add extensible hook for RStudio session initialization

src/cpp/session/CMakeLists.txt

@@ -87,6 +87,7 @@ set (SESSION_SOURCE_FILES
    modules/SessionPath.cpp
    modules/SessionPlots.cpp
    modules/SessionProfiler.cpp
+   modules/SessionRHooks.cpp
    modules/SessionRPubs.cpp
    modules/SessionShinyApps.cpp
    modules/SessionShinyViewer.cpp

src/cpp/session/SessionMain.cpp

@@ -116,6 +116,7 @@ extern "C" const char *locale2charset(const char *);
 #include "modules/SessionPackrat.hpp"
 #include "modules/SessionProfiler.hpp"
 #include "modules/SessionRPubs.hpp"
+#include "modules/SessionRHooks.hpp"
 #include "modules/SessionShinyApps.hpp"
 #include "modules/SessionShinyViewer.hpp"
 #include "modules/SessionSpelling.hpp"
@@ -1627,6 +1628,7 @@ Error rInit(const r::session::RInitInfo& rInitInfo)
       (modules::shiny_viewer::initialize)
       (modules::shiny_apps::initialize)
       (modules::packrat::initialize)
+      (modules::rhooks::initialize)
 
       // workers
       (workers::web_request::initialize)
@@ -1725,6 +1727,9 @@ void rDeferredInit(bool newSession)
 {
    module_context::events().onDeferredInit(newSession);
 
+   // allow any packages listening to complete initialization
+   modules::rhooks::invokeHook(kSessionInitHook, newSession);
+
    // fire an event to the client
    ClientEvent event(client_events::kDeferredInitCompleted);
    module_context::enqueClientEvent(event);

src/cpp/session/modules/SessionRHooks.R

@@ -0,0 +1,32 @@
+#
+# SessionRHooks.R
+#
+# Copyright (C) 2009-14 by RStudio, Inc.
+#
+# Unless you have received this program directly from RStudio pursuant
+# to the terms of a commercial license agreement with RStudio, then
+# this program is licensed to you under the terms of version 3 of the
+# GNU Affero General Public License. This program is distributed WITHOUT
+# ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING THOSE OF NON-INFRINGEMENT,
+# MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Please refer to the
+# AGPL (http://www.gnu.org/licenses/agpl-3.0.txt) for more details.
+#
+#
+
+.rs.addFunction("invokeHook", function(hookName, ...) {
+  # ensure that the list of hooks can be iterated over as a list
+  hooks <- getHook(hookName)
+  if (!is.list(hooks))
+    hooks <- list(hooks)
+
+  # execute each attached hook with the given parameters
+  for (fun in hooks) {
+    if (is.character(fun))
+      fun <- get(fun)
+    tryCatch(fun(...),
+             error = function(e) { 
+                # ignore errors occurring during hook execution
+             })
+  }
+})
+

src/cpp/session/modules/SessionRHooks.cpp

@@ -0,0 +1,46 @@
+/*
+ * SessionRHooks.cpp
+ *
+ * Copyright (C) 2009-14 by RStudio, Inc.
+ *
+ * Unless you have received this program directly from RStudio pursuant
+ * to the terms of a commercial license agreement with RStudio, then
+ * this program is licensed to you under the terms of version 3 of the
+ * GNU Affero General Public License. This program is distributed WITHOUT
+ * ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING THOSE OF NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Please refer to the
+ * AGPL (http://www.gnu.org/licenses/agpl-3.0.txt) for more details.
+ *
+ */
+
+#include <core/Exec.hpp>
+
+#include <r/RSexp.hpp>
+#include <r/RExec.hpp>
+
+#include <session/SessionModuleContext.hpp>
+
+#include <boost/bind.hpp>
+
+#include "SessionRHooks.hpp"
+
+namespace session {
+namespace modules { 
+namespace rhooks {
+
+using namespace core;
+
+Error initialize()
+{
+   using boost::bind;
+   using namespace module_context;
+   ExecBlock initBlock;
+   initBlock.addFunctions()
+      (bind(sourceModuleRFile, "SessionRHooks.R"));
+   return initBlock.execute();
+}
+
+} // namespace rhooks
+} // namespace modules
+} // namespace session
+

src/cpp/session/modules/SessionRHooks.hpp

@@ -0,0 +1,43 @@
+/*
+ * SessionRHooks.hpp
+ *
+ * Copyright (C) 2009-14 by RStudio, Inc.
+ *
+ * Unless you have received this program directly from RStudio pursuant
+ * to the terms of a commercial license agreement with RStudio, then
+ * this program is licensed to you under the terms of version 3 of the
+ * GNU Affero General Public License. This program is distributed WITHOUT
+ * ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING THOSE OF NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Please refer to the
+ * AGPL (http://www.gnu.org/licenses/agpl-3.0.txt) for more details.
+ *
+ */
+
+#ifndef SESSION_RHOOKS_HPP
+#define SESSION_RHOOKS_HPP
+
+#define kSessionInitHook "rstudio.sessionInit"
+
+namespace core {
+   class Error;
+}
+
+namespace session {
+namespace modules { 
+namespace rhooks {
+
+core::Error initialize();
+
+// thin wrapper around hook invocation 
+template<typename ParamType> 
+core::Error invokeHook(const std::string& hookName, const ParamType& param)
+{
+   return r::exec::RFunction(".rs.invokeHook", hookName, param).call();
+}
+
+} // namespace packrat
+} // namespace modules
+} // namespace rhooks
+
+#endif // SESSION_RHOOKS_HPP
+