sqlparse.go

package main

import (
	"flag"
	"fmt"
	"log"
	"unsafe"

	"modernc.org/libc"
	"modernc.org/libc/sys/types"
	sqlite3 "modernc.org/sqlite/lib"
)

func main() {
	flag.Parse()
	if flag.NArg() == 0 {
		log.Fatal(`usage: parse "<sql string>"`)
	}

	sql := flag.Arg(0)
	err := Parse(sql)
	if err == nil {
		fmt.Println("valid sql")
	} else {
		log.Fatal(err)
	}
}

func Parse(sql string) error {
	tls := libc.NewTLS()

	csql, err := libc.CString(sql)
	if err != nil {
		return err
	}

	filename, err := libc.CString(":memory:")
	if err != nil {
		return err
	}

	ptrSize := unsafe.Sizeof(uintptr(0))
	dbP := libc.Xmalloc(tls, types.Size_t(ptrSize))
	defer func() {
		if dbP != 0 {
			libc.Xfree(tls, dbP)
		}
	}()

	db := (*sqlite3.Sqlite3)(unsafe.Pointer(dbP))
	defer sqlite3.Xsqlite3_close_v2(tls, dbP)

	result := sqlite3.Xsqlite3_open_v2(tls, filename, dbP, sqlite3.SQLITE_OPEN_READWRITE, 0)
	if err := sqliteErr(tls, result); err != nil {
		return fmt.Errorf("open failed: %w", err)
	}

	db.FaLimit = [12]int32{
		sqlite3.SQLITE_MAX_LENGTH,
		sqlite3.SQLITE_MAX_SQL_LENGTH,
		sqlite3.SQLITE_MAX_COLUMN,
		sqlite3.SQLITE_MAX_EXPR_DEPTH,
		sqlite3.SQLITE_MAX_COMPOUND_SELECT,
		sqlite3.SQLITE_MAX_VDBE_OP,
		sqlite3.SQLITE_MAX_FUNCTION_ARG,
		sqlite3.SQLITE_MAX_ATTACHED,
		sqlite3.SQLITE_MAX_LIKE_PATTERN_LENGTH,
		sqlite3.SQLITE_MAX_VARIABLE_NUMBER, // IMP: R-38091-32352
		sqlite3.SQLITE_MAX_TRIGGER_DEPTH,
		sqlite3.SQLITE_MAX_WORKER_THREADS,
	}

	parse := sqlite3.Parse{
		Fdb: dbP,
	}
	parseP := uintptr(unsafe.Pointer(&parse))

	errMsgP := libc.Xmalloc(tls, types.Size_t(ptrSize))
	defer func() {
		if errMsgP != 0 {
			libc.Xfree(tls, errMsgP)
		}
	}()

	sqlite3.Xsqlite3RunParser(tls, parseP, csql, errMsgP)

	errMsg := *(*uintptr)(unsafe.Pointer(errMsgP))
	if errMsg != 0 {
		return fmt.Errorf("parse error: %s", libc.GoString(errMsg))
	}

	return nil
}

func sqliteErr(tls *libc.TLS, rc int32) error {
	if rc == sqlite3.SQLITE_OK {
		return nil
	}
	cstr := sqlite3.Xsqlite3ErrStr(tls, rc)
	return fmt.Errorf(libc.GoString(cstr))
}