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package _select
import (
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"github.com/pkg/errors"
"github.com/MichaelMure/git-bug/cache"
"github.com/MichaelMure/git-bug/entity"
)
type ErrNoValidId struct {
typename string
}
func NewErrNoValidId(typename string) *ErrNoValidId {
return &ErrNoValidId{typename: typename}
}
func (e ErrNoValidId) Error() string {
return fmt.Sprintf("you must provide a %s id or use the \"select\" command first", e.typename)
}
func IsErrNoValidId(err error) bool {
_, ok := err.(*ErrNoValidId)
return ok
}
type Resolver[CacheT cache.CacheEntity] interface {
Resolve(id entity.Id) (CacheT, error)
ResolvePrefix(prefix string) (CacheT, error)
}
// Resolve first try to resolve an entity using the first argument of the command
// line. If it fails, it falls back to the select mechanism.
//
// Returns:
// - the entity if any
// - the new list of command line arguments with the entity prefix removed if it
// has been used
// - an error if the process failed
func Resolve[CacheT cache.CacheEntity](repo *cache.RepoCache,
typename string, namespace string, resolver Resolver[CacheT],
args []string) (CacheT, []string, error) {
// At first, try to use the first argument as an entity prefix
if len(args) > 0 {
cached, err := resolver.ResolvePrefix(args[0])
if err == nil {
return cached, args[1:], nil
}
if !entity.IsErrNotFound(err) {
return *new(CacheT), nil, err
}
}
// first arg is not a valid entity prefix, we can safely use the preselected entity if any
cached, err := selected(repo, resolver, namespace)
// selected entity is invalid
if entity.IsErrNotFound(err) {
// we clear the selected bug
err = Clear(repo, namespace)
if err != nil {
return *new(CacheT), nil, err
}
return *new(CacheT), nil, NewErrNoValidId(typename)
}
// another error when reading the entity
if err != nil {
return *new(CacheT), nil, err
}
// entity is successfully retrieved
if cached != nil {
return *cached, args, nil
}
// no selected bug and no valid first argument
return *new(CacheT), nil, NewErrNoValidId(typename)
}
func selectFileName(namespace string) string {
return filepath.Join("select", namespace)
}
// Select will select a bug for future use
func Select(repo *cache.RepoCache, namespace string, id entity.Id) error {
filename := selectFileName(namespace)
f, err := repo.LocalStorage().OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
if err != nil {
return err
}
_, err = f.Write([]byte(id.String()))
if err != nil {
return err
}
return f.Close()
}
// Clear will clear the selected entity, if any
func Clear(repo *cache.RepoCache, namespace string) error {
filename := selectFileName(namespace)
return repo.LocalStorage().Remove(filename)
}
func selected[CacheT cache.CacheEntity](repo *cache.RepoCache, resolver Resolver[CacheT], namespace string) (*CacheT, error) {
filename := selectFileName(namespace)
f, err := repo.LocalStorage().Open(filename)
if err != nil {
if os.IsNotExist(err) {
return nil, nil
} else {
return nil, err
}
}
buf, err := ioutil.ReadAll(io.LimitReader(f, 100))
if err != nil {
return nil, err
}
if len(buf) == 100 {
return nil, fmt.Errorf("the select file should be < 100 bytes")
}
id := entity.Id(buf)
if err := id.Validate(); err != nil {
err = repo.LocalStorage().Remove(filename)
if err != nil {
return nil, errors.Wrap(err, "error while removing invalid select file")
}
return nil, fmt.Errorf("select file in invalid, removing it")
}
cached, err := resolver.Resolve(id)
if err != nil {
return nil, err
}
err = f.Close()
if err != nil {
return nil, err
}
return &cached, nil
}
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