C: Add Node.js and WASM extension helpers for hb_string_T (marcoroth#749)

This PR adds helpers that allow to work with `hb_string_T` types in WASM
and node apis.

The functions are later used in marcoroth#750

Author: timkaechele

javascript/packages/node/extension/extension_helpers.cpp

@@ -46,6 +46,13 @@ napi_value CreateString(napi_env env, const char* str) {
   return result;
 }
 
+napi_value CreateStringFromHbString(napi_env env, hb_string_T string) {
+  napi_value result;
+  napi_create_string_utf8(env, string.data, string.length, &result);
+  return result;
+}
+
+
 napi_value CreatePosition(napi_env env, position_T position) {
   napi_value result;
   napi_create_object(env, &result);

javascript/packages/node/extension/extension_helpers.h

@@ -6,10 +6,12 @@
 extern "C" {
 #include "../extension/libherb/include/ast_nodes.h"
 #include "../extension/libherb/include/util/hb_array.h"
+#include "../extension/libherb/include/util/hb_string.h"
 }
 
 char* CheckString(napi_env env, napi_value value);
 napi_value CreateString(napi_env env, const char* str);
+napi_value CreateStringFromHbString(napi_env env, hb_string_T string);
 napi_value ReadFileToString(napi_env env, const char* file_path);
 napi_value CreateLexResult(napi_env env, hb_array_T* tokens, napi_value source);
 napi_value CreateParseResult(napi_env env, AST_DOCUMENT_NODE_T* root, napi_value source);

wasm/extension_helpers.cpp

@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <string>
 
 #include "nodes.h"
 
@@ -27,6 +28,16 @@ val CreateString(const char* string) {
   return string ? val(string) : val::null();
 }
 
+val CreateStringFromHbString(hb_string_T string) {
+  if (hb_string_is_empty(string)) {
+    return val::null();
+  } else {
+    std::string cppString(string.data, string.length);
+
+    return val(cppString);
+  }
+}
+
 val CreatePosition(position_T position) {
   val Object = val::global("Object");
   val result = Object.new_();

wasm/extension_helpers.h

@@ -14,6 +14,7 @@ extern "C" {
 }
 
 emscripten::val CreateString(const char* string);
+emscripten::val CreateStringFromHbString(hb_string_T string);
 emscripten::val CreatePosition(position_T position);
 emscripten::val CreateLocation(location_T location);
 emscripten::val CreateRange(range_T range);