[PPAPI] It is now possible to pass filesystems from JavaScript to NaCl modules.

If a DOMFileSystem is passed as a message to the NaCl module, it will be
converted into a resource var which is available to the plugin via the dev
interface PPB_VarResource_Dev.

BUG=177017

Review URL: https://codereview.chromium.org/26564009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232080 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 75 insertions, 8 deletions

diff --git a/ppapi/proxy/plugin_var_tracker.cc b/ppapi/proxy/plugin_var_tracker.cc
index 0788b99..a9cbd9c 100644
--- a/ppapi/proxy/plugin_var_tracker.cc
+++ b/ppapi/proxy/plugin_var_tracker.cc
@@ -6,10 +6,13 @@
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/singleton.h"
+#include "ipc/ipc_message.h"
 #include "ppapi/c/dev/ppp_class_deprecated.h"
 #include "ppapi/c/ppb_var.h"
+#include "ppapi/proxy/file_system_resource.h"
 #include "ppapi/proxy/plugin_array_buffer_var.h"
 #include "ppapi/proxy/plugin_dispatcher.h"
+#include "ppapi/proxy/plugin_globals.h"
 #include "ppapi/proxy/plugin_resource_var.h"
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/proxy/proxy_object_var.h"
@@ -22,6 +25,16 @@
 namespace ppapi {
 namespace proxy {
 
+namespace {
+
+Connection GetConnectionForInstance(PP_Instance instance) {
+  PluginDispatcher* dispatcher = PluginDispatcher::GetForInstance(instance);
+  DCHECK(dispatcher);
+  return Connection(PluginGlobals::Get()->GetBrowserSender(), dispatcher);
+}
+
+}  // namespace
+
 PluginVarTracker::HostVar::HostVar(PluginDispatcher* d, int32 i)
     : dispatcher(d),
       host_object_id(i) {
@@ -154,6 +167,41 @@ void PluginVarTracker::ReleaseHostObject(PluginDispatcher* dispatcher,
   ReleaseVar(found->second);
 }
 
+PP_Var PluginVarTracker::MakeResourcePPVarFromMessage(
+    PP_Instance instance,
+    const IPC::Message& creation_message,
+    int pending_renderer_id,
+    int pending_browser_id) {
+  DCHECK(pending_renderer_id);
+  DCHECK(pending_browser_id);
+  switch (creation_message.type()) {
+    case PpapiPluginMsg_FileSystem_CreateFromPendingHost::ID: {
+      PP_FileSystemType file_system_type;
+      if (!UnpackMessage<PpapiPluginMsg_FileSystem_CreateFromPendingHost>(
+               creation_message, &file_system_type)) {
+        NOTREACHED() << "Invalid message of type "
+                        "PpapiPluginMsg_FileSystem_CreateFromPendingHost";
+        return PP_MakeNull();
+      }
+      // Create a plugin-side resource and attach it to the host resource.
+      // Note: This only makes sense when the plugin is out of process (which
+      // should always be true when passing resource vars).
+      PP_Resource pp_resource =
+          (new FileSystemResource(GetConnectionForInstance(instance),
+                                  instance,
+                                  pending_renderer_id,
+                                  pending_browser_id,
+                                  file_system_type))->GetReference();
+      return MakeResourcePPVar(pp_resource);
+    }
+    default: {
+      NOTREACHED() << "Creation message has unexpected type "
+                   << creation_message.type();
+      return PP_MakeNull();
+    }
+  }
+}
+
 ResourceVar* PluginVarTracker::MakeResourceVar(PP_Resource pp_resource) {
   // The resource 0 returns a null resource var.
   if (!pp_resource)
diff --git a/ppapi/proxy/plugin_var_tracker.h b/ppapi/proxy/plugin_var_tracker.h
index 126c8fc..03a9e5e 100644
--- a/ppapi/proxy/plugin_var_tracker.h
+++ b/ppapi/proxy/plugin_var_tracker.h
@@ -59,6 +59,11 @@ class PPAPI_PROXY_EXPORT PluginVarTracker : public VarTracker {
                          const PP_Var& host_object);
 
   // VarTracker public overrides.
+  virtual PP_Var MakeResourcePPVarFromMessage(
+      PP_Instance instance,
+      const IPC::Message& creation_message,
+      int pending_renderer_id,
+      int pending_browser_id) OVERRIDE;
   virtual ResourceVar* MakeResourceVar(PP_Resource pp_resource) OVERRIDE;
   virtual void DidDeleteInstance(PP_Instance instance) OVERRIDE;
   virtual int TrackSharedMemoryHandle(PP_Instance instance,
diff --git a/ppapi/proxy/ppapi_messages.h b/ppapi/proxy/ppapi_messages.h
index 02c4d84..2313cf7 100644
--- a/ppapi/proxy/ppapi_messages.h
+++ b/ppapi/proxy/ppapi_messages.h
@@ -1291,6 +1291,16 @@ IPC_MESSAGE_CONTROL0(PpapiPluginMsg_FileSystem_OpenReply)
 IPC_MESSAGE_CONTROL1(PpapiHostMsg_FileSystem_InitIsolatedFileSystem,
                      std::string /* fsid */)
 IPC_MESSAGE_CONTROL0(PpapiPluginMsg_FileSystem_InitIsolatedFileSystemReply)
+// Passed from renderer to browser. Creates an already-open file system with a
+// given |root_url| and |file_system_type|.
+IPC_MESSAGE_CONTROL2(PpapiHostMsg_FileSystem_CreateFromRenderer,
+                     std::string /* root_url */,
+                     PP_FileSystemType /* file_system_type */)
+// Nested within a ResourceVar for file systems being passed from the renderer
+// to the plugin. Creates an already-open file system resource on the plugin,
+// linked to the existing resource host given in the ResourceVar.
+IPC_MESSAGE_CONTROL1(PpapiPluginMsg_FileSystem_CreateFromPendingHost,
+                     PP_FileSystemType /* file_system_type */)
 
 // Flash DRM ------------------------------------------------------------------
 IPC_MESSAGE_CONTROL0(PpapiHostMsg_FlashDRM_Create)
diff --git a/ppapi/proxy/raw_var_data.cc b/ppapi/proxy/raw_var_data.cc
index 91bcfbfd..49ee8c2 100644
--- a/ppapi/proxy/raw_var_data.cc
+++ b/ppapi/proxy/raw_var_data.cc
@@ -695,14 +695,18 @@ bool ResourceRawVarData::Init(const PP_Var& var, PP_Instance /*instance*/) {
 }
 
 PP_Var ResourceRawVarData::CreatePPVar(PP_Instance instance) {
-  // If pp_resource_ is NULL, it could be because we are on the plugin side and
-  // there is a pending resource host on the renderer.
-  // TODO(mgiuca): Create a plugin-side resource in this case.
-  // Currently, this should never occur. This will be needed when passing a
-  // resource from the renderer to the plugin (http://crbug.com/177017).
-  DCHECK(pp_resource_);
-
-  return PpapiGlobals::Get()->GetVarTracker()->MakeResourcePPVar(pp_resource_);
+  // If this is not a pending resource host, just create the var.
+  if (pp_resource_ || !creation_message_) {
+    return PpapiGlobals::Get()->GetVarTracker()->MakeResourcePPVar(
+        pp_resource_);
+  }
+
+  // This is a pending resource host, so create the resource and var.
+  return PpapiGlobals::Get()->GetVarTracker()->MakeResourcePPVarFromMessage(
+      instance,
+      *creation_message_,
+      pending_renderer_host_id_,
+      pending_browser_host_id_);
 }
 
 void ResourceRawVarData::PopulatePPVar(const PP_Var& var,