n-api: add napi_get_node_version

Add `napi_get_node_version`, to help with feature-detecting
Node.js as an environment.

PR-URL: #14696
Reviewed-By: Kyle Farnung <kfarnung@microsoft.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

doc/api/n-api.md

@@ -3285,6 +3285,35 @@ callback invocation, even if it has been successfully cancelled.
 
 ## Version Management
 
+### napi_get_node_version
+<!-- YAML
+added: REPLACEME
+-->
+
+```C
+typedef struct {
+  uint32_t major;
+  uint32_t minor;
+  uint32_t patch;
+  const char* release;
+} napi_node_version;
+
+NAPI_EXTERN
+napi_status napi_get_node_version(napi_env env,
+                                  const napi_node_version** version);
+```
+
+- `[in] env`: The environment that the API is invoked under.
+- `[out] version`: A pointer to version information for Node itself.
+
+Returns `napi_ok` if the API succeeded.
+
+This function fills the `version` struct with the major, minor and patch version
+of Node that is currently running, and the `release` field with the
+value of [`process.release.name`][`process.release`].
+
+The returned buffer is statically allocated and does not need to be freed.
+
 ### napi_get_version
 <!-- YAML
 added: v8.0.0
@@ -3368,3 +3397,5 @@ support it:
 [`napi_throw_type_error`]: #n_api_napi_throw_type_error
 [`napi_unwrap`]: #n_api_napi_unwrap
 [`napi_wrap`]: #n_api_napi_wrap
+
+[`process.release`]: process.html#process_process_release

src/node.cc

@@ -3266,7 +3266,8 @@ void SetupProcessObject(Environment* env,
   // process.release
   Local<Object> release = Object::New(env->isolate());
   READONLY_PROPERTY(process, "release", release);
-  READONLY_PROPERTY(release, "name", OneByteString(env->isolate(), "node"));
+  READONLY_PROPERTY(release, "name",
+                    OneByteString(env->isolate(), NODE_RELEASE));
 
 // if this is a release build and no explicit base has been set
 // substitute the standard release download URL

src/node_api.cc

@@ -3119,6 +3119,20 @@ napi_status napi_get_version(napi_env env, uint32_t* result) {
   return napi_clear_last_error(env);
 }
 
+napi_status napi_get_node_version(napi_env env,
+                                  const napi_node_version** result) {
+  CHECK_ENV(env);
+  CHECK_ARG(env, result);
+  static const napi_node_version version = {
+    NODE_MAJOR_VERSION,
+    NODE_MINOR_VERSION,
+    NODE_PATCH_VERSION,
+    NODE_RELEASE
+  };
+  *result = &version;
+  return napi_clear_last_error(env);
+}
+
 namespace uvimpl {
 
 static napi_status ConvertUVErrorCode(int code) {

src/node_api.h

@@ -536,6 +536,10 @@ NAPI_EXTERN napi_status napi_cancel_async_work(napi_env env,
 // version management
 NAPI_EXTERN napi_status napi_get_version(napi_env env, uint32_t* result);
 
+NAPI_EXTERN
+napi_status napi_get_node_version(napi_env env,
+                                  const napi_node_version** version);
+
 EXTERN_C_END
 
 #endif  // SRC_NODE_API_H_

src/node_api_types.h

@@ -102,4 +102,11 @@ typedef struct {
   napi_status error_code;
 } napi_extended_error_info;
 
+typedef struct {
+  uint32_t major;
+  uint32_t minor;
+  uint32_t patch;
+  const char* release;
+} napi_node_version;
+
 #endif  // SRC_NODE_API_TYPES_H_

src/node_version.h

@@ -33,6 +33,10 @@
 #define NODE_STRINGIFY_HELPER(n) #n
 #endif
 
+#ifndef NODE_RELEASE
+#define NODE_RELEASE "node"
+#endif
+
 #ifndef NODE_TAG
 # if NODE_VERSION_IS_RELEASE
 #  define NODE_TAG ""

test/addons-napi/test_general/test.js

@@ -35,6 +35,11 @@ assert.ok(test_general.testGetPrototype(baseObject) !==
 // expected version is currently 1
 assert.strictEqual(test_general.testGetVersion(), 1);
 
+const [ major, minor, patch, release ] = test_general.testGetNodeVersion();
+assert.strictEqual(process.version.split('-')[0],
+                   `v${major}.${minor}.${patch}`);
+assert.strictEqual(release, process.release.name);
+
 [
   123,
   'test string',

test/addons-napi/test_general/test_general.c

@@ -33,6 +33,25 @@ napi_value testGetVersion(napi_env env, napi_callback_info info) {
   return result;
 }
 
+napi_value testGetNodeVersion(napi_env env, napi_callback_info info) {
+  const napi_node_version* node_version;
+  napi_value result, major, minor, patch, release;
+  NAPI_CALL(env, napi_get_node_version(env, &node_version));
+  NAPI_CALL(env, napi_create_uint32(env, node_version->major, &major));
+  NAPI_CALL(env, napi_create_uint32(env, node_version->minor, &minor));
+  NAPI_CALL(env, napi_create_uint32(env, node_version->patch, &patch));
+  NAPI_CALL(env, napi_create_string_utf8(env,
+                                         node_version->release,
+                                         (size_t)-1,
+                                         &release));
+  NAPI_CALL(env, napi_create_array_with_length(env, 4, &result));
+  NAPI_CALL(env, napi_set_element(env, result, 0, major));
+  NAPI_CALL(env, napi_set_element(env, result, 1, minor));
+  NAPI_CALL(env, napi_set_element(env, result, 2, patch));
+  NAPI_CALL(env, napi_set_element(env, result, 3, release));
+  return result;
+}
+
 napi_value doInstanceOf(napi_env env, napi_callback_info info) {
   size_t argc = 2;
   napi_value args[2];
@@ -142,6 +161,7 @@ void Init(napi_env env, napi_value exports, napi_value module, void* priv) {
     DECLARE_NAPI_PROPERTY("testStrictEquals", testStrictEquals),
     DECLARE_NAPI_PROPERTY("testGetPrototype", testGetPrototype),
     DECLARE_NAPI_PROPERTY("testGetVersion", testGetVersion),
+    DECLARE_NAPI_PROPERTY("testGetNodeVersion", testGetNodeVersion),
     DECLARE_NAPI_PROPERTY("doInstanceOf", doInstanceOf),
     DECLARE_NAPI_PROPERTY("getUndefined", getUndefined),
     DECLARE_NAPI_PROPERTY("getNull", getNull),