musiclink/vendor/modernc.org/sqlite/stmt.go

473 lines
10 KiB
Go

// Copyright 2025 The Sqlite Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package sqlite // import "modernc.org/sqlite"
import (
"context"
"database/sql/driver"
"sync/atomic"
"unsafe"
"modernc.org/libc"
sqlite3 "modernc.org/sqlite/lib"
)
type stmt struct {
c *conn
psql uintptr
pstmt uintptr // The cached SQLite statement handle
}
func newStmt(c *conn, sql string) (*stmt, error) {
p, err := libc.CString(sql)
if err != nil {
return nil, err
}
s := &stmt{c: c, psql: p}
// Attempt to prepare the statement immediately
// We make a copy of the pointer because prepareV2 advances it
psql := p
pstmt, err := c.prepareV2(&psql)
if err != nil {
c.free(p)
return nil, err
}
// Check if there is trailing SQL (indicating a script/multi-statement)
// If *psql (the tail) is 0, we consumed the whole string.
hasTail := *(*byte)(unsafe.Pointer(psql)) != 0
if pstmt != 0 && !hasTail {
// Optimization: Single statement. Cache it.
s.pstmt = pstmt
return s, nil
}
// It is either a script (hasTail) or a comment-only string (pstmt==0).
// For scripts: Finalize now. We will re-parse iteratively in Exec/Query
// to handle the multiple statements correctly using the existing loop logic.
if pstmt != 0 {
if err := c.finalize(pstmt); err != nil {
c.free(p)
return nil, err
}
}
return s, nil
}
// Close closes the statement.
//
// As of Go 1.1, a Stmt will not be closed if it's in use by any queries.
func (s *stmt) Close() (err error) {
if s.pstmt != 0 {
if e := s.c.finalize(s.pstmt); e != nil {
err = e
}
s.pstmt = 0
}
if s.psql != 0 {
s.c.free(s.psql)
s.psql = 0
}
return err
}
// Exec executes a query that doesn't return rows, such as an INSERT or UPDATE.
//
// Deprecated: Drivers should implement StmtExecContext instead (or
// additionally).
func (s *stmt) Exec(args []driver.Value) (driver.Result, error) { //TODO StmtExecContext
return s.exec(context.Background(), toNamedValues(args))
}
// toNamedValues converts []driver.Value to []driver.NamedValue
func toNamedValues(vals []driver.Value) (r []driver.NamedValue) {
r = make([]driver.NamedValue, len(vals))
for i, val := range vals {
r[i] = driver.NamedValue{Value: val, Ordinal: i + 1}
}
return r
}
func (s *stmt) exec(ctx context.Context, args []driver.NamedValue) (r driver.Result, err error) {
var pstmt uintptr
var done int32
if ctx != nil {
if ctxDone := ctx.Done(); ctxDone != nil {
select {
case <-ctxDone:
return nil, ctx.Err()
default:
}
defer interruptOnDone(ctx, s.c, &done)()
}
}
defer func() {
if ctx != nil && atomic.LoadInt32(&done) != 0 {
r, err = nil, ctx.Err()
}
if pstmt != 0 {
// ensure stmt finalized.
e := s.c.finalize(pstmt)
if err == nil && e != nil {
// prioritize original
// returned error.
err = e
}
}
}()
// OPTIMIZED PATH: Single Cached Statement
if s.pstmt != 0 {
err = func() error {
// Bind
n, err := s.c.bindParameterCount(s.pstmt)
if err != nil {
return err
}
if n != 0 {
allocs, err := s.c.bind(s.pstmt, n, args)
if err != nil {
return err
}
// Free allocations after step
if len(allocs) != 0 {
defer func() {
for _, v := range allocs {
s.c.free(v)
}
}()
}
}
// Step
rc, err := s.c.step(s.pstmt)
if err != nil {
return err
}
// Handle Result
switch rc & 0xff {
case sqlite3.SQLITE_DONE, sqlite3.SQLITE_ROW:
r, err = newResult(s.c)
default:
return s.c.errstr(int32(rc))
}
return nil
}()
// RESET (Crucial: Do not finalize)
// We must reset the VM to allow reuse.
// We also clear bindings to prevent leaking memory or state to next call.
if resetErr := s.c.reset(s.pstmt); resetErr != nil && err == nil {
err = resetErr
}
if clearErr := s.c.clearBindings(s.pstmt); clearErr != nil && err == nil {
err = clearErr
}
return r, err
}
// FALLBACK PATH: Multi-statement script
for psql := s.psql; *(*byte)(unsafe.Pointer(psql)) != 0 && atomic.LoadInt32(&done) == 0; {
if pstmt, err = s.c.prepareV2(&psql); err != nil {
return nil, err
}
if pstmt == 0 {
continue
}
err = func() (err error) {
n, err := s.c.bindParameterCount(pstmt)
if err != nil {
return err
}
if n != 0 {
allocs, err := s.c.bind(pstmt, n, args)
if err != nil {
return err
}
if len(allocs) != 0 {
defer func() {
for _, v := range allocs {
s.c.free(v)
}
}()
}
}
rc, err := s.c.step(pstmt)
if err != nil {
return err
}
switch rc & 0xff {
case sqlite3.SQLITE_DONE, sqlite3.SQLITE_ROW:
r, err = newResult(s.c)
default:
return s.c.errstr(int32(rc))
}
return nil
}()
e := s.c.finalize(pstmt)
pstmt = 0 // done with
if err == nil && e != nil {
// prioritize original
// returned error.
err = e
}
if err != nil {
return nil, err
}
}
return r, err
}
// NumInput returns the number of placeholder parameters.
//
// If NumInput returns >= 0, the sql package will sanity check argument counts
// from callers and return errors to the caller before the statement's Exec or
// Query methods are called.
//
// NumInput may also return -1, if the driver doesn't know its number of
// placeholders. In that case, the sql package will not sanity check Exec or
// Query argument counts.
func (s *stmt) NumInput() (n int) {
return -1
}
// Query executes a query that may return rows, such as a
// SELECT.
//
// Deprecated: Drivers should implement StmtQueryContext instead (or
// additionally).
func (s *stmt) Query(args []driver.Value) (driver.Rows, error) { //TODO StmtQueryContext
return s.query(context.Background(), toNamedValues(args))
}
func (s *stmt) query(ctx context.Context, args []driver.NamedValue) (r driver.Rows, err error) {
var pstmt uintptr
var done int32
if ctx != nil {
if ctxDone := ctx.Done(); ctxDone != nil {
select {
case <-ctxDone:
return nil, ctx.Err()
default:
}
defer interruptOnDone(ctx, s.c, &done)()
}
}
var allocs []uintptr
defer func() {
if ctx != nil && atomic.LoadInt32(&done) != 0 {
if r != nil {
r.Close()
}
r, err = nil, ctx.Err()
} else if r == nil && err == nil {
r, err = newRows(s.c, pstmt, allocs, true)
}
if pstmt != 0 {
// ensure stmt finalized.
e := s.c.finalize(pstmt)
if err == nil && e != nil {
// prioritize original
// returned error.
err = e
}
}
}()
// OPTIMIZED PATH: Single Cached Statement
if s.pstmt != 0 {
// Bind
n, err := s.c.bindParameterCount(s.pstmt)
if err != nil {
return nil, err
}
if n != 0 {
if allocs, err = s.c.bind(s.pstmt, n, args); err != nil {
return nil, err
}
}
// Step
rc, err := s.c.step(s.pstmt)
if err != nil {
// On error, we must free allocs manually because 'newRows' won't take ownership
for _, v := range allocs {
s.c.free(v)
}
s.c.reset(s.pstmt)
s.c.clearBindings(s.pstmt)
return nil, err
}
// Handle Result
switch rc & 0xff {
case sqlite3.SQLITE_ROW:
// Pass reuseStmt=true
if r, err = newRows(s.c, s.pstmt, allocs, false); err != nil {
s.c.reset(s.pstmt)
s.c.clearBindings(s.pstmt)
return nil, err
}
r.(*rows).reuseStmt = true
return r, nil
case sqlite3.SQLITE_DONE:
// No rows. Reset immediately.
// We still return a rows object (empty), but we can reset the stmt now
// because the empty rows object won't call step() again.
// However, standard newRows behavior expects a valid stmt to get columns.
// Let's rely on newRows to read columns, then it returns.
// Actually, if we pass reuseStmt=true to an empty set,
// rows.Close() will eventually reset it.
if r, err = newRows(s.c, s.pstmt, allocs, true); err != nil {
s.c.reset(s.pstmt)
s.c.clearBindings(s.pstmt)
return nil, err
}
r.(*rows).reuseStmt = true
return r, nil
default:
// Error case
for _, v := range allocs {
s.c.free(v)
}
s.c.reset(s.pstmt)
s.c.clearBindings(s.pstmt)
return nil, s.c.errstr(int32(rc))
}
}
// FALLBACK PATH: Multi-statement script
for psql := s.psql; *(*byte)(unsafe.Pointer(psql)) != 0 && atomic.LoadInt32(&done) == 0; {
if pstmt, err = s.c.prepareV2(&psql); err != nil {
return nil, err
}
if pstmt == 0 {
continue
}
err = func() (err error) {
n, err := s.c.bindParameterCount(pstmt)
if err != nil {
return err
}
if n != 0 {
if allocs, err = s.c.bind(pstmt, n, args); err != nil {
return err
}
}
rc, err := s.c.step(pstmt)
if err != nil {
return err
}
switch rc & 0xff {
case sqlite3.SQLITE_ROW:
if r != nil {
r.Close()
}
if r, err = newRows(s.c, pstmt, allocs, false); err != nil {
return err
}
pstmt = 0
return nil
case sqlite3.SQLITE_DONE:
if r == nil {
if r, err = newRows(s.c, pstmt, allocs, true); err != nil {
return err
}
pstmt = 0
return nil
}
// nop
default:
return s.c.errstr(int32(rc))
}
if *(*byte)(unsafe.Pointer(psql)) == 0 {
if r != nil {
r.Close()
}
if r, err = newRows(s.c, pstmt, allocs, true); err != nil {
return err
}
pstmt = 0
}
return nil
}()
e := s.c.finalize(pstmt)
pstmt = 0 // done with
if err == nil && e != nil {
// prioritize original
// returned error.
err = e
}
if err != nil {
return nil, err
}
}
return r, err
}
// ExecContext implements driver.StmtExecContext
func (s *stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (dr driver.Result, err error) {
if dmesgs {
defer func() {
dmesg("stmt %p, ctx %p, args %v: (driver.Result %p, err %v)", s, ctx, args, dr, err)
}()
}
return s.exec(ctx, args)
}
// QueryContext implements driver.StmtQueryContext
func (s *stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (dr driver.Rows, err error) {
if dmesgs {
defer func() {
dmesg("stmt %p, ctx %p, args %v: (driver.Rows %p, err %v)", s, ctx, args, dr, err)
}()
}
return s.query(ctx, args)
}
// C documentation
//
// int sqlite3_clear_bindings(sqlite3_stmt*);
func (c *conn) clearBindings(pstmt uintptr) error {
if rc := sqlite3.Xsqlite3_clear_bindings(c.tls, pstmt); rc != sqlite3.SQLITE_OK {
return c.errstr(rc)
}
return nil
}