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Fix dangling directories stored in the cache folder. #14

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Fix dangling directories stored in the cache folder. #14

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66 changes: 41 additions & 25 deletions file_cache.go
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@ type FileCacheEntry struct {
ExpandedDirectoryPath string
directoryInUseCount int
fileInUseCount int
isMarkedAsRemoved bool
}

func NewCache(dir string, maxSizeInBytes int64) *FileCache {
Expand All @@ -63,9 +64,9 @@ func (e *FileCacheEntry) inUse() bool {
return e.directoryInUseCount > 0 || e.fileInUseCount > 0
}

func (e *FileCacheEntry) decrementUse() {
e.decrementFileInUseCount()
e.decrementDirectoryInUseCount()
func (e *FileCacheEntry) validateCacheEntry() {
e.validateFile()
e.validateDirectory()
}

func (e *FileCacheEntry) incrementDirectoryInUseCount() {
Expand All @@ -75,9 +76,15 @@ func (e *FileCacheEntry) incrementDirectoryInUseCount() {
func (e *FileCacheEntry) decrementDirectoryInUseCount() {
e.directoryInUseCount--

// Delete the directory if the tarball is the only asset
// being used or if the directory has been removed (in use count -1)
if e.directoryInUseCount < 0 || (e.directoryInUseCount == 0 && e.fileInUseCount > 0) {
e.validateDirectory()
}

func (e *FileCacheEntry) validateDirectory() {
// once the directory is NOT in use (e.directoryInUseCount == 0), delete the directory in ANY of bellow conditions:
// if the entry is marked as removed (e.isMarkedAsRemoved is true)
// OR
// if the tarball is in use (e.fileInUseCount > 0)
if e.directoryInUseCount == 0 && (e.isMarkedAsRemoved || e.fileInUseCount > 0) {
err := os.RemoveAll(e.ExpandedDirectoryPath)
if err != nil {
fmt.Fprintln(os.Stderr, "Unable to delete cached directory", err)
Expand All @@ -97,9 +104,15 @@ func (e *FileCacheEntry) incrementFileInUseCount() {
func (e *FileCacheEntry) decrementFileInUseCount() {
e.fileInUseCount--

// Delete the file if the file is not being used and there is
// a directory of if the file has been removed (in use count -1)
if e.fileInUseCount < 0 || (e.fileInUseCount == 0 && e.directoryInUseCount > 0) {
e.validateFile()
}

func (e *FileCacheEntry) validateFile() {
// once the file is NOT in use (e.fileInUseCount == 0), delete the file in ANY of bellow conditions:
// if the CacheEntry is marked as removed (e.isMarkedAsRemoved is true)
// OR
// if the related directory is in use (e.directoryInUseCount > 0)
if e.fileInUseCount == 0 && (e.isMarkedAsRemoved || e.directoryInUseCount > 0) {
err := os.RemoveAll(e.FilePath)
if err != nil {
fmt.Fprintln(os.Stderr, "Unable to delete cached file", err)
Expand Down Expand Up @@ -237,8 +250,6 @@ func (c *FileCache) Add(logger lager.Logger, cacheKey, sourcePath string, size i
logger.Info("starting")
defer logger.Info("finished")

oldEntry := c.Entries[cacheKey]

c.makeRoom(logger, size, "")

c.Seq++
Expand All @@ -250,12 +261,11 @@ func (c *FileCache) Add(logger lager.Logger, cacheKey, sourcePath string, size i
return nil, err
}

// before adding the new entry, mark the old one as removed
c.remove(logger, cacheKey)

newEntry := newFileCacheEntry(cachePath, size, cachingInfo)
c.Entries[cacheKey] = newEntry
if oldEntry != nil {
oldEntry.decrementUse()
c.updateOldEntries(logger, cacheKey, oldEntry)
}
return newEntry.readCloser()
}

Expand All @@ -267,8 +277,6 @@ func (c *FileCache) AddDirectory(logger lager.Logger, cacheKey, sourcePath strin
logger.Info("starting")
defer logger.Info("finished")

oldEntry := c.Entries[cacheKey]

c.makeRoom(logger, size, "")

c.Seq++
Expand All @@ -280,12 +288,11 @@ func (c *FileCache) AddDirectory(logger lager.Logger, cacheKey, sourcePath strin
return "", err
}

// before adding the new entry, mark the old one as removed
c.remove(logger, cacheKey)

newEntry := newFileCacheEntry(cachePath, size, cachingInfo)
c.Entries[cacheKey] = newEntry
if oldEntry != nil {
oldEntry.decrementUse()
c.updateOldEntries(logger, cacheKey, oldEntry)
}
return newEntry.expandedDirectory()
}

Expand Down Expand Up @@ -357,19 +364,28 @@ func (c *FileCache) Remove(logger lager.Logger, cacheKey string) {
func (c *FileCache) remove(logger lager.Logger, cacheKey string) {
entry := c.Entries[cacheKey]
if entry != nil {
entry.decrementUse()
// mark the entry as removed
entry.isMarkedAsRemoved = true
// validate the entry to decide if to remove the file or directory
entry.validateCacheEntry()
// store the entry in OldEntries if necessary
c.updateOldEntries(logger, cacheKey, entry)
delete(c.Entries, cacheKey)
}
}

func (c *FileCache) updateOldEntries(logger lager.Logger, cacheKey string, entry *FileCacheEntry) {
if entry != nil {
if !entry.inUse() && entry.ExpandedDirectoryPath != "" {
// put it in the oldEntries Cache since somebody may still be using the directory
logger = logger.Session("update-old-entries", lager.Data{"cache_key": cacheKey, "dir_path": entry.ExpandedDirectoryPath, "in_use_file": entry.fileInUseCount, "in_use_dir": entry.directoryInUseCount, "is_marked_as_removed": entry.isMarkedAsRemoved})
logger.Info(fmt.Sprintf("old_entries_cnt=%d", len(c.OldEntries)))

if entry.inUse() && entry.ExpandedDirectoryPath != "" {
// for directory entry which is still used by someone,
// adding it to OldEntries waiting for close action to finally remove the directory
c.OldEntries[cacheKey+entry.ExpandedDirectoryPath] = entry
} else {
} else if entry.ExpandedDirectoryPath != "" {
// We need to remove it from oldEntries
// Maybe will never run into this branch
delete(c.OldEntries, cacheKey+entry.ExpandedDirectoryPath)
}
}
Expand Down