X fstail move pyquote out + test

t/neo/storage/fs1/cmd/fstail/fstail.go

@@ -28,72 +28,10 @@ import (
 	"io"
 	"log"
 	"os"
-	"strconv"
-	"strings"
-	"unicode/utf8"
 
 	"../../../../storage/fs1"
-
-	"lab.nexedi.com/kirr/go123/mem"
 )
 
-// pyQuote quotes string the way python repr(str) would do
-func pyQuote(s string) string {
-	out := pyQuoteBytes(mem.Bytes(s))
-	return mem.String(out)
-}
-
-func pyQuoteBytes(b []byte) []byte {
-	s := mem.String(b)
-	buf := make([]byte, 0, len(s))
-
-	// smartquotes: choose ' or " as quoting character
-	// https://github.com/python/cpython/blob/v2.7.13-116-g1aa1803b3d/Objects/stringobject.c#L947
-	quote := byte('\'')
-	noquote := byte('"')
-	if strings.ContainsRune(s, '\'') && !strings.ContainsRune(s, '"') {
-		quote, noquote = noquote, quote
-	}
-
-	buf = append(buf, quote)
-
-	for i, r := range s {
-		switch r {
-		case utf8.RuneError:
-			buf = append(buf, []byte(fmt.Sprintf("\\x%02x", s[i]))...)
-		case '\\', rune(quote):
-			buf = append(buf, '\\', byte(r))
-		case rune(noquote):
-			buf = append(buf, noquote)
-
-		// NOTE python converts to \<letter> only \t \n \r  (not e.g. \v)
-		// https://github.com/python/cpython/blob/v2.7.13-116-g1aa1803b3d/Objects/stringobject.c#L963
-		case '\t':
-			buf = append(buf, `\t`...)
-		case '\n':
-			buf = append(buf, `\n`...)
-		case '\r':
-			buf = append(buf, `\r`...)
-
-		default:
-			switch {
-			case r < ' ':
-				// we already converted to \<letter> what python represents as such above
-				buf = append(buf, []byte(fmt.Sprintf("\\x%02x", s[i]))...)
-
-			default:
-				// we already handled ', " and (< ' ') above, so now it
-				// should be safe to reuse strconv.QuoteRune
-				rq := strconv.QuoteRune(r)	// "'\x01'"
-				rq = rq[1:len(rq)-1]		//  "\x01"
-				buf = append(buf, rq...)
-			}
-		}
-	}
-
-	buf = append(buf, quote)
-	return buf
-}
 
 func fsTail(w io.Writer, path string, ntxn int) (err error) {
 	// path & fstail on error context

t/neo/storage/fs1/cmd/fstail/xstrconv.go

+// XXX move me out of here
+
+package main
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"unicode/utf8"
+
+	"lab.nexedi.com/kirr/go123/mem"
+)
+
+// pyQuote quotes string the way python repr(str) would do
+func pyQuote(s string) string {
+	out := pyQuoteBytes(mem.Bytes(s))
+	return mem.String(out)
+}
+
+func pyQuoteBytes(b []byte) []byte {
+	s := mem.String(b)
+	buf := make([]byte, 0, len(s))
+
+	// smartquotes: choose ' or " as quoting character
+	// https://github.com/python/cpython/blob/v2.7.13-116-g1aa1803b3d/Objects/stringobject.c#L947
+	quote := byte('\'')
+	noquote := byte('"')
+	if strings.ContainsRune(s, '\'') && !strings.ContainsRune(s, '"') {
+		quote, noquote = noquote, quote
+	}
+
+	buf = append(buf, quote)
+
+	for i, r := range s {
+		switch r {
+		case utf8.RuneError:
+			buf = append(buf, []byte(fmt.Sprintf("\\x%02x", s[i]))...)
+		case '\\', rune(quote):
+			buf = append(buf, '\\', byte(r))
+		case rune(noquote):
+			buf = append(buf, noquote)
+
+		// NOTE python converts to \<letter> only \t \n \r  (not e.g. \v)
+		// https://github.com/python/cpython/blob/v2.7.13-116-g1aa1803b3d/Objects/stringobject.c#L963
+		case '\t':
+			buf = append(buf, `\t`...)
+		case '\n':
+			buf = append(buf, `\n`...)
+		case '\r':
+			buf = append(buf, `\r`...)
+
+		default:
+			switch {
+			case r < ' ':
+				// we already converted to \<letter> what python represents as such above
+				buf = append(buf, []byte(fmt.Sprintf("\\x%02x", s[i]))...)
+
+			default:
+				// we already handled ', " and (< ' ') above, so now it
+				// should be safe to reuse strconv.QuoteRune
+				rq := strconv.QuoteRune(r)	// "'\x01'"
+				rq = rq[1:len(rq)-1]		//  "\x01"
+				buf = append(buf, rq...)
+			}
+		}
+	}
+
+	buf = append(buf, quote)
+	return buf
+}

t/neo/storage/fs1/cmd/fstail/xstrconv_test.go

+// XXX move me to common place
+
+package main
+
+import (
+	"testing"
+)
+
+// byterange returns []byte with element [start,stop)
+func byterange(start, stop byte) []byte {
+	b := make([]byte, 0, stop-start)
+	for ; start < stop; start++ {
+		b = append(b, start)
+	}
+	return b
+}
+
+func TestPyQuote(t *testing.T) {
+	// XXX -> global
+	testv := []struct {in, quoted string} {
+		// empty
+		{``, `''`},
+
+		// special characters
+		{string(byterange(0, 32)), `'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f'`},
+
+		// " vs '
+		{`hello world`, `'hello world'`},
+		{`hello ' world`, `"hello ' world"`},
+		{`hello ' " world`, `'hello \' " world'`},
+
+		// \
+		{`hello \ world`, `'hello \\ world'`},
+
+		// utf-8
+		// XXX python escapes non-ascii, but since FileStorage connot
+		// commit such strings we take the freedom and output them as
+		// readable
+		//{`привет мир`, `'\xd0\xbf\xd1\x80\xd0\xb8\xd0\xb2\xd0\xb5\xd1\x82 \xd0\xbc\xd0\xb8\xd1\x80'`},
+		{`привет мир`, `'привет мир'`},
+
+		// invalid utf-8
+		{"\xd0a", `'\xd0a'`},
+	}
+
+	for _, tt := range testv {
+		quoted := pyQuote(tt.in)
+		if quoted != tt.quoted {
+			t.Errorf("pyQuote(%q) -> %s  ; want %s", tt.in, quoted, tt.quoted)
+		}
+	}
+}