cmd/pprof: don't print binary outputs in interactive mode

Some commands generate binary outputs which are not human readable.
In interactive mode, there are no use-cases for such outputs.
Instead, the new code writes it to the temporary file on the $CWD and
shows the file name. So the user can use any program to display the
file outside interactive shell.

Fixes #17465

Change-Id: I5c479db26017607f7a28eafbff2385533e5c584e
Reviewed-on: https://go-review.googlesource.com/31123Reviewed-by: Russ Cox <rsc@golang.org>

src/cmd/pprof/internal/commands/commands.go

@@ -58,26 +58,26 @@ func PProf(c Completer, interactive **bool) Commands {
 		"peek":   {c, report.Tree, nil, true, "Output callers/callees of functions matching regexp"},
 
 		// Save binary formats to a file
-		"callgrind": {c, report.Callgrind, awayFromTTY("callgraph.out"), false, "Outputs a graph in callgrind format"},
-		"proto":     {c, report.Proto, awayFromTTY("pb.gz"), false, "Outputs the profile in compressed protobuf format"},
+		"callgrind": {c, report.Callgrind, awayFromTTY(interactive, "callgraph.out"), false, "Outputs a graph in callgrind format"},
+		"proto":     {c, report.Proto, awayFromTTY(interactive, "pb.gz"), false, "Outputs the profile in compressed protobuf format"},
 
 		// Generate report in DOT format and postprocess with dot
-		"gif": {c, report.Dot, invokeDot("gif"), false, "Outputs a graph image in GIF format"},
-		"pdf": {c, report.Dot, invokeDot("pdf"), false, "Outputs a graph in PDF format"},
-		"png": {c, report.Dot, invokeDot("png"), false, "Outputs a graph image in PNG format"},
-		"ps":  {c, report.Dot, invokeDot("ps"), false, "Outputs a graph in PS format"},
+		"gif": {c, report.Dot, invokeDot(interactive, "gif"), false, "Outputs a graph image in GIF format"},
+		"pdf": {c, report.Dot, invokeDot(interactive, "pdf"), false, "Outputs a graph in PDF format"},
+		"png": {c, report.Dot, invokeDot(interactive, "png"), false, "Outputs a graph image in PNG format"},
+		"ps":  {c, report.Dot, invokeDot(interactive, "ps"), false, "Outputs a graph in PS format"},
 
 		// Save SVG output into a file after including svgpan library
-		"svg": {c, report.Dot, saveSVGToFile(), false, "Outputs a graph in SVG format"},
+		"svg": {c, report.Dot, saveSVGToFile(interactive), false, "Outputs a graph in SVG format"},
 
 		// Visualize postprocessed dot output
-		"eog":    {c, report.Dot, invokeVisualizer(interactive, invokeDot("svg"), "svg", []string{"eog"}), false, "Visualize graph through eog"},
-		"evince": {c, report.Dot, invokeVisualizer(interactive, invokeDot("pdf"), "pdf", []string{"evince"}), false, "Visualize graph through evince"},
-		"gv":     {c, report.Dot, invokeVisualizer(interactive, invokeDot("ps"), "ps", []string{"gv --noantialias"}), false, "Visualize graph through gv"},
-		"web":    {c, report.Dot, invokeVisualizer(interactive, saveSVGToFile(), "svg", browsers()), false, "Visualize graph through web browser"},
+		"eog":    {c, report.Dot, invokeVisualizer(interactive, invokeDot(nil, "svg"), "svg", []string{"eog"}), false, "Visualize graph through eog"},
+		"evince": {c, report.Dot, invokeVisualizer(interactive, invokeDot(nil, "pdf"), "pdf", []string{"evince"}), false, "Visualize graph through evince"},
+		"gv":     {c, report.Dot, invokeVisualizer(interactive, invokeDot(nil, "ps"), "ps", []string{"gv --noantialias"}), false, "Visualize graph through gv"},
+		"web":    {c, report.Dot, invokeVisualizer(interactive, saveSVGToFile(nil), "svg", browsers()), false, "Visualize graph through web browser"},
 
 		// Visualize HTML directly generated by report.
-		"weblist": {c, report.WebList, invokeVisualizer(interactive, awayFromTTY("html"), "html", browsers()), true, "Output annotated source in HTML for functions matching regexp or address"},
+		"weblist": {c, report.WebList, invokeVisualizer(interactive, awayFromTTY(nil, "html"), "html", browsers()), true, "Output annotated source in HTML for functions matching regexp or address"},
 	}
 }
 
@@ -133,9 +133,9 @@ func NewCompleter(cs Commands) Completer {
 // awayFromTTY saves the output in a file if it would otherwise go to
 // the terminal screen. This is used to avoid dumping binary data on
 // the screen.
-func awayFromTTY(format string) PostProcessor {
+func awayFromTTY(interactive **bool, format string) PostProcessor {
 	return func(input *bytes.Buffer, output io.Writer, ui plugin.UI) error {
-		if output == os.Stdout && ui.IsTerminal() {
+		if output == os.Stdout && (ui.IsTerminal() || interactive != nil && **interactive) {
 			tempFile, err := tempfile.New("", "profile", "."+format)
 			if err != nil {
 				return err
@@ -149,8 +149,8 @@ func awayFromTTY(format string) PostProcessor {
 	}
 }
 
-func invokeDot(format string) PostProcessor {
-	divert := awayFromTTY(format)
+func invokeDot(interactive **bool, format string) PostProcessor {
+	divert := awayFromTTY(interactive, format)
 	return func(input *bytes.Buffer, output io.Writer, ui plugin.UI) error {
 		if _, err := exec.LookPath("dot"); err != nil {
 			ui.PrintErr("Cannot find dot, have you installed Graphviz?")
@@ -166,9 +166,9 @@ func invokeDot(format string) PostProcessor {
 	}
 }
 
-func saveSVGToFile() PostProcessor {
-	generateSVG := invokeDot("svg")
-	divert := awayFromTTY("svg")
+func saveSVGToFile(interactive **bool) PostProcessor {
+	generateSVG := invokeDot(nil, "svg")
+	divert := awayFromTTY(interactive, "svg")
 	return func(input *bytes.Buffer, output io.Writer, ui plugin.UI) error {
 		baseSVG := &bytes.Buffer{}
 		generateSVG(input, baseSVG, ui)