chore: initial commit

versions.go

@@ -0,0 +1,101 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+)
+
+type emacsVersions []*emacsVersion
+
+func newEmacsVersions(conf *config) (emacsVersions, error) {
+	results := emacsVersions{}
+
+	entries, err := os.ReadDir(conf.Path.Versions)
+	if err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return nil, err
+	}
+
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+
+		vi, err := newEmacsVersion(conf, entry.Name())
+		if err != nil {
+			return nil, err
+		}
+
+		results = append(results, vi)
+	}
+
+	return results, nil
+}
+
+type emacsVersion struct {
+	Version  string   `yaml:"version" json:"version"`
+	Current  bool     `yaml:"current" json:"current"`
+	Path     string   `yaml:"path" json:"path"`
+	Bin      string   `yaml:"bin" json:"bin"`
+	Binaries []string `yaml:"binaries" json:"binaries"`
+}
+
+func (ev *emacsVersion) BinPath(name string) (string, bool) {
+	for _, b := range ev.Binaries {
+		if filepath.Base(b) == name {
+			return filepath.Join(ev.Bin, b), true
+		}
+	}
+
+	return "", false
+}
+
+func newEmacsVersion(conf *config, version string) (*emacsVersion, error) {
+	path := filepath.Join(conf.Path.Versions, version)
+
+	_, err := os.Stat(path)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"Version %s is not available in %s",
+			version, conf.Path.Versions,
+		)
+	}
+
+	ev := &emacsVersion{
+		Version: version,
+		Path:    path,
+		Bin:     filepath.Join(path, "bin"),
+		Current: version == conf.Current.Version,
+	}
+
+	entries, err := os.ReadDir(ev.Bin)
+	if err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return nil, err
+	}
+
+	for _, entry := range entries {
+		binPath := filepath.Join(ev.Bin, entry.Name())
+
+		f, err := os.Stat(binPath)
+		if err != nil {
+			if errors.Is(err, fs.ErrNotExist) {
+				continue
+			}
+			return nil, err
+		}
+
+		relPath, err := filepath.Rel(ev.Bin, binPath)
+		if err != nil {
+			return nil, err
+		}
+
+		// Regular and executable file.
+		if f.Mode().IsRegular() && f.Mode().Perm()&0111 == 0111 {
+			ev.Binaries = append(ev.Binaries, relPath)
+		}
+	}
+
+	return ev, nil
+}