rearrange, rename, refactor

check.go

@@ -15,78 +15,38 @@ import (
 	"sync"
 )
 
-type checksum struct {
-	filename string
-	hash     hash.Hash
-	checksum string
-}
-
-func parseCS(line string) (checksum, error) {
-	elems := strings.Fields(line)
-	if len(elems) != 2 {
-		return checksum{}, fmt.Errorf("unexpected content: %d != 2", len(elems))
-	}
-	cs, f := elems[0], elems[1]
-	var hsh hash.Hash
-	switch len(cs) {
-	case 32:
-		hsh = md5.New()
-	case 40:
-		hsh = sha1.New()
-	case 64:
-		hsh = sha256.New()
-	case 128:
-		hsh = sha512.New()
-	default:
-		return checksum{}, fmt.Errorf("unknown format: %q", line)
-	}
-	return checksum{filename: f, hash: hsh, checksum: cs}, nil
-}
-
+// input contains a file-ish piece of work to perform
 type input struct {
 	f   io.ReadCloser
 	err error
 }
 
-type work struct {
-	cs  checksum
-	err error
+// checksum contains the path to a file, a way to hash it, and the results of
+// the hash
+type checksum struct {
+	filename string
+	hash     hash.Hash
+	checksum string
+	err      error
 }
 
-func streams(files []string) chan input {
-	r := make(chan input)
+// check is the entry point for -c operation.
+func check(args []string) chan error {
+	jobs := make(chan checksum)
 
 	go func() {
-		for _, name := range files {
-			f, err := os.Open(name)
-			r <- input{f, err}
-		}
-		if len(files) == 0 {
-			r <- input{f: os.Stdin}
-		}
-		close(r)
-	}()
-
-	return r
-}
-
-func check(files []string) chan error {
-	jobs := make(chan work)
-
-	go func() {
-		for stream := range streams(files) {
-			if stream.err != nil {
-				jobs <- work{err: stream.err}
+		for i := range toInput(args) {
+			if i.err != nil {
+				jobs <- checksum{err: i.err}
 				break
 			}
-			s := bufio.NewScanner(stream.f)
+			s := bufio.NewScanner(i.f)
 			for s.Scan() {
-				cs, err := parseCS(s.Text())
-				jobs <- work{cs, err}
+				jobs <- parseCS(s.Text())
 			}
-			stream.f.Close()
+			i.f.Close()
 			if s.Err() != nil {
-				jobs <- work{err: s.Err()}
+				jobs <- checksum{err: s.Err()}
 			}
 		}
 		close(jobs)
@@ -101,6 +61,77 @@ func check(files []string) chan error {
 	return merge(results)
 }
 
+// toInput converts args to a stream of input
+func toInput(args []string) chan input {
+	r := make(chan input)
+
+	go func() {
+		for _, name := range args {
+			f, err := os.Open(name)
+			r <- input{f, err}
+		}
+		if len(args) == 0 {
+			r <- input{f: os.Stdin}
+		}
+		close(r)
+	}()
+
+	return r
+}
+
+// parseCS picks apart a line from a checksum file and returns everything
+// needed to perform a checksum.
+func parseCS(line string) checksum {
+	elems := strings.Fields(line)
+	if len(elems) != 2 {
+		return checksum{err: fmt.Errorf("unexpected content: %d != 2", len(elems))}
+	}
+	cs, f := elems[0], elems[1]
+	var hsh hash.Hash
+	switch len(cs) {
+	case 32:
+		hsh = md5.New()
+	case 40:
+		hsh = sha1.New()
+	case 64:
+		hsh = sha256.New()
+	case 128:
+		hsh = sha512.New()
+	default:
+		return checksum{err: fmt.Errorf("unknown format: %q", line)}
+	}
+	return checksum{filename: f, hash: hsh, checksum: cs}
+}
+
+// verify does grunt work of verifying a stream of jobs (filenames).
+func verify(jobs chan checksum) chan error {
+	r := make(chan error)
+	go func() {
+		for job := range jobs {
+			if job.err != nil {
+				log.Printf("%+v", job.err)
+				continue
+			}
+			f, err := os.Open(job.filename)
+			if err != nil {
+				r <- err
+				continue
+			}
+			if _, err := io.Copy(job.hash, f); err != nil {
+				r <- err
+				continue
+			}
+			f.Close()
+			if fmt.Sprintf("%x", job.hash.Sum(nil)) != job.checksum {
+				r <- fmt.Errorf("%s: bad", job.filename)
+			}
+		}
+		close(r)
+	}()
+	return r
+}
+
+// merge is simple error fan-in
 func merge(cs []<-chan error) chan error {
 	out := make(chan error)
 
@@ -124,30 +155,3 @@ func merge(cs []<-chan error) chan error {
 	}()
 	return out
 }
-
-func verify(jobs chan work) chan error {
-	r := make(chan error)
-	go func() {
-		for job := range jobs {
-			if job.err != nil {
-				log.Printf("%+v", job.err)
-				continue
-			}
-			f, err := os.Open(job.cs.filename)
-			if err != nil {
-				r <- fmt.Errorf("open: %v", err)
-				continue
-			}
-			if _, err := io.Copy(job.cs.hash, f); err != nil {
-				r <- err
-				continue
-			}
-			f.Close()
-			if fmt.Sprintf("%x", job.cs.hash.Sum(nil)) != job.cs.checksum {
-				r <- fmt.Errorf("%s: bad", job.cs.filename)
-			}
-		}
-		close(r)
-	}()
-	return r
-}