Fix paste for terminals ending with ESC-backslash instead of BEL, and add debug logging

3 files changed, 120 insertions, 38 deletions

diff --git a/go.mod b/go.mod
index 3e15e7b..340b5d1 100644
--- a/go.mod
+++ b/go.mod
@@ -10,6 +10,7 @@ require (
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
 	github.com/mattn/go-runewidth v0.0.14 // indirect
 	github.com/rivo/uniseg v0.4.3 // indirect
+	golang.org/x/exp v0.0.0-20230713183714-613f0c0eb8a1 // indirect
 	golang.org/x/term v0.5.0 // indirect
 	golang.org/x/text v0.7.0 // indirect
 )
diff --git a/go.sum b/go.sum
index 3ef6b84..9a8e104 100644
--- a/go.sum
+++ b/go.sum
@@ -12,6 +12,8 @@ github.com/rivo/uniseg v0.4.3/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUc
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/exp v0.0.0-20230713183714-613f0c0eb8a1 h1:MGwJjxBy0HJshjDNfLsYO8xppfqWlA5ZT9OhtUUhTNw=
+golang.org/x/exp v0.0.0-20230713183714-613f0c0eb8a1/go.mod h1:FXUEEKJgO7OQYeo8N01OfiKP8RXMtf6e8aTskBGqWdc=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
diff --git a/main.go b/main.go
index 2afae80..8a0b1c1 100644
--- a/main.go
+++ b/main.go
@@ -6,6 +6,7 @@ import (
 	"flag"
 	"fmt"
 	"github.com/gdamore/tcell/v2"
+	"golang.org/x/exp/slog"
 	"io"
 	"log"
 	"os"
@@ -47,28 +48,63 @@ func closetty(tty tcell.Tty) {
 
 func main() {
 	var fnames []string
+	var err error
 
 	flag.Usage = func() {
-		template := `Usage:
-%s [file1 [...fileN]]
-Copies file contents to system clipboard using the ANSI OSC52 escape sequence.
+		template := `Reads or writes the system clipboard using the ANSI OSC52 escape sequence.
+
+Usage:
+
+COPY mode (default):
+
+    %s [file1 [...fileN]]
+
 With no arguments, will read from stdin.
+
+PASTE mode:
+
+    %s --paste
+
+Outputs clipboard contents to stdout.
+
+Options:
 `
-		fmt.Fprintf(flag.CommandLine.Output(), template, os.Args[0])
+		fmt.Fprintf(flag.CommandLine.Output(), template, os.Args[0], os.Args[0])
+		flag.PrintDefaults()
 	}
 
-	pasteFlag := flag.Bool("paste", false, "paste operation")
+	var pasteFlag bool
+	var verboseFlag bool
+	var logfileFlag string
+	flag.BoolVar(&pasteFlag, "paste", pasteFlag, "paste operation")
+	flag.BoolVar(&verboseFlag, "verbose", verboseFlag, "verbose logging")
+	flag.BoolVar(&verboseFlag, "v", verboseFlag, "verbose logging")
+	flag.StringVar(&logfileFlag, "logFile", logfileFlag, "redirect logs to file")
 
 	flag.Parse()
 
-	tty, err := opentty()
-	if err != nil {
-		fmt.Fprintln(os.Stderr, "ERROR: opentty:", err)
-		return
+	logLevel := &slog.LevelVar{} // INFO
+	logOutput := os.Stdout
+
+	if logfileFlag != "" {
+		if logOutput, err = os.OpenFile(logfileFlag, os.O_APPEND|os.O_RDWR|os.O_CREATE, 0644); err != nil {
+			log.Fatalf("Failed to open file %v: %v", logfileFlag, err)
+		} else {
+			defer logOutput.Close()
+		}
 	}
-	defer closetty(tty)
 
-	if !*pasteFlag {
+	if verboseFlag {
+		logLevel.Set(slog.LevelDebug)
+	}
+
+	logger := slog.New(slog.NewTextHandler(logOutput, &slog.HandlerOptions{
+		Level: logLevel,
+	}))
+	slog.SetDefault(logger)
+	slog.Debug("logging started")
+
+	if !pasteFlag {
 		// copy
 		if len(flag.Args()) > 0 {
 			fnames = flag.Args()
@@ -76,11 +112,19 @@ With no arguments, will read from stdin.
 			fnames = []string{"-"}
 		}
 
+		tty, err := opentty()
+		if err != nil {
+			slog.Error("ERROR: opentty:", err)
+			return
+		}
+		defer closetty(tty)
+
 		// Open buffered output, using default max OSC52 length as buffer size
 		// TODO limit size
 		out := bufio.NewWriterSize(tty, 1000000)
 
 		// Start OSC52
+		slog.Debug("Beginning osc52 copy operation")
 		fmt.Fprintf(out, "\033]52;c;")
 
 		b64 := base64.NewEncoder(base64.StdEncoding, out)
@@ -93,36 +137,71 @@ With no arguments, will read from stdin.
 		fmt.Fprintf(out, "\a")
 
 		out.Flush()
+		slog.Debug("Ended osc52")
 	} else {
 		// paste
 
-		// Start OSC52
-		fmt.Fprintf(tty, "\033]52;c;?\a")
-
-		ttyReader := bufio.NewReader(tty)
-
-		buf, err := ttyReader.ReadBytes('\a')
-		if err != nil {
-			fmt.Fprintln(os.Stderr, "Read error:", err)
-			return
-		}
-
-		// fmt.Fprintf(os.Stderr, "Read %d bytes, %x\n", len(buf), buf)
-		// fmt.Fprintf(os.Stderr, "buf[:7]: %q\n", buf[:7])
-		// fmt.Fprintf(os.Stderr, "buf[len(buf)-1]: %q\n", buf[len(buf)-1])
-		// fmt.Fprintf(os.Stderr, "%x\n", buf)
-		buf = buf[7 : len(buf)-1]
-		// fmt.Fprintf(os.Stderr, "%x\n", buf)
-
-		dst := make([]byte, base64.StdEncoding.DecodedLen(len(buf)))
-		n, err := base64.StdEncoding.Decode(dst, []byte(buf))
-		if err != nil {
-			fmt.Fprintln(os.Stderr, "decode error:", err)
-			return
-		}
-		dst = dst[:n]
-		if _, err := os.Stdout.Write(dst); err != nil {
-			fmt.Fprintln(os.Stderr, "Error writing to stdout:", err)
+		data := func() []byte {
+
+			tty, err := opentty()
+			if err != nil {
+				slog.Error("ERROR: opentty:", err)
+				return nil
+			}
+			defer closetty(tty)
+
+			// Start OSC52
+			slog.Debug("Beginning osc52 paste operation")
+			fmt.Fprintf(tty, "\033]52;c;?\a")
+
+			ttyReader := bufio.NewReader(tty)
+			buf := make([]byte, 0, 1024)
+			for {
+				if b, err := ttyReader.ReadByte(); err != nil {
+					slog.Error("ReadByte error:", err)
+					return nil
+				} else {
+					slog.Debug(fmt.Sprintf("Read: %x '%s'", b, string(b)))
+					if b == '\a' {
+						break
+					}
+					buf = append(buf, b)
+					if len(buf) > 2 && buf[len(buf)-2] == '\033' && buf[len(buf)-1] == '\\' {
+						buf = buf[:len(buf)-2]
+						break
+					}
+				}
+			}
+
+			// buf, err := ttyReader.ReadBytes('\a')
+			// if err != nil {
+			// 	slog.Error("Read error:", err)
+			// 	return nil
+			// }
+
+			// slog.Debug("Read %d bytes, %x\n", len(buf), buf)
+			// fmt.Fprintf(os.Stderr, "buf[:7]: %q\n", buf[:7])
+			// fmt.Fprintf(os.Stderr, "buf[len(buf)-1]: %q\n", buf[len(buf)-1])
+			// fmt.Fprintf(os.Stderr, "%x\n", buf)
+			buf = buf[7:]
+			// fmt.Fprintf(os.Stderr, "%x\n", buf)
+
+			dst := make([]byte, base64.StdEncoding.DecodedLen(len(buf)))
+			n, err := base64.StdEncoding.Decode(dst, []byte(buf))
+			if err != nil {
+				slog.Error("decode error:", err)
+				return nil
+			}
+			dst = dst[:n]
+
+			return dst
+		}()
+
+		if data != nil {
+			if _, err := os.Stdout.Write(data); err != nil {
+				slog.Error("Error writing to stdout:", err)
+			}
 		}
+		slog.Debug("Ended osc52")
 	}
 }