Node.js native module programming

Separate application algorithm codes and Node.js plug codes

• Application codes should be removed any node.js and v8 related definitions.
  • it can use another languages for application code. e.g. C, Objective-C
• Node.js plug codes are almost for convert arguments and result.

About v8 Handles

3 Handle (smart pointer) type exists

• Handle: as smart pointer of RAII (release the holding resource by its destructor)
• Local: automatically managed by HandleScope
• Persistent: explicitly call Dispose() to release

HandleScope instance is stacked memory manager for Local handle.

• HandleScope scope: make scope upon top of HandleScope stack.
• Local<...> v = ...: managed by stack top scope. the scope destructor release all managed handle
• return scope.Close(localHandle): unmanage a localHandle object on the scope, then return localHandle as Handle

Convert C type to v8::Value

• char* => String: String::New(s) or String::NewSymbol(s)
• String => char*: String::Utf8Value utf8(str); char* s = *utf8;
• int32_t => Integer: Integer::New(i)
• Integer => int32_t: v->Int32Value()
• uint32_t => Integer: Integer::NewFromUnsigned(i)
• Integer => uint32_t: v->Uint32Value()