PPAPI/NaCl: Make nacl_ipc_adapter handle ImageData creation

chrome/nacl/nacl_ipc_adapter.cc

Index: chrome/nacl/nacl_ipc_adapter.cc
diff --git a/chrome/nacl/nacl_ipc_adapter.cc b/chrome/nacl/nacl_ipc_adapter.cc
index 187eb8b602f85c4ffe4b4df23d48c3c84a2a8728..4d46a2d15d01192f2553fa76640160272ceeb754 100644
--- a/chrome/nacl/nacl_ipc_adapter.cc
+++ b/chrome/nacl/nacl_ipc_adapter.cc
@@ -129,6 +129,106 @@ void WriteFileDescriptor(IPC::Message* message, int index) {
   message->WriteInt(index);
 }
 
+typedef std::vector<ppapi::proxy::SerializedSharedMemoryHandle> ShmHandles;
+typedef std::vector<ppapi::proxy::SerializedFileDescriptor> FDs;
+
+void ExtractHandle(const ppapi::proxy::SerializedSharedMemoryHandle& handle,
+                   ShmHandles* handles, FDs* /* fds */, IPC::Message* msg,
+                   int* index) {
+  handles->push_back(handle);
+  if (msg)
+    WriteFileDescriptor(msg, (*index)++);
+}
+void ExtractHandle(const ppapi::proxy::SerializedFileDescriptor& fd,
+                   ShmHandles* /* handles */, FDs* fds, IPC::Message* msg,
+                   int* index) {
+  fds->push_back(fd);
+  if (msg)
+    WriteFileDescriptor(msg, (*index)++);
+}
+template <class T>
+ExtractHandle(cont T& param, ShmHandles* /* handles */, FDs* /* fds */,
+              IPC::Message* msg, int* index) {
+  // It's not a handle, so just write to the output message, if necessary.
+  if (msg)
+    IPC::WriteParam(m, param);
+}
+
+// These just break apart the given tuple and run ExtractHandle over each param.
+// The idea is to extract any handles in the tuple, while writing all data to
+// msg (if msg is valid). The msg will only be valid on Windows, where we need
+// to re-write the message to include the handles in POSIX style for NaCl.
+template <class A>
+void ExtractHandlesImpl(const Tuple1<A>& t1, ShmHandles* handles, FDs* fds,
+                        IPC::Message* msg) {
+  int fd_index = 0;
+  ExtractHandle(t1.a, handles, fds, msg, &fd_index);
+}
+template <class A, class B>
+void ExtractHandlesImpl(const Tuple2<A, B>& t1, ShmHandles* handles, FDs* fds,
+                        IPC::Message* msg) {
+  int fd_index = 0;
+  ExtractHandle(t1.a, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.b, handles, fds, msg, &fd_index);
+}
+template <class A, class B, class C>
+void ExtractHandlesImpl(const Tuple3<A, B, C>& t1, ShmHandles* handles,
+                        FDs* fds, IPC::Message* msg) {
+  int fd_index = 0;
+  ExtractHandle(t1.a, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.b, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.c, handles, fds, msg, &fd_index);
+}
+template <class A, class B, class C, class D>
+void ExtractHandlesImpl(const Tuple4<A, B, C, D>& t1, ShmHandles* handles,
+                        FDs* fds, IPC::Message* msg) {
+  int fd_index = 0;
+  ExtractHandle(t1.a, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.b, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.c, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.d, handles, fds, msg, &fd_index);
+}
+template <class A, class B, class C, class D, class E>
+void ExtractHandlesImpl(const Tuple5<A, B, C, D, E>& t1, ShmHandles* handles,
+                        FDs* fds, IPC::Message* msg) {
+  int fd_index = 0;
+  ExtractHandle(t1.a, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.b, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.c, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.d, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.e, handles, fds, msg, &fd_index);
+}
+template <class A, class B, class C, class D, class E, class F>
+void ExtractHandlesImpl(const Tuple6<A, B, C, D, E, F>& t1, ShmHandles* handles,
+                        FDs* fds, IPC::Message* msg) {
+  int fd_index = 0;
+  ExtractHandle(t1.a, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.b, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.c, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.d, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.e, handles, fds, msg, &fd_index);
+  ExtractHandle(t1.f, handles, fds, msg, &fd_index);
+}
+
+template <class MessageType>
+class HandleExtractor {
+ public:
+  explicit HandleExtractor(const IPC::Message* msg)
+      : msg_(static_cast<MessageType>(msg)) {
+  }
+  bool TranslateMessage(std::vector<base::SharedMemoryHandle>* shm_handles,
+                        std::vector<IPC::PlatformFileForTransit>* fds,
+                        IPC::Message* msg) {
+    typename MessageType::Schema::Param params;
+    if (!Read(msg, &params))
+      return false;
+    ExtractHandlesImpl(params, shm_handles, fds, msg);
+    return true;
+  }
+ private:
+  const MessageType* msg_;
+};
+
 }  // namespace
 
 class NaClIPCAdapter::RewrittenMessage
@@ -346,54 +446,67 @@ bool NaClIPCAdapter::OnMessageReceived(const IPC::Message& message) {
     // Clear any descriptors left from the prior message.
     locked_data_.nacl_descs_.clear();
 
-    PickleIterator it(message);
+    // Pointer to the "new" message we will rewrite on Windows. On posix, this
+    // isn't necessary, so it will stay NULL.
+    IPC::Message new_message_ptr = NULL;
+#if defined(OS_WIN)
+    IPC::Message new_msg(message.routing_id(),
+                             PpapiMsg_PPBAudio_NotifyAudioStreamCreated::ID,
+                             message.priority());
+        new_message_ptr = &new_msg;
+#endif
+    ShmHandles handles;
+    FDs fds;
     switch (message.type()) {
+      // Note that the case for each message is now pretty much boilerplate...
+      // We can condense it to a macro if we want to save lines of code. So you
+      // might get:
+      //   CASE_FOR_MESSAGE(PpapiMsg_PPB_Audio_NotifyAudioStreamCreated);
+      //   CASE_FOR_MESSAGE(PpapiMsg_PPB_AudioInput_NotifyAudioStreamCreated);
+      //   etc.
       case PpapiMsg_PPBAudio_NotifyAudioStreamCreated::ID: {
-        int instance_id;
-        int resource_id;
-        int result_code;
-        NaClHandle sock_handle;
-        NaClHandle shm_handle;
-        uint32_t shm_length;
-        if (ReadHostResource(&it, &instance_id, &resource_id) &&
-            it.ReadInt(&result_code) &&
-            ReadFileDescriptor(message, &it, &sock_handle) &&
-            ReadFileDescriptor(message, &it, &shm_handle) &&
-            it.ReadUInt32(&shm_length)) {
-          // Our caller, OnMessageReceived, holds the lock for locked_data_.
-          // Import the sync socket. Use DescWrappers to simplify clean up.
-          nacl::DescWrapperFactory factory;
-          scoped_ptr<nacl::DescWrapper> socket_wrapper(
-              factory.ImportSyncSocketHandle(sock_handle));
-          // Import the shared memory handle and increase its size by 4 bytes to
-          // accommodate the length data we write to signal the host.
-          scoped_ptr<nacl::DescWrapper> shm_wrapper(
-              factory.ImportShmHandle(shm_handle, shm_length + sizeof(uint32)));
-          if (shm_wrapper.get() && socket_wrapper.get()) {
-            locked_data_.nacl_descs_.push_back(socket_wrapper.release());
-            locked_data_.nacl_descs_.push_back(shm_wrapper.release());
-          }
-#if defined(OS_POSIX)
-          SaveMessage(message);
-#else  // defined(OS_POSIX)
-          // On Windows we must rewrite the message to the POSIX representation.
-          IPC::Message new_msg(message.routing_id(),
-                               PpapiMsg_PPBAudio_NotifyAudioStreamCreated::ID,
-                               message.priority());
-          WriteHostResource(&new_msg, instance_id, resource_id);
-          new_msg.WriteInt(result_code);
-          WriteFileDescriptor(&new_msg, 0);  // socket handle, index = 0
-          WriteFileDescriptor(&new_msg, 1);  // shm handle, index = 1
-          new_msg.WriteUInt32(shm_length);
-          SaveMessage(new_msg);
-#endif
-        }
+        HandleExtractor<PpapiMsg_PPBAudio_NotifyAudioStreamCreated>
+            extractor(message);
+        if (!extractor.TranslateMessage(msg, &handles, &fds, new_message_ptr))
+          return false;
+        break;
+      case IPC_REPLY_ID: {
+        /* TODO(dmichael): Look up the type of the originating message, do
+           another switch here to deal with any reply messages with handles.*/
         break;
       }
-      default: {
-        SaveMessage(message);
+      default:
+#if defined(OS_WIN)
+        // There are no handles, and we didn't have to rewrite the new message.
+        // Just make sure that SaveMessage below saves the valid message, since
+        // new_msg doesn't have any data.
+        new_message_ptr = &message;
+#endif
+        // default case has nothing to do in posix; we'll save the message
+        // below.
+    }
+    // Now add any descriptors we found to nacl_descs_. These are usually both
+    // empty, unless we read a message containing a FD or handle.
+    nacl::DescWrapperFactory factory;
+    for (ShmHandles::const_iterator iter = handles.begin();
+         iter != handles.end();
+         ++iter) {
+      scoped_ptr<nacl::DescWrapper> shm_wrapper(
+          factory.ImportShmHandle(iter->handle, iter->length));
+      if (shm_wrapper.get())
+        locked_data_.nacl_descs_.push_back(shm_wrapper.release());
+    }
+    for (FDs::const_iterator iter = fds.begin(); iter != fds.end(); ++iter) {
+      scoped_ptr<nacl::DescWrapper> socket_wrapper(
+          factory.ImportSyncSocketHandle(sock_handle));
+        if (socket_wrapper.get())
+          locked_data_.nacl_descs_.push_back(socket_wrapper.release());
       }
     }
+    if (new_message_ptr)
+      SaveMessage(*new_message_ptr);  // For Windows
+    else
+      SaveMessage(message);
   }
   cond_var_.Signal();
   return true;
@@ -467,6 +580,21 @@ bool NaClIPCAdapter::SendCompleteMessage(const char* buffer,
   if (locked_data_.channel_closed_)
     return false;  // TODO(brettw) clean up handles here when we add support!
 
+  // Deal with sync messages with handles in the reply.
+  if (msg->is_sync()) {
+    if (msg->type() == PpapiHostMsg_PPBImageData_CreateNaCl::ID) {
+      int id = IPC::SyncMessage::GetMessageId(*msg);
+      PickleIterator iter(IPC::SyncMessage::GetDataIterator(msg.get()));
+      int dummy, height, width;
+      if (iter.ReadInt(&dummy) &&  // instance
+          iter.ReadInt(&dummy) &&  // format
+          iter.ReadInt(&height) &&
+          iter.ReadInt(&width)) {
+        uint32_t size = height * width * 4;
+        locked_data_.pending_image_data_msgs_[id] = size;
+      }
+    }
+  }
   // Actual send must be done on the I/O thread.
   task_runner_->PostTask(FROM_HERE,
       base::Bind(&NaClIPCAdapter::SendMessageOnIOThread, this,
@@ -496,6 +624,7 @@ void NaClIPCAdapter::SendMessageOnIOThread(scoped_ptr<IPC::Message> message) {
 }
 
 void NaClIPCAdapter::SaveMessage(const IPC::Message& message) {
+  lock_.AssertAcquired();
   // There is some padding in this structure (the "padding" member is 16
   // bits but this then gets padded to 32 bits). We want to be sure not to
   // leak data to the untrusted plugin, so zero everything out first.