forward iteration

lsm2/cli/main.go

@@ -0,0 +1,85 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"iter"
+	"os"
+	"path/filepath"
+
+	"github.com/docopt/docopt-go"
+	"go.sour.is/pkg/lsm2"
+)
+
+var usage = `
+Usage: lsm2 create <archive> <files>...`
+
+type args struct {
+	Create  bool
+	Archive string   `docopt:"<archive>"`
+	Files   []string `docopt:"<files>"`
+}
+
+func main() {
+	opts, err := docopt.ParseDoc(usage)
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	fmt.Println(opts, must(opts.Bool("create")))
+	console := console{os.Stdin, os.Stdout, os.Stderr}
+	args := args{}
+	err = opts.Bind(&args)
+	fmt.Println(err)
+	run(console, args)
+}
+
+type console struct {
+	Stdin  io.Reader
+	Stdout io.Writer
+	Stderr io.Writer
+}
+
+func (c console) Write(b []byte) (int, error) {
+	return c.Stdout.Write(b)
+}
+
+func run(console console, args args) error {
+	switch {
+	case args.Create:
+		fmt.Fprintf(console, "creating %s from %v\n", filepath.Base(args.Archive), args.Files)
+		out, err := os.OpenFile(args.Archive, os.O_CREATE|os.O_WRONLY, 0644)
+		if err != nil {
+			return err
+		}
+		defer out.Close()
+
+		filesWritten := 0
+		defer func() { fmt.Fprintln(console, "wrote", filesWritten, "files") }()
+
+		return lsm2.WriteIter(out, iter.Seq[io.Reader](func(yield func(io.Reader) bool) {
+			for _, name := range args.Files {
+				f, err := os.Open(name)
+				if err != nil {
+					continue
+				}
+				filesWritten++
+				if !yield(f) {
+					f.Close()
+					return
+				}
+				f.Close()
+			}
+		}))
+	default:
+		return errors.New("unknown command")
+	}
+}
+
+func must[T any](v T, err error) T {
+	if err != nil {
+		panic(err)
+	}
+	return v
+}

lsm2/cli/main_test.go

@@ -0,0 +1,104 @@
+package main
+
+import (
+	"bytes"
+	"os"
+	"testing"
+)
+
+func TestCreate(t *testing.T) {
+	tests := []struct {
+		name       string
+		args       args
+		wantErr    bool
+		wantOutput string
+	}{
+		{
+			name: "no input files",
+			args: args{
+				Create:  true,
+				Archive: "test.txt",
+				Files:   []string{},
+			},
+			wantErr:    false,
+			wantOutput: "creating test.txt from []\nwrote 0 files\n",
+		},
+		{
+			name: "one input file",
+			args: args{
+				Create:  true,
+				Archive: "test.txt",
+				Files:   []string{"test_input.txt"},
+			},
+			wantErr:    false,
+			wantOutput: "creating test.txt from [test_input.txt]\nwrote 1 files\n",
+		},
+		{
+			name: "multiple input files",
+			args: args{
+				Create:  true,
+				Archive: "test.txt",
+				Files:   []string{"test_input1.txt", "test_input2.txt"},
+			},
+			wantErr:    false,
+			wantOutput: "creating test.txt from [test_input1.txt test_input2.txt]\nwrote 2 files\n",
+		},
+		{
+			name: "non-existent input files",
+			args: args{
+				Create:  true,
+				Archive: "test.txt",
+				Files:   []string{"non_existent_file.txt"},
+			}, wantErr: false,
+			wantOutput: "creating test.txt from [non_existent_file.txt]\nwrote 0 files\n",
+		},
+		{
+			name: "invalid command",
+			args: args{
+				Create:  false,
+				Archive: "test.txt",
+				Files:   []string{},
+			},
+			wantErr:    true,
+			wantOutput: "",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			// Create a temporary directory for the input files
+			tmpDir, err := os.MkdirTemp("", "lsm2-cli-test")
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer os.RemoveAll(tmpDir)
+			os.Chdir(tmpDir)
+
+			// Create the input files
+			for _, file := range tc.args.Files {
+				if file == "non_existent_file.txt" {
+					continue
+				}
+				if err := os.WriteFile(file, []byte(file), 0o644); err != nil {
+					t.Fatal(err)
+				}
+			}
+
+			// Create a buffer to capture the output
+			var output bytes.Buffer
+
+			// Call the create function
+			err = run(console{Stdout: &output}, tc.args)
+
+			// Check the output
+			if output.String() != tc.wantOutput {
+				t.Errorf("run() output = %q, want %q", output.String(), tc.wantOutput)
+			}
+
+			// Check for errors
+			if tc.wantErr && err == nil {
+				t.Errorf("run() did not return an error")
+			}
+		})
+	}
+}