v0.0.304 add support for WithModifyingPipeline to wmo

wmo/queryList.go

@@ -34,7 +34,7 @@ func (c *Coll[TData]) List(ctx context.Context, filter ct.Filter, pageSize *int,
 		sortDirSecondary = nil
 	}
 
-	paginationPipeline, err := CreatePagination(c, inTok, sortPrimary, sortDirPrimary, sortSecondary, sortDirSecondary, pageSize)
+	paginationPipeline, err := createPaginationPipeline(c, inTok, sortPrimary, sortDirPrimary, sortSecondary, sortDirSecondary, pageSize)
 	if err != nil {
 		return nil, ct.CursorToken{}, exerr.
 			Wrap(err, "failed to create pagination").
@@ -50,6 +50,7 @@ func (c *Coll[TData]) List(ctx context.Context, filter ct.Filter, pageSize *int,
 	}
 
 	pipeline = append(pipeline, paginationPipeline...)
+	pipeline = append(pipeline, c.extraModPipeline...)
 
 	cursor, err := c.coll.Aggregate(ctx, pipeline)
 	if err != nil {
@@ -130,3 +131,83 @@ func (c *Coll[TData]) ListWithCount(ctx context.Context, filter ct.Filter, pageS
 	}
 	return data, token, count, nil
 }
+
+func createPaginationPipeline[TData any](coll *Coll[TData], token ct.CursorToken, fieldPrimary string, sortPrimary ct.SortDirection, fieldSecondary *string, sortSecondary *ct.SortDirection, pageSize *int) ([]bson.D, error) {
+
+	cond := bson.A{}
+	sort := bson.D{}
+
+	valuePrimary, err := coll.getTokenValueAsMongoType(token.ValuePrimary, fieldPrimary)
+	if err != nil {
+		return nil, exerr.Wrap(err, "failed to get (primary) token-value as mongo-type").Build()
+	}
+
+	if sortPrimary == ct.SortASC {
+		// We sort ASC on <field> - so we want all entries newer ($gt) than the $primary
+		cond = append(cond, bson.M{fieldPrimary: bson.M{"$gt": valuePrimary}})
+		sort = append(sort, bson.E{Key: fieldPrimary, Value: +1})
+	} else if sortPrimary == ct.SortDESC {
+		// We sort DESC on <field> - so we want all entries older ($lt) than the $primary
+		cond = append(cond, bson.M{fieldPrimary: bson.M{"$lt": valuePrimary}})
+		sort = append(sort, bson.E{Key: fieldPrimary, Value: -1})
+	}
+
+	if fieldSecondary != nil && sortSecondary != nil && *fieldSecondary != fieldPrimary {
+
+		valueSecondary, err := coll.getTokenValueAsMongoType(token.ValueSecondary, *fieldSecondary)
+		if err != nil {
+			return nil, exerr.Wrap(err, "failed to get (secondary) token-value as mongo-type").Build()
+		}
+
+		if *sortSecondary == ct.SortASC {
+
+			// the conflict-resolution condition, for entries with the _same_ <field> as the $primary we take the ones with a greater $secondary (= newer)
+			cond = append(cond, bson.M{"$and": bson.A{
+				bson.M{fieldPrimary: valuePrimary},
+				bson.M{*fieldSecondary: bson.M{"$gt": valueSecondary}},
+			}})
+
+			sort = append(sort, bson.E{Key: fieldPrimary, Value: +1})
+
+		} else if *sortSecondary == ct.SortDESC {
+
+			// the conflict-resolution condition, for entries with the _same_ <field> as the $primary we take the ones with a smaller $secondary (= older)
+			cond = append(cond, bson.M{"$and": bson.A{
+				bson.M{fieldPrimary: valuePrimary},
+				bson.M{*fieldSecondary: bson.M{"$lt": valueSecondary}},
+			}})
+
+			sort = append(sort, bson.E{Key: fieldPrimary, Value: -1})
+
+		}
+	}
+
+	pipeline := make([]bson.D, 0, 3)
+
+	if token.Mode == ct.CTMStart {
+
+		// no gt/lt condition
+
+	} else if token.Mode == ct.CTMNormal {
+
+		pipeline = append(pipeline, bson.D{{Key: "$match", Value: bson.M{"$or": cond}}})
+
+	} else if token.Mode == ct.CTMEnd {
+
+		// false
+		pipeline = append(pipeline, bson.D{{Key: "$match", Value: bson.M{"$expr": bson.M{"$eq": bson.A{"1", "0"}}}}})
+
+	} else {
+
+		return nil, exerr.New(exerr.TypeInternal, "unknown ct mode: "+string(token.Mode)).Any("token.Mode", token.Mode).Build()
+
+	}
+
+	pipeline = append(pipeline, bson.D{{Key: "$sort", Value: sort}})
+
+	if pageSize != nil {
+		pipeline = append(pipeline, bson.D{{Key: "$limit", Value: int64(*pageSize + 1)}})
+	}
+
+	return pipeline, nil
+}