[WIP] Experiment with a WebAssembly distribution

Signed-off-by: Juan Cruz Viotti <[email protected]>

.gitignore

@@ -12,3 +12,4 @@ _deps
 Brewfile.lock.json
 .DS_Store
 .cache
+/bindings/*/build

CMakeLists.txt

@@ -77,6 +77,7 @@ endif()
 
 if(PROJECT_IS_TOP_LEVEL)
   noa_target_clang_format(SOURCES
+    bindings/*.cc
     src/*.h src/*.cc
     benchmark/*.h benchmark/*.cc
     test/*.h test/*.cc)

bindings/webassembly/Makefile

@@ -0,0 +1,26 @@
+EMCC = emcc
+MKDIR = mkdir
+NODE = node
+
+CXX_FLAGS = -O3 -std=c++20 -flto
+
+all: compile test
+compile: build/jsontoolkit.js .always
+test: test.js .always
+	$(NODE) $<
+
+build:
+	$(MKDIR) $@
+build/json: | build
+	$(MKDIR) $@
+
+build/json/%.o: ../../src/json/%.cc | build/json
+	$(EMCC) $(CXX_FLAGS) -o $@ $< -I../../src/json/include -c
+
+build/jsontoolkit.js: module.cc build/json/json.o build/json/json_value.o | build
+	$(EMCC) $(CXX_FLAGS) -o $@ $^ -I../../src/json/include -lembind \
+		-s EVAL_CTORS=2 -s EXPORT_NAME=jsontoolkit \
+		-s WASM=1 -s NO_EXIT_RUNTIME=1 -s MODULARIZE=1 \
+		-s EXPORT_ES6=1 -s ENVIRONMENT=node
+
+.always:

bindings/webassembly/module.cc

@@ -0,0 +1,17 @@
+#include <sourcemeta/jsontoolkit/json.h>
+
+// See https://emscripten.org/docs/porting/connecting_cpp_and_javascript/embind.html
+#include <emscripten/bind.h>
+
+#include <cstdlib>  // EXIT_SUCCESS
+#include <iostream> // std::cout
+
+static auto hello() -> void {
+  const sourcemeta::jsontoolkit::JSON document{"Hello World"};
+  sourcemeta::jsontoolkit::stringify(document, std::cout);
+  std::cout << std::endl;
+}
+
+EMSCRIPTEN_BINDINGS(jsontoolkit) {
+  emscripten::function("hello", &hello);
+}

bindings/webassembly/test.js

@@ -0,0 +1,4 @@
+import wrapper from './build/jsontoolkit.js';
+wrapper().then((jsontoolkit) => {
+  jsontoolkit.hello();
+});

src/json/include/sourcemeta/jsontoolkit/json.h

@@ -1,7 +1,11 @@
 #ifndef SOURCEMETA_JSONTOOLKIT_JSON_H_
 #define SOURCEMETA_JSONTOOLKIT_JSON_H_
 
+#ifdef __EMSCRIPTEN__
+#define SOURCEMETA_JSONTOOLKIT_JSON_EXPORT
+#else
 #include "json_export.h"
+#endif
 
 #include <sourcemeta/jsontoolkit/json_error.h>
 #include <sourcemeta/jsontoolkit/json_value.h>

src/json/include/sourcemeta/jsontoolkit/json_error.h

@@ -1,7 +1,11 @@
 #ifndef SOURCEMETA_JSONTOOLKIT_JSON_ERROR_H_
 #define SOURCEMETA_JSONTOOLKIT_JSON_ERROR_H_
 
+#ifdef __EMSCRIPTEN__
+#define SOURCEMETA_JSONTOOLKIT_JSON_EXPORT
+#else
 #include "json_export.h"
+#endif
 
 #include <cstdint>    // std::uint64_t
 #include <exception>  // std::exception

src/json/include/sourcemeta/jsontoolkit/json_value.h

@@ -1,7 +1,11 @@
 #ifndef SOURCEMETA_JSONTOOLKIT_JSON_VALUE_H_
 #define SOURCEMETA_JSONTOOLKIT_JSON_VALUE_H_
 
+#ifdef __EMSCRIPTEN__
+#define SOURCEMETA_JSONTOOLKIT_JSON_EXPORT
+#else
 #include "json_export.h"
+#endif
 
 #include <sourcemeta/jsontoolkit/json_array.h>
 #include <sourcemeta/jsontoolkit/json_object.h>