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/*
* Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
*/
@file:JvmMultifileClass
@file:JvmName("FilesKt")
package kotlin.io
import java.io.File
/**
* Estimation of a root name by a given file name.
*
* This implementation is able to find /, Drive:/, Drive: or
* //network.name/root as possible root names.
* / denotes File.separator here so \ can be used instead.
* All other possible roots cannot be identified by this implementation.
* It's also not guaranteed (but possible) that function will be able to detect a root
* which is incorrect for current OS. For instance, in Unix function cannot detect
* network root names like //network.name/root, but can detect Windows roots like C:/.
*
* @return length or a substring representing the root for this path, or zero if this file name is relative.
*/
private fun String.getRootLength(): Int {
// Note: separators should be already replaced to system ones
var first = indexOf(File.separatorChar, 0)
if (first == 0) {
if (length > 1 && this[1] == File.separatorChar) {
// Network names like //my.host/home/something ? => //my.host/home/ should be root
// NB: does not work in Unix because //my.host/home is converted into /my.host/home there
// So in Windows we'll have root of //my.host/home but in Unix just /
first = indexOf(File.separatorChar, 2)
if (first >= 0) {
first = indexOf(File.separatorChar, first + 1)
if (first >= 0)
return first + 1
else
return length
}
}
return 1
}
// C:\
if (first > 0 && this[first - 1] == ':') {
first++
return first
}
// C:
if (first == -1 && endsWith(':'))
return length
return 0
}
/**
* Estimation of a root name for this file.
*
* This implementation is able to find /, Drive:/, Drive: or
* //network.name/root as possible root names.
* / denotes File.separator here so \ can be used instead.
* All other possible roots cannot be identified by this implementation.
* It's also not guaranteed (but possible) that function will be able to detect a root
* which is incorrect for current OS. For instance, in Unix function cannot detect
* network root names like //network.name/root, but can detect Windows roots like C:/.
*
* @return string representing the root for this file, or empty string is this file name is relative.
*/
internal val File.rootName: String
get() = path.substring(0, path.getRootLength())
/**
* Returns root component of this abstract name, like / from /home/user, or C:\ from C:\file.tmp,
* or //my.host/home for //my.host/home/user
*/
internal val File.root: File
get() = File(rootName)
/**
* Determines whether this file has a root or it represents a relative path.
*
* Returns `true` when this file has non-empty root.
*/
public val File.isRooted: Boolean
get() = path.getRootLength() > 0
/**
* Represents the path to a file as a collection of directories.
*
* @property root the [File] object representing root of the path (for example, `/` or `C:` or empty for relative paths).
* @property segments the list of [File] objects representing every directory in the path to the file,
* up to an including the file itself.
*/
internal data class FilePathComponents
internal constructor(public val root: File, public val segments: List) {
/**
* Returns a string representing the root for this file, or an empty string is this file name is relative.
*/
public val rootName: String get() = root.path
/**
* Returns `true` when the [root] is not empty.
*/
public val isRooted: Boolean get() = root.path.isNotEmpty()
/**
* Returns the number of elements in the path to the file.
*/
public val size: Int get() = segments.size
/**
* Returns a sub-path of the path, starting with the directory at the specified [beginIndex] and up
* to the specified [endIndex].
*/
public fun subPath(beginIndex: Int, endIndex: Int): File {
if (beginIndex < 0 || beginIndex > endIndex || endIndex > size)
throw IllegalArgumentException()
return File(segments.subList(beginIndex, endIndex).joinToString(File.separator))
}
}
/**
* Splits the file into path components (the names of containing directories and the name of the file
* itself) and returns the resulting collection of components.
*/
internal fun File.toComponents(): FilePathComponents {
val path = path
val rootLength = path.getRootLength()
val rootName = path.substring(0, rootLength)
val subPath = path.substring(rootLength)
val list = if (subPath.isEmpty()) listOf() else subPath.split(File.separatorChar).map(::File)
return FilePathComponents(File(rootName), list)
}
/**
* Returns a relative pathname which is a subsequence of this pathname,
* beginning from component [beginIndex], inclusive,
* ending at component [endIndex], exclusive.
* Number 0 belongs to a component closest to the root,
* number count-1 belongs to a component farthest from the root.
* @throws IllegalArgumentException if [beginIndex] is negative,
* or [endIndex] is greater than existing number of components,
* or [beginIndex] is greater than [endIndex].
*/
internal fun File.subPath(beginIndex: Int, endIndex: Int): File = toComponents().subPath(beginIndex, endIndex)