output: improve Windows console handling

CHANGELOG.md

@@ -9,6 +9,12 @@
 
 All notable changes to `src-cli` are documented in this file.
 
+## Unreleased changes
+
+### Fixed
+
+- `src campaigns` output has been improved in the Windows console. [#274](https://github.com/sourcegraph/src-cli/pull/274)
+
 ## 3.18.0
 
 ### Added

go.mod

@@ -22,7 +22,7 @@ require (
 	github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb // indirect
 	github.com/xeipuuv/gojsonschema v1.2.0
 	golang.org/x/net v0.0.0-20200625001655-4c5254603344
-	golang.org/x/sys v0.0.0-20200622214017-ed371f2e16b4 // indirect
+	golang.org/x/sys v0.0.0-20200622214017-ed371f2e16b4
 	gopkg.in/yaml.v2 v2.3.0
 	jaytaylor.com/html2text v0.0.0-20200412013138-3577fbdbcff7
 )

internal/output/output.go

@@ -47,13 +47,24 @@ type OutputOpts struct {
 	Verbose    bool
 }
 
+// newOutputPlatformQuirks provides a way for conditionally compiled code to
+// hook into NewOutput to perform any required setup.
+var newOutputPlatformQuirks func(o *Output) error
+
 func NewOutput(w io.Writer, opts OutputOpts) *Output {
 	caps := detectCapabilities()
 	if opts.ForceColor {
 		caps.Color = true
 	}
 
-	return &Output{caps: caps, opts: opts, w: w}
+	o := &Output{caps: caps, opts: opts, w: w}
+	if newOutputPlatformQuirks != nil {
+		if err := newOutputPlatformQuirks(o); err != nil {
+			o.Verbosef("Error handling platform quirks: %v", err)
+		}
+	}
+
+	return o
 }
 
 func (o *Output) Verbose(s string) {

internal/output/output_windows.go

@@ -0,0 +1,36 @@
+package output
+
+import (
+	"github.com/hashicorp/go-multierror"
+	"golang.org/x/sys/windows"
+)
+
+func init() {
+	newOutputPlatformQuirks = func(o *Output) error {
+		var errs *multierror.Error
+
+		if err := setConsoleMode(windows.Stdout, windows.ENABLE_VIRTUAL_TERMINAL_PROCESSING); err != nil {
+			errs = multierror.Append(errs, err)
+		}
+		if err := setConsoleMode(windows.Stderr, windows.ENABLE_VIRTUAL_TERMINAL_PROCESSING); err != nil {
+			errs = multierror.Append(errs, err)
+		}
+
+		return errs.ErrorOrNil()
+	}
+}
+
+func setConsoleMode(handle windows.Handle, flags uint32) error {
+	// This is shamelessly lifted from gitlab-runner, specifically
+	// https://gitlab.com/gitlab-org/gitlab-runner/blob/f8d87f1e3e3af1cc8aadcea3e40bbb069eee72ef/helpers/cli/init_cli_windows.go
+
+	// First we have to get the current console mode so we can add the desired
+	// flags.
+	var mode uint32
+	if err := windows.GetConsoleMode(handle, &mode); err != nil {
+		return err
+	}
+
+	// Now we can set the console mode.
+	return windows.SetConsoleMode(handle, mode|flags)
+}