Adding URLResponse Disk Cache to mojo.

shell/application_manager/local_fetcher.cc

 // Copyright 2015 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 "shell/application_manager/local_fetcher.h"
 
 #include "base/bind.h"
+#include "base/files/file_enumerator.h"
 #include "base/files/file_util.h"
 #include "base/format_macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/trace_event/trace_event.h"
 #include "mojo/common/common_type_converters.h"
 #include "mojo/common/data_pipe_utils.h"
+#include <sys/stat.h>
 #include "url/url_util.h"
 
 namespace shell {
 
 namespace {
 
 void IgnoreResult(bool result) {
 }
 
 }  // namespace
@@ skipping 23 matching lines @@
 GURL LocalFetcher::GetRedirectURL() const {
   return GURL::EmptyGURL();
 }
 
 mojo::URLResponsePtr LocalFetcher::AsURLResponse(base::TaskRunner* task_runner,
                                                  uint32_t skip) {
   mojo::URLResponsePtr response(mojo::URLResponse::New());
   response->url = mojo::String::From(url_);
   mojo::DataPipe data_pipe;
   response->body = data_pipe.consumer_handle.Pass();
-  int64 file_size;
-  if (base::GetFileSize(path_, &file_size)) {
-    response->headers = mojo::Array<mojo::String>(1);
+  base::stat_wrapper_t stat_result;
+  if (stat64(path_.value().c_str(), &stat_result) == 0) {
+    response->headers = mojo::Array<mojo::String>(2);
     response->headers[0] =
-        base::StringPrintf("Content-Length: %" PRId64, file_size);
+        base::StringPrintf("Content-Length: %" PRId64, stat_result.st_size);
+    response->headers[1] = base::StringPrintf(
+        "ETag: \"%" PRId64 "-%" PRId64 "\"", stat_result.st_ino,

[blundell, 2015/05/07 11:29:22]

Should this include st_dev as well for completeness?

http://pubs.opengroup.org/onlinepubs/009695399/basedefs/sys/stat.h.html

[qsr, 2015/05/07 12:49:02]

mtime is already a little overkill, but I guess this doesn't cost that much.
Done

+        static_cast<uint64_t>(stat_result.st_mtime));
   }
   mojo::common::CopyFromFile(path_, data_pipe.producer_handle.Pass(), skip,
                              task_runner, base::Bind(&IgnoreResult));
   return response.Pass();
 }
 
 void LocalFetcher::AsPath(
     base::TaskRunner* task_runner,
     base::Callback<void(const base::FilePath&, bool)> callback) {
   // Async for consistency with network case.
@@ skipping 15 matching lines @@
   std::string start_of_file;
   ReadFileToString(path_, &start_of_file, kMaxShebangLength);
   size_t return_position = start_of_file.find('\n');
   if (return_position == std::string::npos)
     return false;
   *line = start_of_file.substr(0, return_position + 1);
   return true;
 }
 
 }  // namespace shell