tree based RipgrepResultCache implementation

# Conflicts:
#	src/integrations/workspace/__tests__/WorkspaceTracker.spec.ts

Author: Naituw

src/integrations/workspace/RipgrepResultCache.ts

@@ -0,0 +1,357 @@
+import { spawn } from "child_process"
+import { dirname, resolve as pathResolve, relative } from "path"
+
+// Simplified tree structure - files represented by true, directories by nested objects
+export type SimpleTreeNode = {
+	[key: string]: true | SimpleTreeNode
+}
+
+/**
+ * Ripgrep result cache class
+ * Provides file tree caching functionality with incremental updates
+ */
+export class RipgrepResultCache {
+	private rgPath: string
+	private _targetPath: string
+	private cachedTree: SimpleTreeNode | null = null
+	private invalidatedDirectories = new Set<string>()
+	private rgArgs: string[]
+	private currentBuildPromise: Promise<SimpleTreeNode> | null = null
+	private fileLimit: number
+
+	constructor(rgPath: string, targetPath: string, rgArgs: string[] = [], fileLimit: number = 5000) {
+		this.rgPath = rgPath
+		this._targetPath = pathResolve(targetPath)
+		this.fileLimit = fileLimit
+		this.rgArgs = rgArgs.length > 0 ? rgArgs : ["--files"]
+	}
+
+	get targetPath(): string {
+		return this._targetPath
+	}
+
+	/**
+	 * Asynchronously get file tree
+	 * - If there's valid cache and no invalid directories, return cache
+	 * - If currently building, wait for current build result
+	 * - Otherwise trigger new build
+	 */
+	async getTree(): Promise<SimpleTreeNode> {
+		// If there's valid cache, return directly
+		if (this.cachedTree && this.invalidatedDirectories.size === 0) {
+			return this.cachedTree
+		}
+
+		// If already building, wait for current build result
+		if (this.currentBuildPromise) {
+			return this.currentBuildPromise
+		}
+
+		// Start new build
+		try {
+			this.currentBuildPromise = this.buildTree()
+			const result = await this.currentBuildPromise
+			return result
+		} finally {
+			// Clear Promise cache after build completion
+			this.currentBuildPromise = null
+		}
+	}
+
+	/**
+	 * Internal method: build or update tree
+	 */
+	private async buildTree(): Promise<SimpleTreeNode> {
+		try {
+			if (this.cachedTree && this.invalidatedDirectories.size > 0) {
+				// Has cache but has invalid directories, perform incremental update
+				await this.updateInvalidatedDirectories()
+			} else {
+				// No cache, complete rebuild
+				this.cachedTree = await this.buildTreeStreaming()
+			}
+
+			// Clear invalid directory markers
+			this.invalidatedDirectories.clear()
+			return this.cachedTree
+		} catch (error) {
+			// Clear cache state on error
+			this.cachedTree = null
+			this.invalidatedDirectories.clear()
+			throw error
+		}
+	}
+
+	/**
+	 * Called when file is added
+	 * Mark parent directory as invalid and remove corresponding subtree from tree
+	 */
+	fileAdded(filePath: string): void {
+		this.fileAddedOrRemoved(filePath)
+	}
+
+	/**
+	 * Called when file is removed
+	 * Mark parent directory as invalid and remove corresponding subtree from tree
+	 */
+	fileRemoved(filePath: string): void {
+		this.fileAddedOrRemoved(filePath)
+	}
+
+	private fileAddedOrRemoved(filePath: string): void {
+		const relativePath = relative(this._targetPath, pathResolve(this._targetPath, filePath))
+		const parentDir = dirname(relativePath)
+
+		if (parentDir !== "." && parentDir !== "") {
+			this.invalidateDirectory(parentDir)
+		}
+	}
+
+	/**
+	 * Mark directory as invalid
+	 * Check containment relationship with existing invalid directories to avoid duplicate marking
+	 */
+	private invalidateDirectory(dirPath: string): void {
+		if (!this.cachedTree) {
+			return
+		}
+
+		const normalizedPath = dirPath.replace(/\\/g, "/")
+
+		// Check if already contained by larger scope invalid directory
+		for (const invalidDir of this.invalidatedDirectories) {
+			if (normalizedPath.startsWith(invalidDir + "/") || normalizedPath === invalidDir) {
+				// Current directory already contained in invalid directory, no need to mark again
+				return
+			}
+		}
+
+		// Remove existing invalid directories contained by current directory
+		const toRemove: string[] = []
+		for (const invalidDir of this.invalidatedDirectories) {
+			if (invalidDir.startsWith(normalizedPath + "/")) {
+				toRemove.push(invalidDir)
+			}
+		}
+
+		// Remove contained invalid directories
+		for (const dir of toRemove) {
+			this.invalidatedDirectories.delete(dir)
+		}
+
+		// Mark current directory as invalid
+		this.invalidatedDirectories.add(normalizedPath)
+
+		// Remove corresponding subtree from cache tree
+		this.removeDirectoryFromTree(normalizedPath)
+	}
+
+	/**
+	 * Remove specified directory subtree from simplified tree
+	 */
+	private removeDirectoryFromTree(dirPath: string): void {
+		if (!this.cachedTree) {
+			return
+		}
+
+		const pathParts = dirPath.split("/").filter(Boolean)
+		this.removeNodeByPath(this.cachedTree, pathParts, 0)
+	}
+
+	/**
+	 * Recursively remove simplified tree node
+	 */
+	private removeNodeByPath(tree: SimpleTreeNode, pathParts: string[], depth: number): boolean {
+		if (depth >= pathParts.length) {
+			return false
+		}
+
+		const currentPart = pathParts[depth]
+
+		if (!(currentPart in tree)) {
+			return false
+		}
+
+		if (depth === pathParts.length - 1) {
+			// Found target node, remove it
+			delete tree[currentPart]
+			return true
+		}
+
+		// Continue searching in child nodes
+		const childNode = tree[currentPart]
+		if (childNode !== true && typeof childNode === "object") {
+			const removed = this.removeNodeByPath(childNode, pathParts, depth + 1)
+
+			// If child node is removed and current node is empty object, remove current node
+			if (removed && Object.keys(childNode).length === 0) {
+				delete tree[currentPart]
+				return true
+			}
+		}
+
+		return false
+	}
+
+	/**
+	 * Update directories marked as invalid
+	 * Use ripgrep's multi-path support to update all invalid directories at once
+	 */
+	private async updateInvalidatedDirectories(): Promise<void> {
+		if (this.invalidatedDirectories.size === 0) {
+			return
+		}
+
+		try {
+			// Stream build subtrees for all invalid directories (pass directory paths directly)
+			const invalidDirectories = Array.from(this.invalidatedDirectories)
+			const subtree = await this.buildTreeStreaming(invalidDirectories)
+
+			// Merge subtrees into main tree (replace original invalid parts)
+			this.mergeInvalidatedSubtrees(subtree)
+		} catch (error) {
+			console.warn("Error updating invalid directories:", error)
+			// If incremental update fails, fallback to complete rebuild
+			this.cachedTree = await this.buildTreeStreaming()
+		}
+	}
+
+	/**
+	 * Unified streaming tree building method (simplified version, builds SimpleTreeNode)
+	 * @param targetPaths Array of target paths to scan, scans entire targetPath when empty
+	 */
+	private async buildTreeStreaming(targetPaths: string[] = []): Promise<SimpleTreeNode> {
+		return new Promise((resolve, reject) => {
+			// Build ripgrep arguments
+			const args = [...this.rgArgs]
+
+			// If target paths specified, use relative paths directly (ripgrep supports multiple paths)
+			if (targetPaths.length > 0) {
+				args.push(...targetPaths)
+			}
+
+			const child = spawn(this.rgPath, args, {
+				cwd: this._targetPath,
+				stdio: ["pipe", "pipe", "pipe"],
+			})
+
+			const tree: SimpleTreeNode = {}
+			let buffer = ""
+			let fileCount = 0
+
+			// Stream add file paths to simplified tree structure
+			const addFileToTree = (filePath: string) => {
+				// ripgrep output is already relative path, use directly
+				const parts = filePath.split("/").filter(Boolean)
+				let currentNode: SimpleTreeNode = tree
+
+				for (let i = 0; i < parts.length; i++) {
+					const part = parts[i]
+					const isFile = i === parts.length - 1 // Last part is file
+
+					if (isFile) {
+						// Files represented by true
+						currentNode[part] = true
+						fileCount++
+
+						// Check if file limit reached
+						if (fileCount >= this.fileLimit) {
+							child.kill()
+							return true // Indicate limit reached
+						}
+					} else {
+						// Directories represented by nested objects
+						if (!currentNode[part] || currentNode[part] === true) {
+							currentNode[part] = {}
+						}
+						currentNode = currentNode[part] as SimpleTreeNode
+					}
+				}
+				return false // Limit not reached
+			}
+
+			child.stdout.on("data", (data: Buffer) => {
+				buffer += data.toString()
+				const lines = buffer.split("\n")
+				buffer = lines.pop() || ""
+
+				for (const line of lines) {
+					const trimmedLine = line.trim()
+					if (trimmedLine) {
+						const limitReached = addFileToTree(trimmedLine)
+						if (limitReached) {
+							break
+						}
+					}
+				}
+			})
+
+			let errorOutput = ""
+
+			child.stderr.on("data", (data: Buffer) => {
+				errorOutput += data.toString()
+			})
+
+			child.on("close", (code: number | null) => {
+				// Process final buffer content
+				if (buffer.trim() && fileCount < this.fileLimit) {
+					addFileToTree(buffer.trim())
+				}
+
+				if (errorOutput && Object.keys(tree).length === 0) {
+					reject(new Error(`ripgrep process error: ${errorOutput}`))
+				} else {
+					resolve(tree)
+				}
+			})
+
+			child.on("error", (error: Error) => {
+				reject(error)
+			})
+		})
+	}
+
+	/**
+	 * Merge invalidated subtrees into main tree
+	 * subtree already contains complete content of all invalid directories, merge directly
+	 */
+	private mergeInvalidatedSubtrees(subtree: SimpleTreeNode): void {
+		if (!this.cachedTree) {
+			this.cachedTree = subtree
+			return
+		}
+
+		// Modify original object directly to avoid new object creation overhead
+		this.mergeSimpleTreeNodesInPlace(this.cachedTree, subtree)
+	}
+
+	/**
+	 * In-place merge two simplified tree nodes (optimized version, reduces object creation)
+	 */
+	private mergeSimpleTreeNodesInPlace(existing: SimpleTreeNode, newTree: SimpleTreeNode): void {
+		for (const [key, value] of Object.entries(newTree)) {
+			if (value === true) {
+				// New node is file, overwrite directly
+				existing[key] = true
+			} else {
+				// New node is directory
+				if (!existing[key] || existing[key] === true) {
+					// Original doesn't exist or is file, replace with directory directly
+					existing[key] = value
+				} else {
+					// Original is also directory, merge recursively
+					this.mergeSimpleTreeNodesInPlace(existing[key] as SimpleTreeNode, value)
+				}
+			}
+		}
+	}
+
+	/**
+	 * Clear cache
+	 */
+	clearCache(): void {
+		this.cachedTree = null
+		this.invalidatedDirectories.clear()
+		this.currentBuildPromise = null
+	}
+}