open files plz

bzip.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"compress/bzip2"
+	"io"
+)
+
+// bzipCloser wraps an io.ReadCloser in a bzip reader, while allowing a caller
+// to close the underlying source
+type bzipCloser struct {
+	reader io.Reader
+	source io.ReadCloser
+}
+
+func newBzipCloser(r io.ReadCloser) io.ReadCloser {
+	return &bzipCloser{reader: bzip2.NewReader(r), source: r}
+}
+
+func (b *bzipCloser) Read(p []byte) (int, error) { return b.reader.Read(p) }
+
+func (b *bzipCloser) Close() error { return b.source.Close() }

main.go

@@ -1,9 +1,64 @@
 package main
 
 import (
+	"flag"
 	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
 )
 
+func ensureNewline(t string) string {
+	if strings.HasSuffix(t, "\n") {
+		return t
+	}
+	return t + "\n"
+}
+
+func usage(t string, args ...interface{}) {
+	t = ensureNewline(t) + "\n"
+	fmt.Fprintf(os.Stderr, t, args...)
+	fmt.Fprintln(os.Stderr, "Usage:")
+	fmt.Fprintln(os.Stderr, "\thyperstone replay-id")
+	os.Exit(1)
+}
+
+func bail(status int, t string, args ...interface{}) {
+	var out io.Writer
+	if status == 0 {
+		out = os.Stdout
+	} else {
+		out = os.Stderr
+	}
+
+	fmt.Fprintf(out, ensureNewline(t), args...)
+	os.Exit(status)
+}
+
+func openReplayFile(path string) (io.ReadCloser, error) {
+	fi, err := os.Open(path)
+	if err != nil {
+		return nil, fmt.Errorf("unable to open replay file: %v", err)
+	}
+
+	switch filepath.Ext(path) {
+	case ".bz2":
+		return newBzipCloser(fi), nil
+	default:
+		return fi, nil
+	}
+	return nil, io.EOF
+}
+
 func main() {
-	fmt.Println("hi")
+	flag.Parse()
+	if flag.NArg() != 1 {
+		usage("please supply the path to a valid replay file")
+	}
+	f, err := openReplayFile(flag.Arg(0))
+	if err != nil {
+		bail(1, "unable to open replay file: %v", err)
+	}
+	defer f.Close()
 }