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// Copyright 2018 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package feeds
import (
"fmt"
"strconv"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/swarm/storage/feeds/lookup"
)
// Query is used to specify constraints when performing an update lookup
// TimeLimit indicates an upper bound for the search. Set to 0 for "now"
type Query struct {
Feed
Hint lookup.Epoch
TimeLimit uint64
}
// FromValues deserializes this instance from a string key-value store
// useful to parse query strings
func (q *Query) FromValues(values Values) error {
time, _ := strconv.ParseUint(values.Get("time"), 10, 64)
q.TimeLimit = time
level, _ := strconv.ParseUint(values.Get("hint.level"), 10, 32)
q.Hint.Level = uint8(level)
q.Hint.Time, _ = strconv.ParseUint(values.Get("hint.time"), 10, 64)
if q.Feed.User == (common.Address{}) {
return q.Feed.FromValues(values)
}
return nil
}
// AppendValues serializes this structure into the provided string key-value store
// useful to build query strings
func (q *Query) AppendValues(values Values) {
if q.TimeLimit != 0 {
values.Set("time", fmt.Sprintf("%d", q.TimeLimit))
}
if q.Hint.Level != 0 {
values.Set("hint.level", fmt.Sprintf("%d", q.Hint.Level))
}
if q.Hint.Time != 0 {
values.Set("hint.time", fmt.Sprintf("%d", q.Hint.Time))
}
q.Feed.AppendValues(values)
}
// NewQuery constructs an Query structure to find updates on or before `time`
// if time == 0, the latest update will be looked up
func NewQuery(feed *Feed, time uint64, hint lookup.Epoch) *Query {
return &Query{
TimeLimit: time,
Feed: *feed,
Hint: hint,
}
}
// NewQueryLatest generates lookup parameters that look for the latest update to a feed
func NewQueryLatest(feed *Feed, hint lookup.Epoch) *Query {
return NewQuery(feed, 0, hint)
}
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