149 lines
3.5 KiB
Go
149 lines
3.5 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 fuseops
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import (
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"fmt"
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"log"
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"reflect"
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"strings"
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"github.com/jacobsa/fuse/internal/fuseshim"
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"github.com/jacobsa/reqtrace"
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"golang.org/x/net/context"
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)
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// An interface that all ops inside which commonOp is embedded must
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// implement.
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type internalOp interface {
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Op
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// Respond to the underlying fuseshim request, successfully.
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respond()
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}
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// A helper for embedding common behavior.
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type commonOp struct {
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// The context exposed to the user.
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ctx context.Context
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// The op in which this struct is embedded.
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op internalOp
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// The underlying fuseshim request for this op.
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bazilReq fuseshim.Request
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// A function that can be used to log debug information about the op. The
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// first argument is a call depth.
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//
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// May be nil.
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debugLog func(int, string, ...interface{})
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// A logger to be used for logging exceptional errors.
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//
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// May be nil.
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errorLogger *log.Logger
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// A function that is invoked with the error given to Respond, for use in
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// closing off traces and reporting back to the connection.
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finished func(error)
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}
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func (o *commonOp) ShortDesc() (desc string) {
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opName := reflect.TypeOf(o.op).String()
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// Attempt to better handle the usual case: a string that looks like
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// "*fuseops.GetInodeAttributesOp".
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const prefix = "*fuseops."
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const suffix = "Op"
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if strings.HasPrefix(opName, prefix) && strings.HasSuffix(opName, suffix) {
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opName = opName[len(prefix) : len(opName)-len(suffix)]
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}
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// Include the inode number to which the op applies.
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desc = fmt.Sprintf("%s(inode=%v)", opName, o.bazilReq.Hdr().Node)
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return
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}
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func (o *commonOp) init(
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ctx context.Context,
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op internalOp,
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bazilReq fuseshim.Request,
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debugLog func(int, string, ...interface{}),
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errorLogger *log.Logger,
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finished func(error)) {
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// Initialize basic fields.
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o.ctx = ctx
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o.op = op
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o.bazilReq = bazilReq
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o.debugLog = debugLog
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o.errorLogger = errorLogger
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o.finished = finished
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// Set up a trace span for this op.
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var reportForTrace reqtrace.ReportFunc
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o.ctx, reportForTrace = reqtrace.StartSpan(o.ctx, o.op.ShortDesc())
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// When the op is finished, report to both reqtrace and the connection.
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prevFinish := o.finished
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o.finished = func(err error) {
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reportForTrace(err)
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prevFinish(err)
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}
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}
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func (o *commonOp) Context() context.Context {
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return o.ctx
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}
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func (o *commonOp) Logf(format string, v ...interface{}) {
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if o.debugLog == nil {
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return
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}
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const calldepth = 2
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o.debugLog(calldepth, format, v...)
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}
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func (o *commonOp) Respond(err error) {
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// Report that the user is responding.
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o.finished(err)
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// If successful, we should respond to fuseshim with the appropriate struct.
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if err == nil {
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o.op.respond()
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return
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}
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// Log the error.
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if o.debugLog != nil {
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o.Logf(
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"-> (%s) error: %v",
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o.op.ShortDesc(),
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err)
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}
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if o.errorLogger != nil {
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o.errorLogger.Printf(
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"(%s) error: %v",
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o.op.ShortDesc(),
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err)
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}
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// Send a response to the kernel.
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o.bazilReq.RespondError(err)
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}
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