From 610b6764443fe37d703147e42cbef4fa230f0364 Mon Sep 17 00:00:00 2001
From: Alexander Neumann <alexander@bumpern.de>
Date: Mon, 11 Sep 2017 21:37:10 +0200
Subject: [PATCH] Automatically exclude current restic cache

---
 cmd/restic/cmd_backup.go | 10 ++++++++++
 cmd/restic/exclude.go    | 25 +++++++++++++++++++++++++
 internal/cache/cache.go  |  5 +++++
 internal/restic/cache.go |  3 +++
 4 files changed, 43 insertions(+)

diff --git a/cmd/restic/cmd_backup.go b/cmd/restic/cmd_backup.go
index c8b9154fb..0c254738a 100644
--- a/cmd/restic/cmd_backup.go
+++ b/cmd/restic/cmd_backup.go
@@ -387,6 +387,16 @@ func runBackup(opts BackupOptions, gopts GlobalOptions, args []string) error {
 		return err
 	}
 
+	// exclude restic cache
+	if repo.Cache != nil {
+		f, err := rejectResticCache(repo)
+		if err != nil {
+			return err
+		}
+
+		rejectFuncs = append(rejectFuncs, f)
+	}
+
 	err = repo.LoadIndex(context.TODO())
 	if err != nil {
 		return err
diff --git a/cmd/restic/exclude.go b/cmd/restic/exclude.go
index 369c4df9a..bb14bfafb 100644
--- a/cmd/restic/exclude.go
+++ b/cmd/restic/exclude.go
@@ -12,6 +12,7 @@ import (
 	"github.com/restic/restic/internal/errors"
 	"github.com/restic/restic/internal/filter"
 	"github.com/restic/restic/internal/fs"
+	"github.com/restic/restic/internal/repository"
 )
 
 // RejectFunc is a function that takes a filename and os.FileInfo of a
@@ -177,3 +178,27 @@ func rejectByDevice(samples []string) (RejectFunc, error) {
 		panic(fmt.Sprintf("item %v, device id %v not found, allowedDevs: %v", item, id, allowed))
 	}, nil
 }
+
+// rejectResticCache returns a RejectFunc that rejects the restic cache
+// directory (if set).
+func rejectResticCache(repo *repository.Repository) (RejectFunc, error) {
+	if repo.Cache == nil {
+		return func(string, os.FileInfo) bool {
+			return false
+		}, nil
+	}
+	cacheBase := repo.Cache.BaseDir()
+
+	if cacheBase == "" {
+		return nil, errors.New("cacheBase is empty string")
+	}
+
+	return func(item string, _ os.FileInfo) bool {
+		if fs.HasPathPrefix(cacheBase, item) {
+			debug.Log("rejecting restic cache directory %v", item)
+			return true
+		}
+
+		return false
+	}, nil
+}
diff --git a/internal/cache/cache.go b/internal/cache/cache.go
index 0f610127e..6e75b8743 100644
--- a/internal/cache/cache.go
+++ b/internal/cache/cache.go
@@ -152,3 +152,8 @@ func (c *Cache) Wrap(be restic.Backend) restic.Backend {
 		Cache:   c,
 	}
 }
+
+// BaseDir returns the base directory.
+func (c *Cache) BaseDir() string {
+	return c.Base
+}
diff --git a/internal/restic/cache.go b/internal/restic/cache.go
index ab9d4fb16..56ed060ac 100644
--- a/internal/restic/cache.go
+++ b/internal/restic/cache.go
@@ -4,6 +4,9 @@ import "io"
 
 // Cache manages a local cache.
 type Cache interface {
+	// BaseDir returns the base directory of the cache.
+	BaseDir() string
+
 	// Wrap returns a backend with a cache.
 	Wrap(Backend) Backend