116 lines
3.2 KiB
Go
116 lines
3.2 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 fuse
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import (
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"fmt"
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"golang.org/x/net/context"
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)
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// A type that knows how to serve ops read from a connection.
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type Server interface {
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// Read and serve ops from the supplied connection until EOF. Do not return
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// until all operations have been responded to. Must not be called more than
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// once.
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ServeOps(*Connection)
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}
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// A struct representing the status of a mount operation, with a method that
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// waits for unmounting.
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type MountedFileSystem struct {
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dir string
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// The result to return from Join. Not valid until the channel is closed.
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joinStatus error
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joinStatusAvailable chan struct{}
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}
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// Return the directory on which the file system is mounted (or where we
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// attempted to mount it.)
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func (mfs *MountedFileSystem) Dir() string {
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return mfs.dir
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}
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// Block until a mounted file system has been unmounted. Do not return
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// successfully until all ops read from the connection have been responded to
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// (i.e. the file system server has finished processing all in-flight ops).
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//
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// The return value will be non-nil if anything unexpected happened while
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// serving. May be called multiple times.
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func (mfs *MountedFileSystem) Join(ctx context.Context) error {
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select {
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case <-mfs.joinStatusAvailable:
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return mfs.joinStatus
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case <-ctx.Done():
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return ctx.Err()
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}
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}
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// Attempt to mount a file system on the given directory, using the supplied
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// Server to serve connection requests. This function blocks until the file
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// system is successfully mounted.
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func Mount(
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dir string,
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server Server,
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config *MountConfig) (mfs *MountedFileSystem, err error) {
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// Initialize the struct.
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mfs = &MountedFileSystem{
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dir: dir,
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joinStatusAvailable: make(chan struct{}),
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}
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// Begin the mounting process, which will continue in the background.
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ready := make(chan error, 1)
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dev, err := mount(dir, config, ready)
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if err != nil {
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err = fmt.Errorf("mount: %v", err)
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return
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}
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// Choose a parent context for ops.
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opContext := config.OpContext
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if opContext == nil {
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opContext = context.Background()
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}
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// Create a Connection object wrapping the device.
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connection, err := newConnection(
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opContext,
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config.DebugLogger,
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config.ErrorLogger,
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dev)
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if err != nil {
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err = fmt.Errorf("newConnection: %v", err)
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return
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}
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// Serve the connection in the background. When done, set the join status.
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go func() {
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server.ServeOps(connection)
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mfs.joinStatus = connection.close()
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close(mfs.joinStatusAvailable)
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}()
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// Wait for the mount process to complete.
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if err = <-ready; err != nil {
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err = fmt.Errorf("mount (background): %v", err)
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return
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}
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return
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}
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