separated utilities by category and grouped, grouped crypto

pkg/util/appdata/appdata.go

@@ -0,0 +1,88 @@
+package appdata
+
+import (
+	"os"
+	"os/user"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"unicode"
+)
+
+// GetDataDir returns an operating system specific directory to be used for
+// storing application data for an application.
+// See Dir for more details. This unexported version takes an operating system argument primarily to enable the testing
+// package to properly test the function by forcing an operating system that is not the currently one.
+func GetDataDir(goos, appName string, roaming bool) string {
+	if appName == "" || appName == "." {
+		return "."
+	}
+	// The caller really shouldn't prepend the appName with a period, but if they do, handle it gracefully by trimming
+	// it.
+	appName = strings.TrimPrefix(appName, ".")
+	appNameUpper := string(unicode.ToUpper(rune(appName[0]))) + appName[1:]
+	appNameLower := string(unicode.ToLower(rune(appName[0]))) + appName[1:]
+	// Get the OS specific home directory via the Go standard lib.
+	var homeDir string
+	var usr *user.User
+	var e error
+	if usr, e = user.Current(); e == nil {
+		homeDir = usr.HomeDir
+	}
+	// Fall back to standard HOME environment variable that works for most POSIX OSes if the directory from the Go
+	// standard lib failed.
+	if e != nil || homeDir == "" {
+		homeDir = os.Getenv("HOME")
+	}
+	switch goos {
+	// Attempt to use the LOCALAPPDATA or APPDATA environment variable on Windows.
+	case "windows":
+		// Windows XP and before didn't have a LOCALAPPDATA, so fallback to regular APPDATA when LOCALAPPDATA is not
+		// set.
+		appData := os.Getenv("LOCALAPPDATA")
+		if roaming || appData == "" {
+			appData = os.Getenv("APPDATA")
+		}
+		if appData != "" {
+			return filepath.Join(appData, appNameUpper)
+		}
+	case "darwin":
+		if homeDir != "" {
+			return filepath.Join(
+				homeDir, "Library",
+				"Application Support", appNameUpper,
+			)
+		}
+	case "plan9":
+		if homeDir != "" {
+			return filepath.Join(homeDir, appNameLower)
+		}
+	default:
+		if homeDir != "" {
+			return filepath.Join(homeDir, "."+appNameLower)
+		}
+	}
+	// Fall back to the current directory if all else fails.
+	return "."
+}
+
+// Dir returns an operating system specific directory to be used for storing application data for an application. The
+// appName parameter is the name of the application the data directory is being requested for.  This function will
+// prepend a period to the appName for POSIX style operating systems since that is standard practice.
+//
+// An empty appName or one with a single dot is treated as requesting the current directory so only "." will be
+// returned. Further, the first character of appName will be made lowercase for POSIX style operating systems and
+// uppercase for Mac and Windows since that is standard practice.
+//
+// The roaming parameter only applies to Windows where it specifies the roaming application data profile (%APPDATA%)
+// should be used instead of the local one (%LOCALAPPDATA%) that is used by default. Example results:
+//
+//	dir := Dir("myapp", false)
+//
+//	 POSIX (Linux/BSD): ~/.myapp
+//	 Mac OS: $HOME/Library/Application Support/Myapp
+//	 Windows: %LOCALAPPDATA%\Myapp
+//	 Plan 9: $home/myapp
+func Dir(appName string, roaming bool) string {
+	return GetDataDir(runtime.GOOS, appName, roaming)
+}