Expand ~ to correct home directory on all OSes.

This fixes the behavior of expanding ~ on Windows and macOS, as well
as adding support for ~otheruser to expand to the home directory of
otheruser.

Modify the default sample config to reflect the change in the meaning
of ~ on Windows, and the unintended meaning of ~ on macOS.  Include
defaults for all 3 of the major operating system classes since
uncommenting the default Unix option on macOS or Windows would change
the blockchain data directory to a non-default location.

cmd/checkdevpremine/config.go

@@ -8,7 +8,9 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"os/user"
 	"path/filepath"
+	"runtime"
 	"strings"
 
 	"github.com/decred/dcrd/dcrutil"
@@ -47,18 +49,53 @@ func normalizeAddress(addr string) string {
 	return addr
 }
 
-// cleanAndExpandPath expands environement variables and leading ~ in the
+// cleanAndExpandPath expands environment variables and leading ~ in the
 // passed path, cleans the result, and returns it.
 func cleanAndExpandPath(path string) string {
-	// Expand initial ~ to OS specific home directory.
-	if strings.HasPrefix(path, "~") {
-		homeDir := filepath.Dir(appHomeDir)
-		path = strings.Replace(path, "~", homeDir, 1)
+	// NOTE: The os.ExpandEnv doesn't work with Windows cmd.exe-style
+	// %VARIABLE%, but the variables can still be expanded via POSIX-style
+	// $VARIABLE.
+	path = os.ExpandEnv(path)
+
+	if !strings.HasPrefix(path, "~") {
+		return filepath.Clean(path)
 	}
 
-	// NOTE: The os.ExpandEnv doesn't work with Windows-style %VARIABLE%,
-	// but they variables can still be expanded via POSIX-style $VARIABLE.
-	return filepath.Clean(os.ExpandEnv(path))
+	// Expand initial ~ to the current user's home directory, or ~otheruser
+	// to otheruser's home directory.  On Windows, both forward and backward
+	// slashes can be used.
+	path = path[1:]
+
+	var pathSeparators string
+	if runtime.GOOS == "windows" {
+		pathSeparators = string(os.PathSeparator) + "/"
+	} else {
+		pathSeparators = string(os.PathSeparator)
+	}
+
+	userName := ""
+	if i := strings.IndexAny(path, pathSeparators); i != -1 {
+		userName = path[:i]
+		path = path[i:]
+	}
+
+	homeDir := ""
+	var u *user.User
+	var err error
+	if userName == "" {
+		u, err = user.Current()
+	} else {
+		u, err = user.Lookup(userName)
+	}
+	if err == nil {
+		homeDir = u.HomeDir
+	}
+	// Fallback to CWD if user lookup fails or user has no home directory.
+	if homeDir == "" {
+		homeDir = "."
+	}
+
+	return filepath.Join(homeDir, path)
 }
 
 // loadConfig initializes and parses the config using a config file and command

cmd/dcrctl/config.go

@@ -10,8 +10,10 @@ import (
 	"io/ioutil"
 	"net"
 	"os"
+	"os/user"
 	"path/filepath"
 	"regexp"
+	"runtime"
 	"strings"
 
 	"github.com/decred/dcrd/dcrjson"
@@ -146,18 +148,53 @@ func normalizeAddress(addr string, useTestNet, useSimNet, useWallet bool) string
 	return addr
 }
 
-// cleanAndExpandPath expands environement variables and leading ~ in the
+// cleanAndExpandPath expands environment variables and leading ~ in the
 // passed path, cleans the result, and returns it.
 func cleanAndExpandPath(path string) string {
-	// Expand initial ~ to OS specific home directory.
-	if strings.HasPrefix(path, "~") {
-		homeDir := filepath.Dir(dcrctlHomeDir)
-		path = strings.Replace(path, "~", homeDir, 1)
+	// NOTE: The os.ExpandEnv doesn't work with Windows cmd.exe-style
+	// %VARIABLE%, but the variables can still be expanded via POSIX-style
+	// $VARIABLE.
+	path = os.ExpandEnv(path)
+
+	if !strings.HasPrefix(path, "~") {
+		return filepath.Clean(path)
 	}
 
-	// NOTE: The os.ExpandEnv doesn't work with Windows-style %VARIABLE%,
-	// but they variables can still be expanded via POSIX-style $VARIABLE.
-	return filepath.Clean(os.ExpandEnv(path))
+	// Expand initial ~ to the current user's home directory, or ~otheruser
+	// to otheruser's home directory.  On Windows, both forward and backward
+	// slashes can be used.
+	path = path[1:]
+
+	var pathSeparators string
+	if runtime.GOOS == "windows" {
+		pathSeparators = string(os.PathSeparator) + "/"
+	} else {
+		pathSeparators = string(os.PathSeparator)
+	}
+
+	userName := ""
+	if i := strings.IndexAny(path, pathSeparators); i != -1 {
+		userName = path[:i]
+		path = path[i:]
+	}
+
+	homeDir := ""
+	var u *user.User
+	var err error
+	if userName == "" {
+		u, err = user.Current()
+	} else {
+		u, err = user.Lookup(userName)
+	}
+	if err == nil {
+		homeDir = u.HomeDir
+	}
+	// Fallback to CWD if user lookup fails or user has no home directory.
+	if homeDir == "" {
+		homeDir = "."
+	}
+
+	return filepath.Join(homeDir, path)
 }
 
 // filesExists reports whether the named file or directory exists.

cmd/gencerts/gencerts.go

@@ -10,12 +10,13 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"os/user"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"time"
 
 	"github.com/decred/dcrd/certgen"
-	"github.com/decred/dcrd/dcrutil"
 	flags "github.com/jessevdk/go-flags"
 )
 
@@ -79,19 +80,53 @@ func main() {
 	}
 }
 
-// cleanAndExpandPath expands environement variables and leading ~ in the
+// cleanAndExpandPath expands environment variables and leading ~ in the
 // passed path, cleans the result, and returns it.
 func cleanAndExpandPath(path string) string {
-	// Expand initial ~ to OS specific home directory.
-	if strings.HasPrefix(path, "~") {
-		appHomeDir := dcrutil.AppDataDir("gencerts", false)
-		homeDir := filepath.Dir(appHomeDir)
-		path = strings.Replace(path, "~", homeDir, 1)
+	// NOTE: The os.ExpandEnv doesn't work with Windows cmd.exe-style
+	// %VARIABLE%, but the variables can still be expanded via POSIX-style
+	// $VARIABLE.
+	path = os.ExpandEnv(path)
+
+	if !strings.HasPrefix(path, "~") {
+		return filepath.Clean(path)
 	}
 
-	// NOTE: The os.ExpandEnv doesn't work with Windows-style %VARIABLE%,
-	// but they variables can still be expanded via POSIX-style $VARIABLE.
-	return filepath.Clean(os.ExpandEnv(path))
+	// Expand initial ~ to the current user's home directory, or ~otheruser
+	// to otheruser's home directory.  On Windows, both forward and backward
+	// slashes can be used.
+	path = path[1:]
+
+	var pathSeparators string
+	if runtime.GOOS == "windows" {
+		pathSeparators = string(os.PathSeparator) + "/"
+	} else {
+		pathSeparators = string(os.PathSeparator)
+	}
+
+	userName := ""
+	if i := strings.IndexAny(path, pathSeparators); i != -1 {
+		userName = path[:i]
+		path = path[i:]
+	}
+
+	homeDir := ""
+	var u *user.User
+	var err error
+	if userName == "" {
+		u, err = user.Current()
+	} else {
+		u, err = user.Lookup(userName)
+	}
+	if err == nil {
+		homeDir = u.HomeDir
+	}
+	// Fallback to CWD if user lookup fails or user has no home directory.
+	if homeDir == "" {
+		homeDir = "."
+	}
+
+	return filepath.Join(homeDir, path)
 }
 
 // filesExists reports whether the named file or directory exists.

config.go

@@ -12,6 +12,7 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"os/user"
 	"path/filepath"
 	"regexp"
 	"runtime"
@@ -179,15 +180,50 @@ type serviceOptions struct {
 // cleanAndExpandPath expands environment variables and leading ~ in the
 // passed path, cleans the result, and returns it.
 func cleanAndExpandPath(path string) string {
-	// Expand initial ~ to OS specific home directory.
-	if strings.HasPrefix(path, "~") {
-		homeDir := filepath.Dir(defaultHomeDir)
-		path = strings.Replace(path, "~", homeDir, 1)
+	// NOTE: The os.ExpandEnv doesn't work with Windows cmd.exe-style
+	// %VARIABLE%, but the variables can still be expanded via POSIX-style
+	// $VARIABLE.
+	path = os.ExpandEnv(path)
+
+	if !strings.HasPrefix(path, "~") {
+		return filepath.Clean(path)
 	}
 
-	// NOTE: The os.ExpandEnv doesn't work with Windows-style %VARIABLE%,
-	// but they variables can still be expanded via POSIX-style $VARIABLE.
-	return filepath.Clean(os.ExpandEnv(path))
+	// Expand initial ~ to the current user's home directory, or ~otheruser
+	// to otheruser's home directory.  On Windows, both forward and backward
+	// slashes can be used.
+	path = path[1:]
+
+	var pathSeparators string
+	if runtime.GOOS == "windows" {
+		pathSeparators = string(os.PathSeparator) + "/"
+	} else {
+		pathSeparators = string(os.PathSeparator)
+	}
+
+	userName := ""
+	if i := strings.IndexAny(path, pathSeparators); i != -1 {
+		userName = path[:i]
+		path = path[i:]
+	}
+
+	homeDir := ""
+	var u *user.User
+	var err error
+	if userName == "" {
+		u, err = user.Current()
+	} else {
+		u, err = user.Lookup(userName)
+	}
+	if err == nil {
+		homeDir = u.HomeDir
+	}
+	// Fallback to CWD if user lookup fails or user has no home directory.
+	if homeDir == "" {
+		homeDir = "."
+	}
+
+	return filepath.Join(homeDir, path)
 }
 
 // validLogLevel returns whether or not logLevel is a valid debug log level.

sampleconfig/sampleconfig.go

@@ -14,11 +14,13 @@ const FileContents = `[Application Options]
 ; The directory to store data such as the block chain and peer addresses.  The
 ; block chain takes several GB, so this location must have a lot of free space.
 ; The default is ~/.dcrd/data on POSIX OSes, $LOCALAPPDATA/Dcrd/data on Windows,
-; ~/Library/Application Support/Dcrd/data on Mac OS, and $homed/dcrd/data on
+; ~/Library/Application Support/Dcrd/data on macOS, and $homed/dcrd/data on
 ; Plan9.  Environment variables are expanded so they may be used.  NOTE: Windows
 ; environment variables are typically %VARIABLE%, but they must be accessed with
-; $VARIABLE here.  Also, ~ is expanded to $LOCALAPPDATA on Windows.
-; datadir=~/.dcrd/data
+; $VARIABLE here.
+; datadir=~/.dcrd/data                            ; Unix
+; datadir=$LOCALAPPDATA/Dcrd/data                 ; Windows
+; datadir=~/Library/Application Support/Dcrd/data ; macOS
 
 
 ; ------------------------------------------------------------------------------