126 lines
2.8 KiB
Go
126 lines
2.8 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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"reflect"
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"strings"
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"sync"
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"github.com/jacobsa/bazilfuse"
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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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// A helper for embedding common behavior.
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type commonOp struct {
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opType string
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r bazilfuse.Request
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log func(int, string, ...interface{})
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opsInFlight *sync.WaitGroup
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ctx context.Context
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report reqtrace.ReportFunc
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}
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func describeOpType(t reflect.Type) (desc string) {
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name := t.String()
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// The usual case: a string that looks like "*fuseops.GetInodeAttributesOp".
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const prefix = "*fuseops."
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const suffix = "Op"
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if strings.HasPrefix(name, prefix) && strings.HasSuffix(name, suffix) {
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desc = name[len(prefix) : len(name)-len(suffix)]
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return
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}
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// Otherwise, it's not clear what to do.
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desc = t.String()
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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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opType reflect.Type,
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r bazilfuse.Request,
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log func(int, string, ...interface{}),
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opsInFlight *sync.WaitGroup) {
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// Initialize basic fields.
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o.opType = describeOpType(opType)
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o.r = r
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o.log = log
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o.opsInFlight = opsInFlight
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// Set up a trace span for this op.
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o.ctx, o.report = reqtrace.StartSpan(ctx, o.opType)
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}
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func (o *commonOp) Header() OpHeader {
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bh := o.r.Hdr()
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return OpHeader{
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Uid: bh.Uid,
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Gid: bh.Gid,
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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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const calldepth = 2
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o.log(calldepth, format, v...)
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}
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func (o *commonOp) respondErr(err error) {
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if err == nil {
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panic("Expect non-nil here.")
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}
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o.report(err)
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o.Logf(
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"-> (%s) error: %v",
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o.opType,
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err)
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o.r.RespondError(err)
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}
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// Respond with the supplied response struct, which must be accepted by a
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// method called Respond on o.r.
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//
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// Special case: nil means o.r.Respond accepts no parameters.
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func (o *commonOp) respond(resp interface{}) {
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// We were successful.
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o.report(nil)
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// Find the Respond method.
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v := reflect.ValueOf(o.r)
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respond := v.MethodByName("Respond")
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// Special case: handle successful ops with no response struct.
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if resp == nil {
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o.Logf("-> (%s) OK", o.opType)
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respond.Call([]reflect.Value{})
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return
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}
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// Otherwise, pass along the response struct.
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o.Logf("-> %v", resp)
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respond.Call([]reflect.Value{reflect.ValueOf(resp)})
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}
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