commonMain.io.ktor.http.RangesSpecifier.kt Maven / Gradle / Ivy
/*
* Copyright 2014-2021 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
*/
package io.ktor.http
/**
* Range specifier for partial content requests (RFC 2616 sec 14.35.1)
* @property unit range units, usually bytes
* @property ranges a list of requested ranges (could be open or closed ranges)
*/
public data class RangesSpecifier(val unit: String = RangeUnits.Bytes.unitToken, val ranges: List) {
public constructor(unit: RangeUnits, ranges: List) : this(unit.unitToken, ranges)
init {
require(ranges.isNotEmpty()) { "It should be at least one range" }
}
/**
* Verify ranges
*/
public fun isValid(rangeUnitPredicate: (String) -> Boolean = { it == RangeUnits.Bytes.unitToken }): Boolean =
rangeUnitPredicate(unit) && ranges.none {
when (it) {
is ContentRange.Bounded -> it.from < 0 || it.to < it.from
is ContentRange.TailFrom -> it.from < 0
is ContentRange.Suffix -> it.lastCount < 0
}
}
/**
* Resolve and merge all overlapping and neighbours ranges
* @param length content length
* @return a list of absolute long ranges
*/
public fun merge(length: Long, maxRangeCount: Int = 50): List {
if (ranges.size > maxRangeCount) {
return mergeToSingle(length).toList()
}
// TODO rangeMergeMaxGap
return merge(length)
}
/**
* Merges all overlapping and neighbours ranges. Currently gaps collapse is not supported but should be, one day.
*/
public fun merge(length: Long): List = ranges.toLongRanges(length).mergeRangesKeepOrder()
/**
* Merge all ranges into a single absolute long range
* @param length content length
*/
public fun mergeToSingle(length: Long): LongRange? {
val mapped = ranges.toLongRanges(length)
if (mapped.isEmpty()) {
return null
}
val start = mapped.minByOrNull { it.start }!!.start
val endInclusive = mapped.maxByOrNull { it.endInclusive }!!.endInclusive.coerceAtMost(length - 1)
return start..endInclusive
}
override fun toString(): String = ranges.joinToString(",", prefix = unit + "=")
private fun T?.toList(): List = if (this == null) emptyList() else listOf(this)
}