PNaCl: Use Chrome IPC to talk to the linker process, instead of SRPC

ppapi/proxy/nacl_message_scanner.cc

Index: ppapi/proxy/nacl_message_scanner.cc
diff --git a/ppapi/proxy/nacl_message_scanner.cc b/ppapi/proxy/nacl_message_scanner.cc
index 769a03f2885ceb2cfbde6694c86506e09ce529a4..8874bbfb83026cf6f2b070680fd170c547dc7c4c 100644
--- a/ppapi/proxy/nacl_message_scanner.cc
+++ b/ppapi/proxy/nacl_message_scanner.cc
@@ -138,6 +138,15 @@ void ScanParam(const IPC::Message& param, ScanningResults* results) {
     IPC::WriteParam(results->new_msg.get(), param);
 }
 
+template <class T>
+void ScanParam(const std::vector<T>& vec, ScanningResults* results) {
+  if (results->new_msg)
+    IPC::WriteParam(results->new_msg.get(), static_cast<int>(vec.size()));
+  for (const T& element : vec) {
+    ScanParam(element, results);
+  }
+}
+
 // Overload to match all other types. If we need to rewrite the message, write
 // the parameter.
 template <class T>
@@ -187,7 +196,22 @@ class MessageScannerImpl {
     return true;
   }
 
-  bool ScanReply(ScanningResults* results) {
+  bool ScanSyncMessage(ScanningResults* results) {

[bbudge, 2015/12/16 20:30:06]

David Michael has implemented this in a patch we haven't landed yet:

https://codereview.chromium.org/1440423003/diff/40001/ppapi/proxy/nacl_messag...

[Mark Seaborn, 2015/12/17 06:09:56]

Thanks for pointing that out!  I was able to debug why that change doesn't work
on Windows. :-)

[bbudge, 2015/12/17 19:10:21]

Not at all. Thank you for figuring out the problem!

+    typename base::TupleTypes<typename MessageType::Schema::SendParam>
+        ::ValueTuple params;
+    if (!MessageType::ReadSendParam(msg_, &params))
+      return false;
+    // If we need to rewrite the message, write the message id first.
+    if (results->new_msg) {
+      results->new_msg->set_sync();
+      int id = IPC::SyncMessage::GetMessageId(*msg_);
+      results->new_msg->WriteInt(id);
+    }
+    ScanTuple(params, results);
+    return true;
+  }
+
+  bool ScanSyncReply(ScanningResults* results) {

[bbudge, 2015/12/16 20:30:06]

ScanReply?

[Mark Seaborn, 2015/12/17 06:09:56]

I renamed the existing ScanReply() to ScanSyncReply() just because I thought it
would make it clearer that ScanSyncMessage()+ScanSyncReply() handle the two
parts of a synchronous request+reply pair.  This isn't entirely obvious to
readers who aren't very familiar with Chrome IPC.

[bbudge, 2015/12/17 19:10:21]

It makes the code in CASE_FOR_REPLY confusing though, because those are async
replies. Maybe a comment would help here.

[Mark Seaborn, 2015/12/21 22:58:50]

OK, I can just rename this back to ScanReply().  It makes the change smaller.
:-)

     typename base::TupleTypes<typename MessageType::Schema::ReplyParam>
         ::ValueTuple params;
     if (!MessageType::ReadReplyParam(msg_, &params))
@@ -201,8 +225,6 @@ class MessageScannerImpl {
     ScanTuple(params, results);
     return true;
   }
-  // TODO(dmichael): Add ScanSyncMessage for outgoing sync messages, if we ever
-  //                 need to scan those.
 
  private:
   const MessageType* msg_;
@@ -221,6 +243,17 @@ class MessageScannerImpl {
           return false; \
         break; \
       }
+#define CASE_FOR_SYNC_MESSAGE(MESSAGE_TYPE) \
+      case MESSAGE_TYPE::ID: { \
+        MessageScannerImpl<MESSAGE_TYPE> scanner(&msg); \
+        if (rewrite_msg) \
+          results.new_msg.reset( \
+              new IPC::Message(msg.routing_id(), msg.type(), \
+                               IPC::Message::PRIORITY_NORMAL)); \
+        if (!scanner.ScanSyncMessage(&results)) \
+          return false; \
+        break; \
+      }
 #define CASE_FOR_REPLY(MESSAGE_TYPE) \
       case MESSAGE_TYPE::ID: { \
         MessageScannerImpl<MESSAGE_TYPE> scanner(&msg); \
@@ -228,7 +261,7 @@ class MessageScannerImpl {
           results.new_msg.reset( \
               new IPC::Message(msg.routing_id(), msg.type(), \
                                IPC::Message::PRIORITY_NORMAL)); \
-        if (!scanner.ScanReply(&results)) \
+        if (!scanner.ScanSyncReply(&results)) \
           return false; \
         break; \
       }
@@ -326,6 +359,7 @@ bool NaClMessageScanner::ScanMessage(
     CASE_FOR_MESSAGE(PpapiMsg_PPBAudio_NotifyAudioStreamCreated)
     CASE_FOR_MESSAGE(PpapiMsg_PPPMessaging_HandleMessage)
     CASE_FOR_MESSAGE(PpapiPluginMsg_ResourceReply)
+    CASE_FOR_SYNC_MESSAGE(PpapiMsg_PnaclTranslatorLink)
     CASE_FOR_REPLY(PpapiHostMsg_OpenResource)
     CASE_FOR_REPLY(PpapiHostMsg_PPBGraphics3D_Create)
     CASE_FOR_REPLY(PpapiHostMsg_PPBGraphics3D_CreateTransferBuffer)