Issue 5183 - Provide async interface for FileSystem

include/AdblockPlus/JsValue.h

Index: include/AdblockPlus/JsValue.h
===================================================================
--- a/include/AdblockPlus/JsValue.h
+++ b/include/AdblockPlus/JsValue.h
@@ -18,31 +18,35 @@
 #ifndef ADBLOCK_PLUS_JS_VALUE_H
 #define ADBLOCK_PLUS_JS_VALUE_H
 
 #include <stdint.h>
 #include <string>
 #include <vector>
 #include <memory>
 
+#include <AdblockPlus/IFileSystem.h>
+
 namespace v8
 {
   class Value;
   class Object;
   template<class T> class Local;
   template<class T> class Global;
 }
 
 namespace AdblockPlus
 {
   class JsValue;
   class JsEngine;
 
   typedef std::shared_ptr<JsEngine> JsEnginePtr;
 
+  typedef IFileSystem::IOBuffer StringBuffer;
+
   /**
    * List of JavaScript values.
    */
   typedef std::vector<AdblockPlus::JsValue> JsValueList;
 
   /**
    * Wrapper for JavaScript values.
    * See `JsEngine` for creating `JsValue` objects.
@@ -62,16 +66,17 @@
     bool IsNull() const;
     bool IsString() const;
     bool IsNumber() const;
     bool IsBool() const;
     bool IsObject() const;
     bool IsArray() const;
     bool IsFunction() const;
     std::string AsString() const;
+    StringBuffer AsStringBuffer() const;
     int64_t AsInt() const;
     bool AsBool() const;
     JsValueList AsList() const;
 
     /**
      * Returns a list of property names if this is an object (see `IsObject()`).
      * @return List of property names.
      */
@@ -87,16 +92,17 @@
 
     //@{
     /**
      * Sets a property value if this is an object (see `IsObject()`).
      * @param name Property name.
      * @param val Property value.
      */
     void SetProperty(const std::string& name, const std::string& val);
+    void SetProperty(const std::string& name, const StringBuffer& val);
     void SetProperty(const std::string& name, int64_t val);
     void SetProperty(const std::string& name, bool val);
     void SetProperty(const std::string& name, const JsValue& value);
     inline void SetProperty(const std::string& name, const char* val)
     {
       SetProperty(name, std::string(val));
     }
     inline void SetProperty(const std::string& name, int val)