refactor(addon-search): extract components

- Extract SearchEngine for core search algorithms
- Extract DecorationManager for visual decorations
- Extract SearchState for state management
- Extract SearchResultTracker for result tracking
- Simplify SearchAddon by delegating to components
- Improve modularity and maintainability

addons/addon-search/src/DecorationManager.ts

@@ -0,0 +1,157 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import type { Terminal, IDisposable, IDecoration } from '@xterm/xterm';
+import type { ISearchDecorationOptions } from '@xterm/addon-search';
+import { dispose, Disposable, toDisposable } from 'vs/base/common/lifecycle';
+import type { ISearchResult } from './SearchEngine';
+
+/**
+ * Interface for managing a highlight decoration.
+ */
+export interface IHighlight extends IDisposable {
+  decoration: IDecoration;
+  match: ISearchResult;
+}
+
+/**
+ * Interface for managing multiple decorations for a single match.
+ */
+export interface IMultiHighlight extends IDisposable {
+  decorations: IDecoration[];
+  match: ISearchResult;
+}
+
+/**
+ * Manages visual decorations for search results including highlighting and active selection
+ * indicators. This class handles the creation, styling, and disposal of search-related decorations.
+ */
+export class DecorationManager extends Disposable {
+  private _highlightDecorations: IHighlight[] = [];
+  private _highlightedLines: Set<number> = new Set();
+
+  constructor(private readonly _terminal: Terminal) {
+    super();
+    this._register(toDisposable(() => this.clearHighlightDecorations()));
+  }
+
+  /**
+   * Creates decorations for all provided search results.
+   * @param results The search results to create decorations for.
+   * @param options The decoration options.
+   */
+  public createHighlightDecorations(results: ISearchResult[], options: ISearchDecorationOptions): void {
+    this.clearHighlightDecorations();
+
+    for (const match of results) {
+      const decorations = this._createResultDecorations(match, options, false);
+      if (decorations) {
+        for (const decoration of decorations) {
+          this._storeDecoration(decoration, match);
+        }
+      }
+    }
+  }
+
+  /**
+   * Creates decorations for the currently active search result.
+   * @param result The active search result.
+   * @param options The decoration options.
+   * @returns The multi-highlight decoration or undefined if creation failed.
+   */
+  public createActiveDecoration(result: ISearchResult, options: ISearchDecorationOptions): IMultiHighlight | undefined {
+    const decorations = this._createResultDecorations(result, options, true);
+    if (decorations) {
+      return { decorations, match: result, dispose() { dispose(decorations); } };
+    }
+    return undefined;
+  }
+
+  /**
+   * Clears all highlight decorations.
+   */
+  public clearHighlightDecorations(): void {
+    dispose(this._highlightDecorations);
+    this._highlightDecorations = [];
+    this._highlightedLines.clear();
+  }
+
+  /**
+   * Stores a decoration and tracks it for management.
+   * @param decoration The decoration to store.
+   * @param match The search result this decoration represents.
+   */
+  private _storeDecoration(decoration: IDecoration, match: ISearchResult): void {
+    this._highlightedLines.add(decoration.marker.line);
+    this._highlightDecorations.push({ decoration, match, dispose() { decoration.dispose(); } });
+  }
+
+  /**
+   * Applies styles to the decoration when it is rendered.
+   * @param element The decoration's element.
+   * @param borderColor The border color to apply.
+   * @param isActiveResult Whether the element is part of the active search result.
+   */
+  private _applyStyles(element: HTMLElement, borderColor: string | undefined, isActiveResult: boolean): void {
+    if (!element.classList.contains('xterm-find-result-decoration')) {
+      element.classList.add('xterm-find-result-decoration');
+      if (borderColor) {
+        element.style.outline = `1px solid ${borderColor}`;
+      }
+    }
+    if (isActiveResult) {
+      element.classList.add('xterm-find-active-result-decoration');
+    }
+  }
+
+  /**
+   * Creates a decoration for the result and applies styles
+   * @param result the search result for which to create the decoration
+   * @param options the options for the decoration
+   * @param isActiveResult whether this is the currently active result
+   * @returns the decorations or undefined if the marker has already been disposed of
+   */
+  private _createResultDecorations(result: ISearchResult, options: ISearchDecorationOptions, isActiveResult: boolean): IDecoration[] | undefined {
+    // Gather decoration ranges for this match as it could wrap
+    const decorationRanges: [number, number, number][] = [];
+    let currentCol = result.col;
+    let remainingSize = result.size;
+    let markerOffset = -this._terminal.buffer.active.baseY - this._terminal.buffer.active.cursorY + result.row;
+    while (remainingSize > 0) {
+      const amountThisRow = Math.min(this._terminal.cols - currentCol, remainingSize);
+      decorationRanges.push([markerOffset, currentCol, amountThisRow]);
+      currentCol = 0;
+      remainingSize -= amountThisRow;
+      markerOffset++;
+    }
+
+    // Create the decorations
+    const decorations: IDecoration[] = [];
+    for (const range of decorationRanges) {
+      const marker = this._terminal.registerMarker(range[0]);
+      const decoration = this._terminal.registerDecoration({
+        marker,
+        x: range[1],
+        width: range[2],
+        backgroundColor: isActiveResult ? options.activeMatchBackground : options.matchBackground,
+        overviewRulerOptions: this._highlightedLines.has(marker.line) ? undefined : {
+          color: isActiveResult ? options.activeMatchColorOverviewRuler : options.matchOverviewRuler,
+          position: 'center'
+        }
+      });
+      if (decoration) {
+        const disposables: IDisposable[] = [];
+        disposables.push(marker);
+        disposables.push(decoration.onRender((e) => this._applyStyles(e, isActiveResult ? options.activeMatchBorder : options.matchBorder, false)));
+        disposables.push(decoration.onDispose(() => dispose(disposables)));
+        decorations.push(decoration);
+      }
+    }
+
+    return decorations.length === 0 ? undefined : decorations;
+  }
+}
+
+

addons/addon-search/src/SearchEngine.ts

@@ -0,0 +1,385 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import type { Terminal } from '@xterm/xterm';
+import type { ISearchOptions } from '@xterm/addon-search';
+import type { SearchLineCache } from './SearchLineCache';
+
+/**
+ * Represents the position to start a search from.
+ */
+export interface ISearchPosition {
+  startCol: number;
+  startRow: number;
+}
+
+/**
+ * Represents a search result with its position and content.
+ */
+export interface ISearchResult {
+  term: string;
+  col: number;
+  row: number;
+  size: number;
+}
+
+/**
+ * Configuration constants for the search engine functionality.
+ */
+const enum Constants {
+  /**
+   * Characters that are considered non-word characters for search boundary detection. These
+   * characters are used to determine word boundaries when performing whole-word searches. Includes
+   * common punctuation, symbols, and whitespace characters.
+   */
+  NON_WORD_CHARACTERS = ' ~!@#$%^&*()+`-=[]{}|\\;:"\',./<>?'
+}
+
+/**
+ * Core search engine that handles finding text within terminal content.
+ * This class is responsible for the actual search algorithms and position calculations.
+ */
+export class SearchEngine {
+  constructor(
+    private readonly _terminal: Terminal,
+    private readonly _lineCache: SearchLineCache
+  ) {}
+
+  /**
+   * Find the first occurrence of a term starting from a specific position.
+   * @param term The search term.
+   * @param startRow The row to start searching from.
+   * @param startCol The column to start searching from.
+   * @param searchOptions Search options.
+   * @returns The search result if found, undefined otherwise.
+   */
+  public find(term: string, startRow: number, startCol: number, searchOptions?: ISearchOptions): ISearchResult | undefined {
+    if (!term || term.length === 0) {
+      this._terminal.clearSelection();
+      return undefined;
+    }
+    if (startCol > this._terminal.cols) {
+      throw new Error(`Invalid col: ${startCol} to search in terminal of ${this._terminal.cols} cols`);
+    }
+
+    this._lineCache.initLinesCache();
+
+    const searchPosition: ISearchPosition = {
+      startRow,
+      startCol
+    };
+
+    // Search startRow
+    let result = this._findInLine(term, searchPosition, searchOptions);
+    // Search from startRow + 1 to end
+    if (!result) {
+      for (let y = startRow + 1; y < this._terminal.buffer.active.baseY + this._terminal.rows; y++) {
+        searchPosition.startRow = y;
+        searchPosition.startCol = 0;
+        result = this._findInLine(term, searchPosition, searchOptions);
+        if (result) {
+          break;
+        }
+      }
+    }
+    return result;
+  }
+
+  /**
+   * Find the next occurrence of a term with wrapping and selection management.
+   * @param term The search term.
+   * @param searchOptions Search options.
+   * @returns The search result if found, undefined otherwise.
+   */
+  public findNextWithSelection(term: string, searchOptions?: ISearchOptions): ISearchResult | undefined {
+    if (!term || term.length === 0) {
+      this._terminal.clearSelection();
+      return undefined;
+    }
+
+    const prevSelectedPos = this._terminal.getSelectionPosition();
+    this._terminal.clearSelection();
+
+    let startCol = 0;
+    let startRow = 0;
+    if (prevSelectedPos) {
+      startCol = prevSelectedPos.end.x;
+      startRow = prevSelectedPos.end.y;
+    }
+
+    this._lineCache.initLinesCache();
+
+    const searchPosition: ISearchPosition = {
+      startRow,
+      startCol
+    };
+
+    // Search startRow
+    let result = this._findInLine(term, searchPosition, searchOptions);
+    // Search from startRow + 1 to end
+    if (!result) {
+      for (let y = startRow + 1; y < this._terminal.buffer.active.baseY + this._terminal.rows; y++) {
+        searchPosition.startRow = y;
+        searchPosition.startCol = 0;
+        result = this._findInLine(term, searchPosition, searchOptions);
+        if (result) {
+          break;
+        }
+      }
+    }
+    // If we hit the bottom and didn't search from the very top wrap back up
+    if (!result && startRow !== 0) {
+      for (let y = 0; y < startRow; y++) {
+        searchPosition.startRow = y;
+        searchPosition.startCol = 0;
+        result = this._findInLine(term, searchPosition, searchOptions);
+        if (result) {
+          break;
+        }
+      }
+    }
+
+    // If there is only one result, wrap back and return selection if it exists.
+    if (!result && prevSelectedPos) {
+      searchPosition.startRow = prevSelectedPos.start.y;
+      searchPosition.startCol = 0;
+      result = this._findInLine(term, searchPosition, searchOptions);
+    }
+
+    return result;
+  }
+
+  /**
+   * Find the previous occurrence of a term with wrapping and selection management.
+   * @param term The search term.
+   * @param searchOptions Search options.
+   * @returns The search result if found, undefined otherwise.
+   */
+  public findPreviousWithSelection(term: string, searchOptions?: ISearchOptions): ISearchResult | undefined {
+    if (!term || term.length === 0) {
+      this._terminal.clearSelection();
+      return undefined;
+    }
+
+    const prevSelectedPos = this._terminal.getSelectionPosition();
+    this._terminal.clearSelection();
+
+    let startRow = this._terminal.buffer.active.baseY + this._terminal.rows - 1;
+    let startCol = this._terminal.cols;
+    const isReverseSearch = true;
+
+    this._lineCache.initLinesCache();
+    const searchPosition: ISearchPosition = {
+      startRow,
+      startCol
+    };
+
+    let result: ISearchResult | undefined;
+    if (prevSelectedPos) {
+      searchPosition.startRow = startRow = prevSelectedPos.start.y;
+      searchPosition.startCol = startCol = prevSelectedPos.start.x;
+      // Try to expand selection to right first.
+      result = this._findInLine(term, searchPosition, searchOptions, false);
+      if (!result) {
+        // If selection was not able to be expanded to the right, then try reverse search
+        searchPosition.startRow = startRow = prevSelectedPos.end.y;
+        searchPosition.startCol = startCol = prevSelectedPos.end.x;
+      }
+    }
+
+    if (!result) {
+      result = this._findInLine(term, searchPosition, searchOptions, isReverseSearch);
+    }
+
+    // Search from startRow - 1 to top
+    if (!result) {
+      searchPosition.startCol = Math.max(searchPosition.startCol, this._terminal.cols);
+      for (let y = startRow - 1; y >= 0; y--) {
+        searchPosition.startRow = y;
+        result = this._findInLine(term, searchPosition, searchOptions, isReverseSearch);
+        if (result) {
+          break;
+        }
+      }
+    }
+    // If we hit the top and didn't search from the very bottom wrap back down
+    if (!result && startRow !== (this._terminal.buffer.active.baseY + this._terminal.rows - 1)) {
+      for (let y = (this._terminal.buffer.active.baseY + this._terminal.rows - 1); y >= startRow; y--) {
+        searchPosition.startRow = y;
+        result = this._findInLine(term, searchPosition, searchOptions, isReverseSearch);
+        if (result) {
+          break;
+        }
+      }
+    }
+
+    return result;
+  }
+
+  /**
+   * A found substring is a whole word if it doesn't have an alphanumeric character directly
+   * adjacent to it.
+   * @param searchIndex starting index of the potential whole word substring
+   * @param line entire string in which the potential whole word was found
+   * @param term the substring that starts at searchIndex
+   */
+  private _isWholeWord(searchIndex: number, line: string, term: string): boolean {
+    return ((searchIndex === 0) || (Constants.NON_WORD_CHARACTERS.includes(line[searchIndex - 1]))) &&
+      (((searchIndex + term.length) === line.length) || (Constants.NON_WORD_CHARACTERS.includes(line[searchIndex + term.length])));
+  }
+
+  /**
+   * Searches a line for a search term. Takes the provided terminal line and searches the text line,
+   * which may contain subsequent terminal lines if the text is wrapped. If the provided line number
+   * is part of a wrapped text line that started on an earlier line then it is skipped since it will
+   * be properly searched when the terminal line that the text starts on is searched.
+   * @param term The search term.
+   * @param searchPosition The position to start the search.
+   * @param searchOptions Search options.
+   * @param isReverseSearch Whether the search should start from the right side of the terminal and
+   * search to the left.
+   * @returns The search result if it was found.
+   */
+  private _findInLine(term: string, searchPosition: ISearchPosition, searchOptions: ISearchOptions = {}, isReverseSearch: boolean = false): ISearchResult | undefined {
+    const row = searchPosition.startRow;
+    const col = searchPosition.startCol;
+
+    // Ignore wrapped lines, only consider on unwrapped line (first row of command string).
+    const firstLine = this._terminal.buffer.active.getLine(row);
+    if (firstLine?.isWrapped) {
+      if (isReverseSearch) {
+        searchPosition.startCol += this._terminal.cols;
+        return;
+      }
+
+      // This will iterate until we find the line start.
+      // When we find it, we will search using the calculated start column.
+      searchPosition.startRow--;
+      searchPosition.startCol += this._terminal.cols;
+      return this._findInLine(term, searchPosition, searchOptions);
+    }
+    let cache = this._lineCache.getLineFromCache(row);
+    if (!cache) {
+      cache = this._lineCache.translateBufferLineToStringWithWrap(row, true);
+      this._lineCache.setLineInCache(row, cache);
+    }
+    const [stringLine, offsets] = cache;
+
+    const offset = this._bufferColsToStringOffset(row, col);
+    let searchTerm = term;
+    let searchStringLine = stringLine;
+    if (!searchOptions.regex) {
+      searchTerm = searchOptions.caseSensitive ? term : term.toLowerCase();
+      searchStringLine = searchOptions.caseSensitive ? stringLine : stringLine.toLowerCase();
+    }
+
+    let resultIndex = -1;
+    if (searchOptions.regex) {
+      const searchRegex = RegExp(searchTerm, searchOptions.caseSensitive ? 'g' : 'gi');
+      let foundTerm: RegExpExecArray | null;
+      if (isReverseSearch) {
+        // This loop will get the resultIndex of the _last_ regex match in the range 0..offset
+        while (foundTerm = searchRegex.exec(searchStringLine.slice(0, offset))) {
+          resultIndex = searchRegex.lastIndex - foundTerm[0].length;
+          term = foundTerm[0];
+          searchRegex.lastIndex -= (term.length - 1);
+        }
+      } else {
+        foundTerm = searchRegex.exec(searchStringLine.slice(offset));
+        if (foundTerm && foundTerm[0].length > 0) {
+          resultIndex = offset + (searchRegex.lastIndex - foundTerm[0].length);
+          term = foundTerm[0];
+        }
+      }
+    } else {
+      if (isReverseSearch) {
+        if (offset - searchTerm.length >= 0) {
+          resultIndex = searchStringLine.lastIndexOf(searchTerm, offset - searchTerm.length);
+        }
+      } else {
+        resultIndex = searchStringLine.indexOf(searchTerm, offset);
+      }
+    }
+
+    if (resultIndex >= 0) {
+      if (searchOptions.wholeWord && !this._isWholeWord(resultIndex, searchStringLine, term)) {
+        return;
+      }
+
+      // Adjust the row number and search index if needed since a "line" of text can span multiple
+      // rows
+      let startRowOffset = 0;
+      while (startRowOffset < offsets.length - 1 && resultIndex >= offsets[startRowOffset + 1]) {
+        startRowOffset++;
+      }
+      let endRowOffset = startRowOffset;
+      while (endRowOffset < offsets.length - 1 && resultIndex + term.length >= offsets[endRowOffset + 1]) {
+        endRowOffset++;
+      }
+      const startColOffset = resultIndex - offsets[startRowOffset];
+      const endColOffset = resultIndex + term.length - offsets[endRowOffset];
+      const startColIndex = this._stringLengthToBufferSize(row + startRowOffset, startColOffset);
+      const endColIndex = this._stringLengthToBufferSize(row + endRowOffset, endColOffset);
+      const size = endColIndex - startColIndex + this._terminal.cols * (endRowOffset - startRowOffset);
+
+      return {
+        term,
+        col: startColIndex,
+        row: row + startRowOffset,
+        size
+      };
+    }
+  }
+
+  private _stringLengthToBufferSize(row: number, offset: number): number {
+    const line = this._terminal.buffer.active.getLine(row);
+    if (!line) {
+      return 0;
+    }
+    for (let i = 0; i < offset; i++) {
+      const cell = line.getCell(i);
+      if (!cell) {
+        break;
+      }
+      // Adjust the searchIndex to normalize emoji into single chars
+      const char = cell.getChars();
+      if (char.length > 1) {
+        offset -= char.length - 1;
+      }
+      // Adjust the searchIndex for empty characters following wide unicode
+      // chars (eg. CJK)
+      const nextCell = line.getCell(i + 1);
+      if (nextCell && nextCell.getWidth() === 0) {
+        offset++;
+      }
+    }
+    return offset;
+  }
+
+  private _bufferColsToStringOffset(startRow: number, cols: number): number {
+    let lineIndex = startRow;
+    let offset = 0;
+    let line = this._terminal.buffer.active.getLine(lineIndex);
+    while (cols > 0 && line) {
+      for (let i = 0; i < cols && i < this._terminal.cols; i++) {
+        const cell = line.getCell(i);
+        if (!cell) {
+          break;
+        }
+        if (cell.getWidth()) {
+          // Treat null characters as whitespace to align with the translateToString API
+          offset += cell.getCode() === 0 ? 1 : cell.getChars().length;
+        }
+      }
+      lineIndex++;
+      line = this._terminal.buffer.active.getLine(lineIndex);
+      if (line && !line.isWrapped) {
+        break;
+      }
+      cols -= this._terminal.cols;
+    }
+    return offset;
+  }
+}

addons/addon-search/src/SearchLineCache.ts

@@ -39,7 +39,7 @@ export class SearchLineCache extends Disposable {
   private _linesCacheTimeout = this._register(new MutableDisposable());
   private _linesCacheDisposables = this._register(new MutableDisposable());
 
-  constructor(private _terminal: Terminal) {
+  constructor(private readonly _terminal: Terminal) {
     super();
     this._register(toDisposable(() => this._destroyLinesCache()));
   }

addons/addon-search/src/SearchResultTracker.ts

@@ -0,0 +1,119 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import type { ISearchResultChangeEvent } from '@xterm/addon-search';
+import { Emitter, Event } from 'vs/base/common/event';
+import { Disposable } from 'vs/base/common/lifecycle';
+import type { ISearchResult } from './SearchEngine';
+
+/**
+ * Interface for managing a currently selected decoration.
+ */
+export interface ISelectedDecoration {
+  match: ISearchResult;
+  dispose(): void;
+}
+
+/**
+ * Tracks search results, manages result indexing, and fires events when results change.
+ * This class provides centralized management of search result state and notifications.
+ */
+export class SearchResultTracker extends Disposable {
+  private _searchResults: ISearchResult[] = [];
+  private _selectedDecoration: ISelectedDecoration | undefined;
+
+  private readonly _onDidChangeResults = this._register(new Emitter<ISearchResultChangeEvent>());
+  public get onDidChangeResults(): Event<ISearchResultChangeEvent> { return this._onDidChangeResults.event; }
+
+  /**
+   * Gets the current search results.
+   */
+  public get searchResults(): ReadonlyArray<ISearchResult> {
+    return this._searchResults;
+  }
+
+  /**
+   * Gets the currently selected decoration.
+   */
+  public get selectedDecoration(): ISelectedDecoration | undefined {
+    return this._selectedDecoration;
+  }
+
+  /**
+   * Sets the currently selected decoration.
+   */
+  public set selectedDecoration(decoration: ISelectedDecoration | undefined) {
+    this._selectedDecoration = decoration;
+  }
+
+  /**
+   * Updates the search results with a new set of results.
+   * @param results The new search results.
+   * @param maxResults The maximum number of results to track.
+   */
+  public updateResults(results: ISearchResult[], maxResults: number): void {
+    this._searchResults = results.slice(0, maxResults);
+  }
+
+  /**
+   * Clears all search results.
+   */
+  public clearResults(): void {
+    this._searchResults = [];
+  }
+
+  /**
+   * Clears the selected decoration.
+   */
+  public clearSelectedDecoration(): void {
+    if (this._selectedDecoration) {
+      this._selectedDecoration.dispose();
+      this._selectedDecoration = undefined;
+    }
+  }
+
+  /**
+   * Finds the index of a result in the current results array.
+   * @param result The result to find.
+   * @returns The index of the result, or -1 if not found.
+   */
+  public findResultIndex(result: ISearchResult): number {
+    for (let i = 0; i < this._searchResults.length; i++) {
+      const match = this._searchResults[i];
+      if (match.row === result.row && match.col === result.col && match.size === result.size) {
+        return i;
+      }
+    }
+    return -1;
+  }
+
+  /**
+   * Fires a result change event with the current state.
+   * @param hasDecorations Whether decorations are enabled.
+   */
+  public fireResultsChanged(hasDecorations: boolean): void {
+    if (!hasDecorations) {
+      return;
+    }
+
+    let resultIndex = -1;
+    if (this._selectedDecoration) {
+      resultIndex = this.findResultIndex(this._selectedDecoration.match);
+    }
+
+    this._onDidChangeResults.fire({
+      resultIndex,
+      resultCount: this._searchResults.length
+    });
+  }
+
+  /**
+   * Resets all state.
+   */
+  public reset(): void {
+    this.clearSelectedDecoration();
+    this.clearResults();
+  }
+}

addons/addon-search/src/SearchState.ts

@@ -0,0 +1,106 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import type { ISearchOptions } from '@xterm/addon-search';
+
+/**
+ * Manages search state including cached search terms, options tracking, and validation.
+ * This class provides a centralized way to handle search state consistency and option changes.
+ */
+export class SearchState {
+  private _cachedSearchTerm: string | undefined;
+  private _lastSearchOptions: ISearchOptions | undefined;
+
+  /**
+   * Gets the currently cached search term.
+   */
+  public get cachedSearchTerm(): string | undefined {
+    return this._cachedSearchTerm;
+  }
+
+  /**
+   * Sets the cached search term.
+   */
+  public set cachedSearchTerm(term: string | undefined) {
+    this._cachedSearchTerm = term;
+  }
+
+  /**
+   * Gets the last search options used.
+   */
+  public get lastSearchOptions(): ISearchOptions | undefined {
+    return this._lastSearchOptions;
+  }
+
+  /**
+   * Sets the last search options used.
+   */
+  public set lastSearchOptions(options: ISearchOptions | undefined) {
+    this._lastSearchOptions = options;
+  }
+
+  /**
+   * Validates a search term to ensure it's not empty or invalid.
+   * @param term The search term to validate.
+   * @returns true if the term is valid for searching.
+   */
+  public isValidSearchTerm(term: string): boolean {
+    return !!(term && term.length > 0);
+  }
+
+  /**
+   * Determines if search options have changed compared to the last search.
+   * @param newOptions The new search options to compare.
+   * @returns true if the options have changed.
+   */
+  public didOptionsChange(newOptions?: ISearchOptions): boolean {
+    if (!this._lastSearchOptions) {
+      return true;
+    }
+    if (!newOptions) {
+      return false;
+    }
+    if (this._lastSearchOptions.caseSensitive !== newOptions.caseSensitive) {
+      return true;
+    }
+    if (this._lastSearchOptions.regex !== newOptions.regex) {
+      return true;
+    }
+    if (this._lastSearchOptions.wholeWord !== newOptions.wholeWord) {
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Determines if a new search should trigger highlighting updates.
+   * @param term The search term.
+   * @param options The search options.
+   * @returns true if highlighting should be updated.
+   */
+  public shouldUpdateHighlighting(term: string, options?: ISearchOptions): boolean {
+    if (!options?.decorations) {
+      return false;
+    }
+    return this._cachedSearchTerm === undefined ||
+           term !== this._cachedSearchTerm ||
+           this.didOptionsChange(options);
+  }
+
+  /**
+   * Clears the cached search term.
+   */
+  public clearCachedTerm(): void {
+    this._cachedSearchTerm = undefined;
+  }
+
+  /**
+   * Resets all state.
+   */
+  public reset(): void {
+    this._cachedSearchTerm = undefined;
+    this._lastSearchOptions = undefined;
+  }
+}