From 6b9f68f0607f2b6c7a94b6b7c96d7188eeb0f8ef Mon Sep 17 00:00:00 2001
From: hackyminer <hackyminer@gmail.com>
Date: Sat, 22 Sep 2018 05:38:31 +0900
Subject: [PATCH 1/4] node: use APPDATA env to support cygwin/msys correctly

---
 node/defaults.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/node/defaults.go b/node/defaults.go
index c1376dba0f33..8e0655848b61 100644
--- a/node/defaults.go
+++ b/node/defaults.go
@@ -59,7 +59,7 @@ func DefaultDataDir() string {
 		if runtime.GOOS == "darwin" {
 			return filepath.Join(home, "Library", "Ethereum")
 		} else if runtime.GOOS == "windows" {
-			return filepath.Join(home, "AppData", "Roaming", "Ethereum")
+			return filepath.Join(os.Getenv("APPDATA"), "Ethereum")
 		} else {
 			return filepath.Join(home, ".ethereum")
 		}

From c5549ae256605671815be64e2656f0aa46844949 Mon Sep 17 00:00:00 2001
From: hackyminer <hackyminer@gmail.com>
Date: Sun, 21 Oct 2018 19:06:58 +0900
Subject: [PATCH 2/4] cmd, node: use APPDATA env if it available

---
 cmd/clef/main.go | 7 ++++++-
 node/defaults.go | 7 ++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/cmd/clef/main.go b/cmd/clef/main.go
index c060285be604..b5451a9b4f29 100644
--- a/cmd/clef/main.go
+++ b/cmd/clef/main.go
@@ -494,7 +494,12 @@ func DefaultConfigDir() string {
 		if runtime.GOOS == "darwin" {
 			return filepath.Join(home, "Library", "Signer")
 		} else if runtime.GOOS == "windows" {
-			return filepath.Join(home, "AppData", "Roaming", "Signer")
+			appdata := os.Getenv("APPDATA")
+			if appdata != "" {
+				return filepath.Join(appdata, "Signer")
+			} else {
+				return filepath.Join(home, "AppData", "Roaming", "Signer")
+			}
 		} else {
 			return filepath.Join(home, ".clef")
 		}
diff --git a/node/defaults.go b/node/defaults.go
index 8e0655848b61..350e3dcd8e93 100644
--- a/node/defaults.go
+++ b/node/defaults.go
@@ -59,7 +59,12 @@ func DefaultDataDir() string {
 		if runtime.GOOS == "darwin" {
 			return filepath.Join(home, "Library", "Ethereum")
 		} else if runtime.GOOS == "windows" {
-			return filepath.Join(os.Getenv("APPDATA"), "Ethereum")
+			appdata := os.Getenv("APPDATA")
+			if appdata != "" {
+				return filepath.Join(appdata, "Ethereum")
+			} else {
+				return filepath.Join(home, "AppData", "Roaming", "Ethereum")
+			}
 		} else {
 			return filepath.Join(home, ".ethereum")
 		}

From e7bb3468d3e32f79b4a40e63040c344abc1f9062 Mon Sep 17 00:00:00 2001
From: hackyminer <hackyminer@gmail.com>
Date: Sun, 21 Oct 2018 19:31:18 +0900
Subject: [PATCH 3/4] eth: use LOCALAPPDATA env variable for the Ethash cache
 dir.

---
 eth/config.go | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/eth/config.go b/eth/config.go
index efbaafb6a2d3..de7558a0de71 100644
--- a/eth/config.go
+++ b/eth/config.go
@@ -67,8 +67,15 @@ func init() {
 			home = user.HomeDir
 		}
 	}
-	if runtime.GOOS == "windows" {
-		DefaultConfig.Ethash.DatasetDir = filepath.Join(home, "AppData", "Ethash")
+	if runtime.GOOS == "darwin" {
+		DefaultConfig.Ethash.DatasetDir = filepath.Join(home, "Library", "Ethash")
+	} else if runtime.GOOS == "windows" {
+		localappdata := os.Getenv("LOCALAPPDATA")
+		if localappdata != "" {
+			DefaultConfig.Ethash.DatasetDir = filepath.Join(localappdata, "Ethash")
+		} else {
+			DefaultConfig.Ethash.DatasetDir = filepath.Join(home, "AppData", "Local", "Ethash")
+		}
 	} else {
 		DefaultConfig.Ethash.DatasetDir = filepath.Join(home, ".ethash")
 	}

From 3ef8310edbceca297214bbabc332ed62e378f12e Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Mon, 11 Feb 2019 12:30:24 +0100
Subject: [PATCH 4/4] node: check for previous default datadir

---
 node/defaults.go | 40 ++++++++++++++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 8 deletions(-)

diff --git a/node/defaults.go b/node/defaults.go
index 350e3dcd8e93..95cf8c2ca5e9 100644
--- a/node/defaults.go
+++ b/node/defaults.go
@@ -56,16 +56,20 @@ func DefaultDataDir() string {
 	// Try to place the data folder in the user's home dir
 	home := homeDir()
 	if home != "" {
-		if runtime.GOOS == "darwin" {
+		switch runtime.GOOS {
+		case "darwin":
 			return filepath.Join(home, "Library", "Ethereum")
-		} else if runtime.GOOS == "windows" {
-			appdata := os.Getenv("APPDATA")
-			if appdata != "" {
-				return filepath.Join(appdata, "Ethereum")
-			} else {
-				return filepath.Join(home, "AppData", "Roaming", "Ethereum")
+		case "windows":
+			// We used to put everything in %HOME%\AppData\Roaming, but this caused
+			// problems with non-typical setups. If this fallback location exists and
+			// is non-empty, use it, otherwise DTRT and check %LOCALAPPDATA%.
+			fallback := filepath.Join(home, "AppData", "Roaming", "Ethereum")
+			appdata := windowsAppData()
+			if appdata == "" || isNonEmptyDir(fallback) {
+				return fallback
 			}
-		} else {
+			return filepath.Join(appdata, "Ethereum")
+		default:
 			return filepath.Join(home, ".ethereum")
 		}
 	}
@@ -73,6 +77,26 @@ func DefaultDataDir() string {
 	return ""
 }
 
+func windowsAppData() string {
+	if v := os.Getenv("LOCALAPPDATA"); v != "" {
+		return v // Vista+
+	}
+	if v := os.Getenv("APPDATA"); v != "" {
+		return filepath.Join(v, "Local")
+	}
+	return ""
+}
+
+func isNonEmptyDir(dir string) bool {
+	f, err := os.Open(dir)
+	if err != nil {
+		return false
+	}
+	names, _ := f.Readdir(1)
+	f.Close()
+	return len(names) > 0
+}
+
 func homeDir() string {
 	if home := os.Getenv("HOME"); home != "" {
 		return home