fix(teacher): 改善只读工具分页与读取预算

electron/coding-projects/project-files.ts

@@ -277,6 +277,32 @@ export class CodingProjectFileService {
     }));
   }
 
+  async *textChunks(projectPath: string, requestedPath: string, signal: AbortSignal): AsyncGenerator<string> {
+    const relativePath = normalizeRelativePath(requestedPath);
+    const target = await containedExistingTarget(projectPath, relativePath);
+    if (!(await lstat(target)).isFile()) throw new Error('Project file path is not a file');
+    const handle = await open(target, 'r');
+    const stream = handle.createReadStream({ autoClose: false });
+    const decoder = new TextDecoder('utf-8', { fatal: true });
+    let pendingCR = '';
+    try {
+      for await (const chunk of stream) {
+        signal.throwIfAborted();
+        let text = pendingCR + decoder.decode(chunk as Buffer, { stream: true });
+        if (text.includes('\0')) throw new Error('Project file is not UTF-8 text');
+        // A Windows newline can straddle two filesystem chunks.
+        pendingCR = text.endsWith('\r') ? '\r' : '';
+        if (pendingCR) text = text.slice(0, -1);
+        if (text) yield text.replaceAll('\r\n', '\n');
+      }
+      const final = pendingCR + decoder.decode();
+      if (final) yield final;
+    } finally {
+      stream.destroy();
+      await handle.close();
+    }
+  }
+
   async content(projectPath: string, requestedPath: string): Promise<CodingProjectFileContent> {
     const relativePath = normalizeRelativePath(requestedPath);
     const result = await readBoundedFile(projectPath, relativePath, MAX_CONTENT_BYTES);