initial commit [ci skip]

engine/compiler/shell/shell.go

@@ -0,0 +1,56 @@
+// Copyright 2019 Drone.IO Inc. All rights reserved.
+// Use of this source code is governed by the Polyform License
+// that can be found in the LICENSE file.
+
+// Package shell provides functions for converting shell commands
+// to posix shell scripts.
+package shell
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+)
+
+// Script converts a slice of individual shell commands to
+// a posix-compliant shell script.
+func Script(commands []string) string {
+	buf := new(bytes.Buffer)
+	fmt.Fprintln(buf)
+	fmt.Fprintf(buf, optionScript)
+	fmt.Fprintln(buf)
+	for _, command := range commands {
+		escaped := fmt.Sprintf("%q", command)
+		escaped = strings.Replace(escaped, "$", `\$`, -1)
+		buf.WriteString(fmt.Sprintf(
+			traceScript,
+			escaped,
+			command,
+		))
+	}
+	return buf.String()
+}
+
+// optionScript is a helper script this is added to the build
+// to set shell options, in this case, to exit on error.
+const optionScript = `
+if [[ ! -z "${DRONE_NETRC_FILE}" ]]; then
+	echo $DRONE_NETRC_FILE > $HOME/.netrc
+EOF
+fi
+
+unset DRONE_SCRIPT
+unset DRONE_NETRC_MACHINE
+unset DRONE_NETRC_USERNAME
+unset DRONE_NETRC_PASSWORD
+unset DRONE_NETRC_FILE
+
+set -e
+`
+
+// traceScript is a helper script that is added to
+// the build script to trace a command.
+const traceScript = `
+echo + %s
+%s
+`