Wrap ctx so we don't mangle with libsass

Use a wrapper to store the callback info and the context, this way we
can use the unmodified libsass

binding.cpp

@@ -4,20 +4,23 @@
 #include <cstring>
 #include <iostream>
 #include <cstdlib>
-#include "libsass/sass_interface.h"
+#include "sass_context_wrapper.h"
 
 using namespace v8;
 using namespace std;
 
+
 void WorkOnContext(uv_work_t* req) {
-    sass_context* ctx = static_cast<sass_context*>(req->data);
+    sass_context_wrapper* ctx_w = static_cast<sass_context_wrapper*>(req->data);
+    sass_context* ctx = static_cast<sass_context*>(ctx_w->ctx);
     sass_compile(ctx);
 }
 
 void MakeCallback(uv_work_t* req) {
     HandleScope scope;
     TryCatch try_catch;
-    sass_context* ctx = static_cast<sass_context*>(req->data);
+    sass_context_wrapper* ctx_w = static_cast<sass_context_wrapper*>(req->data);
+    sass_context* ctx = static_cast<sass_context*>(ctx_w->ctx);
 
     if (ctx->error_status == 0) {
         // if no error, do callback(null, result)
@@ -27,7 +30,7 @@ void MakeCallback(uv_work_t* req) {
             Local<Value>::New(String::New(ctx->output_string))
         };
 
-        ctx->callback->Call(Context::GetCurrent()->Global(), argc, argv);
+        ctx_w->callback->Call(Context::GetCurrent()->Global(), argc, argv);
     } else {
         // if error, do callback(error)
         const unsigned argc = 1;
@@ -35,31 +38,35 @@ void MakeCallback(uv_work_t* req) {
             Local<Value>::New(String::New(ctx->error_message))
         };
 
-        ctx->callback->Call(Context::GetCurrent()->Global(), argc, argv);
+        ctx_w->callback->Call(Context::GetCurrent()->Global(), argc, argv);
     }
     if (try_catch.HasCaught()) {
         node::FatalException(try_catch);
     }
-    sass_free_context(ctx);
+    sass_free_context_wrapper(ctx_w);
 }
 
 Handle<Value> Render(const Arguments& args) {
     HandleScope scope;
     sass_context* ctx = sass_new_context();
+    sass_context_wrapper* ctx_w = sass_new_context_wrapper();
+    char *source;
     String::AsciiValue astr(args[0]);
     Local<Function> callback = Local<Function>::Cast(args[1]);
     String::AsciiValue bstr(args[2]);
 
-    ctx->source_string = new char[strlen(*astr)+1];
-    strcpy(ctx->source_string, *astr);
+    source = new char[strlen(*astr)+1];
+    strcpy(source, *astr);
+    ctx->source_string = source;
     ctx->options.include_paths = new char[strlen(*bstr)+1];
     strcpy(ctx->options.include_paths, *bstr);
     // ctx->options.output_style = SASS_STYLE_NESTED;
     ctx->options.output_style = args[3]->Int32Value();
-    ctx->callback = Persistent<Function>::New(callback);
-    ctx->request.data = ctx;
+    ctx_w->ctx = ctx;
+    ctx_w->callback = Persistent<Function>::New(callback);
+    ctx_w->request.data = ctx_w;
 
-    int status = uv_queue_work(uv_default_loop(), &ctx->request, WorkOnContext, MakeCallback);
+    int status = uv_queue_work(uv_default_loop(), &ctx_w->request, WorkOnContext, MakeCallback);
     assert(status == 0);
 
     return Undefined();

binding.gyp

@@ -4,6 +4,7 @@
       'target_name': 'binding',
       'sources': [
         'binding.cpp',
+        'sass_context_wrapper.cpp',
         'libsass/constants.cpp',
         'libsass/context.cpp',
         'libsass/document.cpp',

sass_context_wrapper.cpp

+#include "sass_context_wrapper.h"
+#include <cstdlib>
+
+extern "C" {
+  using namespace std;
+
+  sass_context_wrapper* sass_new_context_wrapper()
+  {
+    return (sass_context_wrapper*) calloc(1, sizeof(sass_context_wrapper));
+  }
+
+  void sass_free_context_wrapper(sass_context_wrapper* ctx_w)
+  {
+    if (ctx_w->ctx) sass_free_context(ctx_w->ctx);
+
+    free(ctx_w);
+  }
+}

sass_context_wrapper.h

+#include "libsass/sass_interface.h"
+#include <node.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct sass_context_wrapper {
+  sass_context* ctx;
+  uv_work_t request;
+  v8::Persistent<v8::Function> callback;
+};
+
+struct sass_context_wrapper*      sass_new_context_wrapper(void);
+void sass_free_context_wrapper(struct sass_context_wrapper* ctx);
+
+#ifdef __cplusplus
+}
+#endif