From 96725ec63e12e76d6d93345d35d42b141180f4e1 Mon Sep 17 00:00:00 2001
From: René 'Necoro' Neumann <necoro@necoro.eu>
Date: Sat, 25 Apr 2020 17:20:19 +0200
Subject: Split cache file

---
 internal/feed/cache.go | 131 ++++---------------------------------------------
 1 file changed, 10 insertions(+), 121 deletions(-)

(limited to 'internal/feed/cache.go')

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
 	}
-- 
cgit v1.2.3-54-g00ecf