Validate incoming JS Message Headers

mojo/bindings/js/file_io.cc

+// Copyright 2013 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 "mojo/bindings/js/file_io.h"
+
+#include <iostream>
+
+#include "base/strings/string_util.h"
+#include "gin/arguments.h"
+#include "gin/converter.h"
+#include "gin/object_template_builder.h"
+#include "gin/per_isolate_data.h"
+#include "gin/public/wrapper_info.h"
+#include "mojo/public/cpp/test_support/test_support.h"

[abarth-chromium, 2014/07/22 03:51:00]

This module shouldn't need anything from Mojo.  I can be in //gin/test

[hansmuller, 2014/07/22 15:49:06]

I'm loading mojo data files from a source relative pathname and so I used
test::OpenSourceRootRelativeFile(). It looks like I can get the root "src"
pathname from  PathService::Get(base::DIR_SOURCE_ROOT, &path). I could add
support for looking up the root src path to a //gin/test FileIO module as well,
and eliminate this dependency.

+
+using v8::ObjectTemplate;
+
+namespace mojo {
+namespace js {
+
+namespace {
+
+v8::Handle<v8::Value> ReadFileAsString(gin::Arguments* args) {
+  std::string filename;
+  if (!args->GetNext(&filename))
+    return v8::Null(args->isolate());
+
+  FILE* fp = test::OpenSourceRootRelativeFile(filename.c_str());
+  if (!fp)
+    return v8::Null(args->isolate());
+
+  fseek(fp, 0, SEEK_END);
+  size_t size = static_cast<size_t>(ftell(fp));
+  if (size == 0) {
+    fclose(fp);
+    return v8::Null(args->isolate());
+  }
+
+  fseek(fp, 0, SEEK_SET);
+  std::string result;
+  result.resize(size);
+  size_t size_read = fread(&result.at(0), 1, size, fp);

[abarth-chromium, 2014/07/22 03:51:00]

I thought there was a function in base that did all this work for you.

[hansmuller, 2014/07/22 15:49:06]

You are correct: base::ReadFileToString(). I'll use that here.

+  fclose(fp);
+  if (size != size_read)
+    return v8::Null(args->isolate());
+
+  return gin::Converter<std::string>::ToV8(args->isolate(), result);
+}
+
+  gin::WrapperInfo g_wrapper_info = { gin::kEmbedderNativeGin };

[abarth-chromium, 2014/07/22 03:51:00]

Bad indent

[hansmuller, 2014/07/22 15:49:06]

Will fix.

+
+}  // namespace
+
+const char FileIO::kModuleName[] = "mojo/public/js/bindings/fileio";

[abarth-chromium, 2014/07/22 03:51:00]

This path should match the location of the C++ code.  In particular, this module
isn't part of the public API and therefore should not have "public" in its name.

[hansmuller, 2014/07/22 15:49:06]

OK. And if I'm reading you correctly, the FileIO module should end up in
gin/test, not in mojo at all.

+
+v8::Local<v8::Value> FileIO::GetModule(v8::Isolate* isolate) {
+  gin::PerIsolateData* data = gin::PerIsolateData::From(isolate);
+  v8::Local<ObjectTemplate> templ = data->GetObjectTemplate(&g_wrapper_info);
+  if (templ.IsEmpty()) {
+    templ = gin::ObjectTemplateBuilder(isolate)
+        .SetMethod("readSourceRelativeFileAsString", ReadFileAsString)
+        .Build();
+    data->SetObjectTemplate(&g_wrapper_info, templ);
+  }
+  return templ->NewInstance();
+}
+
+}  // namespace js
+}  // namespace mojo
+