exchange.Collection to fill in key information from selectors (#457)

Selectors and scope information are used to create the correct populate methods. Populate methods changed to fit type abstractions definitions for iteration, querying, and collection population.

src/internal/connector/exchange/exchange_data_collection.go

@@ -32,10 +32,8 @@ const (
 	RestoreCanonicalEnableValue = "4"
 )
 
-// ExchangeDataCollection represents exchange mailbox
-// data for a single user.
-//
-// It implements the DataCollection interface
+// Collection implements the interface from data.Collection
+// Structure holds data for an Exchange application for a single user
 type Collection struct {
 	// M365 user
 	user string // M365 user
@@ -43,34 +41,52 @@ type Collection struct {
 	// jobs represents items from the inventory of M365 objectIds whose information
 	// is desired to be sent through the data channel for eventual storage
 	jobs []string
-
-	service  graph.Service
+	// service - client/adapter pair used to access M365 back store
+	service graph.Service
+	// populate - Utility function to populate collection based on the M365 application type and granularity
+	populate populater
 	statusCh chan<- *support.ConnectorOperationStatus
 	// FullPath is the slice representation of the action context passed down through the hierarchy.
 	//The original request can be gleaned from the slice. (e.g. {<tenant ID>, <user ID>, "emails"})
 	fullPath []string
 }
 
+// Populater are a class of functions that can be used to fill exchange.Collections with
+// the corresponding information
+type populater func(context.Context, graph.Service, *Collection, chan<- *support.ConnectorOperationStatus)
+
 // NewExchangeDataCollection creates an ExchangeDataCollection with fullPath is annotated
 func NewCollection(
-	aUser string,
-	pathRepresentation []string,
+	user string,
+	fullPath []string,
 	collectionType optionIdentifier,
-	aService graph.Service,
+	service graph.Service,
 	statusCh chan<- *support.ConnectorOperationStatus,
 ) Collection {
 	collection := Collection{
-		user:     aUser,
+		user:     user,
 		data:     make(chan data.Stream, collectionChannelBufferSize),
 		jobs:     make([]string, 0),
-		service:  aService,
+		service:  service,
 		statusCh: statusCh,
-		fullPath: pathRepresentation,
+		fullPath: fullPath,
+		populate: getPopulateFunction(collectionType),
 	}
 	return collection
 }
 
-// AddJob appends additional objectID to job field job
+// getPopulateFunction is a function to set populate function field
+// with exchange-application specific functions
+func getPopulateFunction(optId optionIdentifier) populater {
+	switch optId {
+	case messages:
+		return PopulateFromCollection
+	default:
+		return nil
+	}
+}
+
+// AddJob appends additional objectID to structure's jobs field
 func (eoc *Collection) AddJob(objID string) {
 	eoc.jobs = append(eoc.jobs, objID)
 }
@@ -78,18 +94,22 @@ func (eoc *Collection) AddJob(objID string) {
 // Items utility function to asynchronously execute process to fill data channel with
 // M365 exchange objects and returns the data channel
 func (eoc *Collection) Items() <-chan data.Stream {
-	go eoc.PopulateFromCollection(context.TODO(), eoc.service, eoc.statusCh)
+	if eoc.populate != nil {
+		go eoc.populate(context.TODO(), eoc.service, eoc, eoc.statusCh)
+	}
 	return eoc.data
 }
 
+// FullPath returns the Collection's fullPath []string
 func (edc *Collection) FullPath() []string {
 	return append([]string{}, edc.fullPath...)
 }
 
-// populateFromTaskList async call to fill DataCollection via channel implementation
-func (edc *Collection) PopulateFromCollection(
+// PopulateFromCollection async call to fill DataCollection via channel implementation
+func PopulateFromCollection(
 	ctx context.Context,
 	service graph.Service,
+	edc *Collection,
 	statusChannel chan<- *support.ConnectorOperationStatus,
 ) {
 	var errs error

src/internal/connector/exchange/exchange_data_collection_test.go

@@ -2,10 +2,19 @@ package exchange
 
 import (
 	"bytes"
+	"context"
 	"testing"
+	"time"
 
+	"github.com/google/uuid"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
+
+	"github.com/alcionai/corso/internal/connector/graph"
+	"github.com/alcionai/corso/internal/connector/mockconnector"
+	"github.com/alcionai/corso/internal/connector/support"
+	"github.com/alcionai/corso/internal/data"
+	"github.com/alcionai/corso/pkg/backup/details"
 )
 
 type ExchangeDataCollectionSuite struct {
@@ -73,3 +82,35 @@ func (suite *ExchangeDataCollectionSuite) TestExchangeCollection_AddJob() {
 	suite.Equal(len(shopping), len(eoc.jobs))
 
 }
+
+// TestExchangeCollection_Items() tests for the Collection.Items() ability
+// to asynchronously fill `data` field with Stream objects
+func (suite *ExchangeDataCollectionSuite) TestExchangeCollection_Items() {
+	expected := 5
+	testFunction := func(ctx context.Context,
+		service graph.Service,
+		eoc *Collection,
+		notUsed chan<- *support.ConnectorOperationStatus) {
+		detail := &details.ExchangeInfo{Sender: "foo@bar.com", Subject: "Hello world!", Received: time.Now()}
+		for i := 0; i < expected; i++ {
+			temp := NewStream(uuid.NewString(), mockconnector.GetMockMessageBytes("Test_Items()"), *detail)
+			eoc.data <- &temp
+		}
+		close(eoc.data)
+	}
+
+	eoc := Collection{
+		user:     "Dexter",
+		fullPath: []string{"Today", "is", "currently", "different"},
+		data:     make(chan data.Stream, expected),
+		populate: testFunction,
+	}
+	t := suite.T()
+	itemsReturn := eoc.Items()
+	retrieved := 0
+	for item := range itemsReturn {
+		assert.NotNil(t, item)
+		retrieved++
+	}
+	suite.Equal(expected, retrieved)
+}

src/internal/connector/mockconnector/mock_data_collection.go

@@ -39,7 +39,7 @@ func NewMockExchangeCollection(pathRepresentation []string, numMessagesToReturn
 
 	for i := 0; i < c.messageCount; i++ {
 		// We can plug in whatever data we want here (can be an io.Reader to a test data file if needed)
-		c.Data = append(c.Data, getMockMessageBytes("From: NewMockExchangeCollection"))
+		c.Data = append(c.Data, GetMockMessageBytes("From: NewMockExchangeCollection"))
 		c.Names = append(c.Names, uuid.NewString())
 	}
 	return c
@@ -85,9 +85,9 @@ func (med *MockExchangeData) Info() details.ItemInfo {
 	return details.ItemInfo{Exchange: &details.ExchangeInfo{Sender: "foo@bar.com", Subject: "Hello world!", Received: time.Now()}}
 }
 
-// getMockMessageBytes returns bytes for Messageable item.
+// GetMockMessageBytes returns bytes for Messageable item.
 // Contents verified as working with sample data from kiota-serialization-json-go v0.5.5
-func getMockMessageBytes(subject string) []byte {
+func GetMockMessageBytes(subject string) []byte {
 
 	userID, err := tester.M365UserID()
 	if err != nil {