70 lines
2.0 KiB
Kotlin
70 lines
2.0 KiB
Kotlin
/*
|
|
* Copyright 2023 Tusky Contributors
|
|
*
|
|
* This file is a part of Tusky.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it under the terms of the
|
|
* GNU General Public License as published by the Free Software Foundation; either version 3 of the
|
|
* License, or (at your option) any later version.
|
|
*
|
|
* Tusky 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 General
|
|
* Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along with Tusky; if not,
|
|
* see <http://www.gnu.org/licenses>.
|
|
*/
|
|
|
|
package com.keylesspalace.tusky.util
|
|
|
|
import kotlinx.coroutines.flow.Flow
|
|
import kotlinx.coroutines.flow.flow
|
|
import kotlin.time.Duration
|
|
import kotlin.time.ExperimentalTime
|
|
import kotlin.time.TimeMark
|
|
import kotlin.time.TimeSource
|
|
|
|
/**
|
|
* Returns a flow that mirrors the original flow, but filters out values that occur within
|
|
* [timeout] of the previously emitted value. The first value is always emitted.
|
|
*
|
|
* Example:
|
|
*
|
|
* ```kotlin
|
|
* flow {
|
|
* emit(1)
|
|
* delay(90.milliseconds)
|
|
* emit(2)
|
|
* delay(90.milliseconds)
|
|
* emit(3)
|
|
* delay(1010.milliseconds)
|
|
* emit(4)
|
|
* delay(1010.milliseconds)
|
|
* emit(5)
|
|
* }.throttleFirst(1000.milliseconds)
|
|
* ```
|
|
*
|
|
* produces the following emissions.
|
|
*
|
|
* ```text
|
|
* 1, 4, 5
|
|
* ```
|
|
*
|
|
* @see kotlinx.coroutines.flow.debounce(Duration)
|
|
* @param timeout Emissions within this duration of the last emission are filtered
|
|
* @param timeSource Used to measure elapsed time. Normally only overridden in tests
|
|
*/
|
|
@OptIn(ExperimentalTime::class)
|
|
fun <T> Flow<T>.throttleFirst(
|
|
timeout: Duration,
|
|
timeSource: TimeSource = TimeSource.Monotonic
|
|
) = flow {
|
|
var marker: TimeMark? = null
|
|
collect {
|
|
if (marker == null || marker!!.elapsedNow() >= timeout) {
|
|
emit(it)
|
|
marker = timeSource.markNow()
|
|
}
|
|
}
|
|
}
|