xdg: add functions to deal with user home paths

These are intended to replace the following deprecated libraries:

	github.com/kyoh86/xdg
	github.com/mitchellh/go-homedir

The feature set should be roughly equivalent with some tweaks to make
our life easier in aerc.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Reviewed-by: Moritz Poldrack <moritz@poldrack.dev>

1 files changed, 89 insertions, 0 deletions

diff --git a/lib/xdg/xdg.go b/lib/xdg/xdg.go
new file mode 100644
index 00000000..c1eaab03
--- /dev/null
+++ b/lib/xdg/xdg.go
@@ -0,0 +1,89 @@
+package xdg
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"strconv"
+)
+
+// Return a path relative to the user home cache dir
+func CachePath(paths ...string) string {
+	res := filepath.Join(paths...)
+	if !filepath.IsAbs(res) {
+		var cache string
+		if runtime.GOOS == "darwin" {
+			// preserve backward compat with github.com/kyoh86/xdg
+			cache = os.Getenv("XDG_CACHE_HOME")
+		}
+		if cache == "" {
+			var err error
+			cache, err = os.UserCacheDir()
+			if err != nil {
+				cache = ExpandHome("~/.cache")
+			}
+		}
+		res = filepath.Join(cache, res)
+	}
+	return res
+}
+
+// Return a path relative to the user home config dir
+func ConfigPath(paths ...string) string {
+	res := filepath.Join(paths...)
+	if !filepath.IsAbs(res) {
+		var config string
+		if runtime.GOOS == "darwin" {
+			// preserve backward compat with github.com/kyoh86/xdg
+			config = os.Getenv("XDG_CONFIG_HOME")
+			if config == "" {
+				config = ExpandHome("~/Library/Preferences")
+			}
+		} else {
+			var err error
+			config, err = os.UserConfigDir()
+			if err != nil {
+				config = ExpandHome("~/.config")
+			}
+		}
+		res = filepath.Join(config, res)
+	}
+	return res
+}
+
+// Return a path relative to the user data home dir
+func DataPath(paths ...string) string {
+	res := filepath.Join(paths...)
+	if !filepath.IsAbs(res) {
+		data := os.Getenv("XDG_DATA_HOME")
+		// preserve backward compat with github.com/kyoh86/xdg
+		if data == "" && runtime.GOOS == "darwin" {
+			data = ExpandHome("~/Library/Application Support")
+		} else if data == "" {
+			data = ExpandHome("~/.local/share")
+		}
+		res = filepath.Join(data, res)
+	}
+	return res
+}
+
+// ugly: there's no other way to allow mocking a function in go...
+var userRuntimePath = func() string {
+	return filepath.Join("/run/user", strconv.Itoa(os.Getuid()))
+}
+
+// Return a path relative to the user runtime dir
+func RuntimePath(paths ...string) string {
+	res := filepath.Join(paths...)
+	if !filepath.IsAbs(res) {
+		run := os.Getenv("XDG_RUNTIME_DIR")
+		// preserve backward compat with github.com/kyoh86/xdg
+		if run == "" && runtime.GOOS == "darwin" {
+			run = ExpandHome("~/Library/Application Support")
+		} else if run == "" {
+			run = userRuntimePath()
+		}
+		res = filepath.Join(run, res)
+	}
+	return res
+}