[experiment] add alternative wasm sqlite3 implementation available via build-tag (#2863)

This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).

vendor/github.com/ncruces/go-sqlite3/error.go

@@ -0,0 +1,162 @@
+package sqlite3
+
+import (
+	"errors"
+	"strconv"
+	"strings"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+// Error wraps an SQLite Error Code.
+//
+// https://sqlite.org/c3ref/errcode.html
+type Error struct {
+	str  string
+	msg  string
+	sql  string
+	code uint64
+}
+
+// Code returns the primary error code for this error.
+//
+// https://sqlite.org/rescode.html
+func (e *Error) Code() ErrorCode {
+	return ErrorCode(e.code)
+}
+
+// ExtendedCode returns the extended error code for this error.
+//
+// https://sqlite.org/rescode.html
+func (e *Error) ExtendedCode() ExtendedErrorCode {
+	return ExtendedErrorCode(e.code)
+}
+
+// Error implements the error interface.
+func (e *Error) Error() string {
+	var b strings.Builder
+	b.WriteString("sqlite3: ")
+
+	if e.str != "" {
+		b.WriteString(e.str)
+	} else {
+		b.WriteString(strconv.Itoa(int(e.code)))
+	}
+
+	if e.msg != "" {
+		b.WriteString(": ")
+		b.WriteString(e.msg)
+	}
+
+	return b.String()
+}
+
+// Is tests whether this error matches a given [ErrorCode] or [ExtendedErrorCode].
+//
+// It makes it possible to do:
+//
+//	if errors.Is(err, sqlite3.BUSY) {
+//		// ... handle BUSY
+//	}
+func (e *Error) Is(err error) bool {
+	switch c := err.(type) {
+	case ErrorCode:
+		return c == e.Code()
+	case ExtendedErrorCode:
+		return c == e.ExtendedCode()
+	}
+	return false
+}
+
+// As converts this error to an [ErrorCode] or [ExtendedErrorCode].
+func (e *Error) As(err any) bool {
+	switch c := err.(type) {
+	case *ErrorCode:
+		*c = e.Code()
+		return true
+	case *ExtendedErrorCode:
+		*c = e.ExtendedCode()
+		return true
+	}
+	return false
+}
+
+// Temporary returns true for [BUSY] errors.
+func (e *Error) Temporary() bool {
+	return e.Code() == BUSY
+}
+
+// Timeout returns true for [BUSY_TIMEOUT] errors.
+func (e *Error) Timeout() bool {
+	return e.ExtendedCode() == BUSY_TIMEOUT
+}
+
+// SQL returns the SQL starting at the token that triggered a syntax error.
+func (e *Error) SQL() string {
+	return e.sql
+}
+
+// Error implements the error interface.
+func (e ErrorCode) Error() string {
+	return util.ErrorCodeString(uint32(e))
+}
+
+// Temporary returns true for [BUSY] errors.
+func (e ErrorCode) Temporary() bool {
+	return e == BUSY
+}
+
+// Error implements the error interface.
+func (e ExtendedErrorCode) Error() string {
+	return util.ErrorCodeString(uint32(e))
+}
+
+// Is tests whether this error matches a given [ErrorCode].
+func (e ExtendedErrorCode) Is(err error) bool {
+	c, ok := err.(ErrorCode)
+	return ok && c == ErrorCode(e)
+}
+
+// As converts this error to an [ErrorCode].
+func (e ExtendedErrorCode) As(err any) bool {
+	c, ok := err.(*ErrorCode)
+	if ok {
+		*c = ErrorCode(e)
+	}
+	return ok
+}
+
+// Temporary returns true for [BUSY] errors.
+func (e ExtendedErrorCode) Temporary() bool {
+	return ErrorCode(e) == BUSY
+}
+
+// Timeout returns true for [BUSY_TIMEOUT] errors.
+func (e ExtendedErrorCode) Timeout() bool {
+	return e == BUSY_TIMEOUT
+}
+
+func errorCode(err error, def ErrorCode) (msg string, code uint32) {
+	switch code := err.(type) {
+	case nil:
+		return "", _OK
+	case ErrorCode:
+		return "", uint32(code)
+	case xErrorCode:
+		return "", uint32(code)
+	case *Error:
+		return code.msg, uint32(code.code)
+	}
+
+	var ecode ErrorCode
+	var xcode xErrorCode
+	switch {
+	case errors.As(err, &xcode):
+		code = uint32(xcode)
+	case errors.As(err, &ecode):
+		code = uint32(ecode)
+	default:
+		code = uint32(def)
+	}
+	return err.Error(), code
+}