okhttp3.internal.io.FileSystem.kt Maven / Gradle / Ivy
/*
* Copyright (C) 2015 Square, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package okhttp3.internal.io
import java.io.File
import java.io.FileNotFoundException
import java.io.IOException
import okio.Sink
import okio.Source
import okio.appendingSink
import okio.sink
import okio.source
/**
* Access to read and write files on a hierarchical data store. Most callers should use the
* [SYSTEM] implementation, which uses the host machine's local file system. Alternate
* implementations may be used to inject faults (for testing) or to transform stored data (to add
* encryption, for example).
*
* All operations on a file system are racy. For example, guarding a call to [source] with
* [exists] does not guarantee that [FileNotFoundException] will not be thrown. The
* file may be moved between the two calls!
*
* This interface is less ambitious than [java.nio.file.FileSystem] introduced in Java 7.
* It lacks important features like file watching, metadata, permissions, and disk space
* information. In exchange for these limitations, this interface is easier to implement and works
* on all versions of Java and Android.
*/
interface FileSystem {
companion object {
/** The host machine's local file system. */
@JvmField
val SYSTEM: FileSystem = SystemFileSystem()
private class SystemFileSystem : FileSystem {
@Throws(FileNotFoundException::class)
override fun source(file: File): Source = file.source()
@Throws(FileNotFoundException::class)
override fun sink(file: File): Sink {
return try {
file.sink()
} catch (_: FileNotFoundException) {
// Maybe the parent directory doesn't exist? Try creating it first.
file.parentFile.mkdirs()
file.sink()
}
}
@Throws(FileNotFoundException::class)
override fun appendingSink(file: File): Sink {
return try {
file.appendingSink()
} catch (_: FileNotFoundException) {
// Maybe the parent directory doesn't exist? Try creating it first.
file.parentFile.mkdirs()
file.appendingSink()
}
}
@Throws(IOException::class)
override fun delete(file: File) {
// If delete() fails, make sure it's because the file didn't exist!
if (!file.delete() && file.exists()) {
throw IOException("failed to delete $file")
}
}
override fun exists(file: File): Boolean = file.exists()
override fun size(file: File): Long = file.length()
@Throws(IOException::class)
override fun rename(from: File, to: File) {
delete(to)
if (!from.renameTo(to)) {
throw IOException("failed to rename $from to $to")
}
}
@Throws(IOException::class)
override fun deleteContents(directory: File) {
val files = directory.listFiles() ?: throw IOException("not a readable directory: $directory")
for (file in files) {
if (file.isDirectory) {
deleteContents(file)
}
if (!file.delete()) {
throw IOException("failed to delete $file")
}
}
}
override fun toString() = "FileSystem.SYSTEM"
}
}
/** Reads from [file]. */
@Throws(FileNotFoundException::class)
fun source(file: File): Source
/**
* Writes to [file], discarding any data already present. Creates parent directories if
* necessary.
*/
@Throws(FileNotFoundException::class)
fun sink(file: File): Sink
/**
* Writes to [file], appending if data is already present. Creates parent directories if
* necessary.
*/
@Throws(FileNotFoundException::class)
fun appendingSink(file: File): Sink
/** Deletes [file] if it exists. Throws if the file exists and cannot be deleted. */
@Throws(IOException::class)
fun delete(file: File)
/** Returns true if [file] exists on the file system. */
fun exists(file: File): Boolean
/** Returns the number of bytes stored in [file], or 0 if it does not exist. */
fun size(file: File): Long
/** Renames [from] to [to]. Throws if the file cannot be renamed. */
@Throws(IOException::class)
fun rename(from: File, to: File)
/**
* Recursively delete the contents of [directory]. Throws an IOException if any file could
* not be deleted, or if `dir` is not a readable directory.
*/
@Throws(IOException::class)
fun deleteContents(directory: File)
}