source: branches/EnhancedProgress/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Highlighting/DocumentHighlighter.cs @ 15683

// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
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// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using ICSharpCode.NRefactory.Editor;
using ICSharpCode.AvalonEdit.Document;
using ICSharpCode.AvalonEdit.Utils;
using SpanStack = ICSharpCode.AvalonEdit.Utils.ImmutableStack<ICSharpCode.AvalonEdit.Highlighting.HighlightingSpan>;

namespace ICSharpCode.AvalonEdit.Highlighting
{
  /// <summary>
  /// This class can syntax-highlight a document.
  /// It automatically manages invalidating the highlighting when the document changes.
  /// </summary>
  public class DocumentHighlighter : ILineTracker, IHighlighter
  {
    /// <summary>
    /// Stores the span state at the end of each line.
    /// storedSpanStacks[0] = state at beginning of document
    /// storedSpanStacks[i] = state after line i
    /// </summary>
    readonly CompressingTreeList<SpanStack> storedSpanStacks = new CompressingTreeList<SpanStack>(object.ReferenceEquals);
    readonly CompressingTreeList<bool> isValid = new CompressingTreeList<bool>((a, b) => a == b);
    readonly IDocument document;
    readonly IHighlightingDefinition definition;
    readonly HighlightingEngine engine;
    readonly WeakLineTracker weakLineTracker;
    bool isHighlighting;
    bool isInHighlightingGroup;
    bool isDisposed;
    
    /// <summary>
    /// Gets the document that this DocumentHighlighter is highlighting.
    /// </summary>
    public IDocument Document {
      get { return document; }
    }
    
    /// <summary>
    /// Creates a new DocumentHighlighter instance.
    /// </summary>
    public DocumentHighlighter(TextDocument document, IHighlightingDefinition definition)
    {
      if (document == null)
        throw new ArgumentNullException("document");
      if (definition == null)
        throw new ArgumentNullException("definition");
      this.document = document;
      this.definition = definition;
      this.engine = new HighlightingEngine(definition.MainRuleSet);
      document.VerifyAccess();
      weakLineTracker = WeakLineTracker.Register(document, this);
      InvalidateHighlighting();
    }
    
    #if NREFACTORY
    /// <summary>
    /// Creates a new DocumentHighlighter instance.
    /// </summary>
    public DocumentHighlighter(ReadOnlyDocument document, IHighlightingDefinition definition)
    {
      if (document == null)
        throw new ArgumentNullException("document");
      if (definition == null)
        throw new ArgumentNullException("definition");
      this.document = document;
      this.definition = definition;
      this.engine = new HighlightingEngine(definition.MainRuleSet);
      InvalidateHighlighting();
    }
    #endif
    
    /// <summary>
    /// Disposes the document highlighter.
    /// </summary>
    public void Dispose()
    {
      if (weakLineTracker != null)
        weakLineTracker.Deregister();
      isDisposed = true;
    }
    
    void ILineTracker.BeforeRemoveLine(DocumentLine line)
    {
      CheckIsHighlighting();
      int number = line.LineNumber;
      storedSpanStacks.RemoveAt(number);
      isValid.RemoveAt(number);
      if (number < isValid.Count) {
        isValid[number] = false;
        if (number < firstInvalidLine)
          firstInvalidLine = number;
      }
    }
    
    void ILineTracker.SetLineLength(DocumentLine line, int newTotalLength)
    {
      CheckIsHighlighting();
      int number = line.LineNumber;
      isValid[number] = false;
      if (number < firstInvalidLine)
        firstInvalidLine = number;
    }
    
    void ILineTracker.LineInserted(DocumentLine insertionPos, DocumentLine newLine)
    {
      CheckIsHighlighting();
      Debug.Assert(insertionPos.LineNumber + 1 == newLine.LineNumber);
      int lineNumber = newLine.LineNumber;
      storedSpanStacks.Insert(lineNumber, null);
      isValid.Insert(lineNumber, false);
      if (lineNumber < firstInvalidLine)
        firstInvalidLine = lineNumber;
    }
    
    void ILineTracker.RebuildDocument()
    {
      InvalidateHighlighting();
    }
    
    void ILineTracker.ChangeComplete(DocumentChangeEventArgs e)
    {
    }
    
    ImmutableStack<HighlightingSpan> initialSpanStack = SpanStack.Empty;
    
    /// <summary>
    /// Gets/sets the the initial span stack of the document. Default value is <see cref="SpanStack.Empty" />.
    /// </summary>
    public ImmutableStack<HighlightingSpan> InitialSpanStack {
      get { return initialSpanStack; }
      set {
        initialSpanStack = value ?? SpanStack.Empty;
        InvalidateHighlighting();
      }
    }
    
    /// <summary>
    /// Invalidates all stored highlighting info.
    /// When the document changes, the highlighting is invalidated automatically, this method
    /// needs to be called only when there are changes to the highlighting rule set.
    /// </summary>
    public void InvalidateHighlighting()
    {
      CheckIsHighlighting();
      storedSpanStacks.Clear();
      storedSpanStacks.Add(initialSpanStack);
      storedSpanStacks.InsertRange(1, document.LineCount, null);
      isValid.Clear();
      isValid.Add(true);
      isValid.InsertRange(1, document.LineCount, false);
      firstInvalidLine = 1;
    }
    
    int firstInvalidLine;
    
    /// <inheritdoc/>
    public HighlightedLine HighlightLine(int lineNumber)
    {
      ThrowUtil.CheckInRangeInclusive(lineNumber, "lineNumber", 1, document.LineCount);
      CheckIsHighlighting();
      isHighlighting = true;
      try {
        HighlightUpTo(lineNumber - 1);
        IDocumentLine line = document.GetLineByNumber(lineNumber);
        HighlightedLine result = engine.HighlightLine(document, line);
        UpdateTreeList(lineNumber);
        return result;
      } finally {
        isHighlighting = false;
      }
    }
    
    /// <summary>
    /// Gets the span stack at the end of the specified line.
    /// -> GetSpanStack(1) returns the spans at the start of the second line.
    /// </summary>
    /// <remarks>
    /// GetSpanStack(0) is valid and will return <see cref="InitialSpanStack"/>.
    /// The elements are returned in inside-out order (first element of result enumerable is the color of the innermost span).
    /// </remarks>
    public SpanStack GetSpanStack(int lineNumber)
    {
      ThrowUtil.CheckInRangeInclusive(lineNumber, "lineNumber", 0, document.LineCount);
      if (firstInvalidLine <= lineNumber) {
        UpdateHighlightingState(lineNumber);
      }
      return storedSpanStacks[lineNumber];
    }
    
    /// <inheritdoc/>
    public IEnumerable<HighlightingColor> GetColorStack(int lineNumber)
    {
      return GetSpanStack(lineNumber).Select(s => s.SpanColor).Where(s => s != null);
    }
    
    void CheckIsHighlighting()
    {
      if (isDisposed) {
        throw new ObjectDisposedException("DocumentHighlighter");
      }
      if (isHighlighting) {
        throw new InvalidOperationException("Invalid call - a highlighting operation is currently running.");
      }
    }
    
    /// <inheritdoc/>
    public void UpdateHighlightingState(int lineNumber)
    {
      CheckIsHighlighting();
      isHighlighting = true;
      try {
        HighlightUpTo(lineNumber);
      } finally {
        isHighlighting = false;
      }
    }
    
    /// <summary>
    /// Sets the engine's CurrentSpanStack to the end of the target line.
    /// Updates the span stack for all lines up to (and including) the target line, if necessary.
    /// </summary>
    void HighlightUpTo(int targetLineNumber)
    {
      for (int currentLine = 0; currentLine <= targetLineNumber; currentLine++) {
        if (firstInvalidLine > currentLine) {
          // (this branch is always taken on the first loop iteration, as firstInvalidLine > 0)
          
          if (firstInvalidLine <= targetLineNumber) {
            // Skip valid lines to next invalid line:
            engine.CurrentSpanStack = storedSpanStacks[firstInvalidLine - 1];
            currentLine = firstInvalidLine;
          } else {
            // Skip valid lines to target line:
            engine.CurrentSpanStack = storedSpanStacks[targetLineNumber];
            break;
          }
        }
        Debug.Assert(EqualSpanStacks(engine.CurrentSpanStack, storedSpanStacks[currentLine - 1]));
        engine.ScanLine(document, document.GetLineByNumber(currentLine));
        UpdateTreeList(currentLine);
      }
      Debug.Assert(EqualSpanStacks(engine.CurrentSpanStack, storedSpanStacks[targetLineNumber]));
    }
    
    void UpdateTreeList(int lineNumber)
    {
      if (!EqualSpanStacks(engine.CurrentSpanStack, storedSpanStacks[lineNumber])) {
        isValid[lineNumber] = true;
        //Debug.WriteLine("Span stack in line " + lineNumber + " changed from " + storedSpanStacks[lineNumber] + " to " + spanStack);
        storedSpanStacks[lineNumber] = engine.CurrentSpanStack;
        if (lineNumber + 1 < isValid.Count) {
          isValid[lineNumber + 1] = false;
          firstInvalidLine = lineNumber + 1;
        } else {
          firstInvalidLine = int.MaxValue;
        }
        if (lineNumber + 1 < document.LineCount)
          OnHighlightStateChanged(lineNumber + 1, lineNumber + 1);
      } else if (firstInvalidLine == lineNumber) {
        isValid[lineNumber] = true;
        firstInvalidLine = isValid.IndexOf(false);
        if (firstInvalidLine < 0)
          firstInvalidLine = int.MaxValue;
      }
    }
    
    static bool EqualSpanStacks(SpanStack a, SpanStack b)
    {
      // We must use value equality between the stacks because HighlightingColorizer.OnHighlightStateChanged
      // depends on the fact that equal input state + unchanged line contents produce equal output state.
      if (a == b)
        return true;
      if (a == null || b == null)
        return false;
      while (!a.IsEmpty && !b.IsEmpty) {
        if (a.Peek() != b.Peek())
          return false;
        a = a.Pop();
        b = b.Pop();
        if (a == b)
          return true;
      }
      return a.IsEmpty && b.IsEmpty;
    }
    
    /// <inheritdoc/>
    public event HighlightingStateChangedEventHandler HighlightingStateChanged;
    
    /// <summary>
    /// Is called when the highlighting state at the end of the specified line has changed.
    /// </summary>
    /// <remarks>This callback must not call HighlightLine or InvalidateHighlighting.
    /// It may call GetSpanStack, but only for the changed line and lines above.
    /// This method must not modify the document.</remarks>
    protected virtual void OnHighlightStateChanged(int fromLineNumber, int toLineNumber)
    {
      if (HighlightingStateChanged != null)
        HighlightingStateChanged(fromLineNumber, toLineNumber);
    }
    
    /// <inheritdoc/>
    public HighlightingColor DefaultTextColor {
      get { return null; }
    }
    
    /// <inheritdoc/>
    public void BeginHighlighting()
    {
      if (isInHighlightingGroup)
        throw new InvalidOperationException("Highlighting group is already open");
      isInHighlightingGroup = true;
    }
    
    /// <inheritdoc/>
    public void EndHighlighting()
    {
      if (!isInHighlightingGroup)
        throw new InvalidOperationException("Highlighting group is not open");
      isInHighlightingGroup = false;
    }
    
    /// <inheritdoc/>
    public HighlightingColor GetNamedColor(string name)
    {
      return definition.GetNamedColor(name);
    }
  }
}