generic cache

action.go

@@ -11,7 +11,7 @@ import (
 	shlex "github.com/rsteube/carapace-shlex"
 	"github.com/rsteube/carapace/internal/cache"
 	"github.com/rsteube/carapace/internal/common"
-	pkgcache "github.com/rsteube/carapace/pkg/cache"
+	"github.com/rsteube/carapace/pkg/cache/key"
 	"github.com/rsteube/carapace/pkg/match"
 	"github.com/rsteube/carapace/pkg/style"
 	pkgtraverse "github.com/rsteube/carapace/pkg/traverse"
@@ -31,7 +31,7 @@ type ActionMap map[string]Action
 type CompletionCallback func(c Context) Action
 
 // Cache cashes values of a CompletionCallback for given duration and keys.
-func (a Action) Cache(timeout time.Duration, keys ...pkgcache.Key) Action {
+func (a Action) Cache(timeout time.Duration, keys ...key.Key) Action {
 	if a.callback != nil { // only relevant for callback actions
 		cachedCallback := a.callback
 		_, file, line, _ := runtime.Caller(1) // generate uid from wherever Cache() was called
@@ -41,14 +41,14 @@ func (a Action) Cache(timeout time.Duration, keys ...pkgcache.Key) Action {
 				return cachedCallback(c)
 			}
 
-			if cached, err := cache.Load(cacheFile, timeout); err == nil {
+			if cached, err := cache.LoadE(cacheFile, timeout); err == nil {
 				return Action{meta: cached.Meta, rawValues: cached.Values}
 			}
 
 			invokedAction := (Action{callback: cachedCallback}).Invoke(c)
 			if invokedAction.action.meta.Messages.IsEmpty() {
 				if cacheFile, err := cache.File(file, line, keys...); err == nil { // regenerate as cache keys might have changed due to invocation
-					_ = cache.Write(cacheFile, invokedAction.export())
+					_ = cache.WriteE(cacheFile, invokedAction.export())
 				}
 			}
 			return invokedAction.ToA()

example/cmd/modifier.go

@@ -7,7 +7,7 @@ import (
 	"time"
 
 	"github.com/rsteube/carapace"
-	"github.com/rsteube/carapace/pkg/cache"
+	"github.com/rsteube/carapace/pkg/cache/key"
 	"github.com/rsteube/carapace/pkg/condition"
 	"github.com/rsteube/carapace/pkg/style"
 	"github.com/rsteube/carapace/pkg/traverse"
@@ -85,7 +85,7 @@ func init() {
 					return carapace.ActionValues(
 						time.Now().Format("15:04:05"),
 					)
-				}).Cache(10*time.Second, cache.String(c.Parts[0]))
+				}).Cache(10*time.Second, key.String(c.Parts[0]))
 			default:
 				return carapace.ActionValues()
 			}

internal/cache/cache.go

@@ -14,31 +14,41 @@ import (
 	"github.com/rsteube/carapace/internal/env"
 	"github.com/rsteube/carapace/internal/export"
 	"github.com/rsteube/carapace/internal/uid"
-	"github.com/rsteube/carapace/pkg/cache"
+	"github.com/rsteube/carapace/pkg/cache/key"
 	"github.com/rsteube/carapace/pkg/xdg"
 )
 
-// Write persistests given values to file as json.
-func Write(file string, e export.Export) (err error) {
+func WriteE(file string, e export.Export) (err error) {
 	var m []byte
 	if m, err = json.Marshal(e); err == nil {
-		err = os.WriteFile(file, m, 0600)
+		err = Write(file, m)
 	}
 	return
 }
 
-// Load loads values from file unless modification date exceeds timeout.
-func Load(file string, timeout time.Duration) (e export.Export, err error) {
+func Write(file string, content []byte) (err error) {
+	return os.WriteFile(file, content, 0600)
+}
+
+func LoadE(file string, timeout time.Duration) (*export.Export, error) { // TODO reference
+	content, err := Load(file, timeout)
+	if err != nil {
+		return nil, err
+	}
+
+	var e export.Export
+	if err := json.Unmarshal(content, &e); err != nil {
+		return nil, err
+	}
+	return &e, nil
+}
+
+func Load(file string, timeout time.Duration) (b []byte, err error) {
 	var stat os.FileInfo
 	if stat, err = os.Stat(file); os.IsNotExist(err) || (timeout >= 0 && stat.ModTime().Add(timeout).Before(time.Now())) {
-		err = errors.New("not exists or timeout exceeded")
-	} else {
-		var content []byte
-		if content, err = os.ReadFile(file); err == nil {
-			err = json.Unmarshal(content, &e)
-		}
+		return nil, errors.New("not exists or timeout exceeded")
 	}
-	return
+	return os.ReadFile(file)
 }
 
 // CacheDir creates a cache folder for current user and returns the path.
@@ -60,7 +70,7 @@ func CacheDir(name string) (dir string, err error) {
 
 // File returns the cache filename for given values
 // TODO cleanup
-func File(callerFile string, callerLine int, keys ...cache.Key) (file string, err error) {
+func File(callerFile string, callerLine int, keys ...key.Key) (file string, err error) {
 	uid := uidKeys(callerFile, strconv.Itoa(callerLine))
 	ids := make([]string, 0)
 	for _, key := range keys {

pkg/cache/cache.go

@@ -1,46 +1,30 @@
-// Package cache provides cache keys
 package cache
 
 import (
-	"crypto/sha1"
-	"fmt"
-	"os"
-	"path/filepath"
-	"strconv"
-	"strings"
-)
-
-// Key provides a cache key.
-type Key func() (string, error)
+	"runtime"
+	"time"
 
-// String creates a CacheKey for given strings.
-func String(s ...string) Key {
-	return func() (string, error) {
-		return strings.Join(s, "\n"), nil
-	}
-}
+	"github.com/rsteube/carapace/internal/cache"
+	"github.com/rsteube/carapace/pkg/cache/key"
+)
 
-// FileChecksum creates a CacheKey for given file.
-func FileChecksum(file string) Key {
-	return func() (checksum string, err error) {
-		var content []byte
-		if content, err = os.ReadFile(file); err == nil {
-			checksum = fmt.Sprintf("%x", sha1.Sum(content))
+// Cache caches a function for given duration and keys.
+func Cache(timeout time.Duration, keys ...key.Key) func(f func() ([]byte, error)) ([]byte, error) {
+	return func(f func() ([]byte, error)) ([]byte, error) {
+		_, file, line, _ := runtime.Caller(1)
+		cacheFile, err := cache.File(file, line, keys...)
+		if err != nil {
+			return nil, err
 		}
-		return
-	}
-}
 
-// FileStats creates a CacheKey for given file.
-func FileStats(file string) Key {
-	return func() (checksum string, err error) {
-		var path string
-		if path, err = filepath.Abs(file); err == nil {
-			var info os.FileInfo
-			if info, err = os.Stat(file); err == nil {
-				return String(path, strconv.FormatInt(info.Size(), 10), info.ModTime().String())()
+		content, err := cache.Load(cacheFile, timeout)
+		if err != nil {
+			content, err = f()
+			if err != nil {
+				return nil, err
 			}
+			return content, cache.Write(cacheFile, content)
 		}
-		return
+		return content, nil
 	}
 }

pkg/cache/key/cache.go

@@ -0,0 +1,67 @@
+// Package cache provides cache keys
+package key
+
+import (
+	"crypto/sha1"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+// Key provides a cache key.
+type Key func() (string, error)
+
+// String creates a CacheKey for given strings.
+func String(s ...string) Key {
+	return func() (string, error) {
+		return strings.Join(s, "\n"), nil
+	}
+}
+
+// FileChecksum creates a CacheKey for given file.
+func FileChecksum(file string) Key {
+	return func() (checksum string, err error) {
+		var content []byte
+		if content, err = os.ReadFile(file); err == nil {
+			checksum = fmt.Sprintf("%x", sha1.Sum(content))
+		}
+		return
+	}
+}
+
+// FileStats creates a CacheKey for given file.
+func FileStats(file string) Key {
+	return func() (checksum string, err error) {
+		var path string
+		if path, err = filepath.Abs(file); err == nil {
+			var info os.FileInfo
+			if info, err = os.Stat(file); err == nil {
+				return String(path, strconv.FormatInt(info.Size(), 10), info.ModTime().String())()
+			}
+		}
+		return
+	}
+}
+
+func FolderStats(folder string) Key {
+	return func() (string, error) {
+		sums := make([]string, 0)
+		err := filepath.Walk(folder, func(path string, info fs.FileInfo, err error) error {
+			if !info.IsDir() {
+				sum, err := String(info.Name(), strconv.FormatInt(info.Size(), 10), info.ModTime().String())()
+				if err != nil {
+					return err
+				}
+				sums = append(sums, sum)
+			}
+			return nil
+		})
+		if err != nil {
+			return "", err
+		}
+		return strings.Join(sums, "\n"), nil
+	}
+}