public static TResult Extension <TSource, TResult>(this TSource source, ExtensionSelector <TSource, TResult> selector, Action <TResult> callback = null) where TSource : IExtensible <TSource> where TResult : IExtension <TSource>
{
var extensions = (ExtensionCollection <TSource>)Extensions.GetValue(source, (x) => new ExtensionCollection <TSource>());
var extension = (IExtension <TSource>)null;
if (false == extensions.TryGetValue(typeof(TResult), out extension))
{
extension = (TResult)Activator.CreateInstance(typeof(TResult), source);
extensions[typeof(TResult)] = extension;
}
callback?.Invoke((TResult)extension);
return((TResult)extension);
}
public ReloadResult Reload(EditOptions options)
{
if (_isDisposed)
{
throw new ObjectDisposedException(nameof(ITextDocument));
}
if (_raisingDirtyStateChangedEvent || _raisingFileActionChangedEvent)
{
throw new InvalidOperationException();
}
Encoding newEncoding;
var beforeSnapshot = _textBuffer.CurrentSnapshot;
bool characterSubstitutionsOccurred = false;
try {
_reloadingFile = true;
// Load the file and read the contents to the text buffer
long fileSize;
using (var stream = TextDocumentFactoryService.OpenFile(_filePath, out _lastModifiedTimeUtc, out fileSize)) {
var detectors = ExtensionSelector.SelectMatchingExtensions(_textDocumentFactoryService.OrderedEncodingDetectors, _textBuffer.ContentType);
if (_explicitEncoding)
{
// If the user explicitly chose their encoding, we want to respect it.
newEncoding = this.Encoding;
}
else
{
newEncoding = EncodedStreamReader.DetectEncoding(stream, detectors, _textDocumentFactoryService.GuardedOperations);
}
if (newEncoding == null && _attemptUtf8Detection)
{
try {
var detectorEncoding = new ExtendedCharacterDetector();
ReloadBufferFromStream(stream, fileSize, options, detectorEncoding);
if (detectorEncoding.DecodedExtendedCharacters)
{
// Valid UTF-8 but has bytes that are not merely ASCII.
newEncoding = new UTF8Encoding(encoderShouldEmitUTF8Identifier: false);
}
else
{
// Valid UTF8 but no extended characters, so it looks like valid ASCII.
// However, we don't use ASCII here because of the following scenario:
// The user with a non-English US system encoding opens a code file that happens to contain ASCII-only contents
// Therefore we'll just use their system encoding.
newEncoding = Encoding.Default;
}
} catch (DecoderFallbackException) {
// Not valid UTF-8.
// Proceed to the next if block to try the system's default codepage.
// For example, this occurs when you have extended characters like € in a UTF-8 file or ANSI file.
// We reset the stream so we can continue loading with the default system encoding.
Debug.Assert(newEncoding == null);
Debug.Assert(beforeSnapshot.Version.Next == null);
stream.Position = 0;
}
}
// If all else didn't work, use system's default encoding.
if (newEncoding == null)
{
newEncoding = Encoding.Default;
}
//If there is no "Next" version of the original snapshot, we have not successfully reloaded the document
if (beforeSnapshot.Version.Next == null)
{
//We use this fall back detector to observe whether or not character substitutions
//occur while we're reading the stream
var fallbackDetector = new FallbackDetector(newEncoding.DecoderFallback);
var modifiedEncoding = (Encoding)newEncoding.Clone();
modifiedEncoding.DecoderFallback = fallbackDetector;
Debug.Assert(stream.Position == 0);
ReloadBufferFromStream(stream, fileSize, options, modifiedEncoding);
if (fallbackDetector.FallbackOccurred)
{
characterSubstitutionsOccurred = fallbackDetector.FallbackOccurred;
}
}
}
} finally {
_reloadingFile = false;
}
//The snapshot on a reload will change even if the contents of the before & after files are identical (differences will simply find an
//empty set of changes) so this test is a measure of whether of not the reload succeeded.
if (beforeSnapshot.Version.Next != null)
{
// Update status
// set the "clean" reiterated version number to the reiterated version number of the version immediately
// after the before snapshot (which is the state of the buffer after loading the document but before any
// subsequent edits made in the text buffer changed events).
_cleanReiteratedVersion = beforeSnapshot.Version.Next.ReiteratedVersionNumber;
// TODO: the following event really should be queued up through the buffer group so that it comes before
// the text changed event (and any subsequent text changed event invoked from an event handler)
RaiseFileActionChangedEvent(_lastModifiedTimeUtc, FileActionTypes.ContentLoadedFromDisk, _filePath);
this.Encoding = newEncoding;
return(characterSubstitutionsOccurred ? ReloadResult.SucceededWithCharacterSubstitutions : ReloadResult.Succeeded);
}
else
{
return(ReloadResult.Aborted);
}
}
public ITextDocument CreateAndLoadTextDocument(string filePath, IContentType contentType, bool attemptUtf8Detection, out bool characterSubstitutionsOccurred)
{
if (filePath == null)
{
throw new ArgumentNullException(nameof(filePath));
}
if (contentType == null)
{
throw new ArgumentNullException(nameof(contentType));
}
characterSubstitutionsOccurred = false;
Encoding chosenEncoding = null;
ITextBuffer buffer = null;
DateTime lastModified;
long fileSize;
// select matching detectors without instantiating any
var detectors = ExtensionSelector.SelectMatchingExtensions(OrderedEncodingDetectors, contentType);
using (Stream stream = OpenFile(filePath, out lastModified, out fileSize))
{
// First, look for a byte order marker and let the encoding detecters
// suggest encodings.
chosenEncoding = EncodedStreamReader.DetectEncoding(stream, detectors, GuardedOperations);
// If that didn't produce a result, tentatively try to open as UTF 8.
if (chosenEncoding == null && attemptUtf8Detection)
{
try
{
var detectorEncoding = new ExtendedCharacterDetector();
using (StreamReader reader = new EncodedStreamReader.NonStreamClosingStreamReader(stream, detectorEncoding, false))
{
buffer = ((ITextBufferFactoryService2)BufferFactoryService).CreateTextBuffer(reader, contentType, fileSize, filePath);
characterSubstitutionsOccurred = false;
}
if (detectorEncoding.DecodedExtendedCharacters)
{
// Valid UTF-8 but has bytes that are not merely ASCII.
chosenEncoding = new UTF8Encoding(encoderShouldEmitUTF8Identifier: false);
}
else
{
// Valid UTF8 but no extended characters, so it's valid ASCII.
// We don't use ASCII here because of the following scenario:
// The user with a non-ENU system encoding opens a code file with ASCII-only contents
chosenEncoding = DefaultEncoding;
}
}
catch (DecoderFallbackException)
{
// Not valid UTF-8.
// Proceed to the next if block to try the system's default codepage.
Debug.Assert(buffer == null);
buffer = null;
stream.Position = 0;
}
}
Debug.Assert(buffer == null || chosenEncoding != null);
// If all else didn't work, use system's default encoding.
if (chosenEncoding == null)
{
chosenEncoding = DefaultEncoding;
}
if (buffer == null)
{
var fallbackDetector = new FallbackDetector(chosenEncoding.DecoderFallback);
var modifiedEncoding = (Encoding)chosenEncoding.Clone();
modifiedEncoding.DecoderFallback = fallbackDetector;
Debug.Assert(stream.Position == 0);
using (StreamReader reader = new EncodedStreamReader.NonStreamClosingStreamReader(stream, modifiedEncoding, detectEncodingFromByteOrderMarks: false))
{
Debug.Assert(chosenEncoding.CodePage == reader.CurrentEncoding.CodePage);
buffer = ((ITextBufferFactoryService2)BufferFactoryService).CreateTextBuffer(reader, contentType, fileSize, filePath);
}
characterSubstitutionsOccurred = fallbackDetector.FallbackOccurred;
}
}
TextDocument textDocument = new TextDocument(buffer, filePath, lastModified, this, chosenEncoding, attemptUtf8Detection: attemptUtf8Detection);
RaiseTextDocumentCreated(textDocument);
return(textDocument);
}