refactor: new interface

Author: Luca Bianconi

Diff for: buildcache/build_cache.go

@@ -25,26 +25,31 @@ import (
 
 const lastUsedFileName = ".last-used"
 
+type buildCache struct {
+	baseDir *paths.Path
+}
+
 // GetOrCreate retrieves or creates the cache directory at the given path
 // If the cache already exists the lifetime of the cache is extended.
-func GetOrCreate(dir *paths.Path) (*paths.Path, error) {
-	if !dir.Exist() {
-		if err := dir.MkdirAll(); err != nil {
+func (bc *buildCache) GetOrCreate(key string) (*paths.Path, error) {
+	keyDir := bc.baseDir.Join(key)
+	if !keyDir.Exist() {
+		if err := keyDir.MkdirAll(); err != nil {
 			return nil, err
 		}
 	}
 
-	if err := dir.Join(lastUsedFileName).WriteFile([]byte{}); err != nil {
+	if err := keyDir.Join(lastUsedFileName).WriteFile([]byte{}); err != nil {
 		return nil, err
 	}
-	return dir, nil
+	return keyDir, nil
 }
 
 // Purge removes all cache directories within baseDir that have expired
 // To know how long ago a directory has been last used
 // it checks into the .last-used file.
-func Purge(baseDir *paths.Path, ttl time.Duration) {
-	files, err := baseDir.ReadDir()
+func (bc *buildCache) Purge(ttl time.Duration) {
+	files, err := bc.baseDir.ReadDir()
 	if err != nil {
 		return
 	}
@@ -55,6 +60,11 @@ func Purge(baseDir *paths.Path, ttl time.Duration) {
 	}
 }
 
+// New instantiates a build cache
+func New(baseDir *paths.Path) *buildCache {
+	return &buildCache{baseDir}
+}
+
 func removeIfExpired(dir *paths.Path, ttl time.Duration) {
 	fileInfo, err := dir.Join().Stat()
 	if err != nil {

Diff for: buildcache/build_cache_test.go

@@ -43,7 +43,7 @@ func Test_UpdateLastUsedFileExisting(t *testing.T) {
 }
 
 func requireCorrectUpdate(t *testing.T, dir *paths.Path, prevModTime time.Time) {
-	_, err := GetOrCreate(dir)
+	_, err := New(dir.Parent()).GetOrCreate(dir.Base())
 	require.NoError(t, err)
 	expectedFile := dir.Join(lastUsedFileName)
 	fileInfo, err := expectedFile.Stat()
@@ -71,7 +71,7 @@ func TestPurge(t *testing.T) {
 		require.NoError(t, infoFilePath.Chtimes(accesstime, lastUsedTime))
 	}
 
-	Purge(dirToPurge, ttl)
+	New(dirToPurge).Purge(ttl)
 
 	files, err := dirToPurge.Join("fresh").Stat()
 	require.Nil(t, err)

Diff for: commands/compile/compile.go

@@ -138,7 +138,7 @@ func Compile(ctx context.Context, req *rpc.CompileRequest, outStream, errStream
 		return nil, &arduino.PermissionDeniedError{Message: tr("Cannot create build directory"), Cause: err}
 	}
 
-	buildcache.GetOrCreate(builderCtx.BuildPath)
+	buildcache.New(builderCtx.BuildPath.Parent()).GetOrCreate(builderCtx.BuildPath.Base())
 	// cache is purged after compilation to not remove entries that might be required
 	defer maybePurgeBuildCache()
 
@@ -312,6 +312,6 @@ func maybePurgeBuildCache() {
 	}
 	inventory.Store.Set("build_cache.compilation_count_since_last_purge", 0)
 	cacheTTL := configuration.Settings.GetDuration("build_cache.ttl").Abs()
-	buildcache.Purge(paths.TempDir().Join("arduino", "cores"), cacheTTL)
-	buildcache.Purge(paths.TempDir().Join("arduino", "sketches"), cacheTTL)
+	buildcache.New(paths.TempDir().Join("arduino", "cores")).Purge(cacheTTL)
+	buildcache.New(paths.TempDir().Join("arduino", "sketches")).Purge(cacheTTL)
 }