Load weak-node-api dynamically when injecting

Author: kraenhansen

packages/react-native-node-api-modules/scripts/generate-weak-node-api-injector.ts

@@ -10,25 +10,41 @@ export const CPP_SOURCE_PATH = path.join(__dirname, "../cpp");
  * Generates source code which injects the Node API functions from the host.
  */
 export function generateSource(functions: FunctionDecl[]) {
-  return [
-    "// This file is generated by react-native-node-api-modules",
-    `#include <Logger.hpp>`,
-    `#include <weak_node_api.hpp>`,
-    "namespace callstack::nodeapihost {",
-    "using node_api::internal::inject_host;",
-    "using node_api::internal::NodeApiHost;",
-    "void injectIntoWeakNodeApi() {",
-    `  log_debug("Injecting WeakNodeApiHost");`,
-    "  inject_host(NodeApiHost {",
-    ...functions
-      .filter(({ kind }) => kind === "engine")
-      .flatMap(({ name }) => {
-        return [`.${name} = ${name},`];
-      }),
-    "  });",
-    "}",
-    "} // namespace callstack::nodeapihost",
-  ].join("\n");
+  return `
+    // This file is generated by react-native-node-api-modules
+    #include <Logger.hpp>
+    #include <dlfcn.h>
+    #include <weak_node_api.hpp>
+
+    namespace callstack::nodeapihost {
+    
+    using node_api::internal::inject_host_t;
+    using node_api::internal::NodeApiHost;
+
+    void injectIntoWeakNodeApi() {
+    void *module = dlopen("libweak-node-api.so", RTLD_NOW | RTLD_GLOBAL);
+    if (NULL == module) {
+      log_debug("NapiHost: Failed to load weak-node-api: %s", dlerror());
+      abort();
+    }
+
+    auto inject_host = (inject_host_t)dlsym(
+        module, "_ZN8node_api8internal11inject_hostERKNS0_11NodeApiHostE");
+    if (NULL == inject_host) {
+      log_debug("NapiHost: Failed to find 'inject_host' function: %s", dlerror());
+      abort();
+    }
+
+    log_debug("Injecting WeakNodeApiHost");
+    inject_host(NodeApiHost {
+      ${functions
+        .filter(({ kind }) => kind === "engine")
+        .flatMap(({ name }) => `.${name} = ${name},`)
+        .join("\n")}
+      });
+    }
+    } // namespace callstack::nodeapihost
+  `;
 }
 
 async function run() {

packages/react-native-node-api-modules/scripts/generate-weak-node-api.ts

@@ -23,6 +23,7 @@ export function generateHeader(functions: FunctionDecl[]) {
         `${returnType} (*${name})(${argumentTypes.join(", ")});`
     ),
     "};",
+    "typedef void(*inject_host_t)(const NodeApiHost&);",
     "void inject_host(const NodeApiHost& host);",
     "} // namespace node_api::internal",
   ].join("\n");
@@ -43,10 +44,11 @@ export function generateSource(functions: FunctionDecl[]) {
     "};",
     "} // namespace node_api::internal",
     "using node_api::internal::g_host;",
+    ``,
     // Generate function calling into the host
     ...functions.flatMap(({ returnType, name, argumentTypes }) => {
       return [
-        `__attribute__((weak)) ${returnType} ${name}(${argumentTypes
+        `extern "C" ${returnType} ${name}(${argumentTypes
           .map((type, index) => `${type} arg${index}`)
           .join(", ")}) {`,
         `if (g_host.${name} == nullptr) {`,