49 lines
1.2 KiB
Go
49 lines
1.2 KiB
Go
// Copyright 2015 Google Inc. All Rights Reserved.
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// Author: jacobsa@google.com (Aaron Jacobs)
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package memfs
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import (
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"fmt"
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"github.com/jacobsa/fuse"
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"github.com/jacobsa/fuse/fuseutil"
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"github.com/jacobsa/gcloud/syncutil"
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)
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type memDir struct {
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/////////////////////////
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// Mutable state
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/////////////////////////
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mu syncutil.InvariantMutex
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// The contents of the directory. An entry with inode zero is unused.
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//
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// This array can never be shortened, nor can its elements be moved, because
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// we use its indices for Dirent.Offset, which is exposed to the user who
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// might be calling readdir in a loop while concurrently modifying the
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// directory. Unused entries can, however, be reused.
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//
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// TODO(jacobsa): Add good tests exercising concurrent modifications while
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// doing readdir, seekdir, etc. calls.
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//
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// INVARIANT: For each i, entries[i].Offset == i+1
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entries []fuseutil.Dirent
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}
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func newDir() (d *memDir) {
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d = &memDir{}
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d.mu = syncutil.NewInvariantMutex(d.checkInvariants)
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return
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}
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func (d *memDir) checkInvariants() {
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for i, e := range d.entries {
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if e.Offset != fuse.DirOffset(i+1) {
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panic(fmt.Sprintf("Unexpected offset in entry: %v", e))
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}
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}
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}
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