144 lines
3.1 KiB
Go
144 lines
3.1 KiB
Go
// Copyright 2015 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package interruptfs
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import (
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"fmt"
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"os"
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"sync"
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"github.com/jacobsa/fuse"
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"github.com/jacobsa/fuse/fuseops"
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"github.com/jacobsa/fuse/fuseutil"
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)
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var rootAttrs = fuseops.InodeAttributes{
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Nlink: 1,
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Mode: os.ModeDir | 0777,
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}
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const fooID = fuseops.RootInodeID + 1
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var fooAttrs = fuseops.InodeAttributes{
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Nlink: 1,
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Mode: 0777,
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Size: 1234,
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}
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// A file system containing exactly one file, named "foo". Reads to the file
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// always hang until interrupted. Exposes a method for synchronizing with the
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// arrival of a read.
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//
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// Must be created with New.
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type InterruptFS struct {
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fuseutil.NotImplementedFileSystem
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mu sync.Mutex
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readInFlight bool
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readInFlightChanged sync.Cond
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}
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func New() (fs *InterruptFS) {
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fs = &InterruptFS{}
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fs.readInFlightChanged.L = &fs.mu
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return
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}
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////////////////////////////////////////////////////////////////////////
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// Public interface
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////////////////////////////////////////////////////////////////////////
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// Block until the first read is received.
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//
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// LOCKS_EXCLUDED(fs.mu)
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func (fs *InterruptFS) WaitForReadInFlight() {
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fs.mu.Lock()
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defer fs.mu.Unlock()
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for !fs.readInFlight {
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fs.readInFlightChanged.Wait()
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}
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}
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////////////////////////////////////////////////////////////////////////
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// FileSystem methods
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////////////////////////////////////////////////////////////////////////
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func (fs *InterruptFS) LookUpInode(
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op *fuseops.LookUpInodeOp) (err error) {
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// We support only one parent.
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if op.Parent != fuseops.RootInodeID {
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err = fmt.Errorf("Unexpected parent: %v", op.Parent)
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return
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}
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// We support only one name.
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if op.Name != "foo" {
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err = fuse.ENOENT
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return
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}
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// Fill in the response.
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op.Entry.Child = fooID
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op.Entry.Attributes = fooAttrs
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return
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}
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func (fs *InterruptFS) GetInodeAttributes(
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op *fuseops.GetInodeAttributesOp) (err error) {
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switch op.Inode {
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case fuseops.RootInodeID:
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op.Attributes = rootAttrs
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case fooID:
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op.Attributes = fooAttrs
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default:
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err = fmt.Errorf("Unexpected inode ID: %v", op.Inode)
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return
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}
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return
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}
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func (fs *InterruptFS) OpenFile(
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op *fuseops.OpenFileOp) (err error) {
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return
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}
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func (fs *InterruptFS) ReadFile(
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op *fuseops.ReadFileOp) (err error) {
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// Signal that a read has been received.
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fs.mu.Lock()
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fs.readInFlight = true
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fs.readInFlightChanged.Broadcast()
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fs.mu.Unlock()
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// Wait for cancellation.
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done := op.Context().Done()
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if done == nil {
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panic("Expected non-nil channel.")
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}
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<-done
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// Return the context's error.
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err = op.Context().Err()
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return
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}
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