t).Index) == 0 { + return true + } + return false +} + +// ColScanner is an interface used by MapScan and SliceScan +type ColScanner interface { + Columns() ([]string, error) + Scan(dest ...interface{}) error + Err() error +} + +// Queryer is an interface used by Get and Select +type Queryer interface { + Query(query string, args ...interface{}) (*sql.Rows, error) + Queryx(query string, args ...interface{}) (*Rows, error) + QueryRowx(query string, args ...interface{}) *Row +} + +// Execer is an interface used by MustExec and LoadFile +type Execer interface { + Exec(query string, args ...interface{}) (sql.Result, error) +} + +// Binder is an interface for something which can bind queries (Tx, DB) +type binder interface { + DriverName() string + Rebind(string) string + BindNamed(string, interface{}) (string, []interface{}, error) +} + +// Ext is a union interface which can bind, query, and exec, used by +// NamedQuery and NamedExec. +type Ext interface { + binder + Queryer + Execer +} + +// Preparer is an interface used by Preparex. +type Preparer interface { + Prepare(query string) (*sql.Stmt, error) +} + +// determine if any of our extensions are unsafe +func isUnsafe(i interface{}) bool { + switch v := i.(type) { + case Row: + return v.unsafe + case *Row: + return v.unsafe + case Rows: + return v.unsafe + case *Rows: + return v.unsafe + case NamedStmt: + return v.Stmt.unsafe + case *NamedStmt: + return v.Stmt.unsafe + case Stmt: + return v.unsafe + case *Stmt: + return v.unsafe + case qStmt: + return v.unsafe + case *qStmt: + return v.unsafe + case DB: + return v.unsafe + case *DB: + return v.unsafe + case Tx: + return v.unsafe + case *Tx: + return v.unsafe + case sql.Rows, *sql.Rows: + return false + default: + return false + } +} + +func mapperFor(i interface{}) *reflectx.Mapper { + switch i.(type) { + case DB: + return i.(DB).Mapper + case *DB: + return i.(*DB).Mapper + case Tx: + return i.(Tx).Mapper + case *Tx: + return i.(*Tx).Mapper + default: + return mapper() + } +} + +var _scannerInterface = reflect.TypeOf((*sql.Scanner)(nil)).Elem() +var _valuerInterface = reflect.TypeOf((*driver.Valuer)(nil)).Elem() + +// Row is a reimplementation of sql.Row in order to gain access to the underlying +// sql.Rows.Columns() data, necessary for StructScan. +type Row struct { + err error + unsafe bool + rows *sql.Rows + Mapper *reflectx.Mapper +} + +// Scan is a fixed implementation of sql.Row.Scan, which does not discard the +// underlying error from the internal rows object if it exists. +func (r *Row) Scan(dest ...interface{}) error { + if r.err != nil { + return r.err + } + + // TODO(bradfitz): for now we need to defensively clone all + // []byte that the driver returned (not permitting + // *RawBytes in Rows.Scan), since we're about to close + // the Rows in our defer, when we return from this function. + // the contract with the driver.Next(...) interface is that it + // can return slices into read-only temporary memory that's + // only valid until the next Scan/Close. But the TODO is that + // for a lot of drivers, this copy will be unnecessary. We + // should provide an optional interface for drivers to + // implement to say, "don't worry, the []bytes that I return + // from Next will not be modified again." (for instance, if + // they were obtained from the network anyway) But for now we + // don't care. + defer r.rows.Close() + for _, dp := range dest { + if _, ok := dp.(*sql.RawBytes); ok { + return errors.New("sql: RawBytes isn't allowed on Row.Scan") + } + } + + if !r.rows.Next() { + if err := r.rows.Err(); err != nil { + return err + } + return sql.ErrNoRows + } + err := r.rows.Scan(dest...) + if err != nil { + return err + } + // Make sure the query can be processed to completion with no errors. + if err := r.rows.Close(); err != nil { + return err + } + return nil +} + +// Columns returns the underlying sql.Rows.Columns(), or the deferred error usually +// returned by Row.Scan() +func (r *Row) Columns() ([]string, error) { + if r.err != nil { + return []string{}, r.err + } + return r.rows.Columns() +} + +// Err returns the error encountered while scanning. +func (r *Row) Err() error { + return r.err +} + +// DB is a wrapper around sql.DB which keeps track of the driverName upon Open, +// used mostly to automatically bind named queries using the right bindvars. +type DB struct { + *sql.DB + driverName string + unsafe bool + Mapper *reflectx.Mapper +} + +// NewDb returns a new sqlx DB wrapper for a pre-existing *sql.DB. The +// driverName of the original database is required for named query support. +func NewDb(db *sql.DB, driverName string) *DB { + return &DB{DB: db, driverName: driverName, Mapper: mapper()} +} + +// DriverName returns the driverName passed to the Open function for this DB. +func (db *DB) DriverName() string { + return db.driverName +} + +// Open is the same as sql.Open, but returns an *sqlx.DB instead. +func Open(driverName, dataSourceName string) (*DB, error) { + db, err := sql.Open(driverName, dataSourceName) + if err != nil { + return nil, err + } + return &DB{DB: db, driverName: driverName, Mapper: mapper()}, err +} + +// MustOpen is the same as sql.Open, but returns an *sqlx.DB instead and panics on error. +func MustOpen(driverName, dataSourceName string) *DB { + db, err := Open(driverName, dataSourceName) + if err != nil { + panic(err) + } + return db +} + +// MapperFunc sets a new mapper for this db using the default sqlx struct tag +// and the provided mapper function. +func (db *DB) MapperFunc(mf func(string) string) { + db.Mapper = reflectx.NewMapperFunc("db", mf) +} + +// Rebind transforms a query from QUESTION to the DB driver's bindvar type. +func (db *DB) Rebind(query string) string { + return Rebind(BindType(db.driverName), query) +} + +// Unsafe returns a version of DB which will silently succeed to scan when +// columns in the SQL result have no fields in the destination struct. +// sqlx.Stmt and sqlx.Tx which are created from this DB will inherit its +// safety behavior. +func (db *DB) Unsafe() *DB { + return &DB{DB: db.DB, driverName: db.driverName, unsafe: true, Mapper: db.Mapper} +} + +// BindNamed binds a query using the DB driver's bindvar type. +func (db *DB) BindNamed(query string, arg interface{}) (string, []interface{}, error) { + return bindNamedMapper(BindType(db.driverName), query, arg, db.Mapper) +} + +// NamedQuery using this DB. +// Any named placeholder parameters are replaced with fields from arg. +func (db *DB) NamedQuery(query string, arg interface{}) (*Rows, error) { + return NamedQuery(db, query, arg) +} + +// NamedExec using this DB. +// Any named placeholder parameters are replaced with fields from arg. +func (db *DB) NamedExec(query string, arg interface{}) (sql.Result, error) { + return NamedExec(db, query, arg) +} + +// Select using this DB. +// Any placeholder parameters are replaced with supplied args. +func (db *DB) Select(dest interface{}, query string, args ...interface{}) error { + return Select(db, dest, query, args...) +} + +// Get using this DB. +// Any placeholder parameters are replaced with supplied args. +// An error is returned if the result set is empty. +func (db *DB) Get(dest interface{}, query string, args ...interface{}) error { + return Get(db, dest, query, args...) +} + +// MustBegin starts a transaction, and panics on error. Returns an *sqlx.Tx instead +// of an *sql.Tx. +func (db *DB) MustBegin() *Tx { + tx, err := db.Beginx() + if err != nil { + panic(err) + } + return tx +} + +// Beginx begins a transaction and returns an *sqlx.Tx instead of an *sql.Tx. +func (db *DB) Beginx() (*Tx, error) { + tx, err := db.DB.Begin() + if err != nil { + return nil, err + } + return &Tx{Tx: tx, driverName: db.driverName, unsafe: db.unsafe, Mapper: db.Mapper}, err +} + +// Queryx queries the database and returns an *sqlx.Rows. +// Any placeholder parameters are replaced with supplied args. +func (db *DB) Queryx(query string, args ...interface{}) (*Rows, error) { + r, err := db.DB.Query(query, args...) + if err != nil { + return nil, err + } + return &Rows{Rows: r, unsafe: db.unsafe, Mapper: db.Mapper}, err +} + +// QueryRowx queries the database and returns an *sqlx.Row. +// Any placeholder parameters are replaced with supplied args. +func (db *DB) QueryRowx(query string, args ...interface{}) *Row { + rows, err := db.DB.Query(query, args...) + return &Row{rows: rows, err: err, unsafe: db.unsafe, Mapper: db.Mapper} +} + +// MustExec (panic) runs MustExec using this database. +// Any placeholder parameters are replaced with supplied args. +func (db *DB) MustExec(query string, args ...interface{}) sql.Result { + return MustExec(db, query, args...) +} + +// Preparex returns an sqlx.Stmt instead of a sql.Stmt +func (db *DB) Preparex(query string) (*Stmt, error) { + return Preparex(db, query) +} + +// PrepareNamed returns an sqlx.NamedStmt +func (db *DB) PrepareNamed(query string) (*NamedStmt, error) { + return prepareNamed(db, query) +} + +// Tx is an sqlx wrapper around sql.Tx with extra functionality +type Tx struct { + *sql.Tx + driverName string + unsafe bool + Mapper *reflectx.Mapper +} + +// DriverName returns the driverName used by the DB which began this transaction. +func (tx *Tx) DriverName() string { + return tx.driverName +} + +// Rebind a query within a transaction's bindvar type. +func (tx *Tx) Rebind(query string) string { + return Rebind(BindType(tx.driverName), query) +} + +// Unsafe returns a version of Tx which will silently succeed to scan when +// columns in the SQL result have no fields in the destination struct. +func (tx *Tx) Unsafe() *Tx { + return &Tx{Tx: tx.Tx, driverName: tx.driverName, unsafe: true, Mapper: tx.Mapper} +} + +// BindNamed binds a query within a transaction's bindvar type. +func (tx *Tx) BindNamed(query string, arg interface{}) (string, []interface{}, error) { + return bindNamedMapper(BindType(tx.driverName), query, arg, tx.Mapper) +} + +// NamedQuery within a transaction. +// Any named placeholder parameters are replaced with fields from arg. +func (tx *Tx) NamedQuery(query string, arg interface{}) (*Rows, error) { + return NamedQuery(tx, query, arg) +} + +// NamedExec a named query within a transaction. +// Any named placeholder parameters are replaced with fields from arg. +func (tx *Tx) NamedExec(query string, arg interface{}) (sql.Result, error) { + return NamedExec(tx, query, arg) +} + +// Select within a transaction. +// Any placeholder parameters are replaced with supplied args. +func (tx *Tx) Select(dest interface{}, query string, args ...interface{}) error { + return Select(tx, dest, query, args...) +} + +// Queryx within a transaction. +// Any placeholder parameters are replaced with supplied args. +func (tx *Tx) Queryx(query string, args ...interface{}) (*Rows, error) { + r, err := tx.Tx.Query(query, args...) + if err != nil { + return nil, err + } + return &Rows{Rows: r, unsafe: tx.unsafe, Mapper: tx.Mapper}, err +} + +// QueryRowx within a transaction. +// Any placeholder parameters are replaced with supplied args. +func (tx *Tx) QueryRowx(query string, args ...interface{}) *Row { + rows, err := tx.Tx.Query(query, args...) + return &Row{rows: rows, err: err, unsafe: tx.unsafe, Mapper: tx.Mapper} +} + +// Get within a transaction. +// Any placeholder parameters are replaced with supplied args. +// An error is returned if the result set is empty. +func (tx *Tx) Get(dest interface{}, query string, args ...interface{}) error { + return Get(tx, dest, query, args...) +} + +// MustExec runs MustExec within a transaction. +// Any placeholder parameters are replaced with supplied args. +func (tx *Tx) MustExec(query string, args ...interface{}) sql.Result { + return MustExec(tx, query, args...) +} + +// Preparex a statement within a transaction. +func (tx *Tx) Preparex(query string) (*Stmt, error) { + return Preparex(tx, query) +} + +// Stmtx returns a version of the prepared statement which runs within a transaction. Provided +// stmt can be either *sql.Stmt or *sqlx.Stmt. +func (tx *Tx) Stmtx(stmt interface{}) *Stmt { + var s *sql.Stmt + switch v := stmt.(type) { + case Stmt: + s = v.Stmt + case *Stmt: + s = v.Stmt + case sql.Stmt: + s = &v + case *sql.Stmt: + s = v + default: + panic(fmt.Sprintf("non-statement type %v passed to Stmtx", reflect.ValueOf(stmt).Type())) + } + return &Stmt{Stmt: tx.Stmt(s), Mapper: tx.Mapper} +} + +// NamedStmt returns a version of the prepared statement which runs within a transaction. +func (tx *Tx) NamedStmt(stmt *NamedStmt) *NamedStmt { + return &NamedStmt{ + QueryString: stmt.QueryString, + Params: stmt.Params, + Stmt: tx.Stmtx(stmt.Stmt), + } +} + +// PrepareNamed returns an sqlx.NamedStmt +func (tx *Tx) PrepareNamed(query string) (*NamedStmt, error) { + return prepareNamed(tx, query) +} + +// Stmt is an sqlx wrapper around sql.Stmt with extra functionality +type Stmt struct { + *sql.Stmt + unsafe bool + Mapper *reflectx.Mapper +} + +// Unsafe returns a version of Stmt which will silently succeed to scan when +// columns in the SQL result have no fields in the destination struct. +func (s *Stmt) Unsafe() *Stmt { + return &Stmt{Stmt: s.Stmt, unsafe: true, Mapper: s.Mapper} +} + +// Select using the prepared statement. +// Any placeholder parameters are replaced with supplied args. +func (s *Stmt) Select(dest interface{}, args ...interface{}) error { + return Select(&qStmt{s}, dest, "", args...) +} + +// Get using the prepared statement. +// Any placeholder parameters are replaced with supplied args. +// An error is returned if the result set is empty. +func (s *Stmt) Get(dest interface{}, args ...interface{}) error { + return Get(&qStmt{s}, dest, "", args...) +} + +// MustExec (panic) using this statement. Note that the query portion of the error +// output will be blank, as Stmt does not expose its query. +// Any placeholder parameters are replaced with supplied args. +func (s *Stmt) MustExec(args ...interface{}) sql.Result { + return MustExec(&qStmt{s}, "", args...) +} + +// QueryRowx using this statement. +// Any placeholder parameters are replaced with supplied args. +func (s *Stmt) QueryRowx(args ...interface{}) *Row { + qs := &qStmt{s} + return qs.QueryRowx("", args...) +} + +// Queryx using this statement. +// Any placeholder parameters are replaced with supplied args. +func (s *Stmt) Queryx(args ...interface{}) (*Rows, error) { + qs := &qStmt{s} + return qs.Queryx("", args...) +} + +// qStmt is an unexposed wrapper which lets you use a Stmt as a Queryer & Execer by +// implementing those interfaces and ignoring the `query` argument. +type qStmt struct{ *Stmt } + +func (q *qStmt) Query(query string, args ...interface{}) (*sql.Rows, error) { + return q.Stmt.Query(args...) +} + +func (q *qStmt) Queryx(query string, args ...interface{}) (*Rows, error) { + r, err := q.Stmt.Query(args...) + if err != nil { + return nil, err + } + return &Rows{Rows: r, unsafe: q.Stmt.unsafe, Mapper: q.Stmt.Mapper}, err +} + +func (q *qStmt) QueryRowx(query string, args ...interface{}) *Row { + rows, err := q.Stmt.Query(args...) + return &Row{rows: rows, err: err, unsafe: q.Stmt.unsafe, Mapper: q.Stmt.Mapper} +} + +func (q *qStmt) Exec(query string, args ...interface{}) (sql.Result, error) { + return q.Stmt.Exec(args...) +} + +// Rows is a wrapper around sql.Rows which caches costly reflect operations +// during a looped StructScan +type Rows struct { + *sql.Rows + unsafe bool + Mapper *reflectx.Mapper + // these fields cache memory use for a rows during iteration w/ structScan + started bool + fields [][]int + values []interface{} +} + +// SliceScan using this Rows. +func (r *Rows) SliceScan() ([]interface{}, error) { + return SliceScan(r) +} + +// MapScan using this Rows. +func (r *Rows) MapScan(dest map[string]interface{}) error { + return MapScan(r, dest) +} + +// StructScan is like sql.Rows.Scan, but scans a single Row into a single Struct. +// Use this and iterate over Rows manually when the memory load of Select() might be +// prohibitive. *Rows.StructScan caches the reflect work of matching up column +// positions to fields to avoid that overhead per scan, which means it is not safe +// to run StructScan on the same Rows instance with different struct types. +func (r *Rows) StructScan(dest interface{}) error { + v := reflect.ValueOf(dest) + + if v.Kind() != reflect.Ptr { + return errors.New("must pass a pointer, not a value, to StructScan destination") + } + + v = reflect.Indirect(v) + + if !r.started { + columns, err := r.Columns() + if err != nil { + return err + } + m := r.Mapper + + r.fields = m.TraversalsByName(v.Type(), columns) + // if we are not unsafe and are missing fields, return an error + if f, err := missingFields(r.fields); err != nil && !r.unsafe { + return fmt.Errorf("missing destination name %s in %T", columns[f], dest) + } + r.values = make([]interface{}, len(columns)) + r.started = true + } + + err := fieldsByTraversal(v, r.fields, r.values, true) + if err != nil { + return err + } + // scan into the struct field pointers and append to our results + err = r.Scan(r.values...) + if err != nil { + return err + } + return r.Err() +} + +// Connect to a database and verify with a ping. +func Connect(driverName, dataSourceName string) (*DB, error) { + db, err := Open(driverName, dataSourceName) + if err != nil { + return db, err + } + err = db.Ping() + return db, err +} + +// MustConnect connects to a database and panics on error. +func MustConnect(driverName, dataSourceName string) *DB { + db, err := Connect(driverName, dataSourceName) + if err != nil { + panic(err) + } + return db +} + +// Preparex prepares a statement. +func Preparex(p Preparer, query string) (*Stmt, error) { + s, err := p.Prepare(query) + if err != nil { + return nil, err + } + return &Stmt{Stmt: s, unsafe: isUnsafe(p), Mapper: mapperFor(p)}, err +} + +// Select executes a query using the provided Queryer, and StructScans each row +// into dest, which must be a slice. If the slice elements are scannable, then +// the result set must have only one column. Otherwise, StructScan is used. +// The *sql.Rows are closed automatically. +// Any placeholder parameters are replaced with supplied args. +func Select(q Queryer, dest interface{}, query string, args ...interface{}) error { + rows, err := q.Queryx(query, args...) + if err != nil { + return err + } + // if something happens here, we want to make sure the rows are Closed + defer rows.Close() + return scanAll(rows, dest, false) +} + +// Get does a QueryRow using the provided Queryer, and scans the resulting row +// to dest. If dest is scannable, the result must only have one column. Otherwise, +// StructScan is used. Get will return sql.ErrNoRows like row.Scan would. +// Any placeholder parameters are replaced with supplied args. +// An error is returned if the result set is empty. +func Get(q Queryer, dest interface{}, query string, args ...interface{}) error { + r := q.QueryRowx(query, args...) + return r.scanAny(dest, false) +} + +// LoadFile exec's every statement in a file (as a single call to Exec). +// LoadFile may return a nil *sql.Result if errors are encountered locating or +// reading the file at path. LoadFile reads the entire file into memory, so it +// is not suitable for loading large data dumps, but can be useful for initializing +// schemas or loading indexes. +// +// FIXME: this does not really work with multi-statement files for mattn/go-sqlite3 +// or the go-mysql-driver/mysql drivers; pq seems to be an exception here. Detecting +// this by requiring something with DriverName() and then attempting to split the +// queries will be difficult to get right, and its current driver-specific behavior +// is deemed at least not complex in its incorrectness. +func LoadFile(e Execer, path string) (*sql.Result, error) { + realpath, err := filepath.Abs(path) + if err != nil { + return nil, err + } + contents, err := ioutil.ReadFile(realpath) + if err != nil { + return nil, err + } + res, err := e.Exec(string(contents)) + return &res, err +} + +// MustExec execs the query using e and panics if there was an error. +// Any placeholder parameters are replaced with supplied args. +func MustExec(e Execer, query string, args ...interface{}) sql.Result { + res, err := e.Exec(query, args...) + if err != nil { + panic(err) + } + return res +} + +// SliceScan using this Rows. +func (r *Row) SliceScan() ([]interface{}, error) { + return SliceScan(r) +} + +// MapScan using this Rows. +func (r *Row) MapScan(dest map[string]interface{}) error { + return MapScan(r, dest) +} + +func (r *Row) scanAny(dest interface{}, structOnly bool) error { + if r.err != nil { + return r.err + } + if r.rows == nil { + r.err = sql.ErrNoRows + return r.err + } + defer r.rows.Close() + + v := reflect.ValueOf(dest) + if v.Kind() != reflect.Ptr { + return errors.New("must pass a pointer, not a value, to StructScan destination") + } + if v.IsNil() { + return errors.New("nil pointer passed to StructScan destination") + } + + base := reflectx.Deref(v.Type()) + scannable := isScannable(base) + + if structOnly && scannable { + return structOnlyError(base) + } + + columns, err := r.Columns() + if err != nil { + return err + } + + if scannable && len(columns) > 1 { + return fmt.Errorf("scannable dest type %s with >1 columns (%d) in result", base.Kind(), len(columns)) + } + + if scannable { + return r.Scan(dest) + } + + m := r.Mapper + + fields := m.TraversalsByName(v.Type(), columns) + // if we are not unsafe and are missing fields, return an error + if f, err := missingFields(fields); err != nil && !r.unsafe { + return fmt.Errorf("missing destination name %s in %T", columns[f], dest) + } + values := make([]interface{}, len(columns)) + + err = fieldsByTraversal(v, fields, values, true) + if err != nil { + return err + } + // scan into the struct field pointers and append to our results + return r.Scan(values...) +} + +// StructScan a single Row into dest. +func (r *Row) StructScan(dest interface{}) error { + return r.scanAny(dest, true) +} + +// SliceScan a row, returning a []interface{} with values similar to MapScan. +// This function is primarily intended for use where the number of columns +// is not known. Because you can pass an []interface{} directly to Scan, +// it's recommended that you do that as it will not have to allocate new +// slices per row. +func SliceScan(r ColScanner) ([]interface{}, error) { + // ignore r.started, since we needn't use reflect for anything. + columns, err := r.Columns() + if err != nil { + return []interface{}{}, err + } + + values := make([]interface{}, len(columns)) + for i := range values { + values[i] = new(interface{}) + } + + err = r.Scan(values...) + + if err != nil { + return values, err + } + + for i := range columns { + values[i] = *(values[i].(*interface{})) + } + + return values, r.Err() +} + +// MapScan scans a single Row into the dest map[string]interface{}. +// Use this to get results for SQL that might not be under your control +// (for instance, if you're building an interface for an SQL server that +// executes SQL from input). Please do not use this as a primary interface! +// This will modify the map sent to it in place, so reuse the same map with +// care. Columns which occur more than once in the result will overwrite +// each other! +func MapScan(r ColScanner, dest map[string]interface{}) error { + // ignore r.started, since we needn't use reflect for anything. + columns, err := r.Columns() + if err != nil { + return err + } + + values := make([]interface{}, len(columns)) + for i := range values { + values[i] = new(interface{}) + } + + err = r.Scan(values...) + if err != nil { + return err + } + + for i, column := range columns { + dest[column] = *(values[i].(*interface{})) + } + + return r.Err() +} + +type rowsi interface { + Close() error + Columns() ([]string, error) + Err() error + Next() bool + Scan(...interface{}) error +} + +// structOnlyError returns an error appropriate for type when a non-scannable +// struct is expected but something else is given +func structOnlyError(t reflect.Type) error { + isStruct := t.Kind() == reflect.Struct + isScanner := reflect.PtrTo(t).Implements(_scannerInterface) + if !isStruct { + return fmt.Errorf("expected %s but got %s", reflect.Struct, t.Kind()) + } + if isScanner { + return fmt.Errorf("structscan expects a struct dest but the provided struct type %s implements scanner", t.Name()) + } + return fmt.Errorf("expected a struct, but struct %s has no exported fields", t.Name()) +} + +// scanAll scans all rows into a destination, which must be a slice of any +// type. If the destination slice type is a Struct, then StructScan will be +// used on each row. If the destination is some other kind of base type, then +// each row must only have one column which can scan into that type. This +// allows you to do something like: +// +// rows, _ := db.Query("select id from people;") +// var ids []int +// scanAll(rows, &ids, false) +// +// and ids will be a list of the id results. I realize that this is a desirable +// interface to expose to users, but for now it will only be exposed via changes +// to `Get` and `Select`. The reason that this has been implemented like this is +// this is the only way to not duplicate reflect work in the new API while +// maintaining backwards compatibility. +func scanAll(rows rowsi, dest interface{}, structOnly bool) error { + var v, vp reflect.Value + + value := reflect.ValueOf(dest) + + // json.Unmarshal returns errors for these + if value.Kind() != reflect.Ptr { + return errors.New("must pass a pointer, not a value, to StructScan destination") + } + if value.IsNil() { + return errors.New("nil pointer passed to StructScan destination") + } + direct := reflect.Indirect(value) + + slice, err := baseType(value.Type(), reflect.Slice) + if err != nil { + return err + } + + isPtr := slice.Elem().Kind() == reflect.Ptr + base := reflectx.Deref(slice.Elem()) + scannable := isScannable(base) + + if structOnly && scannable { + return structOnlyError(base) + } + + columns, err := rows.Columns() + if err != nil { + return err + } + + // if it's a base type make sure it only has 1 column; if not return an error + if scannable && len(columns) > 1 { + return fmt.Errorf("non-struct dest type %s with >1 columns (%d)", base.Kind(), len(columns)) + } + + if !scannable { + var values []interface{} + var m *reflectx.Mapper + + switch rows.(type) { + case *Rows: + m = rows.(*Rows).Mapper + default: + m = mapper() + } + + fields := m.TraversalsByName(base, columns) + // if we are not unsafe and are missing fields, return an error + if f, err := missingFields(fields); err != nil && !isUnsafe(rows) { + return fmt.Errorf("missing destination name %s in %T", columns[f], dest) + } + values = make([]interface{}, len(columns)) + + for rows.Next() { + // create a new struct type (which returns PtrTo) and indirect it + vp = reflect.New(base) + v = reflect.Indirect(vp) + + err = fieldsByTraversal(v, fields, values, true) + if err != nil { + return err + } + + // scan into the struct field pointers and append to our results + err = rows.Scan(values...) + if err != nil { + return err + } + + if isPtr { + direct.Set(reflect.Append(direct, vp)) + } else { + direct.Set(reflect.Append(direct, v)) + } + } + } else { + for rows.Next() { + vp = reflect.New(base) + err = rows.Scan(vp.Interface()) + if err != nil { + return err + } + // append + if isPtr { + direct.Set(reflect.Append(direct, vp)) + } else { + direct.Set(reflect.Append(direct, reflect.Indirect(vp))) + } + } + } + + return rows.Err() +} + +// FIXME: StructScan was the very first bit of API in sqlx, and now unfortunately +// it doesn't really feel like it's named properly. There is an incongruency +// between this and the way that StructScan (which might better be ScanStruct +// anyway) works on a rows object. + +// StructScan all rows from an sql.Rows or an sqlx.Rows into the dest slice. +// StructScan will scan in the entire rows result, so if you do not want to +// allocate structs for the entire result, use Queryx and see sqlx.Rows.StructScan. +// If rows is sqlx.Rows, it will use its mapper, otherwise it will use the default. +func StructScan(rows rowsi, dest interface{}) error { + return scanAll(rows, dest, true) + +} + +// reflect helpers + +func baseType(t reflect.Type, expected reflect.Kind) (reflect.Type, error) { + t = reflectx.Deref(t) + if t.Kind() != expected { + return nil, fmt.Errorf("expected %s but got %s", expected, t.Kind()) + } + return t, nil +} + +// fieldsByName fills a values interface with fields from the passed value based +// on the traversals in int. If ptrs is true, return addresses instead of values. +// We write this instead of using FieldsByName to save allocations and map lookups +// when iterating over many rows. Empty traversals will get an interface pointer. +// Because of the necessity of requesting ptrs or values, it's considered a bit too +// specialized for inclusion in reflectx itself. +func fieldsByTraversal(v reflect.Value, traversals [][]int, values []interface{}, ptrs bool) error { + v = reflect.Indirect(v) + if v.Kind() != reflect.Struct { + return errors.New("argument not a struct") + } + + for i, traversal := range traversals { + if len(traversal) == 0 { + values[i] = new(interface{}) + continue + } + f := reflectx.FieldByIndexes(v, traversal) + if ptrs { + values[i] = f.Addr().Interface() + } else { + values[i] = f.Interface() + } + } + return nil +} + +func missingFields(transversals [][]int) (field int, err error) { + for i, t := range transversals { + if len(t) == 0 { + return i, errors.New("missing field") + } + } + return 0, nil +} |