Refactor distributor API so that methods always get the Quest_Desc too.

dm/appengine/distributor/task_description.go

Index: dm/appengine/distributor/task_description.go
diff --git a/dm/appengine/distributor/task_description.go b/dm/appengine/distributor/task_description.go
deleted file mode 100644
index a447c919d8af17aa24fdcf3f283906841fd26f26..0000000000000000000000000000000000000000
--- a/dm/appengine/distributor/task_description.go
+++ /dev/null
@@ -1,75 +0,0 @@
-// Copyright 2016 The LUCI Authors. All rights reserved.
-// Use of this source code is governed under the Apache License, Version 2.0
-// that can be found in the LICENSE file.
-
-package distributor
-
-import (
-	"fmt"
-
-	"github.com/golang/protobuf/proto"
-	"github.com/luci/gae/service/info"
-	"github.com/luci/luci-go/common/gcloud/pubsub"
-	dm "github.com/luci/luci-go/dm/api/service/v1"
-	"golang.org/x/net/context"
-)
-
-// NewTaskDescription builds a new *TaskDescription.
-//
-// It's intended for use by the DM core logic, and not for use by distributor
-// implementations.
-func NewTaskDescription(c context.Context, payload *dm.Quest_Desc, exAuth *dm.Execution_Auth,
-	previousResult *dm.JsonResult) *TaskDescription {
-	return &TaskDescription{
-		c:              c,
-		payload:        payload,
-		executionAuth:  exAuth,
-		previousResult: previousResult,
-	}
-}
-
-// TaskDescription is the parameters for PrepareTask.
-type TaskDescription struct {
-	c              context.Context
-	payload        *dm.Quest_Desc
-	executionAuth  *dm.Execution_Auth
-	previousResult *dm.JsonResult
-}
-
-// PrepareTopic returns the pubsub topic that notifications should be sent to.
-//
-// It returns the full name of the topic and a token that will be used to route
-// PubSub messages back to the Distributor. The publisher to the topic must be
-// instructed to put the token into the 'auth_token' attribute of PubSub
-// messages. DM will know how to route such messages to D.HandleNotification.
-func (t *TaskDescription) PrepareTopic() (topic pubsub.Topic, token string, err error) {
-	topic = pubsub.NewTopic(info.Get(t.c).TrimmedAppID(), notifyTopicSuffix)
-	if err := topic.Validate(); err != nil {
-		panic(fmt.Errorf("failed to validate Topic %q: %s", topic, err))
-	}
-	token, err = encodeAuthToken(t.c, t.executionAuth.Id,
-		t.payload.DistributorConfigName)
-	return
-}
-
-// PreviousResult is the Result of the last successful Execution for the
-// Attempt. This will be nil for the first Execution.
-func (t *TaskDescription) PreviousResult() *dm.JsonResult {
-	if t.previousResult == nil {
-		return nil
-	}
-	return proto.Clone(t.previousResult).(*dm.JsonResult)
-}
-
-// Payload is description of the job to run.
-func (t *TaskDescription) Payload() *dm.Quest_Desc {
-	return proto.Clone(t.payload).(*dm.Quest_Desc)
-}
-
-// ExecutionAuth is the combined execution_id+activation token that the
-// execution must use to call ActivateExecution before making further API calls
-// into DM.
-func (t *TaskDescription) ExecutionAuth() *dm.Execution_Auth {
-	ret := *t.executionAuth
-	return &ret
-}