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// Copyright (c) 2019-2021 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module builtin
// IError holds information about an error instance
pub interface IError {
msg string
code int
}
// Error is the default implementation of IError, that is returned by e.g. `error()`
pub struct Error {
pub:
msg string
code int
}
pub fn (err IError) str() string {
return match err {
None__ { 'none' }
Error { err.msg }
else { '$err.type_name(): $err.msg' }
}
}
const none__ = IError(&None__{})
struct None__ {
msg string
code int
}
fn (_ None__) str() string {
return 'none'
}
[if trace_error ?]
fn trace_error(x string) {
eprintln('> ${@FN} | $x')
}
// error returns a default error instance containing the error given in `message`.
// Example: `if ouch { return error('an error occurred') }`
[inline]
pub fn error(message string) IError {
trace_error(message)
return &Error{
msg: message
}
}
// error_with_code returns a default error instance containing the given `message` and error `code`.
// `if ouch { return error_with_code('an error occurred', 1) }`
[inline]
pub fn error_with_code(message string, code int) IError {
trace_error('$message | code: $code')
return &Error{
msg: message
code: code
}
}
// Option is the base of V's internal optional return system.
struct Option {
state byte
err IError = none__
// Data is trailing after err
// and is not included in here but in the
// derived Option_xxx types
}
fn opt_ok(data voidptr, mut option Option, size int) {
unsafe {
*option = Option{}
// use err to get the end of OptionBase and then memcpy into it
vmemcpy(&byte(&option.err) + sizeof(IError), data, size)
}
}
[unsafe]
pub fn (e &Error) free() {
unsafe { e.msg.free() }
}
[unsafe]
pub fn (n &None__) free() {
unsafe { n.msg.free() }
}
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