Repository navigation
Expand file tree
/
Copy pathrows.go
More file actions
543 lines (442 loc) · 14.3 KB
/
Copy pathrows.go
File metadata and controls
543 lines (442 loc) · 14.3 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
package pgx
import (
"context"
"errors"
"fmt"
"reflect"
"time"
"github.com/jackc/pgx/v5/internal/stmtcache"
"github.com/jackc/pgx/v5/pgconn"
"github.com/jackc/pgx/v5/pgtype"
)
// Rows is the result set returned from *Conn.Query. Rows must be closed before
// the *Conn can be used again. Rows are closed by explicitly calling Close(),
// calling Next() until it returns false, or when a fatal error occurs.
//
// Once a Rows is closed the only methods that may be called are Close(), Err(), and CommandTag().
//
// Rows is an interface instead of a struct to allow tests to mock Query. However,
// adding a method to an interface is technically a breaking change. Because of this
// the Rows interface is partially excluded from semantic version requirements.
// Methods will not be removed or changed, but new methods may be added.
type Rows interface {
// Close closes the rows, making the connection ready for use again. It is safe
// to call Close after rows is already closed.
Close()
// Err returns any error that occurred while reading.
Err() error
// CommandTag returns the command tag from this query. It is only available after Rows is closed.
CommandTag() pgconn.CommandTag
FieldDescriptions() []pgconn.FieldDescription
// Next prepares the next row for reading. It returns true if there is another
// row and false if no more rows are available. It automatically closes rows
// when all rows are read.
Next() bool
// Scan reads the values from the current row into dest values positionally.
// dest can include pointers to core types, values implementing the Scanner
// interface, and nil. nil will skip the value entirely. It is an error to
// call Scan without first calling Next() and checking that it returned true.
Scan(dest ...any) error
// Values returns the decoded row values. As with Scan(), it is an error to
// call Values without first calling Next() and checking that it returned
// true.
Values() ([]any, error)
// RawValues returns the unparsed bytes of the row values. The returned data is only valid until the next Next
// call or the Rows is closed.
RawValues() [][]byte
// Conn returns the underlying *Conn on which the query was executed. This may return nil if Rows did not come from a
// *Conn (e.g. if it was created by RowsFromResultReader)
Conn() *Conn
}
// Row is a convenience wrapper over Rows that is returned by QueryRow.
//
// Row is an interface instead of a struct to allow tests to mock QueryRow. However,
// adding a method to an interface is technically a breaking change. Because of this
// the Row interface is partially excluded from semantic version requirements.
// Methods will not be removed or changed, but new methods may be added.
type Row interface {
// Scan works the same as Rows. with the following exceptions. If no
// rows were found it returns ErrNoRows. If multiple rows are returned it
// ignores all but the first.
Scan(dest ...any) error
}
// RowScanner scans an entire row at a time into the RowScanner.
type RowScanner interface {
// ScanRows scans the row.
ScanRow(rows Rows) error
}
// connRow implements the Row interface for Conn.QueryRow.
type connRow baseRows
func (r *connRow) Scan(dest ...any) (err error) {
rows := (*baseRows)(r)
if rows.Err() != nil {
return rows.Err()
}
for _, d := range dest {
if _, ok := d.(*pgtype.DriverBytes); ok {
rows.Close()
return fmt.Errorf("cannot scan into *pgtype.DriverBytes from QueryRow")
}
}
if !rows.Next() {
if rows.Err() == nil {
return ErrNoRows
}
return rows.Err()
}
rows.Scan(dest...)
rows.Close()
return rows.Err()
}
// baseRows implements the Rows interface for Conn.Query.
type baseRows struct {
typeMap *pgtype.Map
resultReader *pgconn.ResultReader
values [][]byte
commandTag pgconn.CommandTag
err error
closed bool
scanPlans []pgtype.ScanPlan
scanTypes []reflect.Type
conn *Conn
multiResultReader *pgconn.MultiResultReader
queryTracer QueryTracer
batchTracer BatchTracer
ctx context.Context
startTime time.Time
sql string
args []any
rowCount int
}
func (rows *baseRows) FieldDescriptions() []pgconn.FieldDescription {
return rows.resultReader.FieldDescriptions()
}
func (rows *baseRows) Close() {
if rows.closed {
return
}
rows.closed = true
if rows.resultReader != nil {
var closeErr error
rows.commandTag, closeErr = rows.resultReader.Close()
if rows.err == nil {
rows.err = closeErr
}
}
if rows.multiResultReader != nil {
closeErr := rows.multiResultReader.Close()
if rows.err == nil {
rows.err = closeErr
}
}
if rows.err != nil && rows.conn != nil && rows.sql != "" {
if stmtcache.IsStatementInvalid(rows.err) {
if sc := rows.conn.statementCache; sc != nil {
sc.Invalidate(rows.sql)
}
if sc := rows.conn.descriptionCache; sc != nil {
sc.Invalidate(rows.sql)
}
}
}
if rows.batchTracer != nil {
rows.batchTracer.TraceBatchQuery(rows.ctx, rows.conn, TraceBatchQueryData{SQL: rows.sql, Args: rows.args, CommandTag: rows.commandTag, Err: rows.err})
} else if rows.queryTracer != nil {
rows.queryTracer.TraceQueryEnd(rows.ctx, rows.conn, TraceQueryEndData{rows.commandTag, rows.err})
}
}
func (rows *baseRows) CommandTag() pgconn.CommandTag {
return rows.commandTag
}
func (rows *baseRows) Err() error {
return rows.err
}
// fatal signals an error occurred after the query was sent to the server. It
// closes the rows automatically.
func (rows *baseRows) fatal(err error) {
if rows.err != nil {
return
}
rows.err = err
rows.Close()
}
func (rows *baseRows) Next() bool {
if rows.closed {
return false
}
if rows.resultReader.NextRow() {
rows.rowCount++
rows.values = rows.resultReader.Values()
return true
} else {
rows.Close()
return false
}
}
func (rows *baseRows) Scan(dest ...any) error {
m := rows.typeMap
fieldDescriptions := rows.FieldDescriptions()
values := rows.values
if len(fieldDescriptions) != len(values) {
err := fmt.Errorf("number of field descriptions must equal number of values, got %d and %d", len(fieldDescriptions), len(values))
rows.fatal(err)
return err
}
if len(dest) == 1 {
if rc, ok := dest[0].(RowScanner); ok {
return rc.ScanRow(rows)
}
}
if len(fieldDescriptions) != len(dest) {
err := fmt.Errorf("number of field descriptions must equal number of destinations, got %d and %d", len(fieldDescriptions), len(dest))
rows.fatal(err)
return err
}
if rows.scanPlans == nil {
rows.scanPlans = make([]pgtype.ScanPlan, len(values))
rows.scanTypes = make([]reflect.Type, len(values))
for i := range dest {
rows.scanPlans[i] = m.PlanScan(fieldDescriptions[i].DataTypeOID, fieldDescriptions[i].Format, dest[i])
rows.scanTypes[i] = reflect.TypeOf(dest[i])
}
}
for i, dst := range dest {
if dst == nil {
continue
}
if rows.scanTypes[i] != reflect.TypeOf(dst) {
rows.scanPlans[i] = m.PlanScan(fieldDescriptions[i].DataTypeOID, fieldDescriptions[i].Format, dest[i])
rows.scanTypes[i] = reflect.TypeOf(dest[i])
}
err := rows.scanPlans[i].Scan(values[i], dst)
if err != nil {
err = ScanArgError{ColumnIndex: i, Err: err}
rows.fatal(err)
return err
}
}
return nil
}
func (rows *baseRows) Values() ([]any, error) {
if rows.closed {
return nil, errors.New("rows is closed")
}
values := make([]any, 0, len(rows.FieldDescriptions()))
for i := range rows.FieldDescriptions() {
buf := rows.values[i]
fd := &rows.FieldDescriptions()[i]
if buf == nil {
values = append(values, nil)
continue
}
if dt, ok := rows.typeMap.TypeForOID(fd.DataTypeOID); ok {
value, err := dt.Codec.DecodeValue(rows.typeMap, fd.DataTypeOID, fd.Format, buf)
if err != nil {
rows.fatal(err)
}
values = append(values, value)
} else {
switch fd.Format {
case TextFormatCode:
values = append(values, string(buf))
case BinaryFormatCode:
newBuf := make([]byte, len(buf))
copy(newBuf, buf)
values = append(values, newBuf)
default:
rows.fatal(errors.New("Unknown format code"))
}
}
if rows.Err() != nil {
return nil, rows.Err()
}
}
return values, rows.Err()
}
func (rows *baseRows) RawValues() [][]byte {
return rows.values
}
func (rows *baseRows) Conn() *Conn {
return rows.conn
}
type ScanArgError struct {
ColumnIndex int
Err error
}
func (e ScanArgError) Error() string {
return fmt.Sprintf("can't scan into dest[%d]: %v", e.ColumnIndex, e.Err)
}
func (e ScanArgError) Unwrap() error {
return e.Err
}
// ScanRow decodes raw row data into dest. It can be used to scan rows read from the lower level pgconn interface.
//
// typeMap - OID to Go type mapping.
// fieldDescriptions - OID and format of values
// values - the raw data as returned from the PostgreSQL server
// dest - the destination that values will be decoded into
func ScanRow(typeMap *pgtype.Map, fieldDescriptions []pgconn.FieldDescription, values [][]byte, dest ...any) error {
if len(fieldDescriptions) != len(values) {
return fmt.Errorf("number of field descriptions must equal number of values, got %d and %d", len(fieldDescriptions), len(values))
}
if len(fieldDescriptions) != len(dest) {
return fmt.Errorf("number of field descriptions must equal number of destinations, got %d and %d", len(fieldDescriptions), len(dest))
}
for i, d := range dest {
if d == nil {
continue
}
err := typeMap.Scan(fieldDescriptions[i].DataTypeOID, fieldDescriptions[i].Format, values[i], d)
if err != nil {
return ScanArgError{ColumnIndex: i, Err: err}
}
}
return nil
}
// RowsFromResultReader returns a Rows that will read from values resultReader and decode with typeMap. It can be used
// to read from the lower level pgconn interface.
func RowsFromResultReader(typeMap *pgtype.Map, resultReader *pgconn.ResultReader) Rows {
return &baseRows{
typeMap: typeMap,
resultReader: resultReader,
}
}
// ForEachRow iterates through rows. For each row it scans into the elements of scans and calls fn. If any row
// fails to scan or fn returns an error the query will be aborted and the error will be returned. Rows will be closed
// when ForEachRow returns.
func ForEachRow(rows Rows, scans []any, fn func() error) (pgconn.CommandTag, error) {
defer rows.Close()
for rows.Next() {
err := rows.Scan(scans...)
if err != nil {
return pgconn.CommandTag{}, err
}
err = fn()
if err != nil {
return pgconn.CommandTag{}, err
}
}
if err := rows.Err(); err != nil {
return pgconn.CommandTag{}, err
}
return rows.CommandTag(), nil
}
// CollectableRow is the subset of Rows methods that a RowToFunc is allowed to call.
type CollectableRow interface {
FieldDescriptions() []pgconn.FieldDescription
Scan(dest ...any) error
Values() ([]any, error)
RawValues() [][]byte
}
// RowToFunc is a function that scans or otherwise converts row to a T.
type RowToFunc[T any] func(row CollectableRow) (T, error)
// CollectRows iterates through rows, calling fn for each row, and collecting the results into a slice of T.
func CollectRows[T any](rows Rows, fn RowToFunc[T]) ([]T, error) {
defer rows.Close()
slice := []T{}
for rows.Next() {
value, err := fn(rows)
if err != nil {
return nil, err
}
slice = append(slice, value)
}
if err := rows.Err(); err != nil {
return nil, err
}
return slice, nil
}
// CollectOneRow calls fn for the first row in rows and returns the result. If no rows are found returns an error where errors.Is(ErrNoRows) is true.
// CollectOneRow is to CollectRows as QueryRow is to Query.
func CollectOneRow[T any](rows Rows, fn RowToFunc[T]) (T, error) {
defer rows.Close()
var value T
var err error
if !rows.Next() {
return value, ErrNoRows
}
value, err = fn(rows)
if err != nil {
return value, err
}
rows.Close()
return value, rows.Err()
}
// RowTo returns a T scanned from row.
func RowTo[T any](row CollectableRow) (T, error) {
var value T
err := row.Scan(&value)
return value, err
}
// RowTo returns a the address of a T scanned from row.
func RowToAddrOf[T any](row CollectableRow) (*T, error) {
var value T
err := row.Scan(&value)
return &value, err
}
// RowToMap returns a map scanned from row.
func RowToMap(row CollectableRow) (map[string]any, error) {
var value map[string]any
err := row.Scan((*mapRowScanner)(&value))
return value, err
}
type mapRowScanner map[string]any
func (rs *mapRowScanner) ScanRow(rows Rows) error {
values, err := rows.Values()
if err != nil {
return err
}
*rs = make(mapRowScanner, len(values))
for i := range values {
(*rs)[string(rows.FieldDescriptions()[i].Name)] = values[i]
}
return nil
}
// RowToStructByPos returns a T scanned from row. T must be a struct. T must have the same number a public fields as row
// has fields. The row and T fields will by matched by position.
func RowToStructByPos[T any](row CollectableRow) (T, error) {
var value T
err := row.Scan(&positionalStructRowScanner{ptrToStruct: &value})
return value, err
}
// RowToAddrOfStructByPos returns the address of a T scanned from row. T must be a struct. T must have the same number a
// public fields as row has fields. The row and T fields will by matched by position.
func RowToAddrOfStructByPos[T any](row CollectableRow) (*T, error) {
var value T
err := row.Scan(&positionalStructRowScanner{ptrToStruct: &value})
return &value, err
}
type positionalStructRowScanner struct {
ptrToStruct any
}
func (rs *positionalStructRowScanner) ScanRow(rows Rows) error {
dst := rs.ptrToStruct
dstValue := reflect.ValueOf(dst)
if dstValue.Kind() != reflect.Ptr {
return fmt.Errorf("dst not a pointer")
}
dstElemValue := dstValue.Elem()
scanTargets := rs.appendScanTargets(dstElemValue, nil)
if len(rows.RawValues()) > len(scanTargets) {
return fmt.Errorf("got %d values, but dst struct has only %d fields", len(rows.RawValues()), len(scanTargets))
}
return rows.Scan(scanTargets...)
}
func (rs *positionalStructRowScanner) appendScanTargets(dstElemValue reflect.Value, scanTargets []any) []any {
dstElemType := dstElemValue.Type()
if scanTargets == nil {
scanTargets = make([]any, 0, dstElemType.NumField())
}
for i := 0; i < dstElemType.NumField(); i++ {
sf := dstElemType.Field(i)
if sf.PkgPath == "" {
// Handle anoymous struct embedding, but do not try to handle embedded pointers.
if sf.Anonymous && sf.Type.Kind() == reflect.Struct {
scanTargets = append(scanTargets, rs.appendScanTargets(dstElemValue.Field(i), scanTargets)...)
} else {
scanTargets = append(scanTargets, dstElemValue.Field(i).Addr().Interface())
}
}
}
return scanTargets
}