From 9e01b5a4787507f7015bfb6225e01da7159570f0 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Thu, 15 Aug 2013 20:16:05 -0700
Subject: [PATCH] common: detect drive letter with windows file URLs [GH-284]

---
 CHANGELOG.md     | 2 ++
 common/config.go | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 10af0427a..b7f5c2d57 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,6 +27,8 @@ IMPROVEMENTS:
 
 BUG FIXES:
 
+* windows: file URLs are easier to get right as Packer
+  has better parsing and error handling for Windows file paths. [GH-284]
 * builder/amazon-instance: send IAM instance profile data. [GH-294]
 * builder/virtualbox: dowload progress won't be shown until download
   actually starts. [GH-288]
diff --git a/common/config.go b/common/config.go
index 16ab86252..2a2c8b21f 100644
--- a/common/config.go
+++ b/common/config.go
@@ -64,6 +64,15 @@ func DecodeConfig(target interface{}, raws ...interface{}) (*mapstructure.Metada
 // a completely valid URL. For example, the original URL might be "local/file.iso"
 // which isn't a valid URL. DownloadableURL will return "file:///local/file.iso"
 func DownloadableURL(original string) (string, error) {
+	if runtime.GOOS == "windows" {
+		// If the distance to the first ":" is just one character, assume
+		// we're dealing with a drive letter and thus a file path.
+		idx := strings.Index(original, ":")
+		if idx == 1 {
+			original = "file:///" + original
+		}
+	}
+
 	url, err := url.Parse(original)
 	if err != nil {
 		return "", err