Split cache file

3 files changed, 131 insertions, 121 deletions

diff --git a/internal/feed/cache.go b/internal/feed/cache.go
index 411ed47..4a0bfe7 100644
--- a/internal/feed/cache.go
+++ b/internal/feed/cache.go
@@ -2,151 +2,40 @@ package feed
 
 import (
 	"bufio"
-	"crypto/sha256"
 	"encoding/gob"
 	"errors"
 	"fmt"
 	"os"
-	"time"
 
 	"github.com/Necoro/feed2imap-go/pkg/log"
 )
 
+type Version byte
+
 const (
-	currentVersion byte   = 1
-	startFeedId    uint64 = 1
+	currentVersion Version = 1
 )
 
 type Cache interface {
 	findItem(*Feed) CachedFeed
-	Version() byte
+	Version() Version
 	transformToCurrent() (Cache, error)
 }
 
-type feedId uint64
-
-type feedDescriptor struct {
-	Name string
-	Url  string
-}
-
 type CachedFeed interface {
 	Checked(withFailure bool)
 	Failures() uint
 }
 
-type cachedFeed struct {
-	LastCheck   time.Time
-	NumFailures uint // can't be named `Failures` b/c it'll collide with the interface
-	Items       []cachedItem
-}
-
-func (cf *cachedFeed) Checked(withFailure bool) {
-	cf.LastCheck = time.Now()
-	if withFailure {
-		cf.NumFailures++
-	} else {
-		cf.NumFailures = 0
-	}
-}
-
-func (cf *cachedFeed) Failures() uint {
-	return cf.NumFailures
-}
-
-type itemHash [sha256.Size]byte
-
-type cachedItem struct {
-	Uid     string
-	Title   string
-	Link    string
-	Date    time.Time
-	Updated time.Time
-	Creator string
-	Hash    itemHash
-}
-
-type v1Cache struct {
-	version byte
-	Ids     map[feedDescriptor]feedId
-	NextId  uint64
-	Feeds   map[feedId]*cachedFeed
-}
-
-func (cache *v1Cache) Version() byte {
-	return cache.version
-}
-
-func newCache() Cache {
-	cache := v1Cache{
-		Ids:    map[feedDescriptor]feedId{},
-		Feeds:  map[feedId]*cachedFeed{},
-		NextId: startFeedId,
-	}
-	cache.version = currentVersion
-	return &cache
-}
-
-func cacheForVersion(version byte) (Cache, error) {
+func cacheForVersion(version Version) (Cache, error) {
 	switch version {
-	case 1:
-		return newCache(), nil
+	case v1Version:
+		return newV1Cache(), nil
 	default:
 		return nil, fmt.Errorf("unknown cache version '%d'", version)
 	}
 }
 
-func (cache *v1Cache) transformToCurrent() (Cache, error) {
-	return cache, nil
-}
-
-func (cache *v1Cache) getItem(id feedId) CachedFeed {
-	feed, ok := cache.Feeds[id]
-	if !ok {
-		feed = &cachedFeed{}
-		cache.Feeds[id] = feed
-	}
-	return feed
-}
-
-func (cache *v1Cache) findItem(feed *Feed) CachedFeed {
-	if feed.cached != nil {
-		return feed.cached.(*cachedFeed)
-	}
-
-	fDescr := feed.descriptor()
-	id, ok := cache.Ids[fDescr]
-	if !ok {
-		var otherId feedDescriptor
-		changed := false
-		for otherId, id = range cache.Ids {
-			if otherId.Name == fDescr.Name {
-				log.Warnf("Feed %s seems to have changed URLs: newCache '%s', old '%s'. Updating.",
-					fDescr.Name, fDescr.Url, otherId.Url)
-				changed = true
-				break
-			} else if otherId.Url == fDescr.Url {
-				log.Warnf("Feed with URL '%s' seems to have changed its name: newCache '%s', old '%s'. Updating",
-					fDescr.Url, fDescr.Name, otherId.Name)
-				changed = true
-				break
-			}
-		}
-		if changed {
-			delete(cache.Ids, otherId)
-		} else {
-			id = feedId(cache.NextId)
-			cache.NextId++
-		}
-
-		cache.Ids[fDescr] = id
-	}
-
-	item := cache.getItem(id)
-	feed.cached = item
-	return item
-}
-
 func storeCache(cache Cache, fileName string) error {
 	if cache == nil {
 		return fmt.Errorf("trying to store nil cache")
@@ -162,7 +51,7 @@ func storeCache(cache Cache, fileName string) error {
 	defer f.Close()
 
 	writer := bufio.NewWriter(f)
-	if err = writer.WriteByte(currentVersion); err != nil {
+	if err = writer.WriteByte(byte(currentVersion)); err != nil {
 		return fmt.Errorf("writing to '%s': %w", fileName, err)
 	}
 
@@ -182,7 +71,7 @@ func loadCache(fileName string) (Cache, error) {
 	if err != nil {
 		if errors.Is(err, os.ErrNotExist) {
 			// no cache there yet -- make new
-			return newCache(), nil
+			return cacheForVersion(currentVersion)
 		}
 		return nil, fmt.Errorf("opening cache at '%s': %w", fileName, err)
 	}
@@ -196,7 +85,7 @@ func loadCache(fileName string) (Cache, error) {
 		return nil, fmt.Errorf("reading from '%s': %w", fileName, err)
 	}
 
-	cache, err := cacheForVersion(version)
+	cache, err := cacheForVersion(Version(version))
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/feed/cache_v1.go b/internal/feed/cache_v1.go
new file mode 100644
index 0000000..3d46084
--- /dev/null
+++ b/internal/feed/cache_v1.go
@@ -0,0 +1,116 @@
+package feed
+
+import (
+	"crypto/sha256"
+	"time"
+
+	"github.com/Necoro/feed2imap-go/pkg/log"
+)
+
+const (
+	v1Version   Version = 1
+	startFeedId uint64  = 1
+)
+
+type feedId uint64
+
+type v1Cache struct {
+	Ids    map[feedDescriptor]feedId
+	NextId uint64
+	Feeds  map[feedId]*cachedFeed
+}
+
+type cachedFeed struct {
+	LastCheck   time.Time
+	NumFailures uint // can't be named `Failures` b/c it'll collide with the interface
+	Items       []cachedItem
+}
+
+type itemHash [sha256.Size]byte
+
+type cachedItem struct {
+	Uid     string
+	Title   string
+	Link    string
+	Date    time.Time
+	Updated time.Time
+	Creator string
+	Hash    itemHash
+}
+
+func (cf *cachedFeed) Checked(withFailure bool) {
+	cf.LastCheck = time.Now()
+	if withFailure {
+		cf.NumFailures++
+	} else {
+		cf.NumFailures = 0
+	}
+}
+
+func (cf *cachedFeed) Failures() uint {
+	return cf.NumFailures
+}
+
+func (cache *v1Cache) Version() Version {
+	return v1Version
+}
+
+func newV1Cache() *v1Cache {
+	cache := v1Cache{
+		Ids:    map[feedDescriptor]feedId{},
+		Feeds:  map[feedId]*cachedFeed{},
+		NextId: startFeedId,
+	}
+	return &cache
+}
+
+func (cache *v1Cache) transformToCurrent() (Cache, error) {
+	return cache, nil
+}
+
+func (cache *v1Cache) getItem(id feedId) CachedFeed {
+	feed, ok := cache.Feeds[id]
+	if !ok {
+		feed = &cachedFeed{}
+		cache.Feeds[id] = feed
+	}
+	return feed
+}
+
+func (cache *v1Cache) findItem(feed *Feed) CachedFeed {
+	if feed.cached != nil {
+		return feed.cached.(*cachedFeed)
+	}
+
+	fDescr := feed.descriptor()
+	id, ok := cache.Ids[fDescr]
+	if !ok {
+		var otherId feedDescriptor
+		changed := false
+		for otherId, id = range cache.Ids {
+			if otherId.Name == fDescr.Name {
+				log.Warnf("Feed %s seems to have changed URLs: newCache '%s', old '%s'. Updating.",
+					fDescr.Name, fDescr.Url, otherId.Url)
+				changed = true
+				break
+			} else if otherId.Url == fDescr.Url {
+				log.Warnf("Feed with URL '%s' seems to have changed its name: newCache '%s', old '%s'. Updating",
+					fDescr.Url, fDescr.Name, otherId.Name)
+				changed = true
+				break
+			}
+		}
+		if changed {
+			delete(cache.Ids, otherId)
+		} else {
+			id = feedId(cache.NextId)
+			cache.NextId++
+		}
+
+		cache.Ids[fDescr] = id
+	}
+
+	item := cache.getItem(id)
+	feed.cached = item
+	return item
+}
diff --git a/internal/feed/feed.go b/internal/feed/feed.go
index c7fdd5f..686de4c 100644
--- a/internal/feed/feed.go
+++ b/internal/feed/feed.go
@@ -16,6 +16,11 @@ type Feed struct {
 	cached CachedFeed
 }
 
+type feedDescriptor struct {
+	Name string
+	Url  string
+}
+
 type feeditem struct {
 	*gofeed.Feed
 	*gofeed.Item