Added Windows registry value names enumeration

src/main/cpp/win.cpp

@@ -553,4 +553,44 @@ Java_net_rubygrapefruit_platform_internal_jni_WindowsRegistryFunctions_getSubkey
     return true;
 }
 
+JNIEXPORT jboolean JNICALL
+Java_net_rubygrapefruit_platform_internal_jni_WindowsRegistryFunctions_getValueNames(JNIEnv *env, jclass target, jint keyNum, jstring subkey, jobject names, jobject result) {
+    wchar_t* subkeyStr = java_to_wchar(env, subkey, result);
+    jclass subkeys_class = env->GetObjectClass(names);
+    jmethodID method = env->GetMethodID(subkeys_class, "add", "(Ljava/lang/Object;)Z");
+
+    HKEY key;
+    LONG retval = RegOpenKeyExW(get_key_from_ordinal(keyNum), subkeyStr, 0, KEY_READ, &key);
+    if (retval != ERROR_SUCCESS) {
+        free(subkeyStr);
+        if (retval != ERROR_FILE_NOT_FOUND) {
+            mark_failed_with_code(env, "could open registry key", retval, NULL, result);
+        }
+        return false;
+    }
+
+    DWORD valueCount;
+    DWORD maxValueNameLen;
+    retval = RegQueryInfoKeyW(key, NULL, NULL, NULL, NULL, NULL, NULL, &valueCount, &maxValueNameLen, NULL, NULL, NULL);
+    if (retval != ERROR_SUCCESS) {
+        mark_failed_with_code(env, "could query registry key", retval, NULL, result);
+    } else {
+        wchar_t* valueNameStr = (wchar_t*)malloc(sizeof(wchar_t) * (maxValueNameLen+1));
+        for (int i = 0; i < valueCount; i++) {
+            DWORD valueNameLen = maxValueNameLen + 1;
+            retval = RegEnumValueW(key, i, valueNameStr, &valueNameLen, NULL, NULL, NULL, NULL);
+            if (retval != ERROR_SUCCESS) {
+                mark_failed_with_code(env, "could enumerate registry value name", retval, NULL, result);
+                break;
+            }
+            env->CallVoidMethod(names, method, wchar_to_java(env, valueNameStr, wcslen(valueNameStr), result));
+        }
+        free(valueNameStr);
+    }
+
+    RegCloseKey(key);
+    free(subkeyStr);
+    return true;
+}
+
 #endif

src/main/java/net/rubygrapefruit/platform/WindowsRegistry.java

@@ -23,4 +23,13 @@ public interface WindowsRegistry extends NativeIntegration {
      * @throws MissingRegistryEntryException When the requested key does not exist.
      */
     List<String> getSubkeys(Key key, String subkey) throws NativeException;
+
+    /**
+     * Lists the value names of a registry key.
+     *
+     * @throws NativeException On failure.
+     * @throws MissingRegistryEntryException When the requested key does not exist.
+     */
+    List<String> getValueNames(Key key, String subkey) throws NativeException;
+
 }

src/main/java/net/rubygrapefruit/platform/internal/DefaultWindowsRegistry.java

@@ -38,4 +38,20 @@ public class DefaultWindowsRegistry implements WindowsRegistry {
         }
         return subkeys;
     }
+
+    public List<String> getValueNames(Key key, String subkey) throws NativeException {
+        FunctionResult result = new FunctionResult();
+        ArrayList<String> names = new ArrayList<String>();
+        boolean found = WindowsRegistryFunctions.getValueNames(key.ordinal(), subkey, names, result);
+        if (result.isFailed()) {
+            throw new NativeException(String.format("Could not get value names of registry key '%s\\%s': %s", key,
+                    subkey, result.getMessage()));
+        }
+        if (!found) {
+            throw new MissingRegistryEntryException(String.format(
+                    "Could not list the value names of registry key '%s\\%s' as it does not exist.", key, subkey));
+        }
+        return names;
+    }
+
 }

src/main/java/net/rubygrapefruit/platform/internal/jni/WindowsRegistryFunctions.java

@@ -10,4 +10,7 @@ public class WindowsRegistryFunctions {
 
     // Returns false for unknown key
     public static native boolean getSubkeys(int key, String subkey, List<String> subkeys, FunctionResult result);
+
+    // Returns false for unknown key
+    public static native boolean getValueNames(int key, String subkey, List<String> names, FunctionResult result);
 }