nativeMain.okio.FileSource.kt Maven / Gradle / Ivy
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/*
* Copyright (C) 2020 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 okio
import kotlinx.cinterop.CPointer
import kotlinx.cinterop.addressOf
import kotlinx.cinterop.usePinned
import okio.Buffer.UnsafeCursor
import platform.posix.FILE
import platform.posix.errno
import platform.posix.fclose
import platform.posix.feof
import platform.posix.ferror
/** Reads the bytes of a file as a source. */
internal class FileSource(
private val file: CPointer,
) : Source {
private val unsafeCursor = UnsafeCursor()
private var closed = false
override fun read(
sink: Buffer,
byteCount: Long,
): Long {
require(byteCount >= 0L) { "byteCount < 0: $byteCount" }
check(!closed) { "closed" }
val sinkInitialSize = sink.size
// Request a writable segment in `sink`. We request at least 1024 bytes, unless the request is
// for smaller than that, in which case we request only that many bytes.
val cursor = sink.readAndWriteUnsafe(unsafeCursor)
val addedCapacityCount = cursor.expandBuffer(minByteCount = minOf(byteCount, 1024L).toInt())
// Now that we have a writable segment, figure out how many bytes to read. This is the smaller
// of the user's requested byte count, and the segment's writable capacity.
val attemptCount = minOf(byteCount, addedCapacityCount)
// Copy bytes from the file to the segment.
val bytesRead = cursor.data!!.usePinned { pinned ->
variantFread(pinned.addressOf(cursor.start), attemptCount.toUInt(), file).toLong()
}
// Remove new capacity that was added but not used.
cursor.resizeBuffer(sinkInitialSize + bytesRead)
cursor.close()
return when {
bytesRead == attemptCount -> bytesRead
feof(file) != 0 -> if (bytesRead == 0L) -1L else bytesRead
ferror(file) != 0 -> throw errnoToIOException(errno)
else -> bytesRead
}
}
override fun timeout(): Timeout = Timeout.NONE
override fun close() {
if (closed) return
closed = true
fclose(file)
}
}