Update constructor for wasm interpreter

Author: anutosh491

CMakeLists.txt

@@ -148,7 +148,7 @@ function(configure_native_kernel kernel)
 endfunction()
 
 function(configure_wasm_kernel kernel)
-  set(XEUS_CPP_RESOURCE_DIR "/lib/clang/${CPPINTEROP_LLVM_VERSION_MAJOR}")
+  set(XEUS_CPP_RESOURCE_DIR "/lib/clang/${CPPINTEROP_LLVM_VERSION_MAJOR}" PARENT_SCOPE)
 
   configure_file (
     "${CMAKE_CURRENT_SOURCE_DIR}${kernel}wasm_kernel.json.in"
@@ -437,7 +437,7 @@ if(EMSCRIPTEN)
     xeus_wasm_link_options(xcpp "web,worker")
     target_link_options(xcpp
         PUBLIC "SHELL: --preload-file ${SYSROOT_PATH}/include@/include"
-        # PUBLIC "SHELL: --preload-file ${CMAKE_INSTALL_PREFIX}${XEUS_CPP_RESOURCE_DIR}/include@${XEUS_CPP_RESOURCE_DIR}"
+        #PUBLIC "SHELL: --preload-file ${CMAKE_INSTALL_PREFIX}${XEUS_CPP_RESOURCE_DIR}@${XEUS_CPP_RESOURCE_DIR}"
         PUBLIC "SHELL: --preload-file ${XEUS_CPP_DATA_DIR}@/share/xeus-cpp"
         PUBLIC "SHELL: --preload-file ${XEUS_CPP_CONF_DIR}@/etc/xeus-cpp"
         PUBLIC "SHELL: --post-js ${CMAKE_CURRENT_SOURCE_DIR}/wasm_patches/post.js"

include/xeus-cpp/xinterpreter_wasm.hpp

@@ -19,8 +19,7 @@ namespace xcpp
     {
     public:
 
-        wasm_interpreter();
-        wasm_interpreter(int argc, char** argv);
+        wasm_interpreter(int argc = 0, char** argv = nullptr);
         virtual ~wasm_interpreter() = default;
 
     };

src/main_emscripten_kernel.cpp

@@ -15,9 +15,26 @@
 
 #include "xeus-cpp/xinterpreter_wasm.hpp"
 
+template <class interpreter_type>
+static interpreter_type* builder_with_args(emscripten::val js_args)
+{
+    static std::vector<std::string> args = emscripten::vecFromJSArray<std::string>(js_args);
+    static std::vector<const char*> argv_vec;
+
+    for (const auto& s : args)
+    {
+        argv_vec.push_back(s.c_str());
+    }
+
+    int argc = static_cast<int>(argv_vec.size());
+    char** argv = const_cast<char**>(argv_vec.data());
+
+    return new interpreter_type(argc, argv);
+}
+
 EMSCRIPTEN_BINDINGS(my_module)
 {
     xeus::export_core();
     using interpreter_type = xcpp::wasm_interpreter;
-    xeus::export_kernel<interpreter_type>("xkernel");
+    xeus::export_kernel<interpreter_type, &builder_with_args<interpreter_type>>("xkernel");
 }

src/xinterpreter.cpp

@@ -31,10 +31,12 @@ void* createInterpreter(const Args &ExtraArgs = {}) {
   if (std::find_if(ExtraArgs.begin(), ExtraArgs.end(), [](const std::string& s) {
     return s == "-resource-dir";}) == ExtraArgs.end()) {
     std::string resource_dir = Cpp::DetectResourceDir();
-    if (resource_dir.empty())
-      std::cerr << "Failed to detect the resource-dir\n";
-    ClangArgs.push_back("-resource-dir");
-    ClangArgs.push_back(resource_dir.c_str());
+    if (!resource_dir.empty()) {
+        ClangArgs.push_back("-resource-dir");
+        ClangArgs.push_back(resource_dir.c_str());
+    } else {
+        std::cerr << "Failed to detect the resource-dir\n";
+    }
   }
   std::vector<std::string> CxxSystemIncludes;
   Cpp::DetectSystemCompilerIncludePaths(CxxSystemIncludes);

src/xinterpreter_wasm.cpp

@@ -15,12 +15,6 @@
 
 namespace xcpp
 {
-
-    wasm_interpreter::wasm_interpreter()
-        : interpreter(0, nullptr)
-    {
-    }
-
     wasm_interpreter::wasm_interpreter(int argc, char** argv)
         : interpreter(argc, argv)
     {