Thread IO safety: file_util annotated, IO thread blocked from doing IO

chrome/browser/extensions/autoupdate_interceptor.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/autoupdate_interceptor.h"
 
 #include "base/file_util.h"
+#include "base/thread_restrictions.h"
 #include "chrome/browser/browser_thread.h"
 #include "net/url_request/url_request_test_job.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 // This is a specialized version of URLRequestTestJob that lets us specify
 // response data and make sure the response code is 200, which the autoupdate
 // code relies on.
 class AutoUpdateTestRequestJob : public URLRequestTestJob {
  public:
   AutoUpdateTestRequestJob(URLRequest* request,
@@ skipping 15 matching lines @@
 }
 
 
 URLRequestJob* AutoUpdateInterceptor::MaybeIntercept(URLRequest* request) {
   EXPECT_TRUE(BrowserThread::CurrentlyOn(BrowserThread::IO));
   if (request->url().scheme() != "http" ||
       request->url().host() != "localhost") {
       return NULL;
   }
 
+  // It's ok to do a blocking disk access on this thread; this class
+  // is just used for tests.
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
+
   // Search for this request's url, ignoring any query parameters.
   GURL url = request->url();
   if (url.has_query()) {
     GURL::Replacements replacements;
     replacements.ClearQuery();
     url = url.ReplaceComponents(replacements);
   }
   std::map<GURL, FilePath>::iterator i = responses_.find(url);
   if (i == responses_.end()) {
     return NULL;
   }
   std::string contents;
   EXPECT_TRUE(file_util::ReadFileToString(i->second, &contents));
 
   return new AutoUpdateTestRequestJob(request, contents);
 }
 
 
 void AutoUpdateInterceptor::SetResponse(const std::string url,
                                         const FilePath& path) {
   EXPECT_TRUE(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  // It's ok to do a blocking disk access on this thread; this class
+  // is just used for tests.
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
   GURL gurl(url);
   EXPECT_EQ("http", gurl.scheme());
   EXPECT_EQ("localhost", gurl.host());
   EXPECT_TRUE(file_util::PathExists(path));
   responses_[gurl] = path;
 }
 
 
 void AutoUpdateInterceptor::SetResponseOnIOThread(const std::string url,
                                                   const FilePath& path) {
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       NewRunnableMethod(this, &AutoUpdateInterceptor::SetResponse, url, path));
 }