/****************************************************************************
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**
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** Copyright (C) 2018 The Qt Company Ltd.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the Qt VS Tools.
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**
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** $QT_BEGIN_LICENSE:GPL-EXCEPT$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** GNU General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU
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** General Public License version 3 as published by the Free Software
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** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
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** included in the packaging of this file. Please review the following
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** information to ensure the GNU General Public License requirements will
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** be met: https://www.gnu.org/licenses/gpl-3.0.html.
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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/// This file contains the definition of the abstract class QmlAsyncClassifier which is the base
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/// class for asynchronous implementations of text classifiers, e.g. for syntax highlighting and
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/// syntax error annotations
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Threading.Tasks;
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using System.Windows.Threading;
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using Microsoft.VisualStudio.Text;
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using Microsoft.VisualStudio.Text.Editor;
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using Microsoft.VisualStudio.Text.Tagging;
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namespace QtVsTools.Qml.Classification
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{
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using HelperTypes;
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/// <summary>
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/// A SharedTagList is a list of tracking tags (instances of TrackingTag), sorted by starting
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/// location. It works as write-once-read-many data storage. Write access must be requested and
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/// will only be granted to the first object/thread, which will be responsible for filling in
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/// the data. Once writing is complete, concurrent read-only access will then be allowed.
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/// </summary>
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class SharedTagList : Concurrent
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{
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readonly SortedList<int, TrackingTag> data = new SortedList<int, TrackingTag>();
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object owner;
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public bool Ready { get; private set; }
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public enum AccessType { ReadOnly, ReadWrite }
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public AccessType RequestWriteAccess(object client)
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{
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EnterCriticalSection();
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if (owner == null) {
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owner = client;
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return AccessType.ReadWrite;
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} else {
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LeaveCriticalSection();
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return AccessType.ReadOnly;
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}
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}
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public void WriteComplete(object client)
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{
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if (owner != client)
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return;
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Ready = true;
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try {
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LeaveCriticalSection();
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} catch { }
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}
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public void AddRange(object client, IEnumerable<TrackingTag> tags)
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{
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if (owner != client || Ready)
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return;
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foreach (var tag in tags)
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Add(client, tag);
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}
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public void Add(object client, TrackingTag tag)
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{
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if (owner != client || Ready)
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return;
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data[tag.Start] = tag;
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}
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class TrackingTagComparer : Comparer<TrackingTag>
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{
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readonly ITextSnapshot snapshot;
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public TrackingTagComparer(ITextSnapshot snapshot)
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{
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this.snapshot = snapshot;
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}
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public override int Compare(TrackingTag t1, TrackingTag t2)
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{
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int t1Version = t1.Snapshot.Version.VersionNumber;
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int t2Version = t2.Snapshot.Version.VersionNumber;
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if (t1Version == t2Version && t2Version == snapshot.Version.VersionNumber)
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return Comparer<int>.Default.Compare(t1.Start, t2.Start);
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var t1Mapped = t1.MapToSnapshot(snapshot);
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var t2Mapped = t2.MapToSnapshot(snapshot);
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return Comparer<int>.Default.Compare(t1Mapped.Span.Start, t2Mapped.Span.Start);
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}
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}
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/// <summary>
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/// Perform a binary search to find the tag whose start precedes a given location relative
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/// to a text snapshot. If the tags in the list are relative to another version of the
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/// text, their location will be mapped to the given snapshot.
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/// </summary>
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/// <param name="snapshot">Text snapshot</param>
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/// <param name="location">Location in the given snapshot</param>
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/// <returns>
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/// Index of the tag in the list; -1 indicates error
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/// </returns>
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public int FindTagAtLocation(ITextSnapshot snapshot, int location)
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{
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if (!Ready)
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return -1;
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var firstTag = data.Values.FirstOrDefault();
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if (firstTag == null)
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return -1;
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bool sameVersion =
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(firstTag.Snapshot.Version.VersionNumber == snapshot.Version.VersionNumber);
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int? idx = null;
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if (sameVersion) {
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idx = data.Keys.BinarySearch(location);
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} else {
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if (location >= snapshot.Length)
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return -1;
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var locationTag = new TrackingTag(snapshot, location, 1);
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var comparer = new TrackingTagComparer(snapshot);
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idx = data.Values.BinarySearch(locationTag, comparer);
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}
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if (idx == null)
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return -1;
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if (idx < 0) {
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// location was not found; idx has the bitwise complement of the smallest element
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// that is after location, or the bitwise complement of the list count in case all
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// elements are before location.
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if (~idx == 0) // first tag starts after location
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return -1;
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// Because we are looking for the nearest tag that starts before location, we will
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// return the element that precedes the one found
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idx = ~idx - 1;
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}
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return idx.Value;
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}
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public IList<TrackingTag> Values
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{
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get
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{
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if (!Ready)
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return new List<TrackingTag>();
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return data.Values;
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}
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}
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}
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/// <summary>
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/// Base class for QML classifier classes implementing the ITagger interface. This interface
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/// is used in the Visual Studio text editor extensibility for e.g. syntax highlighting. The
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/// processing of the QML source code is done asynchronously in a background thread in order
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/// to prevent the UI thread from blocking.
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///
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/// The result of the processing is a list of tracking tags that is stored in a SharedTagList
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/// and is made available to any instances of QmlAsyncClassifier working on the same source
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/// code. This prevents the processing being invoked more than once for any given version of
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/// that source code.
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///
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/// Derived classes are required to implement the processing of the source code as well as the
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/// conversion from TrackingTag to the type expected by the Visual Studio text editor.
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/// </summary>
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/// <typeparam name="T">
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/// Type of classification tag expected by the Visual Studio text editor extensibility
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/// </typeparam>
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abstract class QmlAsyncClassifier<T> : ITagger<T> where T : ITag
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{
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protected enum ClassificationRefresh
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{
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FullText,
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TagsOnly
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}
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/// <summary>
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/// Process QML source code. Implementations will override this method with the specific
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/// processing required to convert the parser results into a list of tracking tags
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/// </summary>
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/// <param name="snapshot">The current version of the source code</param>
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/// <param name="parseResult">The result of parsing the source code</param>
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/// <param name="tagList">Shared list of tracking tags</param>
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/// <param name="writeAccess">
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/// If true, the instance is required to populate the list of tags;
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/// otherwise, the instance has read-only access and cannot modify the list.
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/// </param>
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/// <returns>
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/// Hint on how to notify Visual Studio concerning the tags in the list
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/// FullText: refresh the entire contents of the text editor
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/// TagsOnly: refresh only the spans pointed to by the tags
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/// </returns>
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protected abstract ClassificationRefresh ProcessText(
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ITextSnapshot snapshot,
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Parser parseResult,
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SharedTagList tagList,
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bool writeAccess);
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/// <summary>
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/// Conversion from TrackingTag to the type T of classification tag expected by the
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/// Visual Studio text editor extensibility.
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/// </summary>
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/// <param name="tag">TrackingTag to convert</param>
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/// <returns>Instance of T corresponding to the given TrackingTag</returns>
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protected abstract T GetClassification(TrackingTag tag);
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private ITextView TextView { get; }
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private ITextBuffer Buffer { get; }
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readonly object criticalSection = new object();
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readonly string classificationType;
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ParserKey currentParserKey;
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TagListKey currentTagListKey;
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SharedTagList currentTagList;
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readonly Dispatcher dispatcher;
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readonly DispatcherTimer timer;
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bool flag = false;
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protected QmlAsyncClassifier(
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string classificationType,
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ITextView textView,
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ITextBuffer buffer)
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{
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TextView = textView;
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textView.Closed += TextView_Closed;
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Buffer = buffer;
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buffer.Changed += Buffer_Changed;
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dispatcher = Dispatcher.CurrentDispatcher;
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timer = new DispatcherTimer(DispatcherPriority.ApplicationIdle, dispatcher)
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{
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Interval = TimeSpan.FromMilliseconds(250)
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};
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timer.Tick += Timer_Tick;
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currentParserKey = null;
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currentTagListKey = null;
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currentTagList = null;
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this.classificationType = classificationType;
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Parse(buffer.CurrentSnapshot);
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}
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private void TextView_Closed(object sender, EventArgs e)
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{
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if (currentParserKey != null) {
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ParserStore.Instance.Release(this, currentParserKey);
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currentParserKey = null;
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}
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if (currentTagListKey != null) {
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TagListStore.Instance.Release(this, currentTagListKey);
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currentTagListKey = null;
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}
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currentTagList = null;
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}
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private void Buffer_Changed(object sender, TextContentChangedEventArgs e)
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{
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timer.Stop();
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Parse(e.After);
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}
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private void Timer_Tick(object sender, EventArgs e)
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{
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timer.Stop();
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Parse(Buffer.CurrentSnapshot);
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}
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private void Parse(ITextSnapshot snapshot)
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{
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lock (criticalSection) {
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if (flag)
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return;
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flag = true;
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}
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var newParserKey = new ParserKey(snapshot);
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var newTagListKey = new TagListKey(classificationType, snapshot);
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if (newParserKey == currentParserKey || newTagListKey == currentTagListKey)
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return;
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ParserKey oldParserKey = null;
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TagListKey oldTagListKey = null;
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_ = Task.Run(() =>
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{
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var parser = ParserStore.Instance.Get(this, newParserKey);
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var tagList = TagListStore.Instance.Get(this, newTagListKey);
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var refresh = ClassificationRefresh.FullText;
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try {
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var accessType = tagList.RequestWriteAccess(this);
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refresh = ProcessText(snapshot, parser, tagList,
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accessType == SharedTagList.AccessType.ReadWrite);
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} finally {
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tagList.WriteComplete(this);
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}
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oldParserKey = currentParserKey;
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currentParserKey = newParserKey;
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oldTagListKey = currentTagListKey;
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currentTagListKey = newTagListKey;
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currentTagList = tagList;
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RefreshClassification(snapshot, refresh, tagList);
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var currentVersion = Buffer.CurrentSnapshot.Version;
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if (snapshot.Version.VersionNumber == currentVersion.VersionNumber)
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timer.Stop();
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else
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timer.Start();
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});
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lock (criticalSection) {
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flag = false;
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}
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_ = Task.Run(() =>
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{
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if (oldParserKey != null)
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ParserStore.Instance.Release(this, oldParserKey);
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if (oldTagListKey != null)
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TagListStore.Instance.Release(this, oldTagListKey);
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});
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}
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private void RefreshClassification(
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ITextSnapshot snapshot,
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ClassificationRefresh refresh,
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SharedTagList tagList)
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{
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var tagsChangedHandler = TagsChanged;
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if (refresh == ClassificationRefresh.FullText) {
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var span = new SnapshotSpan(Buffer.CurrentSnapshot,
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0, Buffer.CurrentSnapshot.Length);
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if (tagsChangedHandler != null)
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tagsChangedHandler.Invoke(this, new SnapshotSpanEventArgs(span));
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} else {
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foreach (var tag in tagList.Values) {
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var tagMapped = tag.MapToSnapshot(snapshot);
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if (tagsChangedHandler != null)
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tagsChangedHandler.Invoke(this, new SnapshotSpanEventArgs(tagMapped.Span));
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}
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}
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}
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public IEnumerable<ITagSpan<T>> GetTags(NormalizedSnapshotSpanCollection spans)
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{
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if (currentTagList == null || !currentTagList.Ready)
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yield break;
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var firstTag = currentTagList.Values.FirstOrDefault();
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if (firstTag == null)
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yield break;
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var snapshot = spans[0].Snapshot;
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bool sameVersion =
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(firstTag.Snapshot.Version.VersionNumber == snapshot.Version.VersionNumber);
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foreach (var span in spans) {
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int idx = currentTagList.FindTagAtLocation(snapshot, span.Start);
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if (idx == -1)
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continue;
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for (; idx < currentTagList.Values.Count; idx++) {
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var tag = currentTagList.Values[idx];
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if (sameVersion && tag.Start > span.End)
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break;
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var tagMapped = tag.MapToSnapshot(snapshot);
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if (tagMapped.Span.Length == 0)
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continue;
|
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if (!sameVersion && tagMapped.Span.Start > span.End)
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break;
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if (!span.IntersectsWith(tagMapped.Span))
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continue;
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var classification = GetClassification(tag);
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if (classification == null)
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continue;
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var tracking = tagMapped.Tag.Span;
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yield return
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new TagSpan<T>(tracking.GetSpan(snapshot), classification);
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}
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}
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}
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public event EventHandler<SnapshotSpanEventArgs> TagsChanged;
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}
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namespace HelperTypes
|
{
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public static class BinarySearchExtensions
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{
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/// <summary>
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/// Generic BinarySearch method that will work on any IList(T),
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/// based on Microsoft’s ownArray.BinarySearch(T) implementation
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/// Adapted from http://philosopherdeveloper.com/posts/whats-annoying-about-sorted-list-index-of-key.html
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/// </summary>
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/// <returns>
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/// The index of the specified value in the specified list, if value is found;
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/// otherwise, a negative number. If value is not found and value is less than one or
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/// more elements in list, the negative number returned is the bitwise complement of
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/// the index of the first element that is larger than value. If value is not found and
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/// value is greater than all elements in list, the negative number returned is the
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/// bitwise complement of (the index of the last element plus 1). If this method is
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/// called with a non-sorted list, the return value can be incorrect and a negative
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/// number could be returned, even if value is present in list.
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/// (cf. https://docs.microsoft.com/en-us/dotnet/api/system.array.binarysearch)
|
///
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/// In case of error, returns null.
|
/// </returns>
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public static int? BinarySearch<T>(
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this IList<T> list,
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int index,
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int length,
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T value,
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IComparer<T> comparer)
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{
|
if (list == null)
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return null;
|
if (index < 0 || length < 0)
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return null;
|
if (list.Count - index < length)
|
return null;
|
|
int lower = index;
|
int upper = (index + length) - 1;
|
|
while (lower <= upper) {
|
int adjustedIndex = lower + ((upper - lower) >> 1);
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int comparison = comparer.Compare(list[adjustedIndex], value);
|
if (comparison == 0)
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return adjustedIndex;
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else if (comparison < 0)
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lower = adjustedIndex + 1;
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else
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upper = adjustedIndex - 1;
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}
|
|
return ~lower;
|
}
|
|
public static int? BinarySearch<T>(this IList<T> list, T value, IComparer<T> comparer)
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{
|
return list.BinarySearch(0, list.Count, value, comparer);
|
}
|
|
public static int? BinarySearch<T>(this IList<T> list, T value)
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where T : IComparable<T>
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{
|
return list.BinarySearch(value, Comparer<T>.Default);
|
}
|
}
|
|
/// <summary>
|
/// Base class for thread-safe, indexed data storage. References to stored values are
|
/// explicitly tracked to allow for timely disposal as soon as a value becomes
|
/// unreferenced. Shared data stores are intended to be used as singletons. For this
|
/// purpose, classes that inherit from SharedDataStore will include a static instance
|
/// member.
|
/// </summary>
|
/// <typeparam name="TKey">Value key type</typeparam>
|
/// <typeparam name="TValue">Value type</typeparam>
|
/// <typeparam name="TInstance">
|
/// Type of singleton instance, i.e. the same class that is derived from SharedDataStore
|
/// </typeparam>
|
abstract class SharedDataStore<TKey, TValue, TInstance>
|
where TInstance : SharedDataStore<TKey, TValue, TInstance>, new()
|
{
|
protected abstract TValue GetDefaultValue(TKey key);
|
|
class ValueRef
|
{
|
public TValue Value { get; set; }
|
public HashSet<object> ClientObjects { get; set; }
|
}
|
readonly Dictionary<TKey, ValueRef> data = new Dictionary<TKey, ValueRef>();
|
|
static readonly object staticCriticalSection = new object();
|
readonly object criticalSection = new object();
|
|
protected SharedDataStore()
|
{
|
data = new Dictionary<TKey, ValueRef>();
|
}
|
|
public TValue Get(object client, TKey key)
|
{
|
lock (criticalSection) {
|
if (!data.TryGetValue(key, out ValueRef valueRef)) {
|
valueRef = new ValueRef
|
{
|
Value = GetDefaultValue(key),
|
ClientObjects = new HashSet<object> { client }
|
};
|
data.Add(key, valueRef);
|
} else {
|
valueRef.ClientObjects.Add(client);
|
}
|
return valueRef.Value;
|
}
|
}
|
|
public void Release(object client, TKey key)
|
{
|
IDisposable disposable = null;
|
lock (criticalSection) {
|
if (data.TryGetValue(key, out ValueRef valueRef)) {
|
valueRef.ClientObjects.Remove(client);
|
if (valueRef.ClientObjects.Count == 0) {
|
data.Remove(key);
|
disposable = valueRef.Value as IDisposable;
|
}
|
}
|
}
|
if (disposable != null)
|
disposable.Dispose();
|
}
|
|
private static TInstance instance = null;
|
public static TInstance Instance
|
{
|
get
|
{
|
lock (staticCriticalSection) {
|
if (instance == null) {
|
instance = new TInstance();
|
}
|
return instance;
|
}
|
}
|
}
|
}
|
|
class TagListKey
|
{
|
private string Classification { get; }
|
private ITextSnapshot Snapshot { get; }
|
public TagListKey(string classification, ITextSnapshot snapshot)
|
{
|
Classification = classification;
|
Snapshot = snapshot;
|
}
|
|
public override bool Equals(object obj)
|
{
|
var that = obj as TagListKey;
|
if (that == null)
|
return false;
|
if (Classification != that.Classification)
|
return false;
|
if (Snapshot.TextBuffer != that.Snapshot.TextBuffer)
|
return false;
|
if (Snapshot.Version.VersionNumber != that.Snapshot.Version.VersionNumber)
|
return false;
|
return true;
|
}
|
|
public override int GetHashCode()
|
{
|
var hashBase = new Tuple<string, ITextBuffer, int>(
|
Classification, Snapshot.TextBuffer,
|
Snapshot.Version.VersionNumber);
|
return hashBase.GetHashCode();
|
}
|
}
|
|
class TagListStore : SharedDataStore<TagListKey, SharedTagList, TagListStore>
|
{
|
protected override SharedTagList GetDefaultValue(TagListKey key)
|
{
|
return new SharedTagList();
|
}
|
}
|
|
class ParserKey
|
{
|
public ITextSnapshot Snapshot { get; }
|
public ParserKey(ITextSnapshot snapshot)
|
{
|
Snapshot = snapshot;
|
}
|
|
public override bool Equals(object obj)
|
{
|
var that = obj as ParserKey;
|
if (that == null)
|
return false;
|
if (Snapshot.TextBuffer != that.Snapshot.TextBuffer)
|
return false;
|
if (Snapshot.Version.VersionNumber != that.Snapshot.Version.VersionNumber)
|
return false;
|
return true;
|
}
|
|
public override int GetHashCode()
|
{
|
var hashBase = new Tuple<ITextBuffer, int>(
|
Snapshot.TextBuffer, Snapshot.Version.VersionNumber);
|
return hashBase.GetHashCode();
|
}
|
}
|
|
class ParserStore : SharedDataStore<ParserKey, Parser, ParserStore>
|
{
|
protected override Parser GetDefaultValue(ParserKey key)
|
{
|
return Parser.Parse(key.Snapshot.GetText());
|
}
|
}
|
}
|
}
|
