From 4f66d66755da63c78b09201c6c72353009251cf2 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Wed, 2 Jan 2019 22:32:21 +0100
Subject: fusefrontend: add dirCache

---
 internal/nametransform/dirivcache/dirivcache.go | 102 ------------------------
 1 file changed, 102 deletions(-)
 delete mode 100644 internal/nametransform/dirivcache/dirivcache.go

(limited to 'internal/nametransform/dirivcache')

diff --git a/internal/nametransform/dirivcache/dirivcache.go b/internal/nametransform/dirivcache/dirivcache.go
deleted file mode 100644
index 962ae37..0000000
--- a/internal/nametransform/dirivcache/dirivcache.go
+++ /dev/null
@@ -1,102 +0,0 @@
-package dirivcache
-
-import (
-	"log"
-	"strings"
-	"sync"
-	"time"
-)
-
-const (
-	maxEntries = 100
-	expireTime = 1 * time.Second
-)
-
-type cacheEntry struct {
-	// DirIV of the directory.
-	iv []byte
-	// Relative ciphertext path of the directory.
-	cDir string
-}
-
-// DirIVCache stores up to "maxEntries" directory IVs.
-type DirIVCache struct {
-	// data in the cache, indexed by relative plaintext path
-	// of the directory.
-	data map[string]cacheEntry
-
-	// The DirIV of the root directory gets special treatment because it
-	// cannot change (the root directory cannot be renamed or deleted).
-	// It is unaffected by the expiry timer and cache clears.
-	rootDirIV []byte
-
-	// expiry is the time when the whole cache expires.
-	// The cached entry might become out-of-date if the ciphertext directory is
-	// modified behind the back of gocryptfs. Having an expiry time limits the
-	// inconstancy to one second, like attr_timeout does for the kernel
-	// getattr cache.
-	expiry time.Time
-
-	sync.RWMutex
-}
-
-// Lookup - fetch entry for "dir" (relative plaintext path) from the cache.
-// Returns the directory IV and the relative encrypted path, or (nil, "")
-// if the entry was not found.
-func (c *DirIVCache) Lookup(dir string) (iv []byte, cDir string) {
-	c.RLock()
-	defer c.RUnlock()
-	if dir == "" {
-		return c.rootDirIV, ""
-	}
-	if c.data == nil {
-		return nil, ""
-	}
-	if time.Since(c.expiry) > 0 {
-		c.data = nil
-		return nil, ""
-	}
-	v := c.data[dir]
-	return v.iv, v.cDir
-}
-
-// Store - write an entry for directory "dir" into the cache.
-// Arguments:
-// dir ... relative plaintext path
-// iv .... directory IV
-// cDir .. relative ciphertext path
-func (c *DirIVCache) Store(dir string, iv []byte, cDir string) {
-	c.Lock()
-	defer c.Unlock()
-	if dir == "" {
-		c.rootDirIV = iv
-	}
-	// Sanity check: plaintext and chiphertext paths must have the same number
-	// of segments
-	if strings.Count(dir, "/") != strings.Count(cDir, "/") {
-		log.Panicf("inconsistent number of path segments: dir=%q cDir=%q", dir, cDir)
-	}
-	// Clear() may have cleared c.data: re-initialize
-	if c.data == nil {
-		c.data = make(map[string]cacheEntry, maxEntries)
-		// Set expiry time one second into the future
-		c.expiry = time.Now().Add(expireTime)
-	}
-	// Delete a random entry from the map if reached maxEntries
-	if len(c.data) >= maxEntries {
-		for k := range c.data {
-			delete(c.data, k)
-			break
-		}
-	}
-	c.data[dir] = cacheEntry{iv, cDir}
-}
-
-// Clear ... clear the cache.
-// Called from fusefrontend when directories are renamed or deleted.
-func (c *DirIVCache) Clear() {
-	c.Lock()
-	defer c.Unlock()
-	// Will be re-initialized in the next Store()
-	c.data = nil
-}
-- 
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