fix: index wire files through the open handle and de-quadratic the remote-control rewriter

syncWireFile now opens the wire file first and stats that handle, so the size and identity the indexer trusts belong to the same fd the reads use. The remote-control response rewriter replaces its trailing-slash and head-tag regex scans with linear scans, removing the polynomial-input findings.

elkaix <melkholy@techmatrix.com>

Author: elkaix

packages/agent-gateway/src/search/indexCore.ts

@@ -1,5 +1,5 @@
 import { createHash } from 'node:crypto';
-import { open, readFile, readdir, stat } from 'node:fs/promises';
+import { open, readFile, readdir, stat, type FileHandle } from 'node:fs/promises';
 import { join, relative } from 'node:path';
 
 import {
@@ -665,11 +665,21 @@ export class SearchIndexCore {
     file: WireFileRef,
     budget: SyncRoundBudget,
   ): Promise<SessionSyncResult> {
+    let handle: FileHandle;
+    try {
+      handle = await open(file.path, 'r');
+    } catch (error) {
+      if ((error as NodeJS.ErrnoException).code === 'ENOENT') {
+        return { truncated: false, failed: false };
+      }
+      return { truncated: false, failed: true, error: errorMessage(error) };
+    }
     let st: { size: number; mtimeMs: number; ino: number };
     try {
-      st = await stat(file.path);
-    } catch {
-      return { truncated: false, failed: false };
+      st = await handle.stat();
+    } catch (error) {
+      await handle.close();
+      return { truncated: false, failed: true, error: errorMessage(error) };
     }
     const size = st.size;
     const metaKey = fileMetaKey(summary.id, file.path);
@@ -730,15 +740,10 @@ export class SearchIndexCore {
         if (legacyKey !== null) ops.push({ op: 'del', key: legacyKey });
         await db.batch(ops);
       }
+      await handle.close();
       return { truncated: false, failed: false };
     }
 
-    let handle: Awaited<ReturnType<typeof open>>;
-    try {
-      handle = await open(file.path, 'r');
-    } catch (error) {
-      return { truncated: false, failed: true, error: errorMessage(error) };
-    }
     const ops: BatchInputOp<SearchDoc>[] = [];
     let byteCursor = offset;
     let position = offset;

packages/remote-control/src/remote-control.ts

@@ -153,7 +153,7 @@ export function buildRemoteControlUrl(
   relayOrigin = REMOTE_CONTROL_RELAY_ORIGIN,
 ): string {
   const url = new URL(relayOrigin);
-  const relayPath = url.pathname.replace(/\/+$/, '');
+  const relayPath = stripTrailingSlashes(url.pathname);
   const devicePath = `${relayPath}/devices/${encodeURIComponent(deviceId)}`;
   url.pathname =
     sessionId === undefined
@@ -231,23 +231,34 @@ export function filterForwardRequestHeaders(
   return result;
 }
 
+function stripTrailingSlashes(value: string): string {
+  let end = value.length;
+  while (end > 0 && value.codePointAt(end - 1) === 47) end -= 1;
+  return end === value.length ? value : value.slice(0, end);
+}
+
+function findHeadTagEnd(text: string): number {
+  const start = /<head(?=[\s>])/i.exec(text);
+  if (start === null) return -1;
+  const close = text.indexOf('>', start.index + 5);
+  return close === -1 ? -1 : close + 1;
+}
+
 export function rewriteRemoteControlResponse(
   contentType: string,
   body: Buffer,
   publicPrefix: string,
 ): Buffer {
-  const normalizedPrefix = publicPrefix.replace(/\/+$/, '');
+  const normalizedPrefix = stripTrailingSlashes(publicPrefix);
   if (contentType.toLowerCase().includes('text/html')) {
     const prefixLiteral = scriptStringLiteral(normalizedPrefix);
     const injected = `<script>(function(){var p=${prefixLiteral};try{sessionStorage.setItem('pythinker-desktop-server-origin',location.origin+p)}catch(e){}var w=function(f){return function(s,t,u){if(typeof u==='string'&&u.charAt(0)==='/'&&u.indexOf(p)!==0)u=p+u;return f.apply(this,[s,t,u])}};history.pushState=w(history.pushState);history.replaceState=w(history.replaceState)})();</script>`;
     let text = body.toString('utf8');
-    const headMatch = /<head(?:\s[^>]*)?>/i.exec(text);
+    const headEnd = findHeadTagEnd(text);
     text =
-      headMatch === null
+      headEnd === -1
         ? injected + text
-        : text.slice(0, headMatch.index + headMatch[0].length) +
-          injected +
-          text.slice(headMatch.index + headMatch[0].length);
+        : text.slice(0, headEnd) + injected + text.slice(headEnd);
     text = text.replaceAll(/\bsrc="\//g, `src="${normalizedPrefix}/`);
     text = text.replaceAll(/\bhref="\//g, `href="${normalizedPrefix}/`);
     return Buffer.from(text);
@@ -318,7 +329,7 @@ export async function startRemoteControl(
   const deviceName = hostname();
   const url = buildRemoteControlUrl(deviceId, undefined, relayOrigin);
   const lock = await acquireRemoteControlLock(options.homeDir, {
-    localOrigin: options.localOrigin.replace(/\/+$/, ''),
+    localOrigin: stripTrailingSlashes(options.localOrigin),
     deviceId,
     url,
   });
@@ -387,7 +398,7 @@ class RemoteControlClient {
       readonly localServerToken: () => string;
     },
   ) {
-    this.localOrigin = options.localOrigin.replace(/\/+$/, '');
+    this.localOrigin = stripTrailingSlashes(options.localOrigin);
     this.localServerToken = options.localServerToken;
     this.clientVersion = options.clientVersion;
     this.relayOrigin = options.relayOrigin;
@@ -758,7 +769,7 @@ class RemoteControlClient {
   }
 
   private publicPrefix(): string {
-    const relayPath = new URL(this.relayOrigin).pathname.replace(/\/+$/, '');
+    const relayPath = stripTrailingSlashes(new URL(this.relayOrigin).pathname);
     return `${relayPath}/devices/${encodeURIComponent(this.deviceId)}`;
   }
 
@@ -1050,7 +1061,7 @@ function isValidCloseCode(code: number): boolean {
 function relayWebSocketUrl(origin: string, path: string): string {
   const url = new URL(origin);
   url.protocol = url.protocol === 'https:' ? 'wss:' : 'ws:';
-  const relayPath = url.pathname.replace(/\/+$/, '');
+  const relayPath = stripTrailingSlashes(url.pathname);
   const [pathname, query] = path.split('?', 2);
   url.pathname = `${relayPath}${pathname}`;
   url.search = query === undefined ? '' : query;