From ce3564bf8e28d1d8eb74c6c2f768692d13e035c2 Mon Sep 17 00:00:00 2001
From: Adam Harvey <adam@adamharvey.name>
Date: Thu, 20 Aug 2020 12:45:02 -0700
Subject: [PATCH] output: improve Windows console handling

The new output code is pretty nifty in Windows Terminal, but users still using
the legacy console with cmd.exe or PowerShell are going to get pretty ugly
output, since the escape codes aren't handled by default. This adds support for
enabling virtual terminal processing, which makes things pretty. (Well,
prettier, anyway. Note also #273.)
---
 CHANGELOG.md                      |  6 ++++++
 go.mod                            |  2 +-
 internal/output/output.go         | 13 ++++++++++-
 internal/output/output_windows.go | 36 +++++++++++++++++++++++++++++++
 4 files changed, 55 insertions(+), 2 deletions(-)
 create mode 100644 internal/output/output_windows.go

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0bc199fedf..fd402d9b89 100644
--- a/CHANGELOG.md
+++ b/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
diff --git a/go.mod b/go.mod
index 0819c64044..092cdca3a8 100644
--- a/go.mod
+++ b/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
 )
diff --git a/internal/output/output.go b/internal/output/output.go
index df1bcda38b..b3115ce45f 100644
--- a/internal/output/output.go
+++ b/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) {
diff --git a/internal/output/output_windows.go b/internal/output/output_windows.go
new file mode 100644
index 0000000000..d55647fbc0
--- /dev/null
+++ b/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)
+}