complete/predicate.go

129 lines
2.7 KiB
Go

package complete
import (
"os"
"path/filepath"
)
// Predicate determines what terms can follow a command or a flag
type Predicate struct {
// Predictor is function that returns list of arguments that can
// come after the flag/command
Predictor func(last string) []Option
}
// Or unions two predicate struct, so that the result predicate
// returns the union of their predication
func (p *Predicate) Or(other *Predicate) *Predicate {
if p == nil || other == nil {
return nil
}
return &Predicate{
Predictor: func(last string) []Option { return append(p.predict(last), other.predict(last)...) },
}
}
func (p *Predicate) predict(last string) []Option {
if p == nil || p.Predictor == nil {
return nil
}
return p.Predictor(last)
}
var (
PredictNothing *Predicate = nil
PredictAnything = &Predicate{}
PredictDirs = &Predicate{Predictor: dirs}
)
func PredictSet(options ...string) *Predicate {
return &Predicate{
Predictor: func(last string) []Option {
ret := make([]Option, len(options))
for i := range options {
ret[i] = Arg(options[i])
}
return ret
},
}
}
func PredictFiles(pattern string) *Predicate {
return &Predicate{Predictor: glob(pattern)}
}
func dirs(last string) (options []Option) {
dir := dirFromLast(last)
return dirsAt(dir)
}
func dirsAt(path string) []Option {
dirs := []string{}
filepath.Walk(path, func(path string, info os.FileInfo, err error) error {
if info.IsDir() {
dirs = append(dirs, path)
}
return nil
})
if !filepath.IsAbs(path) {
filesToRel(dirs)
}
return filesToOptions(dirs)
}
func glob(pattern string) func(last string) []Option {
return func(last string) []Option {
dir := dirFromLast(last)
files, err := filepath.Glob(filepath.Join(dir, pattern))
if err != nil {
Log("failed glob operation with pattern '%s': %s", pattern, err)
}
if !filepath.IsAbs(pattern) {
filesToRel(files)
}
return filesToOptions(files)
}
}
func filesToRel(files []string) {
wd, err := os.Getwd()
if err != nil {
return
}
for i := range files {
abs, err := filepath.Abs(files[i])
if err != nil {
continue
}
rel, err := filepath.Rel(wd, abs)
if err != nil {
continue
}
if rel == "." {
rel = ""
}
files[i] = "./" + rel
}
return
}
func filesToOptions(files []string) []Option {
options := make([]Option, len(files))
for i, f := range files {
options[i] = ArgFileName(f)
}
return options
}
// dirFromLast gives the directory of the current written
// last argument if it represents a file name being written.
// in case that it is not, we fall back to the current directory.
func dirFromLast(last string) string {
dir := filepath.Dir(last)
_, err := os.Stat(dir)
if err != nil {
return "./"
}
return dir
}