From d21881150c09986571a563eaf30bc1687787e63f Mon Sep 17 00:00:00 2001
From: René 'Necoro' Neumann <necoro@necoro.eu>
Date: Sat, 25 Apr 2020 11:27:34 +0200
Subject: Improved caching

---
 internal/cache/cache.go | 120 ------------------------------------------------
 1 file changed, 120 deletions(-)
 delete mode 100644 internal/cache/cache.go

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

diff --git a/internal/cache/cache.go b/internal/cache/cache.go
deleted file mode 100644
index 979d661..0000000
--- a/internal/cache/cache.go
+++ /dev/null
@@ -1,120 +0,0 @@
-package cache
-
-import (
-	"bufio"
-	"encoding/gob"
-	"errors"
-	"fmt"
-	"os"
-
-	"github.com/Necoro/feed2imap-go/internal/log"
-)
-
-const currentVersion byte = 1
-
-type Cache interface {
-	Version() byte
-	transformToCurrent() (Cache, error)
-}
-
-type feedId struct {
-	Name string
-	Url  string
-}
-
-type v1Cache struct {
-	version byte
-	Ids     map[feedId]uint64
-	NextId  uint64
-}
-
-func (cache *v1Cache) Version() byte {
-	return cache.version
-}
-
-func New() Cache {
-	cache := v1Cache{Ids: map[feedId]uint64{}}
-	cache.version = currentVersion
-	return &cache
-}
-
-func cacheForVersion(version byte) (Cache, error) {
-	switch version {
-	case 1:
-		return New(), nil
-	default:
-		return nil, fmt.Errorf("unknown cache version '%d'", version)
-	}
-}
-
-func (cache *v1Cache) transformToCurrent() (Cache, error) {
-	return cache, nil
-}
-
-func Store(fileName string, cache Cache) error {
-	if cache == nil {
-		return fmt.Errorf("trying to store nil cache")
-	}
-	if cache.Version() != currentVersion {
-		return fmt.Errorf("trying to store cache with unsupported version '%d' (current: '%d')", cache.Version(), currentVersion)
-	}
-
-	f, err := os.Create(fileName)
-	if err != nil {
-		return fmt.Errorf("trying to store cache to '%s': %w", fileName, err)
-	}
-	defer f.Close()
-
-	writer := bufio.NewWriter(f)
-	if err = writer.WriteByte(currentVersion); err != nil {
-		return fmt.Errorf("writing to '%s': %w", fileName, err)
-	}
-
-	encoder := gob.NewEncoder(writer)
-	if err = encoder.Encode(cache); err != nil {
-		return fmt.Errorf("encoding cache: %w", err)
-	}
-
-	writer.Flush()
-	log.Printf("Stored cache to '%s'.", fileName)
-
-	return nil
-}
-
-func Read(fileName string) (Cache, error) {
-	f, err := os.Open(fileName)
-	if err != nil {
-		if errors.Is(err, os.ErrNotExist) {
-			// no cache there yet -- make new
-			return New(), nil
-		}
-		return nil, fmt.Errorf("opening cache at '%s': %w", fileName, err)
-	}
-	defer f.Close()
-
-	log.Printf("Loading cache from '%s'", fileName)
-
-	reader := bufio.NewReader(f)
-	version, err := reader.ReadByte()
-	if err != nil {
-		return nil, fmt.Errorf("reading from '%s': %w", fileName, err)
-	}
-
-	cache, err := cacheForVersion(version)
-	if err != nil {
-		return nil, err
-	}
-
-	decoder := gob.NewDecoder(reader)
-	if err = decoder.Decode(cache); err != nil {
-		return nil, fmt.Errorf("decoding for version '%d' from '%s': %w", version, fileName, err)
-	}
-
-	if cache, err = cache.transformToCurrent(); err != nil {
-		return nil, fmt.Errorf("cannot transform from version %d to %d: %w", version, currentVersion, err)
-	}
-
-	log.Printf("Loaded cache (version %d), transformed to version %d.", version, currentVersion)
-
-	return cache, nil
-}
-- 
cgit v1.2.3-54-g00ecf