[PPAPI] It is now possible to pass a FileSystem to JS in PostMessage.

content/renderer/pepper/resource_converter.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 "content/renderer/pepper/resource_converter.h"
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "content/public/renderer/renderer_ppapi_host.h"
 #include "content/renderer/pepper/pepper_file_system_host.h"
 #include "content/renderer/pepper/pepper_media_stream_audio_track_host.h"
 #include "content/renderer/pepper/pepper_media_stream_video_track_host.h"
 #include "ipc/ipc_message.h"
 #include "ppapi/host/ppapi_host.h"
 #include "ppapi/host/resource_host.h"
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/shared_impl/resource_var.h"
 #include "ppapi/shared_impl/scoped_pp_var.h"
 #include "third_party/WebKit/public/platform/WebFileSystem.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 #include "third_party/WebKit/public/web/WebDOMFileSystem.h"
 #include "third_party/WebKit/public/web/WebDOMMediaStreamTrack.h"
+#include "third_party/WebKit/public/web/WebFrame.h"
+// TODO(mgiuca): This include is not allowed from content/renderer. This is
+// needed to parse a file system URL. Perhaps it can be moved to webkit/common?
+#include "webkit/browser/fileapi/file_system_url.h"
+#include "webkit/common/fileapi/file_system_util.h"
 
 using ppapi::ResourceVar;
 
 namespace content {
 namespace {
 
 void FlushComplete(
     const base::Callback<void(bool)>& callback,
     const std::vector<scoped_refptr<content::HostResourceVar> >& browser_vars,
     const std::vector<int>& pending_host_ids) {
@@ skipping 14 matching lines @@
     case blink::WebFileSystem::TypeIsolated:
       return PP_FILESYSTEMTYPE_ISOLATED;
     case blink::WebFileSystem::TypeExternal:
       return PP_FILESYSTEMTYPE_EXTERNAL;
     default:
       NOTREACHED();
       return PP_FILESYSTEMTYPE_LOCALTEMPORARY;
   }
 }
 
+// Converts a fileapi::FileSystemType to a blink::WebFileSystemType.
+// Returns true on success, false on failure.
+bool FileApiFileSystemTypeToWebFileSystemType(
+    fileapi::FileSystemType type,
+    blink::WebFileSystemType* result_type) {
+  switch (type) {
+    case fileapi::kFileSystemTypeTemporary:
+      *result_type = blink::WebFileSystemTypeTemporary;
+      return true;
+    case fileapi::kFileSystemTypePersistent:
+      *result_type = blink::WebFileSystemTypePersistent;
+      return true;
+    case fileapi::kFileSystemTypeIsolated:
+      *result_type = blink::WebFileSystemTypeIsolated;
+      return true;
+    case fileapi::kFileSystemTypeExternal:
+      *result_type = blink::WebFileSystemTypeExternal;

[kinuko, 2014/02/20 11:33:28]

As you can see in file_system_types.h, these are guaranteed to be the same value
so that just static_cast should work.  (If you want extra guarantee you can add
static assertion)

[Matt Giuca, 2014/02/23 23:55:48]

I'm uncomfortable relying on that fact. Besides, I'm converting from
FileSystemType (which is a superset of WebFileSystemType), not the other way
around. We need a switch to ensure that it is one of these four types, and if
not, it needs to be an error.

(Note: I wasn't checking this error before, now I am.)

For example, apparently ParseFileSystemSchemeURL will return a mount_type of
kFileSystemTypeTest if it encounters a path starting with "/test". This should
be an error because it is not convertible to a blink::WebFileSystemType.

+      return true;
+    default:
+      return false;
+  }
+}
+
 // Given a V8 value containing a DOMFileSystem, creates a resource host and
 // returns the resource information for serialization.
 // On error, false.
 bool DOMFileSystemToResource(
     PP_Instance instance,
     RendererPpapiHost* host,
     const blink::WebDOMFileSystem& dom_file_system,
     int* pending_renderer_id,
     scoped_ptr<IPC::Message>* create_message,
     scoped_ptr<IPC::Message>* browser_host_create_message) {
@@ skipping 18 matching lines @@
 
   create_message->reset(
       new PpapiPluginMsg_FileSystem_CreateFromPendingHost(file_system_type));
 
   browser_host_create_message->reset(
       new PpapiHostMsg_FileSystem_CreateFromRenderer(root_url.spec(),
                                                      file_system_type));
   return true;
 }
 
+v8::Handle<v8::Value> ResourceHostToDOMFileSystem(
+    content::PepperFileSystemHost* file_system_host,
+    v8::Handle<v8::Context> context) {
+  GURL root_url = file_system_host->GetRootUrl();
+  GURL origin;
+  fileapi::FileSystemType mount_type;
+  base::FilePath virtual_path;
+  fileapi::FileSystemURL::ParseFileSystemSchemeURL(
+      root_url, &origin, &mount_type, &virtual_path);
+
+  std::string name = GetFileSystemName(origin, mount_type);
+  blink::WebFileSystemType blink_type;
+  FileApiFileSystemTypeToWebFileSystemType(mount_type, &blink_type);
+  blink::WebFrame* frame = blink::WebFrame::frameForContext(context);
+  return frame->createSerializableFileSystem(
+      blink_type,
+      blink::WebString::fromUTF8(name),
+      blink::WebString::fromUTF8(root_url.spec()));
+}
+
 bool DOMMediaStreamTrackToResource(
     PP_Instance instance,
     RendererPpapiHost* host,
     const blink::WebDOMMediaStreamTrack& dom_media_stream_track,
     int* pending_renderer_id,
     scoped_ptr<IPC::Message>* create_message) {
   DCHECK(!dom_media_stream_track.isNull());
   *pending_renderer_id = 0;
 
   const blink::WebMediaStreamTrack track = dom_media_stream_track.component();
@@ skipping 121 matching lines @@
   ::ppapi::host::PpapiHost* ppapi_host =
       renderer_ppapi_host->GetPpapiHost();
   ::ppapi::host::ResourceHost* resource_host =
       ppapi_host->GetResourceHost(resource_id);
   if (resource_host == NULL) {
     LOG(ERROR) << "No resource host for resource #" << resource_id;
     return false;
   }
 
   // Convert to the appropriate type of resource host.
-  // TODO(mgiuca): Convert FileSystemHost resources into DOMFileSystem V8
-  // objects. (http://crbug.com/345158)
-  LOG(ERROR) << "The type of resource #" << resource_id
-             << " cannot be converted to a JavaScript object.";
-  return false;
+  if (resource_host->IsFileSystemHost()) {
+    *result = ResourceHostToDOMFileSystem(
+        static_cast<content::PepperFileSystemHost*>(resource_host), context);
+    return true;
+  } else {
+    LOG(ERROR) << "The type of resource #" << resource_id
+               << " cannot be converted to a JavaScript object.";
+    return false;
+  }
 }
 
 scoped_refptr<HostResourceVar> ResourceConverterImpl::CreateResourceVar(
     int pending_renderer_id,
     const IPC::Message& create_message) {
   return new HostResourceVar(pending_renderer_id, create_message);
 }
 
 scoped_refptr<HostResourceVar>
 ResourceConverterImpl::CreateResourceVarWithBrowserHost(
     int pending_renderer_id,
     const IPC::Message& create_message,
     const IPC::Message& browser_host_create_message) {
   scoped_refptr<HostResourceVar> result =
       CreateResourceVar(pending_renderer_id, create_message);
   browser_host_create_messages_.push_back(browser_host_create_message);
   browser_vars.push_back(result);
   return result;
 }
 
 }  // namespace content