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diff --git a/src/mscorlib/corefx/System/IO/FileStream.Unix.cs b/src/mscorlib/corefx/System/IO/FileStream.Unix.cs
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@@ -1,934 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-using Microsoft.Win32.SafeHandles;
-using System.Diagnostics;
-using System.Threading;
-using System.Threading.Tasks;
-
-namespace System.IO
-{
- /// <summary>Provides an implementation of a file stream for Unix files.</summary>
- public partial class FileStream : Stream
- {
- /// <summary>File mode.</summary>
- private FileMode _mode;
-
- /// <summary>Advanced options requested when opening the file.</summary>
- private FileOptions _options;
-
- /// <summary>If the file was opened with FileMode.Append, the length of the file when opened; otherwise, -1.</summary>
- private long _appendStart = -1;
-
- /// <summary>
- /// Extra state used by the file stream when _useAsyncIO is true. This includes
- /// the semaphore used to serialize all operation, the buffer/offset/count provided by the
- /// caller for ReadAsync/WriteAsync operations, and the last successful task returned
- /// synchronously from ReadAsync which can be reused if the count matches the next request.
- /// Only initialized when <see cref="_useAsyncIO"/> is true.
- /// </summary>
- private AsyncState _asyncState;
-
- /// <summary>Lazily-initialized value for whether the file supports seeking.</summary>
- private bool? _canSeek;
-
- private SafeFileHandle OpenHandle(FileMode mode, FileShare share, FileOptions options)
- {
- // FileStream performs most of the general argument validation. We can assume here that the arguments
- // are all checked and consistent (e.g. non-null-or-empty path; valid enums in mode, access, share, and options; etc.)
- // Store the arguments
- _mode = mode;
- _options = options;
-
- if (_useAsyncIO)
- _asyncState = new AsyncState();
-
- // Translate the arguments into arguments for an open call.
- Interop.Sys.OpenFlags openFlags = PreOpenConfigurationFromOptions(mode, _access, options); // FileShare currently ignored
-
- // If the file gets created a new, we'll select the permissions for it. Most Unix utilities by default use 666 (read and
- // write for all), so we do the same (even though this doesn't match Windows, where by default it's possible to write out
- // a file and then execute it). No matter what we choose, it'll be subject to the umask applied by the system, such that the
- // actual permissions will typically be less than what we select here.
- const Interop.Sys.Permissions OpenPermissions =
- Interop.Sys.Permissions.S_IRUSR | Interop.Sys.Permissions.S_IWUSR |
- Interop.Sys.Permissions.S_IRGRP | Interop.Sys.Permissions.S_IWGRP |
- Interop.Sys.Permissions.S_IROTH | Interop.Sys.Permissions.S_IWOTH;
-
- // Open the file and store the safe handle.
- return SafeFileHandle.Open(_path, openFlags, (int)OpenPermissions);
- }
-
- /// <summary>Initializes a stream for reading or writing a Unix file.</summary>
- /// <param name="mode">How the file should be opened.</param>
- /// <param name="share">What other access to the file should be allowed. This is currently ignored.</param>
- private void Init(FileMode mode, FileShare share)
- {
- _fileHandle.IsAsync = _useAsyncIO;
-
- // Lock the file if requested via FileShare. This is only advisory locking. FileShare.None implies an exclusive
- // lock on the file and all other modes use a shared lock. While this is not as granular as Windows, not mandatory,
- // and not atomic with file opening, it's better than nothing.
- Interop.Sys.LockOperations lockOperation = (share == FileShare.None) ? Interop.Sys.LockOperations.LOCK_EX : Interop.Sys.LockOperations.LOCK_SH;
- if (Interop.Sys.FLock(_fileHandle, lockOperation | Interop.Sys.LockOperations.LOCK_NB) < 0)
- {
- // The only error we care about is EWOULDBLOCK, which indicates that the file is currently locked by someone
- // else and we would block trying to access it. Other errors, such as ENOTSUP (locking isn't supported) or
- // EACCES (the file system doesn't allow us to lock), will only hamper FileStream's usage without providing value,
- // given again that this is only advisory / best-effort.
- Interop.ErrorInfo errorInfo = Interop.Sys.GetLastErrorInfo();
- if (errorInfo.Error == Interop.Error.EWOULDBLOCK)
- {
- throw Interop.GetExceptionForIoErrno(errorInfo, _path, isDirectory: false);
- }
- }
-
- // These provide hints around how the file will be accessed. Specifying both RandomAccess
- // and Sequential together doesn't make sense as they are two competing options on the same spectrum,
- // so if both are specified, we prefer RandomAccess (behavior on Windows is unspecified if both are provided).
- Interop.Sys.FileAdvice fadv =
- (_options & FileOptions.RandomAccess) != 0 ? Interop.Sys.FileAdvice.POSIX_FADV_RANDOM :
- (_options & FileOptions.SequentialScan) != 0 ? Interop.Sys.FileAdvice.POSIX_FADV_SEQUENTIAL :
- 0;
- if (fadv != 0)
- {
- CheckFileCall(Interop.Sys.PosixFAdvise(_fileHandle, 0, 0, fadv),
- ignoreNotSupported: true); // just a hint.
- }
-
- // Jump to the end of the file if opened as Append.
- if (_mode == FileMode.Append)
- {
- _appendStart = SeekCore(0, SeekOrigin.End);
- }
- }
-
- /// <summary>Initializes a stream from an already open file handle (file descriptor).</summary>
- /// <param name="handle">The handle to the file.</param>
- /// <param name="bufferSize">The size of the buffer to use when buffering.</param>
- /// <param name="useAsyncIO">Whether access to the stream is performed asynchronously.</param>
- private void InitFromHandle(SafeFileHandle handle)
- {
- if (_useAsyncIO)
- _asyncState = new AsyncState();
-
- if (CanSeekCore) // use non-virtual CanSeekCore rather than CanSeek to avoid making virtual call during ctor
- SeekCore(0, SeekOrigin.Current);
- }
-
- /// <summary>Translates the FileMode, FileAccess, and FileOptions values into flags to be passed when opening the file.</summary>
- /// <param name="mode">The FileMode provided to the stream's constructor.</param>
- /// <param name="access">The FileAccess provided to the stream's constructor</param>
- /// <param name="options">The FileOptions provided to the stream's constructor</param>
- /// <returns>The flags value to be passed to the open system call.</returns>
- private static Interop.Sys.OpenFlags PreOpenConfigurationFromOptions(FileMode mode, FileAccess access, FileOptions options)
- {
- // Translate FileMode. Most of the values map cleanly to one or more options for open.
- Interop.Sys.OpenFlags flags = default(Interop.Sys.OpenFlags);
- switch (mode)
- {
- default:
- case FileMode.Open: // Open maps to the default behavior for open(...). No flags needed.
- break;
-
- case FileMode.Append: // Append is the same as OpenOrCreate, except that we'll also separately jump to the end later
- case FileMode.OpenOrCreate:
- flags |= Interop.Sys.OpenFlags.O_CREAT;
- break;
-
- case FileMode.Create:
- flags |= (Interop.Sys.OpenFlags.O_CREAT | Interop.Sys.OpenFlags.O_TRUNC);
- break;
-
- case FileMode.CreateNew:
- flags |= (Interop.Sys.OpenFlags.O_CREAT | Interop.Sys.OpenFlags.O_EXCL);
- break;
-
- case FileMode.Truncate:
- flags |= Interop.Sys.OpenFlags.O_TRUNC;
- break;
- }
-
- // Translate FileAccess. All possible values map cleanly to corresponding values for open.
- switch (access)
- {
- case FileAccess.Read:
- flags |= Interop.Sys.OpenFlags.O_RDONLY;
- break;
-
- case FileAccess.ReadWrite:
- flags |= Interop.Sys.OpenFlags.O_RDWR;
- break;
-
- case FileAccess.Write:
- flags |= Interop.Sys.OpenFlags.O_WRONLY;
- break;
- }
-
- // Translate some FileOptions; some just aren't supported, and others will be handled after calling open.
- // - Asynchronous: Handled in ctor, setting _useAsync and SafeFileHandle.IsAsync to true
- // - DeleteOnClose: Doesn't have a Unix equivalent, but we approximate it in Dispose
- // - Encrypted: No equivalent on Unix and is ignored
- // - RandomAccess: Implemented after open if posix_fadvise is available
- // - SequentialScan: Implemented after open if posix_fadvise is available
- // - WriteThrough: Handled here
- if ((options & FileOptions.WriteThrough) != 0)
- {
- flags |= Interop.Sys.OpenFlags.O_SYNC;
- }
-
- return flags;
- }
-
- /// <summary>Gets a value indicating whether the current stream supports seeking.</summary>
- public override bool CanSeek => CanSeekCore;
-
- /// <summary>Gets a value indicating whether the current stream supports seeking.</summary>
- /// <remarks>Separated out of CanSeek to enable making non-virtual call to this logic.</remarks>
- private bool CanSeekCore
- {
- get
- {
- if (_fileHandle.IsClosed)
- {
- return false;
- }
-
- if (!_canSeek.HasValue)
- {
- // Lazily-initialize whether we're able to seek, tested by seeking to our current location.
- _canSeek = Interop.Sys.LSeek(_fileHandle, 0, Interop.Sys.SeekWhence.SEEK_CUR) >= 0;
- }
- return _canSeek.Value;
- }
- }
-
- private long GetLengthInternal()
- {
- // Get the length of the file as reported by the OS
- Interop.Sys.FileStatus status;
- CheckFileCall(Interop.Sys.FStat(_fileHandle, out status));
- long length = status.Size;
-
- // But we may have buffered some data to be written that puts our length
- // beyond what the OS is aware of. Update accordingly.
- if (_writePos > 0 && _filePosition + _writePos > length)
- {
- length = _writePos + _filePosition;
- }
-
- return length;
- }
-
- /// <summary>Releases the unmanaged resources used by the stream.</summary>
- /// <param name="disposing">true to release both managed and unmanaged resources; false to release only unmanaged resources.</param>
- protected override void Dispose(bool disposing)
- {
- try
- {
- if (_fileHandle != null && !_fileHandle.IsClosed)
- {
- // Flush any remaining data in the file
- FlushWriteBuffer();
-
- // If DeleteOnClose was requested when constructed, delete the file now.
- // (Unix doesn't directly support DeleteOnClose, so we mimic it here.)
- if (_path != null && (_options & FileOptions.DeleteOnClose) != 0)
- {
- // Since we still have the file open, this will end up deleting
- // it (assuming we're the only link to it) once it's closed, but the
- // name will be removed immediately.
- Interop.Sys.Unlink(_path); // ignore errors; it's valid that the path may no longer exist
- }
- }
- }
- finally
- {
- if (_fileHandle != null && !_fileHandle.IsClosed)
- {
- _fileHandle.Dispose();
- }
- base.Dispose(disposing);
- }
- }
-
- /// <summary>Flushes the OS buffer. This does not flush the internal read/write buffer.</summary>
- private void FlushOSBuffer()
- {
- if (Interop.Sys.FSync(_fileHandle) < 0)
- {
- Interop.ErrorInfo errorInfo = Interop.Sys.GetLastErrorInfo();
- switch (errorInfo.Error)
- {
- case Interop.Error.EROFS:
- case Interop.Error.EINVAL:
- case Interop.Error.ENOTSUP:
- // Ignore failures due to the FileStream being bound to a special file that
- // doesn't support synchronization. In such cases there's nothing to flush.
- break;
- default:
- throw Interop.GetExceptionForIoErrno(errorInfo, _path, isDirectory: false);
- }
- }
- }
-
- /// <summary>Writes any data in the write buffer to the underlying stream and resets the buffer.</summary>
- private void FlushWriteBuffer()
- {
- AssertBufferInvariants();
- if (_writePos > 0)
- {
- WriteNative(GetBuffer(), 0, _writePos);
- _writePos = 0;
- }
- }
-
- /// <summary>Asynchronously clears all buffers for this stream, causing any buffered data to be written to the underlying device.</summary>
- /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
- /// <returns>A task that represents the asynchronous flush operation.</returns>
- private Task FlushAsyncInternal(CancellationToken cancellationToken)
- {
- if (cancellationToken.IsCancellationRequested)
- {
- return Task.FromCanceled(cancellationToken);
- }
- if (_fileHandle.IsClosed)
- {
- throw Error.GetFileNotOpen();
- }
-
- // As with Win32FileStream, flush the buffers synchronously to avoid race conditions.
- try
- {
- FlushInternalBuffer();
- }
- catch (Exception e)
- {
- return Task.FromException(e);
- }
-
- // We then separately flush to disk asynchronously. This is only
- // necessary if we support writing; otherwise, we're done.
- if (CanWrite)
- {
- return Task.Factory.StartNew(
- state => ((FileStream)state).FlushOSBuffer(),
- this,
- cancellationToken,
- TaskCreationOptions.DenyChildAttach,
- TaskScheduler.Default);
- }
- else
- {
- return Task.CompletedTask;
- }
- }
-
- /// <summary>Sets the length of this stream to the given value.</summary>
- /// <param name="value">The new length of the stream.</param>
- private void SetLengthInternal(long value)
- {
- FlushInternalBuffer();
-
- if (_appendStart != -1 && value < _appendStart)
- {
- throw new IOException(SR.IO_SetLengthAppendTruncate);
- }
-
- long origPos = _filePosition;
-
- VerifyOSHandlePosition();
-
- if (_filePosition != value)
- {
- SeekCore(value, SeekOrigin.Begin);
- }
-
- CheckFileCall(Interop.Sys.FTruncate(_fileHandle, value));
-
- // Return file pointer to where it was before setting length
- if (origPos != value)
- {
- if (origPos < value)
- {
- SeekCore(origPos, SeekOrigin.Begin);
- }
- else
- {
- SeekCore(0, SeekOrigin.End);
- }
- }
- }
-
- /// <summary>Reads a block of bytes from the stream and writes the data in a given buffer.</summary>
- /// <param name="array">
- /// When this method returns, contains the specified byte array with the values between offset and
- /// (offset + count - 1) replaced by the bytes read from the current source.
- /// </param>
- /// <param name="offset">The byte offset in array at which the read bytes will be placed.</param>
- /// <param name="count">The maximum number of bytes to read. </param>
- /// <returns>
- /// The total number of bytes read into the buffer. This might be less than the number of bytes requested
- /// if that number of bytes are not currently available, or zero if the end of the stream is reached.
- /// </returns>
- public override int Read(byte[] array, int offset, int count)
- {
- ValidateReadWriteArgs(array, offset, count);
-
- if (_useAsyncIO)
- {
- _asyncState.Wait();
- try { return ReadCore(array, offset, count); }
- finally { _asyncState.Release(); }
- }
- else
- {
- return ReadCore(array, offset, count);
- }
- }
-
- /// <summary>Reads a block of bytes from the stream and writes the data in a given buffer.</summary>
- /// <param name="array">
- /// When this method returns, contains the specified byte array with the values between offset and
- /// (offset + count - 1) replaced by the bytes read from the current source.
- /// </param>
- /// <param name="offset">The byte offset in array at which the read bytes will be placed.</param>
- /// <param name="count">The maximum number of bytes to read. </param>
- /// <returns>
- /// The total number of bytes read into the buffer. This might be less than the number of bytes requested
- /// if that number of bytes are not currently available, or zero if the end of the stream is reached.
- /// </returns>
- private int ReadCore(byte[] array, int offset, int count)
- {
- PrepareForReading();
-
- // Are there any bytes available in the read buffer? If yes,
- // we can just return from the buffer. If the buffer is empty
- // or has no more available data in it, we can either refill it
- // (and then read from the buffer into the user's buffer) or
- // we can just go directly into the user's buffer, if they asked
- // for more data than we'd otherwise buffer.
- int numBytesAvailable = _readLength - _readPos;
- bool readFromOS = false;
- if (numBytesAvailable == 0)
- {
- // If we're not able to seek, then we're not able to rewind the stream (i.e. flushing
- // a read buffer), in which case we don't want to use a read buffer. Similarly, if
- // the user has asked for more data than we can buffer, we also want to skip the buffer.
- if (!CanSeek || (count >= _bufferLength))
- {
- // Read directly into the user's buffer
- _readPos = _readLength = 0;
- return ReadNative(array, offset, count);
- }
- else
- {
- // Read into our buffer.
- _readLength = numBytesAvailable = ReadNative(GetBuffer(), 0, _bufferLength);
- _readPos = 0;
- if (numBytesAvailable == 0)
- {
- return 0;
- }
-
- // Note that we did an OS read as part of this Read, so that later
- // we don't try to do one again if what's in the buffer doesn't
- // meet the user's request.
- readFromOS = true;
- }
- }
-
- // Now that we know there's data in the buffer, read from it into the user's buffer.
- Debug.Assert(numBytesAvailable > 0, "Data must be in the buffer to be here");
- int bytesRead = Math.Min(numBytesAvailable, count);
- Buffer.BlockCopy(GetBuffer(), _readPos, array, offset, bytesRead);
- _readPos += bytesRead;
-
- // We may not have had enough data in the buffer to completely satisfy the user's request.
- // While Read doesn't require that we return as much data as the user requested (any amount
- // up to the requested count is fine), FileStream on Windows tries to do so by doing a
- // subsequent read from the file if we tried to satisfy the request with what was in the
- // buffer but the buffer contained less than the requested count. To be consistent with that
- // behavior, we do the same thing here on Unix. Note that we may still get less the requested
- // amount, as the OS may give us back fewer than we request, either due to reaching the end of
- // file, or due to its own whims.
- if (!readFromOS && bytesRead < count)
- {
- Debug.Assert(_readPos == _readLength, "bytesToRead should only be < count if numBytesAvailable < count");
- _readPos = _readLength = 0; // no data left in the read buffer
- bytesRead += ReadNative(array, offset + bytesRead, count - bytesRead);
- }
-
- return bytesRead;
- }
-
- /// <summary>Unbuffered, reads a block of bytes from the stream and writes the data in a given buffer.</summary>
- /// <param name="array">
- /// When this method returns, contains the specified byte array with the values between offset and
- /// (offset + count - 1) replaced by the bytes read from the current source.
- /// </param>
- /// <param name="offset">The byte offset in array at which the read bytes will be placed.</param>
- /// <param name="count">The maximum number of bytes to read. </param>
- /// <returns>
- /// The total number of bytes read into the buffer. This might be less than the number of bytes requested
- /// if that number of bytes are not currently available, or zero if the end of the stream is reached.
- /// </returns>
- private unsafe int ReadNative(byte[] array, int offset, int count)
- {
- FlushWriteBuffer(); // we're about to read; dump the write buffer
-
- VerifyOSHandlePosition();
-
- int bytesRead;
- fixed (byte* bufPtr = array)
- {
- bytesRead = CheckFileCall(Interop.Sys.Read(_fileHandle, bufPtr + offset, count));
- Debug.Assert(bytesRead <= count);
- }
- _filePosition += bytesRead;
- return bytesRead;
- }
-
- /// <summary>
- /// Asynchronously reads a sequence of bytes from the current stream and advances
- /// the position within the stream by the number of bytes read.
- /// </summary>
- /// <param name="buffer">The buffer to write the data into.</param>
- /// <param name="offset">The byte offset in buffer at which to begin writing data from the stream.</param>
- /// <param name="count">The maximum number of bytes to read.</param>
- /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
- /// <returns>A task that represents the asynchronous read operation.</returns>
- private Task<int> ReadAsyncInternal(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
- {
- if (_useAsyncIO)
- {
- if (!CanRead) // match Windows behavior; this gets thrown synchronously
- {
- throw Error.GetReadNotSupported();
- }
-
- // Serialize operations using the semaphore.
- Task waitTask = _asyncState.WaitAsync();
-
- // If we got ownership immediately, and if there's enough data in our buffer
- // to satisfy the full request of the caller, hand back the buffered data.
- // While it would be a legal implementation of the Read contract, we don't
- // hand back here less than the amount requested so as to match the behavior
- // in ReadCore that will make a native call to try to fulfill the remainder
- // of the request.
- if (waitTask.Status == TaskStatus.RanToCompletion)
- {
- int numBytesAvailable = _readLength - _readPos;
- if (numBytesAvailable >= count)
- {
- try
- {
- PrepareForReading();
-
- Buffer.BlockCopy(GetBuffer(), _readPos, buffer, offset, count);
- _readPos += count;
-
- return _asyncState._lastSuccessfulReadTask != null && _asyncState._lastSuccessfulReadTask.Result == count ?
- _asyncState._lastSuccessfulReadTask :
- (_asyncState._lastSuccessfulReadTask = Task.FromResult(count));
- }
- catch (Exception exc)
- {
- return Task.FromException<int>(exc);
- }
- finally
- {
- _asyncState.Release();
- }
- }
- }
-
- // Otherwise, issue the whole request asynchronously.
- _asyncState.Update(buffer, offset, count);
- return waitTask.ContinueWith((t, s) =>
- {
- // The options available on Unix for writing asynchronously to an arbitrary file
- // handle typically amount to just using another thread to do the synchronous write,
- // which is exactly what this implementation does. This does mean there are subtle
- // differences in certain FileStream behaviors between Windows and Unix when multiple
- // asynchronous operations are issued against the stream to execute concurrently; on
- // Unix the operations will be serialized due to the usage of a semaphore, but the
- // position /length information won't be updated until after the write has completed,
- // whereas on Windows it may happen before the write has completed.
-
- Debug.Assert(t.Status == TaskStatus.RanToCompletion);
- var thisRef = (FileStream)s;
- try
- {
- byte[] b = thisRef._asyncState._buffer;
- thisRef._asyncState._buffer = null; // remove reference to user's buffer
- return thisRef.ReadCore(b, thisRef._asyncState._offset, thisRef._asyncState._count);
- }
- finally { thisRef._asyncState.Release(); }
- }, this, CancellationToken.None, TaskContinuationOptions.DenyChildAttach, TaskScheduler.Default);
- }
- else
- {
- return base.ReadAsync(buffer, offset, count, cancellationToken);
- }
- }
-
- /// <summary>
- /// Reads a byte from the stream and advances the position within the stream
- /// by one byte, or returns -1 if at the end of the stream.
- /// </summary>
- /// <returns>The unsigned byte cast to an Int32, or -1 if at the end of the stream.</returns>
- public override int ReadByte()
- {
- if (_useAsyncIO)
- {
- _asyncState.Wait();
- try { return ReadByteCore(); }
- finally { _asyncState.Release(); }
- }
- else
- {
- return ReadByteCore();
- }
- }
-
- /// <summary>Writes a block of bytes to the file stream.</summary>
- /// <param name="array">The buffer containing data to write to the stream.</param>
- /// <param name="offset">The zero-based byte offset in array from which to begin copying bytes to the stream.</param>
- /// <param name="count">The maximum number of bytes to write.</param>
- public override void Write(byte[] array, int offset, int count)
- {
- ValidateReadWriteArgs(array, offset, count);
-
- if (_useAsyncIO)
- {
- _asyncState.Wait();
- try { WriteCore(array, offset, count); }
- finally { _asyncState.Release(); }
- }
- else
- {
- WriteCore(array, offset, count);
- }
- }
-
- /// <summary>Writes a block of bytes to the file stream.</summary>
- /// <param name="array">The buffer containing data to write to the stream.</param>
- /// <param name="offset">The zero-based byte offset in array from which to begin copying bytes to the stream.</param>
- /// <param name="count">The maximum number of bytes to write.</param>
- private void WriteCore(byte[] array, int offset, int count)
- {
- PrepareForWriting();
-
- // If no data is being written, nothing more to do.
- if (count == 0)
- {
- return;
- }
-
- // If there's already data in our write buffer, then we need to go through
- // our buffer to ensure data isn't corrupted.
- if (_writePos > 0)
- {
- // If there's space remaining in the buffer, then copy as much as
- // we can from the user's buffer into ours.
- int spaceRemaining = _bufferLength - _writePos;
- if (spaceRemaining > 0)
- {
- int bytesToCopy = Math.Min(spaceRemaining, count);
- Buffer.BlockCopy(array, offset, GetBuffer(), _writePos, bytesToCopy);
- _writePos += bytesToCopy;
-
- // If we've successfully copied all of the user's data, we're done.
- if (count == bytesToCopy)
- {
- return;
- }
-
- // Otherwise, keep track of how much more data needs to be handled.
- offset += bytesToCopy;
- count -= bytesToCopy;
- }
-
- // At this point, the buffer is full, so flush it out.
- FlushWriteBuffer();
- }
-
- // Our buffer is now empty. If using the buffer would slow things down (because
- // the user's looking to write more data than we can store in the buffer),
- // skip the buffer. Otherwise, put the remaining data into the buffer.
- Debug.Assert(_writePos == 0);
- if (count >= _bufferLength)
- {
- WriteNative(array, offset, count);
- }
- else
- {
- Buffer.BlockCopy(array, offset, GetBuffer(), _writePos, count);
- _writePos = count;
- }
- }
-
- /// <summary>Unbuffered, writes a block of bytes to the file stream.</summary>
- /// <param name="array">The buffer containing data to write to the stream.</param>
- /// <param name="offset">The zero-based byte offset in array from which to begin copying bytes to the stream.</param>
- /// <param name="count">The maximum number of bytes to write.</param>
- private unsafe void WriteNative(byte[] array, int offset, int count)
- {
- VerifyOSHandlePosition();
-
- fixed (byte* bufPtr = array)
- {
- while (count > 0)
- {
- int bytesWritten = CheckFileCall(Interop.Sys.Write(_fileHandle, bufPtr + offset, count));
- Debug.Assert(bytesWritten <= count);
-
- _filePosition += bytesWritten;
- count -= bytesWritten;
- offset += bytesWritten;
- }
- }
- }
-
- /// <summary>
- /// Asynchronously writes a sequence of bytes to the current stream, advances
- /// the current position within this stream by the number of bytes written, and
- /// monitors cancellation requests.
- /// </summary>
- /// <param name="buffer">The buffer to write data from.</param>
- /// <param name="offset">The zero-based byte offset in buffer from which to begin copying bytes to the stream.</param>
- /// <param name="count">The maximum number of bytes to write.</param>
- /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
- /// <returns>A task that represents the asynchronous write operation.</returns>
- private Task WriteAsyncInternal(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
- {
- if (cancellationToken.IsCancellationRequested)
- return Task.FromCanceled(cancellationToken);
-
- if (_fileHandle.IsClosed)
- throw Error.GetFileNotOpen();
-
- if (_useAsyncIO)
- {
- if (!CanWrite) // match Windows behavior; this gets thrown synchronously
- {
- throw Error.GetWriteNotSupported();
- }
-
- // Serialize operations using the semaphore.
- Task waitTask = _asyncState.WaitAsync();
-
- // If we got ownership immediately, and if there's enough space in our buffer
- // to buffer the entire write request, then do so and we're done.
- if (waitTask.Status == TaskStatus.RanToCompletion)
- {
- int spaceRemaining = _bufferLength - _writePos;
- if (spaceRemaining >= count)
- {
- try
- {
- PrepareForWriting();
-
- Buffer.BlockCopy(buffer, offset, GetBuffer(), _writePos, count);
- _writePos += count;
-
- return Task.CompletedTask;
- }
- catch (Exception exc)
- {
- return Task.FromException(exc);
- }
- finally
- {
- _asyncState.Release();
- }
- }
- }
-
- // Otherwise, issue the whole request asynchronously.
- _asyncState.Update(buffer, offset, count);
- return waitTask.ContinueWith((t, s) =>
- {
- // The options available on Unix for writing asynchronously to an arbitrary file
- // handle typically amount to just using another thread to do the synchronous write,
- // which is exactly what this implementation does. This does mean there are subtle
- // differences in certain FileStream behaviors between Windows and Unix when multiple
- // asynchronous operations are issued against the stream to execute concurrently; on
- // Unix the operations will be serialized due to the usage of a semaphore, but the
- // position /length information won't be updated until after the write has completed,
- // whereas on Windows it may happen before the write has completed.
-
- Debug.Assert(t.Status == TaskStatus.RanToCompletion);
- var thisRef = (FileStream)s;
- try
- {
- byte[] b = thisRef._asyncState._buffer;
- thisRef._asyncState._buffer = null; // remove reference to user's buffer
- thisRef.WriteCore(b, thisRef._asyncState._offset, thisRef._asyncState._count);
- }
- finally { thisRef._asyncState.Release(); }
- }, this, CancellationToken.None, TaskContinuationOptions.DenyChildAttach, TaskScheduler.Default);
- }
- else
- {
- return base.WriteAsync(buffer, offset, count, cancellationToken);
- }
- }
-
- /// <summary>
- /// Writes a byte to the current position in the stream and advances the position
- /// within the stream by one byte.
- /// </summary>
- /// <param name="value">The byte to write to the stream.</param>
- public override void WriteByte(byte value) // avoids an array allocation in the base implementation
- {
- if (_useAsyncIO)
- {
- _asyncState.Wait();
- try { WriteByteCore(value); }
- finally { _asyncState.Release(); }
- }
- else
- {
- WriteByteCore(value);
- }
- }
-
- /// <summary>Prevents other processes from reading from or writing to the FileStream.</summary>
- /// <param name="position">The beginning of the range to lock.</param>
- /// <param name="length">The range to be locked.</param>
- private void LockInternal(long position, long length)
- {
- CheckFileCall(Interop.Sys.LockFileRegion(_fileHandle, position, length, Interop.Sys.LockType.F_WRLCK));
- }
-
- /// <summary>Allows access by other processes to all or part of a file that was previously locked.</summary>
- /// <param name="position">The beginning of the range to unlock.</param>
- /// <param name="length">The range to be unlocked.</param>
- private void UnlockInternal(long position, long length)
- {
- CheckFileCall(Interop.Sys.LockFileRegion(_fileHandle, position, length, Interop.Sys.LockType.F_UNLCK));
- }
-
- /// <summary>Sets the current position of this stream to the given value.</summary>
- /// <param name="offset">The point relative to origin from which to begin seeking. </param>
- /// <param name="origin">
- /// Specifies the beginning, the end, or the current position as a reference
- /// point for offset, using a value of type SeekOrigin.
- /// </param>
- /// <returns>The new position in the stream.</returns>
- public override long Seek(long offset, SeekOrigin origin)
- {
- if (origin < SeekOrigin.Begin || origin > SeekOrigin.End)
- {
- throw new ArgumentException(SR.Argument_InvalidSeekOrigin, nameof(origin));
- }
- if (_fileHandle.IsClosed)
- {
- throw Error.GetFileNotOpen();
- }
- if (!CanSeek)
- {
- throw Error.GetSeekNotSupported();
- }
-
- VerifyOSHandlePosition();
-
- // Flush our write/read buffer. FlushWrite will output any write buffer we have and reset _bufferWritePos.
- // We don't call FlushRead, as that will do an unnecessary seek to rewind the read buffer, and since we're
- // about to seek and update our position, we can simply update the offset as necessary and reset our read
- // position and length to 0. (In the future, for some simple cases we could potentially add an optimization
- // here to just move data around in the buffer for short jumps, to avoid re-reading the data from disk.)
- FlushWriteBuffer();
- if (origin == SeekOrigin.Current)
- {
- offset -= (_readLength - _readPos);
- }
- _readPos = _readLength = 0;
-
- // Keep track of where we were, in case we're in append mode and need to verify
- long oldPos = 0;
- if (_appendStart >= 0)
- {
- oldPos = SeekCore(0, SeekOrigin.Current);
- }
-
- // Jump to the new location
- long pos = SeekCore(offset, origin);
-
- // Prevent users from overwriting data in a file that was opened in append mode.
- if (_appendStart != -1 && pos < _appendStart)
- {
- SeekCore(oldPos, SeekOrigin.Begin);
- throw new IOException(SR.IO_SeekAppendOverwrite);
- }
-
- // Return the new position
- return pos;
- }
-
- /// <summary>Sets the current position of this stream to the given value.</summary>
- /// <param name="offset">The point relative to origin from which to begin seeking. </param>
- /// <param name="origin">
- /// Specifies the beginning, the end, or the current position as a reference
- /// point for offset, using a value of type SeekOrigin.
- /// </param>
- /// <returns>The new position in the stream.</returns>
- private long SeekCore(long offset, SeekOrigin origin)
- {
- Debug.Assert(!_fileHandle.IsClosed && (GetType() != typeof(FileStream) || CanSeek)); // verify that we can seek, but only if CanSeek won't be a virtual call (which could happen in the ctor)
- Debug.Assert(origin >= SeekOrigin.Begin && origin <= SeekOrigin.End);
-
- long pos = CheckFileCall(Interop.Sys.LSeek(_fileHandle, offset, (Interop.Sys.SeekWhence)(int)origin)); // SeekOrigin values are the same as Interop.libc.SeekWhence values
- _filePosition = pos;
- return pos;
- }
-
- private long CheckFileCall(long result, bool ignoreNotSupported = false)
- {
- if (result < 0)
- {
- Interop.ErrorInfo errorInfo = Interop.Sys.GetLastErrorInfo();
- if (!(ignoreNotSupported && errorInfo.Error == Interop.Error.ENOTSUP))
- {
- throw Interop.GetExceptionForIoErrno(errorInfo, _path, isDirectory: false);
- }
- }
-
- return result;
- }
-
- private int CheckFileCall(int result, bool ignoreNotSupported = false)
- {
- CheckFileCall((long)result, ignoreNotSupported);
-
- return result;
- }
-
- /// <summary>State used when the stream is in async mode.</summary>
- private sealed class AsyncState : SemaphoreSlim
- {
- /// <summary>The caller's buffer currently being used by the active async operation.</summary>
- internal byte[] _buffer;
- /// <summary>The caller's offset currently being used by the active async operation.</summary>
- internal int _offset;
- /// <summary>The caller's count currently being used by the active async operation.</summary>
- internal int _count;
- /// <summary>The last task successfully, synchronously returned task from ReadAsync.</summary>
- internal Task<int> _lastSuccessfulReadTask;
-
- /// <summary>Initialize the AsyncState.</summary>
- internal AsyncState() : base(initialCount: 1, maxCount: 1) { }
-
- /// <summary>Sets the active buffer, offset, and count.</summary>
- internal void Update(byte[] buffer, int offset, int count)
- {
- _buffer = buffer;
- _offset = offset;
- _count = count;
- }
- }
- }
-}