WebWorkers: Add APIs for working with JSObjectRef

Reviewed By: lexs

Differential Revision: D2779267

fb-gh-sync-id: 5c5a49988a1d501f15e5033b2dd5b528d97d96ed

ReactAndroid/src/main/jni/react/JSCHelpers.h

@@ -5,6 +5,8 @@
 #include <JavaScriptCore/JSContextRef.h>
 #include <JavaScriptCore/JSObjectRef.h>
 
+#define throwJSExecutionException(...) jni::throwNewJavaException("com/facebook/react/bridge/JSExecutionException", __VA_ARGS__)
+
 namespace facebook {
 namespace react {
 

ReactAndroid/src/main/jni/react/Value.cpp

@@ -5,6 +5,8 @@
 #include <jni/fbjni.h>
 #include <fb/log.h>
 
+#include "JSCHelpers.h"
+
 namespace facebook {
 namespace react {
 
@@ -37,17 +39,54 @@ std::string Value::toJSONString(unsigned indent) const {
   if (stringToAdopt == nullptr) {
     JSValueProtect(m_context, exn);
     std::string exceptionText = Value(m_context, exn).toString().str();
-    jni::throwNewJavaException(
-        "java/lang/IllegalArgumentException",
-        "Exception creating JSON string: %s",
-        exceptionText.c_str());
+    throwJSExecutionException("Exception creating JSON string: %s", exceptionText.c_str());
   }
   return String::adopt(stringToAdopt).str();
 }
 
 /* static */
-Value Value::fromJSON(JSContextRef& ctx, const String& json) {
-  return Value(ctx, JSValueMakeFromJSONString(ctx, json));
+Value Value::fromJSON(JSContextRef ctx, const String& json) {
+  auto result = JSValueMakeFromJSONString(ctx, json);
+  if (!result) {
+    throwJSExecutionException("Failed to create String from JSON");
+  }
+  return Value(ctx, result);
+}
+
+Object Value::asObject() {
+  JSValueRef exn;
+  JSObjectRef jsObj = JSValueToObject(context(), m_value, &exn);
+  if (!jsObj) {
+    std::string exceptionText = Value(m_context, exn).toString().str();
+    throwJSExecutionException("Failed to convert to object: %s", exceptionText.c_str());
+  }
+  Object ret = Object(context(), jsObj);
+  m_value = nullptr;
+  return std::move(ret);
+}
+
+Value Object::callAsFunction(int nArgs, JSValueRef args[]) {
+  JSValueRef exn;
+  JSValueRef result = JSObjectCallAsFunction(m_context, m_obj, NULL, nArgs, args, &exn);
+  if (!result) {
+    std::string exceptionText = Value(m_context, exn).toString().str();
+    throwJSExecutionException("Exception calling JS function: %s", exceptionText.c_str());
+  }
+  return Value(m_context, result);
+}
+
+Value Object::getProperty(String propName) const {
+  JSValueRef exn;
+  JSValueRef property = JSObjectGetProperty(m_context, m_obj, propName, &exn);
+  if (!property) {
+    std::string exceptionText = Value(m_context, exn).toString().str();
+    throwJSExecutionException("Failed to get property: %s", exceptionText.c_str());
+  }
+  return Value(m_context, property);
+}
+
+Value Object::getProperty(const char *propName) const {
+  return getProperty(String(propName));
 }
 
 } }

ReactAndroid/src/main/jni/react/Value.h

@@ -4,6 +4,7 @@
 
 #include <memory>
 #include <sstream>
+#include <JavaScriptCore/JSObjectRef.h>
 #include <JavaScriptCore/JSRetainPtr.h>
 #include <JavaScriptCore/JSStringRef.h>
 #include <JavaScriptCore/JSValueRef.h>
@@ -15,6 +16,7 @@
 namespace facebook {
 namespace react {
 
+class Value;
 class Context;
 
 class String : public noncopyable {
@@ -84,6 +86,58 @@ private:
   JSRetainPtr<JSStringRef> m_string;
 };
 
+class Object : public noncopyable {
+public:
+  Object(JSContextRef context, JSObjectRef obj) :
+    m_context(context),
+    m_obj(obj)
+  {}
+
+  Object(Object&& other) :
+      m_context(other.m_context),
+      m_obj(other.m_obj),
+      m_isProtected(other.m_isProtected) {
+    other.m_obj = nullptr;
+    other.m_isProtected = false;
+  }
+
+  ~Object() {
+    if (m_isProtected && m_obj) {
+      JSValueUnprotect(m_context, m_obj);
+    }
+  }
+
+  operator JSObjectRef() const {
+    return m_obj;
+  }
+
+  bool isFunction() const {
+    return JSObjectIsFunction(m_context, m_obj);
+  }
+
+  Value callAsFunction(int nArgs, JSValueRef args[]);
+
+  Value getProperty(String propName) const;
+  Value getProperty(const char *propName) const;
+
+  void makeProtected() {
+    if (!m_isProtected && m_obj) {
+      JSValueProtect(m_context, m_obj);
+      m_isProtected = true;
+    }
+  }
+
+  static Object getGlobalObject(JSContextRef ctx) {
+    auto globalObj = JSContextGetGlobalObject(ctx);
+    return Object(ctx, globalObj);
+  }
+
+private:
+  JSContextRef m_context;
+  JSObjectRef m_obj;
+  bool m_isProtected = false;
+};
+
 class Value : public noncopyable {
 public:
   Value(JSContextRef context, JSValueRef value);
@@ -110,6 +164,10 @@ public:
     return JSValueIsNull(context(), m_value);
   }
 
+  bool isUndefined() const {
+    return JSValueIsUndefined(context(), m_value);
+  }
+
   double asNumber() const {
     if (isNumber()) {
       return JSValueToNumber(context(), m_value, nullptr);
@@ -130,6 +188,8 @@ public:
     return JSValueIsObject(context(), m_value);
   }
 
+  Object asObject();
+
   bool isString() const {
     return JSValueIsString(context(), m_value);
   }
@@ -139,7 +199,7 @@ public:
   }
 
   std::string toJSONString(unsigned indent = 0) const;
-  static Value fromJSON(JSContextRef& ctx, const String& json);
+  static Value fromJSON(JSContextRef ctx, const String& json);
 protected:
   JSContextRef context() const;
   JSContextRef m_context;