85 lines
2.7 KiB
Go
85 lines
2.7 KiB
Go
// Copyright 2018 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package feed
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import (
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"encoding/binary"
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"encoding/json"
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"time"
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)
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// TimestampProvider sets the time source of the feeds package
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var TimestampProvider timestampProvider = NewDefaultTimestampProvider()
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// Timestamp encodes a point in time as a Unix epoch
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type Timestamp struct {
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Time uint64 `json:"time"` // Unix epoch timestamp, in seconds
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}
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// 8 bytes uint64 Time
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const timestampLength = 8
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// timestampProvider interface describes a source of timestamp information
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type timestampProvider interface {
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Now() Timestamp // returns the current timestamp information
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}
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// binaryGet populates the timestamp structure from the given byte slice
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func (t *Timestamp) binaryGet(data []byte) error {
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if len(data) != timestampLength {
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return NewError(ErrCorruptData, "timestamp data has the wrong size")
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}
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t.Time = binary.LittleEndian.Uint64(data[:8])
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return nil
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}
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// binaryPut Serializes a Timestamp to a byte slice
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func (t *Timestamp) binaryPut(data []byte) error {
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if len(data) != timestampLength {
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return NewError(ErrCorruptData, "timestamp data has the wrong size")
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}
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binary.LittleEndian.PutUint64(data, t.Time)
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return nil
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}
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// UnmarshalJSON implements the json.Unmarshaller interface
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func (t *Timestamp) UnmarshalJSON(data []byte) error {
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return json.Unmarshal(data, &t.Time)
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}
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// MarshalJSON implements the json.Marshaller interface
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func (t *Timestamp) MarshalJSON() ([]byte, error) {
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return json.Marshal(t.Time)
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}
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// DefaultTimestampProvider is a TimestampProvider that uses system time
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// as time source
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type DefaultTimestampProvider struct {
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}
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// NewDefaultTimestampProvider creates a system clock based timestamp provider
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func NewDefaultTimestampProvider() *DefaultTimestampProvider {
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return &DefaultTimestampProvider{}
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}
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// Now returns the current time according to this provider
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func (dtp *DefaultTimestampProvider) Now() Timestamp {
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return Timestamp{
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Time: uint64(time.Now().Unix()),
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}
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}
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