Deleted commonOp.

fuseops/common_op.go

-// Copyright 2015 Google Inc. All Rights Reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package fuseops
-
-import (
-	"fmt"
-	"log"
-	"reflect"
-	"strings"
-	"syscall"
-
-	"github.com/jacobsa/fuse/internal/buffer"
-	"github.com/jacobsa/reqtrace"
-	"golang.org/x/net/context"
-)
-
-// An interface that all ops inside which commonOp is embedded must
-// implement.
-type internalOp interface {
-	Op
-
-	// Create a response message for the kernel, leaving the leading
-	// fusekernel.OutHeader untouched.
-	//
-	// Special case: a zero return value means that the kernel is not expecting a
-	// response.
-	kernelResponse() (b buffer.OutMessage)
-}
-
-// A function that sends a reply message back to the kernel for the request
-// with the given fuse unique ID. The error argument is for informational
-// purposes only; the error to hand to the kernel is encoded in the message.
-type replyFunc func(Op, uint64, []byte, error) error
-
-// A helper for embedding common behavior.
-type commonOp struct {
-	// The context exposed to the user.
-	ctx context.Context
-
-	// The op in which this struct is embedded.
-	op internalOp
-
-	// The fuse unique ID of this request, as assigned by the kernel.
-	fuseID uint64
-
-	// A function that can be used to send a reply to the kernel.
-	sendReply replyFunc
-
-	// A function that can be used to log debug information about the op. The
-	// first argument is a call depth.
-	//
-	// May be nil.
-	debugLog func(int, string, ...interface{})
-
-	// A logger to be used for logging exceptional errors.
-	//
-	// May be nil.
-	errorLogger *log.Logger
-}
-
-func (o *commonOp) ShortDesc() (desc string) {
-	v := reflect.ValueOf(o.op)
-	opName := v.Type().String()
-
-	// Attempt to better handle the usual case: a string that looks like
-	// "*fuseops.GetInodeAttributesOp".
-	const prefix = "*fuseops."
-	const suffix = "Op"
-	if strings.HasPrefix(opName, prefix) && strings.HasSuffix(opName, suffix) {
-		opName = opName[len(prefix) : len(opName)-len(suffix)]
-	}
-
-	desc = opName
-
-	// Include the inode number to which the op applies, if possible.
-	if f := v.Elem().FieldByName("Inode"); f.IsValid() {
-		desc = fmt.Sprintf("%s(inode=%v)", desc, f.Interface())
-	}
-
-	return
-}
-
-func (o *commonOp) DebugString() string {
-	// By default, defer to ShortDesc.
-	return o.op.ShortDesc()
-}
-
-func (o *commonOp) init(
-	ctx context.Context,
-	op internalOp,
-	fuseID uint64,
-	sendReply replyFunc,
-	debugLog func(int, string, ...interface{}),
-	errorLogger *log.Logger) {
-	// Initialize basic fields.
-	o.ctx = ctx
-	o.op = op
-	o.fuseID = fuseID
-	o.sendReply = sendReply
-	o.debugLog = debugLog
-	o.errorLogger = errorLogger
-
-	// Set up a trace span for this op.
-	var reportForTrace reqtrace.ReportFunc
-	o.ctx, reportForTrace = reqtrace.StartSpan(o.ctx, o.op.ShortDesc())
-
-	// When the op is finished, report to both reqtrace and the connection.
-	prevSendReply := o.sendReply
-	o.sendReply = func(op Op, fuseID uint64, msg []byte, opErr error) (err error) {
-		reportForTrace(opErr)
-		err = prevSendReply(op, fuseID, msg, opErr)
-		return
-	}
-}
-
-func (o *commonOp) Context() context.Context {
-	return o.ctx
-}
-
-func (o *commonOp) Logf(format string, v ...interface{}) {
-	if o.debugLog == nil {
-		return
-	}
-
-	const calldepth = 2
-	o.debugLog(calldepth, format, v...)
-}
-
-func (o *commonOp) Respond(err error) {
-	// If successful, we ask the op for an appopriate response to the kernel, and
-	// it is responsible for leaving room for the fusekernel.OutHeader struct.
-	// Otherwise, create our own.
-	var b buffer.OutMessage
-	if err == nil {
-		b = o.op.kernelResponse()
-	} else {
-		b = buffer.NewOutMessage(0)
-	}
-
-	// Fill in the header if a reply is needed.
-	msg := b.Bytes()
-	if msg != nil {
-		h := b.OutHeader()
-		h.Unique = o.fuseID
-		h.Len = uint32(len(msg))
-		if err != nil {
-			// If the user gave us a syscall.Errno, use that value in the reply.
-			// Otherwise use the generic EIO.
-			if errno, ok := err.(syscall.Errno); ok {
-				h.Error = -int32(errno)
-			} else {
-				h.Error = -int32(syscall.EIO)
-			}
-		}
-	}
-
-	// Reply.
-	replyErr := o.sendReply(o.op, o.fuseID, msg, err)
-	if replyErr != nil && o.errorLogger != nil {
-		o.errorLogger.Printf("Error from sendReply: %v", replyErr)
-	}
-}