Importer: Drops uv_mutex in favor of std::mutex.

It is not safe to use uv_cond_wait
outside of v8 thread (uv loop).

src/binding.cpp

@@ -81,12 +81,14 @@ struct Sass_Import** sass_importer(const char* file, const char* prev, void* coo
      *  can run uv_async_send without a push.
      */
 
+    std::unique_lock<std::mutex> lock(*ctx_w->importer_mutex);
+
     ctx_w->file = file ? strdup(file) : 0;
     ctx_w->prev = prev ? strdup(prev) : 0;
     ctx_w->async.data = (void*)ctx_w;
 
     uv_async_send(&ctx_w->async);
-    uv_cond_wait(&ctx_w->importer_condition_variable, &ctx_w->importer_mutex);
+    ctx_w->importer_condition_variable->wait(lock);
   }
   else {
     NanScope();
@@ -357,7 +359,7 @@ NAN_METHOD(ImportedCallback) {
   sass_context_wrapper* ctx_w = imports_collection[index];
 
   prepare_import_results(returned_value, ctx_w);
-  uv_cond_signal(&ctx_w->importer_condition_variable);
+  ctx_w->importer_condition_variable->notify_all();
 
   if (try_catch.HasCaught()) {
     node::FatalException(try_catch);

src/sass_context_wrapper.cpp

@@ -24,8 +24,9 @@ extern "C" {
 
   sass_context_wrapper* sass_make_context_wrapper() {
     sass_context_wrapper* ctx_w = (sass_context_wrapper*)calloc(1, sizeof(sass_context_wrapper));
-    uv_mutex_init(&ctx_w->importer_mutex);
-    uv_cond_init(&ctx_w->importer_condition_variable);
+
+    ctx_w->importer_mutex = new std::mutex();
+    ctx_w->importer_condition_variable = new std::condition_variable();
 
     return ctx_w;
   }
@@ -38,14 +39,14 @@ extern "C" {
       sass_delete_file_context(ctx_w->fctx);
     }
 
-    delete ctx_w->success_callback;
-    delete ctx_w->error_callback;
-    delete ctx_w->importer_callback;
     delete ctx_w->file;
     delete ctx_w->prev;
+    delete ctx_w->error_callback;
+    delete ctx_w->success_callback;
+    delete ctx_w->importer_callback;
 
-    uv_mutex_destroy(&ctx_w->importer_mutex);
-    uv_cond_destroy(&ctx_w->importer_condition_variable);
+    delete ctx_w->importer_mutex;
+    delete ctx_w->importer_condition_variable;
 
     NanDisposePersistent(ctx_w->result);
 

src/sass_context_wrapper.h

 #include <nan.h>
+#include <condition_variable>
 #include "libsass/sass_context.h"
 
 #ifdef __cplusplus
@@ -12,20 +13,27 @@ extern "C" {
   void compile_it(uv_work_t* req);
 
   struct sass_context_wrapper {
+    // binding related
+    bool is_sync;
+    void* cookie;
+    const char* prev;
+    const char* file;
+    std::mutex* importer_mutex;
+    std::condition_variable* importer_condition_variable;
+
+    // libsass related
+    Sass_Import** imports;
     Sass_Data_Context* dctx;
     Sass_File_Context* fctx;
-    Persistent<Object> result;
-    uv_work_t request;
-    uv_mutex_t importer_mutex;
-    uv_cond_t importer_condition_variable;
+
+    // libuv related
     uv_async_t async;
-    const char* file;
-    const char* prev;
-    void* cookie;
-    bool is_sync;
-    Sass_Import** imports;
-    NanCallback* success_callback;
+    uv_work_t request;
+
+    // v8 and nan related
+    Persistent<Object> result;
     NanCallback* error_callback;
+    NanCallback* success_callback;
     NanCallback* importer_callback;
   };