krino: foundation — sexp reader, config language, init/new/check

1 files changed, 93 insertions, 0 deletions

diff --git a/internal/config/load.go b/internal/config/load.go
new file mode 100644
index 0000000..f6eaeae
--- /dev/null
+++ b/internal/config/load.go
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package config
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+
+	"krino/internal/sexp"
+	"krino/internal/xdg"
+)
+
+// Config is the whole configuration: the main file and the directories it
+// includes.
+type Config struct {
+	Main *Main
+	Dirs []*Dir
+}
+
+// DefaultFile is krino.conf in the XDG config directory.
+func DefaultFile() string {
+	return filepath.Join(xdg.ConfigHome(), "krino", "krino.conf")
+}
+
+// DirFile is where directory name's config lives, beside the main file.
+func DirFile(mainFile, name string) string {
+	return filepath.Join(filepath.Dir(mainFile), "dirs", name+".conf")
+}
+
+// Load reads the main file and the files of the directories it includes.
+// With names, only those directories are read, and each must be included.
+// The Config is nil only when the main file itself cannot be read.
+func Load(mainFile string, names ...string) (*Config, []*Diag) {
+	src, err := os.ReadFile(mainFile)
+	if errors.Is(err, fs.ErrNotExist) {
+		return nil, []*Diag{{File: mainFile, Msg: "not found; create it with: krino init"}}
+	}
+	if err != nil {
+		return nil, []*Diag{{File: mainFile, Msg: err.Error()}}
+	}
+	m, errs := ParseMain(mainFile, src)
+	cfg := &Config{Main: m}
+	if _, perr := sexp.Parse(mainFile, src); perr != nil {
+		// krino.conf itself is unreadable: report just that, and load none
+		// of the directories, so a syntax error never also produces
+		// "NAME is not in include" for names the caller asked for.
+		return cfg, errs
+	}
+	want := m.Include
+	if len(names) > 0 {
+		want = nil
+		for _, n := range names {
+			if _, ok := m.IncludePos[n]; !ok {
+				errs = append(errs, &Diag{File: mainFile, Msg: fmt.Sprintf("%q is not in include", n)})
+				continue
+			}
+			want = append(want, n)
+		}
+	}
+	for _, name := range want {
+		file := DirFile(mainFile, name)
+		src, err := os.ReadFile(file)
+		if err != nil {
+			msg := err.Error()
+			if errors.Is(err, fs.ErrNotExist) {
+				msg = fmt.Sprintf("included %q, but %s does not exist; create it with: krino new %s PATH", name, file, name)
+			}
+			errs = append(errs, &Diag{File: mainFile, Pos: m.IncludePos[name], Msg: msg})
+			continue
+		}
+		dir, derrs := ParseDir(name, file, src)
+		errs = append(errs, derrs...)
+		cfg.Dirs = append(cfg.Dirs, dir)
+	}
+	return cfg, errs
+}
+
+// Resolved is the settings that apply in dir: built-in, then the main
+// file's defaults, then the directory's own.
+func (c *Config) Resolved(dir *Dir) Resolved {
+	return dir.Settings.Over(c.Main.Defaults.Over(Builtin()))
+}
+
+// LogFile is the main file's (log ...), or the default under XDG_STATE_HOME.
+func (c *Config) LogFile() string {
+	if c.Main.Log != "" {
+		return c.Main.Log
+	}
+	return filepath.Join(xdg.StateHome(), "krino", "krino.log")
+}