geotrellis.util.Filesystem.scala Maven / Gradle / Ivy
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GeoTrellis is an open source geographic data processing engine for high performance applications.
/*
* Copyright (c) 2014 Azavea.
*
* 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 geotrellis.util
import java.io._
import java.nio.ByteBuffer
import java.nio.channels.FileChannel.MapMode._
import java.nio.charset.StandardCharsets
import java.nio.file._
object Filesystem {
/**
* Read the contents of a file into an array.
*
* @param path The path to the file to be read
* @param bs The block size; The file will be read in chunks of this size
* @return An array of bytes containing the file contents
*/
def slurp(path: String, bs: Int = (1<<18)): Array[Byte] = {
val f = new File(path)
val fis = new FileInputStream(f)
val size = f.length.toInt
val channel = fis.getChannel
val buffer = channel.map(READ_ONLY, 0, size)
channel.close()
fis.close()
// read 256KiB (2^18 bytes) at a time out of the buffer into our array
var i = 0
val data = Array.ofDim[Byte](size)
while(buffer.hasRemaining()) {
val n = math.min(buffer.remaining(), bs)
buffer.get(data, i, n)
i += n
}
data
}
/**
* Make a contiguous chunk of a file available in the given array.
*
* @param path The path to the file which is to be (partially) mapped into memory
* @param data An array to contain the portion of the file in question
* @param startIndex The offset into the file where the contiguous region begins
* @param size The size of the contiguous region
*/
def mapToByteArray(path: String, data: Array[Byte], startIndex: Int, size: Int): Unit = {
val f = new File(path)
val fis = new FileInputStream(f)
val buffer =
try {
val channel = fis.getChannel
channel.map(READ_ONLY, startIndex, size)
} finally {
fis.close
}
buffer.get(data, startIndex, size)
}
/**
* Return the path string with the final extension removed.
*
* @param path The path whose extension is to be removed (if it has one)
* @return The path minus the extension
*/
def basename(path: String) =
path.lastIndexOf(".") match {
case -1 => path
case n => path.substring(0, n)
}
/**
* Split the given path into a tuple of base and extension.
*
* @param path The path which is to be split
* @return A tuple of the basename and the extension of the given path
*/
def split(path: String) =
path.lastIndexOf(".") match {
case -1 => (path, "")
case n => (path.substring(0, n), path.substring(n + 1, path.length))
}
/**
* Join the given parts into a single string, with the parts
* separated by the system's file separator.
*
* @param parts A list of parts which are to be concatenated
* @return The parts concatenated, separated by the file separator
*/
def join(parts: String*) = parts.mkString(File.separator)
/**
* Return the contents of a file, interpreted as text, as a string.
*
* @param path The path to the file to be read
* @return A string containing the file's contents
*/
def readText(path: String): String = {
val src = scala.io.Source.fromFile(path, "UTF-8")
try {
src.mkString
} finally {
src.close()
}
}
/**
* Return the contents of a file, interpreted as text, as a string.
*
* @param file The the file to be read
* @return A string containing the file's contents
*/
def readText(file: File): String =
readText(file.getAbsolutePath)
/**
* Write the given array of bytes to the file pointed to by the
* given path. This is a truncating write.
*
* @param path The path to the file where the data are to be written
* @param bytes An array of bytes containing the data to be written
*/
def writeBytes(path: String, bytes: Array[Byte]): Unit = {
val bos = new BufferedOutputStream(new FileOutputStream(path))
bos.write(bytes)
bos.close
}
/**
* Write the given text into the file pointed to by the given path.
* The is a truncating write.
*
* @param path The path to the file where the text will be written
* @param text A string containing the text to be written
*/
def writeText(path: String, text: String): Unit =
Files.write(Paths.get(path), text.getBytes(StandardCharsets.UTF_8))
/**
* Write the given text into a file. This is a truncating write.
*
* @param path The path to the file where the text will be written
* @param text A string containing the text to be written
*/
def writeText(file: File, text: String): Unit =
writeText(file.getAbsolutePath, text)
/**
* Move (rename) the given file, obliterating any existing file
* that already has the target name.
*
* @param source The path to the file before moving
* @param target The path to the file after moving
*/
def move(source: String, target: String): Unit =
Files.move(Paths.get(source), Paths.get(target), StandardCopyOption.REPLACE_EXISTING)
/**
* Move (rename) the given file, obliterating any existing file
* that already has the target name.
*
* @param source A [[java.nio.file.File]] representing the desired source
* @param target A [[java.nio.file.File]] representing the desired destination
*/
def move(source: File, target: File): Unit =
move(source.getAbsolutePath, target.getAbsolutePath)
/**
* Copy the given file, obliterating any existing file that already
* has the target name.
*
* @param source The path to the file to be copied
* @param target The path to the place where the file is to be copied
*/
def copy(source: String, target: String): Unit =
Files.copy(Paths.get(source), Paths.get(target), StandardCopyOption.REPLACE_EXISTING)
/**
* Copy the given file, obliterating any existing file that already
* has the target name.
*
* @param source The path to the file to be copied
* @param target The path to the place where the file is to be copied
*/
def copy(source: File, target: File): Unit =
copy(source.getAbsolutePath, target.getAbsolutePath)
/**
* Ensure the existence of a given directory.
*
* @param path The path to the directory
*/
def ensureDirectory(path: String): String = {
val f = new File(path)
if(f.exists) {
require(f.isDirectory, s"$f exists and is not a directory")
} else {
f.mkdirs()
}
path
}
}
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