Merge pull request #82 from github/table-output

Extract generic row printer that adjusts itself for receiving terminal

command/pr.go

@@ -10,7 +10,6 @@ import (
 	"github.com/github/gh-cli/git"
 	"github.com/github/gh-cli/utils"
 	"github.com/spf13/cobra"
-	"golang.org/x/crypto/ssh/terminal"
 )
 
 func init() {
@@ -167,57 +166,38 @@ func prList(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
-	tty := false
-	ttyWidth := 80
-	out := cmd.OutOrStdout()
-	if outFile, isFile := out.(*os.File); isFile {
-		fd := int(outFile.Fd())
-		tty = terminal.IsTerminal(fd)
-		if w, _, err := terminal.GetSize(fd); err == nil {
-			ttyWidth = w
-		}
-	}
-
-	numWidth := 0
-	maxTitleWidth := 0
+	table := utils.NewTablePrinter(cmd.OutOrStdout())
 	for _, pr := range prs {
-		numLen := len(strconv.Itoa(pr.Number)) + 1
-		if numLen > numWidth {
-			numWidth = numLen
-		}
-		if len(pr.Title) > maxTitleWidth {
-			maxTitleWidth = len(pr.Title)
+		prNum := strconv.Itoa(pr.Number)
+		if table.IsTTY() {
+			prNum = "#" + prNum
 		}
+		table.AddField(prNum, nil, colorFuncForState(pr.State))
+		table.AddField(pr.Title, nil, nil)
+		table.AddField(pr.HeadLabel(), nil, utils.Cyan)
+		table.EndRow()
+	}
+	err = table.Render()
+	if err != nil {
+		return err
 	}
 
-	branchWidth := 40
-	titleWidth := ttyWidth - branchWidth - 2 - numWidth - 2
-
-	if maxTitleWidth < titleWidth {
-		branchWidth += titleWidth - maxTitleWidth
-		titleWidth = maxTitleWidth
-	}
-
-	for _, pr := range prs {
-		if tty {
-			prNum := fmt.Sprintf("% *s", numWidth, fmt.Sprintf("#%d", pr.Number))
-			switch pr.State {
-			case "OPEN":
-				prNum = utils.Green(prNum)
-			case "CLOSED":
-				prNum = utils.Red(prNum)
-			case "MERGED":
-				prNum = utils.Magenta(prNum)
-			}
-			prBranch := utils.Cyan(truncate(branchWidth, pr.HeadLabel()))
-			fmt.Fprintf(out, "%s  %-*s  %s\n", prNum, titleWidth, truncate(titleWidth, pr.Title), prBranch)
-		} else {
-			fmt.Fprintf(out, "%d\t%s\t%s\n", pr.Number, pr.Title, pr.HeadLabel())
-		}
-	}
 	return nil
 }
 
+func colorFuncForState(state string) func(string) string {
+	switch state {
+	case "OPEN":
+		return utils.Green
+	case "CLOSED":
+		return utils.Red
+	case "MERGED":
+		return utils.Magenta
+	default:
+		return nil
+	}
+}
+
 func prView(cmd *cobra.Command, args []string) error {
 	ctx := contextForCommand(cmd)
 	baseRepo, err := ctx.BaseRepo()

utils/table_printer.go

@@ -0,0 +1,170 @@
+package utils
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"golang.org/x/crypto/ssh/terminal"
+)
+
+type TablePrinter interface {
+	IsTTY() bool
+	AddField(string, func(int, string) string, func(string) string)
+	EndRow()
+	Render() error
+}
+
+func NewTablePrinter(w io.Writer) TablePrinter {
+	if outFile, isFile := w.(*os.File); isFile {
+		fd := int(outFile.Fd())
+		if terminal.IsTerminal(fd) {
+			ttyWidth := 80
+			if w, _, err := terminal.GetSize(fd); err == nil {
+				ttyWidth = w
+			}
+			return &ttyTablePrinter{
+				out:      w,
+				maxWidth: ttyWidth,
+			}
+		}
+	}
+	return &tsvTablePrinter{
+		out: w,
+	}
+}
+
+type tableField struct {
+	Text         string
+	TruncateFunc func(int, string) string
+	ColorFunc    func(string) string
+}
+
+type ttyTablePrinter struct {
+	out      io.Writer
+	maxWidth int
+	rows     [][]tableField
+}
+
+func (t ttyTablePrinter) IsTTY() bool {
+	return true
+}
+
+func (t *ttyTablePrinter) AddField(text string, truncateFunc func(int, string) string, colorFunc func(string) string) {
+	if truncateFunc == nil {
+		truncateFunc = truncate
+	}
+	if t.rows == nil {
+		t.rows = [][]tableField{[]tableField{}}
+	}
+	rowI := len(t.rows) - 1
+	field := tableField{
+		Text:         text,
+		TruncateFunc: truncateFunc,
+		ColorFunc:    colorFunc,
+	}
+	t.rows[rowI] = append(t.rows[rowI], field)
+}
+
+func (t *ttyTablePrinter) EndRow() {
+	t.rows = append(t.rows, []tableField{})
+}
+
+func (t *ttyTablePrinter) Render() error {
+	if len(t.rows) == 0 {
+		return nil
+	}
+
+	numCols := len(t.rows[0])
+	colWidths := make([]int, numCols)
+	// measure maximum content width per column
+	for _, row := range t.rows {
+		for col, field := range row {
+			textLen := len(field.Text)
+			if textLen > colWidths[col] {
+				colWidths[col] = textLen
+			}
+		}
+	}
+
+	delim := "  "
+	availWidth := t.maxWidth - colWidths[0] - ((numCols - 1) * len(delim))
+	// add extra space from columns that are already narrower than threshold
+	for col := 1; col < numCols; col++ {
+		availColWidth := availWidth / (numCols - 1)
+		if extra := availColWidth - colWidths[col]; extra > 0 {
+			availWidth += extra
+		}
+	}
+	// cap all but first column to fit available terminal width
+	// TODO: support weighted instead of even redistribution
+	for col := 1; col < numCols; col++ {
+		availColWidth := availWidth / (numCols - 1)
+		if colWidths[col] > availColWidth {
+			colWidths[col] = availColWidth
+		}
+	}
+
+	for _, row := range t.rows {
+		for col, field := range row {
+			if col > 0 {
+				_, err := fmt.Fprint(t.out, delim)
+				if err != nil {
+					return err
+				}
+			}
+			truncVal := field.TruncateFunc(colWidths[col], field.Text)
+			if col < numCols-1 {
+				// pad value with spaces on the right
+				truncVal = fmt.Sprintf("%-*s", colWidths[col], truncVal)
+			}
+			if field.ColorFunc != nil {
+				truncVal = field.ColorFunc(truncVal)
+			}
+			_, err := fmt.Fprint(t.out, truncVal)
+			if err != nil {
+				return err
+			}
+		}
+		if len(row) > 0 {
+			_, err := fmt.Fprint(t.out, "\n")
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+type tsvTablePrinter struct {
+	out        io.Writer
+	currentCol int
+}
+
+func (t tsvTablePrinter) IsTTY() bool {
+	return false
+}
+
+func (t *tsvTablePrinter) AddField(text string, _ func(int, string) string, _ func(string) string) {
+	if t.currentCol > 0 {
+		fmt.Fprint(t.out, "\t")
+	}
+	fmt.Fprint(t.out, text)
+	t.currentCol++
+}
+
+func (t *tsvTablePrinter) EndRow() {
+	fmt.Fprint(t.out, "\n")
+	t.currentCol = 0
+}
+
+func (t *tsvTablePrinter) Render() error {
+	return nil
+}
+
+func truncate(maxLength int, title string) string {
+	if len(title) > maxLength {
+		return title[0:maxLength-3] + "..."
+	}
+	return title
+}