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NSData: Refactor write(toFile:options) using FileHandle methods. #1876

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Merged
merged 1 commit into from
Feb 12, 2019
Merged

NSData: Refactor write(toFile:options) using FileHandle methods. #1876

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64 changes: 32 additions & 32 deletions Foundation/FileHandle.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -14,10 +14,12 @@ import CoreFoundation
#if canImport(Darwin)
import Darwin
fileprivate let _read = Darwin.read(_:_:_:)
fileprivate let _write = Darwin.write(_:_:_:)
fileprivate let _close = Darwin.close(_:)
#elseif canImport(Glibc)
import Glibc
fileprivate let _read = Glibc.read(_:_:_:)
fileprivate let _write = Glibc.write(_:_:_:)
fileprivate let _close = Glibc.close(_:)
#endif

Expand Down Expand Up @@ -217,6 +219,34 @@ open class FileHandle : NSObject, NSSecureCoding {
#endif
}

internal func _writeBytes(buf: UnsafeRawPointer, length: Int) throws {
#if os(Windows)
var bytesRemaining = length
while bytesRemaining > 0 {
var bytesWritten: DWORD = 0
if WriteFile(handle, buf.advanced(by: length - bytesRemaining), DWORD(bytesRemaining), &bytesWritten, nil) == FALSE {
throw _NSErrorWithErrno(Int32(GetLastError()), reading: false, path: nil)
}
if bytesWritten == 0 {
throw _NSErrorWithErrno(Int32(GetLastError()), reading: false, path: nil)
}
bytesRemaining -= Int(bytesWritten)
}
#else
var bytesRemaining = length
while bytesRemaining > 0 {
var bytesWritten = 0
repeat {
bytesWritten = _write(_fd, buf.advanced(by: length - bytesRemaining), bytesRemaining)
} while (bytesWritten < 0 && errno == EINTR)
if bytesWritten <= 0 {
throw _NSErrorWithErrno(errno, reading: false, path: nil)
}
bytesRemaining -= bytesWritten
}
#endif
}

#if os(Windows)
public init(handle: HANDLE, closeOnDealloc closeopt: Bool) {
_handle = handle
Expand Down Expand Up @@ -314,13 +344,7 @@ open class FileHandle : NSObject, NSSecureCoding {

for region in data.regions {
try region.withUnsafeBytes { (bytes) in
#if os(Windows)
try NSData.write(toHandle: self._handle, path: nil,
buf: UnsafeRawPointer(bytes.baseAddress!),
length: bytes.count)
#else
try NSData.write(toFileDescriptor: self._fd, path: nil, buf: UnsafeRawPointer(bytes.baseAddress!), length: bytes.count)
#endif
try _writeBytes(buf: UnsafeRawPointer(bytes.baseAddress!), length: bytes.count)
}
}
}
Expand Down Expand Up @@ -446,31 +470,7 @@ open class FileHandle : NSObject, NSSecureCoding {

@available(swift, deprecated: 100000, renamed: "write(contentsOf:)")
open func write(_ data: Data) {
#if os(Windows)
precondition(_handle != INVALID_HANDLE_VALUE, "invalid file handle")
for region in data.regions {
region.withUnsafeBytes { (bytes) in
do {
try NSData.write(toHandle: self._handle, path: nil,
buf: UnsafeRawPointer(bytes.baseAddress!),
length: bytes.count)
} catch {
fatalError("Write failure")
}
}
}
#else
guard _fd >= 0 else { return }
for region in data.regions {
region.withUnsafeBytes { (bytes) in
do {
try NSData.write(toFileDescriptor: self._fd, path: nil, buf: UnsafeRawPointer(bytes.baseAddress!), length: bytes.count)
} catch {
fatalError("Write failure")
}
}
}
#endif
try! write(contentsOf: data)
}

@available(swift, deprecated: 100000, renamed: "offset()")
Expand Down
5 changes: 5 additions & 0 deletions Foundation/FileManager.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -1392,6 +1392,11 @@ open class FileManager : NSObject {
return statInfo
}

internal func _permissionsOfItem(atPath path: String) throws -> Int {
let fileInfo = try _lstatFile(atPath: path)
return Int(fileInfo.st_mode & 0o777)
}

/* -contentsEqualAtPath:andPath: does not take into account data stored in the resource fork or filesystem extended attributes.
*/
open func contentsEqual(atPath path1: String, andPath path2: String) -> Bool {
Expand Down
116 changes: 31 additions & 85 deletions Foundation/NSData.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -433,100 +433,46 @@ open class NSData : NSObject, NSCopying, NSMutableCopying, NSSecureCoding {
return result
}

internal func makeTemporaryFile(inDirectory dirPath: String) throws -> (Int32, String) {
let template = dirPath._nsObject.appendingPathComponent("tmp.XXXXXX")
let maxLength = Int(PATH_MAX) + 1
var buf = [Int8](repeating: 0, count: maxLength)
let _ = template._nsObject.getFileSystemRepresentation(&buf, maxLength: maxLength)
let fd = mkstemp(&buf)
if fd == -1 {
throw _NSErrorWithErrno(errno, reading: false, path: dirPath)
}
let pathResult = FileManager.default.string(withFileSystemRepresentation:buf, length: Int(strlen(buf)))
return (fd, pathResult)
}

internal class func write(toFileDescriptor fd: Int32, path: String? = nil, buf: UnsafeRawPointer, length: Int) throws {
var bytesRemaining = length
while bytesRemaining > 0 {
var bytesWritten : Int
repeat {
#if os(macOS) || os(iOS)
bytesWritten = Darwin.write(fd, buf.advanced(by: length - bytesRemaining), bytesRemaining)
#elseif os(Linux) || os(Android) || CYGWIN
bytesWritten = Glibc.write(fd, buf.advanced(by: length - bytesRemaining), bytesRemaining)
#endif
} while (bytesWritten < 0 && errno == EINTR)
if bytesWritten <= 0 {
throw _NSErrorWithErrno(errno, reading: false, path: path)
} else {
bytesRemaining -= bytesWritten
}
}
}

/// Writes the data object's bytes to the file specified by a given path.
open func write(toFile path: String, options writeOptionsMask: WritingOptions = []) throws {
let fm = FileManager.default
try fm._fileSystemRepresentation(withPath: path, { pathFsRep in
var fd : Int32
var mode : mode_t? = nil
let useAuxiliaryFile = writeOptionsMask.contains(.atomic)
var auxFilePath : String? = nil
if useAuxiliaryFile {
// Preserve permissions.
var info = stat()
if lstat(pathFsRep, &info) == 0 {
let mode = mode_t(info.st_mode)
} else if errno != ENOENT && errno != ENAMETOOLONG {
throw _NSErrorWithErrno(errno, reading: false, path: path)
}
let (newFD, path) = try self.makeTemporaryFile(inDirectory: path._nsObject.deletingLastPathComponent)
fd = newFD
auxFilePath = path
fchmod(fd, 0o666)
} else {
var flags = O_WRONLY | O_CREAT | O_TRUNC
if writeOptionsMask.contains(.withoutOverwriting) {
flags |= O_EXCL
}
fd = _CFOpenFileWithMode(path, flags, 0o666)
}
if fd == -1 {
throw _NSErrorWithErrno(errno, reading: false, path: path)
}
defer {
close(fd)
}

func doWrite(_ fh: FileHandle) throws {
try self.enumerateByteRangesUsingBlockRethrows { (buf, range, stop) in
if range.length > 0 {
do {
try NSData.write(toFileDescriptor: fd, path: path, buf: buf, length: range.length)
if fsync(fd) < 0 {
throw _NSErrorWithErrno(errno, reading: false, path: path)
}
} catch {
if let auxFilePath = auxFilePath {
try? FileManager.default.removeItem(atPath: auxFilePath)
}
throw error
}
try fh._writeBytes(buf: buf, length: range.length)
}
}
if let auxFilePath = auxFilePath {
try fm._fileSystemRepresentation(withPath: auxFilePath, { auxFilePathFsRep in
if rename(auxFilePathFsRep, pathFsRep) != 0 {
let savedErrno = errno
try? FileManager.default.removeItem(atPath: auxFilePath)
throw _NSErrorWithErrno(savedErrno, reading: false, path: path)
}
if let mode = mode {
chmod(pathFsRep, mode)
}
})
try fh.synchronize()
}

let fm = FileManager.default
// The destination file path may not exist so provide a default file permissions of RW user only
let permissions = (try? fm._permissionsOfItem(atPath: path)) ?? 0o600

if writeOptionsMask.contains(.atomic) {
let (newFD, auxFilePath) = try _NSCreateTemporaryFile(path)
let fh = FileHandle(fileDescriptor: newFD, closeOnDealloc: true)
do {
try doWrite(fh)
try _NSCleanupTemporaryFile(auxFilePath, path)
try fm.setAttributes([.posixPermissions: NSNumber(value: permissions)], ofItemAtPath: path)
} catch {
let savedErrno = errno
try? fm.removeItem(atPath: auxFilePath)
throw _NSErrorWithErrno(savedErrno, reading: false, path: path)
}
})
} else {
var flags = O_WRONLY | O_CREAT | O_TRUNC
if writeOptionsMask.contains(.withoutOverwriting) {
flags |= O_EXCL
}

guard let fh = FileHandle(path: path, flags: flags, createMode: permissions) else {
throw _NSErrorWithErrno(errno, reading: false, path: path)
}
try doWrite(fh)
}
}

/// Writes the data object's bytes to the file specified by a given path.
Expand Down