elvish/pkg/eval/external_cmd.go
Qi Xiao 6e8ecc8bd5 pkg/eval: Cleanups for reducing the API surface area number of files.
- Move NewEnvListVar to pkg/eval/vars.

- De-export GlobPattern, GlobFlag and ExternalCmd.

- Merge editor.go and chdir.go into eval.go, value_helper.go into compile_value.go.

- Remove eval_internal_test.go and replace it with a new test for $pid.
2021-01-05 04:33:52 +00:00

107 lines
2.5 KiB
Go

package eval
import (
"errors"
"os"
"os/exec"
"syscall"
"github.com/elves/elvish/pkg/eval/vals"
"github.com/elves/elvish/pkg/fsutil"
"github.com/elves/elvish/pkg/parse"
"github.com/xiaq/persistent/hash"
)
var (
// ErrExternalCmdOpts is thrown when an external command is passed Elvish
// options.
//
// TODO: Catch this kind of errors at compilation time.
ErrExternalCmdOpts = errors.New("external commands don't accept elvish options")
// ErrImplicitCdNoArg is thrown when an implicit cd form is passed arguments.
ErrImplicitCdNoArg = errors.New("implicit cd accepts no arguments")
)
// externalCmd is an external command.
type externalCmd struct {
Name string
}
// NewExternalCmd returns a callable that executes the named external command.
//
// An external command converts all arguments to strings, and does not accept
// any option.
func NewExternalCmd(name string) Callable {
return externalCmd{name}
}
func (e externalCmd) Kind() string {
return "fn"
}
func (e externalCmd) Equal(a interface{}) bool {
return e == a
}
func (e externalCmd) Hash() uint32 {
return hash.String(e.Name)
}
func (e externalCmd) Repr(int) string {
return "<external " + parse.Quote(e.Name) + ">"
}
// Call calls an external command.
func (e externalCmd) Call(fm *Frame, argVals []interface{}, opts map[string]interface{}) error {
if len(opts) > 0 {
return ErrExternalCmdOpts
}
if fsutil.DontSearch(e.Name) {
stat, err := os.Stat(e.Name)
if err == nil && stat.IsDir() {
// implicit cd
if len(argVals) > 0 {
return ErrImplicitCdNoArg
}
return fm.Evaler.Chdir(e.Name)
}
}
files := make([]*os.File, len(fm.ports))
for i, port := range fm.ports {
if port != nil {
files[i] = port.File
}
}
args := make([]string, len(argVals)+1)
for i, a := range argVals {
// TODO: Maybe we should enforce string arguments instead of coercing
// all args to strings.
args[i+1] = vals.ToString(a)
}
path, err := exec.LookPath(e.Name)
if err != nil {
return err
}
args[0] = path
sys := makeSysProcAttr(fm.background)
proc, err := os.StartProcess(path, args, &os.ProcAttr{Files: files, Sys: sys})
if err != nil {
return err
}
state, err := proc.Wait()
if err != nil {
// This should be a can't happen situation. Nonetheless, treat it as a
// soft error rather than panicking since the Go documentation is not
// explicit that this can only happen if we make a mistake. Such as
// calling `Wait` twice on a particular process object.
return err
}
return NewExternalCmdExit(e.Name, state.Sys().(syscall.WaitStatus), proc.Pid)
}