Produce a unique namespace at compile time

binding.cc

@@ -12,6 +12,16 @@
 #include <map>
 #include <vector>
 
+/**
+ * Produce a unique namespace at compile time so that symbols don't
+ * clash when multiple versions of the addon are loaded into node.
+ */
+#define CONCAT_(a,b) a##b
+#define CONCAT(a,b) CONCAT_(a,b)
+#define NS CONCAT(NODE_GYP_MODULE_NAME,MODULE_SEED)
+
+namespace NS {
+
 /**
  * Forward declarations.
  */
@@ -1765,3 +1775,5 @@ NAPI_INIT() {
   NAPI_EXPORT_FUNCTION(batch_clear);
   NAPI_EXPORT_FUNCTION(batch_write);
 }
+
+}

binding.gyp

@@ -1,6 +1,9 @@
 {
   "targets": [{
     "target_name": "leveldown",
+    "defines": [
+      "MODULE_SEED=<!(node -p \"crypto.randomBytes(16).toString('hex')\")"
+    ],
     "conditions": [
       ["OS == 'win'", {
         "defines": [