wip: support reading paths from stdin

Signed-off-by: Brian McGee <brian@bmcgee.ie>

internal/cli/format.go

@@ -1,6 +1,7 @@
 package cli
 
 import (
+	"bufio"
 	"context"
 	"errors"
 	"fmt"
@@ -236,20 +237,29 @@ func (f *Format) Run() error {
 	})
 
 	eg.Go(func() (err error) {
-		var walker walk.Walker
-
-		if Cli.Stdin {
-			walker, err = walk.NewPathReader(os.Stdin)
-		} else if len(Cli.Paths) > 0 {
-			walker, err = walk.NewPathList(Cli.Paths)
-		} else {
-			walker, err = walk.New(Cli.Walk, Cli.TreeRoot)
-		}
 
+		walker, err := walk.New(Cli.Walk, Cli.TreeRoot)
 		if err != nil {
 			return fmt.Errorf("%w: failed to create walker", err)
 		}
 
+		paths := Cli.Paths
+
+		if len(paths) == 0 && Cli.Stdin {
+			// read in all the paths
+			scanner := bufio.NewScanner(os.Stdin)
+			for scanner.Scan() {
+				paths = append(paths, scanner.Text())
+			}
+		}
+
+		if len(paths) > 0 {
+			walker, err = walk.NewSelector(Cli.TreeRoot, paths, walker)
+			if err != nil {
+				return fmt.Errorf("%w: failed to create selector", err)
+			}
+		}
+
 		defer close(pathsCh)
 		return cache.ChangeSet(ctx, walker, pathsCh)
 	})

internal/walk/selector.go

@@ -0,0 +1,59 @@
+package walk
+
+import (
+	"context"
+	"fmt"
+	"git.numtide.com/numtide/treefmt/internal/format"
+	"github.com/gobwas/glob"
+	"io/fs"
+	"os"
+	"path"
+	"path/filepath"
+)
+
+type selector struct {
+	root     string
+	globs    []glob.Glob
+	delegate Walker
+}
+
+func (s selector) Root() string {
+	return s.root
+}
+
+func (s selector) Walk(ctx context.Context, fn filepath.WalkFunc) error {
+	return s.delegate.Walk(ctx, func(path string, info fs.FileInfo, err error) error {
+		for _, g := range s.globs {
+			if !g.Match(path) {
+				continue
+			}
+			return fn(path, info, err)
+		}
+		return nil
+	})
+}
+
+func NewSelector(root string, paths []string, delegate Walker) (Walker, error) {
+	var fullPaths []string
+	for _, p := range paths {
+		info, err := os.Lstat(p)
+		if err != nil {
+			return nil, fmt.Errorf("%w: failed to lstat %v", err, p)
+		}
+
+		if info.Mode()&os.ModeSymlink == os.ModeSymlink {
+			return nil, fmt.Errorf("%v is a symlink which is not supported", p)
+		} else if info.IsDir() {
+			p = path.Join(p, "/*")
+		}
+
+		fullPaths = append(fullPaths, p)
+	}
+
+	globs, err := format.CompileGlobs(fullPaths)
+	if err != nil {
+		return nil, err
+	}
+
+	return &selector{root, globs, delegate}, nil
+}