CRX FileSystem Pepper private API

chrome/browser/renderer_host/pepper/pepper_ext_crx_file_system_browser_host.cc

Index: chrome/browser/renderer_host/pepper/pepper_ext_crx_file_system_browser_host.cc
diff --git a/chrome/browser/renderer_host/pepper/pepper_ext_crx_file_system_browser_host.cc b/chrome/browser/renderer_host/pepper/pepper_ext_crx_file_system_browser_host.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ed6b0e21769459afe35802528022c8df0f530522
--- /dev/null
+++ b/chrome/browser/renderer_host/pepper/pepper_ext_crx_file_system_browser_host.cc
@@ -0,0 +1,165 @@
+// Copyright (c) 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 "chrome/browser/renderer_host/pepper/pepper_ext_crx_file_system_browser_host.h"
+
+#include "base/files/file_path.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_system.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/common/extensions/extension.h"
+#include "content/public/browser/browser_ppapi_host.h"
+#include "content/public/browser/child_process_security_policy.h"
+#include "extensions/common/constants.h"
+#include "googleurl/src/gurl.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/host/dispatch_host_message.h"
+#include "ppapi/host/host_message_context.h"
+#include "ppapi/host/ppapi_host.h"
+#include "ppapi/host/resource_message_filter.h"
+#include "ppapi/proxy/ppapi_messages.h"
+#include "webkit/fileapi/isolated_context.h"
+
+namespace chrome {
+
+namespace {
+
+class CrxFileSystemFilter : public ppapi::host::ResourceMessageFilter {
+ public:
+  CrxFileSystemFilter(content::BrowserPpapiHost* browser_ppapi_host,
+                      PP_Instance instance)
+      : browser_ppapi_host_(browser_ppapi_host), instance_(instance) { }
+
+  // ppapi::host::ResourceMessageFilter implementation.
+  virtual scoped_refptr<base::TaskRunner> OverrideTaskRunnerForMessage(
+      const IPC::Message& msg) OVERRIDE;
+  virtual int32_t OnResourceMessageReceived(
+      const IPC::Message& msg,
+      ppapi::host::HostMessageContext* context) OVERRIDE;
+
+ private:
+  ~CrxFileSystemFilter() {}
+
+  // Returns filesystem id of isolated filesystem if valid, or empty string
+  // otherwise.  This is expected to run in UI thread as ProfileManager only

[palmer, 2013/05/02 21:30:09]

Nit: "This must run on the UI thread because ProfileManager only allows access
on that thread."

[victorhsieh, 2013/05/03 17:26:58]

Done.

+  // allows UI thread access.
+  std::string CreateIsolatedFileSystem(const base::FilePath& profile_directory,
+                                       const GURL& url);
+
+  int32_t OnOpenFileSystem(ppapi::host::HostMessageContext* context);
+
+  void Reply(ppapi::host::HostMessageContext* context,
+             int32_t pp_error,
+             const std::string& fsid);
+
+  content::BrowserPpapiHost* browser_ppapi_host_;
+  PP_Instance instance_;
+
+  DISALLOW_COPY_AND_ASSIGN(CrxFileSystemFilter);
+};
+
+scoped_refptr<base::TaskRunner>
+CrxFileSystemFilter::OverrideTaskRunnerForMessage(
+    const IPC::Message& msg) {
+  // In order to reach ExtensionSystem, we need to get ProfileManager first.
+  // ProfileManager lives in UI thread, so we need to do this in UI thread.
+  return BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI);
+}
+
+int32_t CrxFileSystemFilter::OnResourceMessageReceived(
+    const IPC::Message& msg,
+    ppapi::host::HostMessageContext* context) {
+  IPC_BEGIN_MESSAGE_MAP(CrxFileSystemFilter, msg)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(
+        PpapiHostMsg_Ext_CrxFileSystem_BrowserOpen, OnOpenFileSystem);
+  IPC_END_MESSAGE_MAP()
+  return PP_ERROR_FAILED;
+}
+
+std::string CrxFileSystemFilter::CreateIsolatedFileSystem(
+    const base::FilePath& profile_directory,
+    const GURL& url) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (!url.SchemeIs(extensions::kExtensionScheme))
+    return std::string();
+
+  ProfileManager* profile_manager = g_browser_process->profile_manager();
+  Profile* profile = profile_manager->GetProfile(profile_directory);
+  extensions::ExtensionSystem* extension_system =
+      extensions::ExtensionSystem::Get(profile);
+  if (!extension_system)
+    return std::string();
+
+  const ExtensionService* extension_service =
+      extension_system->extension_service();
+  if (!extension_service)
+    return std::string();
+
+  const extensions::Extension* extension =
+      extension_service->GetExtensionById(url.host(), false);
+  if (!extension)
+    return std::string();
+
+  // First level directory for isolated filesystem to lookup.
+  std::string kFirstLevelDirectory("crxfs");
+  return fileapi::IsolatedContext::GetInstance()->
+      RegisterFileSystemForPath(fileapi::kFileSystemTypeNativeLocal,
+                                extension->path(),
+                                &kFirstLevelDirectory);
+}
+
+int32_t CrxFileSystemFilter::OnOpenFileSystem(
+    ppapi::host::HostMessageContext* context) {
+  const std::string fsid = CreateIsolatedFileSystem(
+      browser_ppapi_host_->GetProfileDataDirectory(),

[palmer, 2013/05/02 21:30:09]

I think this is the only call-site for the function
|CrxFileSystemFilter::CreateIsolateFileSystem|, correct? It would seem that you
could therefore remove the |profile_directory| argument , and have
|CrxFileSystemFilter::CreateIsolateFileSystem| call |GetProfileDataDirectory|.

That would make it easier to understand that it is not possible to visit
arbitrary file pathnames with that function.

[victorhsieh, 2013/05/03 17:26:58]

Done.

+      browser_ppapi_host_->GetDocumentURLForInstance(instance_));
+
+  if (fsid.empty()) {
+    Reply(context, PP_ERROR_NOTSUPPORTED, std::string());
+    return PP_ERROR_FAILED;
+  }
+
+  // Grant readonly access of isolated filesystem to renderer process.
+  int render_process_id;
+  int unused_render_view_id;
+  browser_ppapi_host_->GetRenderViewIDsForInstance(instance_,
+                                                   &render_process_id,
+                                                   &unused_render_view_id);
+  content::ChildProcessSecurityPolicy* policy =
+      content::ChildProcessSecurityPolicy::GetInstance();
+  policy->GrantReadFileSystem(render_process_id, fsid);
+
+  Reply(context, PP_OK, fsid);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+void CrxFileSystemFilter::Reply(
+    ppapi::host::HostMessageContext* context,
+    int32_t pp_error,
+    const std::string& fsid) {
+  ppapi::host::ReplyMessageContext reply_context =
+      context->MakeReplyMessageContext();
+  reply_context.params.set_result(pp_error);
+  browser_ppapi_host_->GetPpapiHost()->SendReply(
+      reply_context,
+      PpapiPluginMsg_Ext_CrxFileSystem_BrowserOpenReply(fsid));
+}
+
+}  // namespace
+
+PepperExtCrxFileSystemBrowserHost::PepperExtCrxFileSystemBrowserHost(
+    content::BrowserPpapiHost* host,
+    PP_Instance instance,
+    PP_Resource resource)
+    : ppapi::host::ResourceHost(host->GetPpapiHost(), instance, resource) {
+  AddFilter(scoped_refptr<ppapi::host::ResourceMessageFilter>(
+      new CrxFileSystemFilter(host, instance)));
+}
+
+PepperExtCrxFileSystemBrowserHost::~PepperExtCrxFileSystemBrowserHost() {
+}
+
+}  // namespace chrome