Store gob cache files under specific directory for easy upgrade in future.

Author: sinclairtarget

cache.go

@@ -19,27 +19,30 @@ func warnFail(cb cache.Backend, err error) cache.Cache {
 }
 
 func getCache() cache.Cache {
-	var cb cache.Backend = cacheBackends.NoopBackend{}
-
-	if cache.IsCachingEnabled() {
-		gitRootPath, err := git.GetRoot()
-		if err != nil {
-			return warnFail(cb, err)
-		}
-
-		p, err := cacheBackends.GobCachePathXDG(gitRootPath)
-		if err != nil {
-			return warnFail(cb, err)
-		}
-
-		err = os.MkdirAll(filepath.Dir(p), 0o700)
-		if err != nil {
-			return warnFail(cb, err)
-		}
-
-		logger().Debug("cache initialized", "path", p)
-		cb = &cacheBackends.GobBackend{Path: p}
+	var fallback cache.Backend = cacheBackends.NoopBackend{}
+
+	if !cache.IsCachingEnabled() {
+		return cache.NewCache(fallback)
 	}
 
-	return cache.NewCache(cb)
+	cacheStorageDir, err := cache.CacheStorageDir(
+		cacheBackends.GobBackendName,
+	)
+	if err != nil {
+		return warnFail(fallback, err)
+	}
+
+	gitRootPath, err := git.GetRoot()
+	if err != nil {
+		return warnFail(fallback, err)
+	}
+
+	p := cacheBackends.GobCachePath(cacheStorageDir, gitRootPath)
+	err = os.MkdirAll(filepath.Dir(p), 0o700)
+	if err != nil {
+		return warnFail(fallback, err)
+	}
+
+	logger().Debug("cache initialized", "path", p)
+	return cache.NewCache(&cacheBackends.GobBackend{Path: p})
 }

internal/cache/backends/gob.go

@@ -12,7 +12,6 @@ import (
 	"io"
 	"io/fs"
 	"os"
-	"os/user"
 	"path/filepath"
 
 	"github.com/sinclairtarget/git-who/internal/cache"
@@ -40,8 +39,10 @@ type GobBackend struct {
 	isDirty   bool
 }
 
+const GobBackendName string = "gob"
+
 func (b *GobBackend) Name() string {
-	return "gob"
+	return GobBackendName
 }
 
 func (b *GobBackend) compressedPath() string {
@@ -284,33 +285,13 @@ func (b *GobBackend) Clear() error {
 	return nil
 }
 
-// Returns the absolute path at which we should store the Gob data.
-//
-// Tries to store it under the XDG_CACHE_HOME dir.
-func GobCachePathXDG(gitRootPath string) (string, error) {
+func GobCachePath(prefix string, gitRootPath string) string {
 	// Filename includes hash of path to repo so we don't collide with other
 	// git-who caches for other repos.
 	h := fnv.New32()
 	h.Write([]byte(gitRootPath))
 
 	base := filepath.Base(gitRootPath)
 	filename := fmt.Sprintf("%s-%x.gobs", base, h.Sum32())
-
-	usr, err := user.Current()
-	if err != nil {
-		return "", err
-	}
-
-	cacheHome := filepath.Join(usr.HomeDir, ".cache")
-	if len(os.Getenv("XDG_CACHE_HOME")) > 0 {
-		cacheHome = os.Getenv("XDG_CACHE_HOME")
-	}
-
-	p := filepath.Join(cacheHome, "git-who", filename)
-	absP, err := filepath.Abs(p)
-	if err != nil {
-		return "", err
-	}
-
-	return absP, nil
+	return filepath.Join(prefix, filename)
 }

internal/cache/cache.go

@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"iter"
 	"os"
+	"os/user"
+	"path/filepath"
 	"slices"
 	"time"
 
@@ -159,3 +161,33 @@ func (c *Cache) Clear() error {
 	logger().Debug("cache clear")
 	return nil
 }
+
+// Returns the absolute path at which we should store data for a given cache
+// backend.
+//
+// Tries to store it under the XDG_CACHE_HOME dir.
+func CacheStorageDir(name string) (_ string, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("failed to determine cache storage path: %w", err)
+		}
+	}()
+
+	usr, err := user.Current()
+	if err != nil {
+		return "", err
+	}
+
+	cacheHome := filepath.Join(usr.HomeDir, ".cache")
+	if len(os.Getenv("XDG_CACHE_HOME")) > 0 {
+		cacheHome = os.Getenv("XDG_CACHE_HOME")
+	}
+
+	p := filepath.Join(cacheHome, "git-who", name)
+	absP, err := filepath.Abs(p)
+	if err != nil {
+		return "", err
+	}
+
+	return absP, nil
+}