gotosocial/vendor/github.com/tetratelabs/wazero/sys/error.go
kim 1e7b32490d
[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/).
2024-05-27 17:46:15 +02:00

83 lines
2.8 KiB
Go

// Package sys includes constants and types used by both public and internal APIs.
package sys
import (
"context"
"fmt"
)
// These two special exit codes are reserved by wazero for context Cancel and Timeout integrations.
// The assumption here is that well-behaving Wasm programs won't use these two exit codes.
const (
// ExitCodeContextCanceled corresponds to context.Canceled and returned by ExitError.ExitCode in that case.
ExitCodeContextCanceled uint32 = 0xffffffff
// ExitCodeDeadlineExceeded corresponds to context.DeadlineExceeded and returned by ExitError.ExitCode in that case.
ExitCodeDeadlineExceeded uint32 = 0xefffffff
)
// ExitError is returned to a caller of api.Function when api.Module CloseWithExitCode was invoked,
// or context.Context passed to api.Function Call was canceled or reached the Timeout.
//
// ExitCode zero value means success while any other value is an error.
//
// Here's an example of how to get the exit code:
//
// main := module.ExportedFunction("main")
// if err := main(ctx); err != nil {
// if exitErr, ok := err.(*sys.ExitError); ok {
// // This means your module exited with non-zero code!
// }
// --snip--
//
// Note: While possible the reason of this was "proc_exit" from "wasi_snapshot_preview1", it could be from other host
// functions, for example an AssemblyScript's abort handler, or any arbitrary caller of CloseWithExitCode.
//
// See https://github.com/WebAssembly/WASI/blob/main/phases/snapshot/docs.md#proc_exit and
// https://www.assemblyscript.org/concepts.html#special-imports
//
// Note: In the case of context cancellation or timeout, the api.Module from which the api.Function created is closed.
type ExitError struct {
// Note: this is a struct not a uint32 type as it was originally one and
// we don't want to break call-sites that cast into it.
exitCode uint32
}
var exitZero = &ExitError{}
func NewExitError(exitCode uint32) *ExitError {
if exitCode == 0 {
return exitZero
}
return &ExitError{exitCode: exitCode}
}
// ExitCode returns zero on success, and an arbitrary value otherwise.
func (e *ExitError) ExitCode() uint32 {
return e.exitCode
}
// Error implements the error interface.
func (e *ExitError) Error() string {
switch e.exitCode {
case ExitCodeContextCanceled:
return fmt.Sprintf("module closed with %s", context.Canceled)
case ExitCodeDeadlineExceeded:
return fmt.Sprintf("module closed with %s", context.DeadlineExceeded)
default:
return fmt.Sprintf("module closed with exit_code(%d)", e.exitCode)
}
}
// Is allows use via errors.Is
func (e *ExitError) Is(err error) bool {
if target, ok := err.(*ExitError); ok {
return e.exitCode == target.exitCode
}
if e.exitCode == ExitCodeContextCanceled && err == context.Canceled {
return true
}
if e.exitCode == ExitCodeDeadlineExceeded && err == context.DeadlineExceeded {
return true
}
return false
}