vfs: factor the vfs cache into its own package

vfs/vfscommon/options.go

@@ -0,0 +1,57 @@
+package vfscommon
+
+import (
+	"os"
+	"runtime"
+	"time"
+
+	"github.com/rclone/rclone/fs"
+)
+
+// Options is options for creating the vfs
+type Options struct {
+	NoSeek            bool          // don't allow seeking if set
+	NoChecksum        bool          // don't check checksums if set
+	ReadOnly          bool          // if set VFS is read only
+	NoModTime         bool          // don't read mod times for files
+	DirCacheTime      time.Duration // how long to consider directory listing cache valid
+	PollInterval      time.Duration
+	Umask             int
+	UID               uint32
+	GID               uint32
+	DirPerms          os.FileMode
+	FilePerms         os.FileMode
+	ChunkSize         fs.SizeSuffix // if > 0 read files in chunks
+	ChunkSizeLimit    fs.SizeSuffix // if > ChunkSize double the chunk size after each chunk until reached
+	CacheMode         CacheMode
+	CacheMaxAge       time.Duration
+	CacheMaxSize      fs.SizeSuffix
+	CachePollInterval time.Duration
+	CaseInsensitive   bool
+	WriteWait         time.Duration // time to wait for in-sequence write
+	ReadWait          time.Duration // time to wait for in-sequence read
+}
+
+// DefaultOpt is the default values uses for Opt
+var DefaultOpt = Options{
+	NoModTime:         false,
+	NoChecksum:        false,
+	NoSeek:            false,
+	DirCacheTime:      5 * 60 * time.Second,
+	PollInterval:      time.Minute,
+	ReadOnly:          false,
+	Umask:             0,
+	UID:               ^uint32(0), // these values instruct WinFSP-FUSE to use the current user
+	GID:               ^uint32(0), // overriden for non windows in mount_unix.go
+	DirPerms:          os.FileMode(0777),
+	FilePerms:         os.FileMode(0666),
+	CacheMode:         CacheModeOff,
+	CacheMaxAge:       3600 * time.Second,
+	CachePollInterval: 60 * time.Second,
+	ChunkSize:         128 * fs.MebiByte,
+	ChunkSizeLimit:    -1,
+	CacheMaxSize:      -1,
+	CaseInsensitive:   runtime.GOOS == "windows" || runtime.GOOS == "darwin", // default to true on Windows and Mac, false otherwise
+	WriteWait:         1000 * time.Millisecond,
+	ReadWait:          5 * time.Millisecond,
+}