fix: implement proactive file caching for read_file deduplication

- Changed from reactive to proactive deduplication approach
- Added getRecentFileContent method to check cache before reading files
- Modified readFileTool to use cached content when available
- Added comprehensive tests for the new caching functionality
- Fixed legacy format handling in getRecentFileContent
- Updated test mocks to include new methods

Author: hannesrudolph

src/core/task/Task.ts

@@ -329,6 +329,79 @@ export class Task extends EventEmitter<ClineEvents> {
 		return readApiMessages({ taskId: this.taskId, globalStoragePath: this.globalStoragePath })
 	}
 
+	public async getRecentFileContent(filePath: string): Promise<string | null> {
+		// Check if the experimental feature is enabled
+		const state = await this.providerRef.deref()?.getState()
+		if (!state?.experiments || !experiments.isEnabled(state.experiments, EXPERIMENT_IDS.READ_FILE_DEDUPLICATION)) {
+			return null
+		}
+
+		// Get the cache window from settings
+		const cacheMinutes = state?.readFileDeduplicationCacheMinutes ?? 5
+		if (cacheMinutes === 0) {
+			// Cache is disabled
+			return null
+		}
+
+		const cacheWindowMs = cacheMinutes * 60 * 1000
+		const now = Date.now()
+
+		// Check recent conversation history for this file
+		for (let i = this.apiConversationHistory.length - 1; i >= 0; i--) {
+			const message = this.apiConversationHistory[i]
+
+			// Only process user messages
+			if (message.role !== "user") {
+				continue
+			}
+
+			// Skip messages outside the cache window
+			if (message.ts && now - message.ts > cacheWindowMs) {
+				break
+			}
+
+			// Process content blocks
+			if (Array.isArray(message.content)) {
+				for (const block of message.content) {
+					if (block.type === "text" && typeof block.text === "string") {
+						// Check for read_file results in text blocks
+						const readFileMatch = block.text.match(/\[read_file(?:\s+for\s+'([^']+)')?.*?\]\s*Result:/i)
+
+						if (readFileMatch) {
+							// Extract file paths from the result content
+							const resultContent = block.text.substring(block.text.indexOf("Result:") + 7).trim()
+
+							// Handle new XML format
+							const xmlFileMatches = resultContent.matchAll(
+								/<file>\s*<path>([^<]+)<\/path>[\s\S]*?<content[^>]*?>([\s\S]*?)<\/content>/g,
+							)
+							for (const match of xmlFileMatches) {
+								const matchedPath = match[1].trim()
+								const content = match[2].trim()
+								if (matchedPath === filePath) {
+									return content
+								}
+							}
+
+							// Handle legacy format (single file)
+							if (
+								readFileMatch[1] &&
+								readFileMatch[1] === filePath &&
+								!resultContent.includes("<files>")
+							) {
+								// For legacy format, the content is directly after "Result:"
+								// Remove any leading/trailing whitespace
+								return resultContent.trim()
+							}
+						}
+					}
+				}
+			}
+		}
+
+		return null
+	}
+
 	public async deduplicateReadFileHistory(): Promise<void> {
 		// Check if the experimental feature is enabled
 		const state = await this.providerRef.deref()?.getState()