1 files changed, 106 insertions, 0 deletions
diff --git a/libs/hwui/jni/graphics_jni_helpers.h b/libs/hwui/jni/graphics_jni_helpers.h
new file mode 100644
index 000000000000..78db54acc9e5
--- /dev/null
+++ b/libs/hwui/jni/graphics_jni_helpers.h
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef GRAPHICS_JNI_HELPERS
+#define GRAPHICS_JNI_HELPERS
+
+#include <log/log.h>
+#include <nativehelper/JNIPlatformHelp.h>
+#include <nativehelper/scoped_local_ref.h>
+#include <nativehelper/scoped_utf_chars.h>
+#include <string>
+
+// Host targets (layoutlib) do not differentiate between regular and critical native methods,
+// and they need all the JNI methods to have JNIEnv* and jclass/jobject as their first two arguments.
+// The following macro allows to have those arguments when compiling for host while omitting them when
+// compiling for Android.
+#ifdef __ANDROID__
+#define CRITICAL_JNI_PARAMS
+#define CRITICAL_JNI_PARAMS_COMMA
+#else
+#define CRITICAL_JNI_PARAMS JNIEnv*, jclass
+#define CRITICAL_JNI_PARAMS_COMMA JNIEnv*, jclass,
+#endif
+
+namespace android {
+
+// Defines some helpful functions.
+
+static inline jclass FindClassOrDie(JNIEnv* env, const char* class_name) {
+    jclass clazz = env->FindClass(class_name);
+    LOG_ALWAYS_FATAL_IF(clazz == NULL, "Unable to find class %s", class_name);
+    return clazz;
+}
+
+static inline jfieldID GetFieldIDOrDie(JNIEnv* env, jclass clazz, const char* field_name,
+                                       const char* field_signature) {
+    jfieldID res = env->GetFieldID(clazz, field_name, field_signature);
+    LOG_ALWAYS_FATAL_IF(res == NULL, "Unable to find static field %s", field_name);
+    return res;
+}
+
+static inline jmethodID GetMethodIDOrDie(JNIEnv* env, jclass clazz, const char* method_name,
+                                         const char* method_signature) {
+    jmethodID res = env->GetMethodID(clazz, method_name, method_signature);
+    LOG_ALWAYS_FATAL_IF(res == NULL, "Unable to find method %s", method_name);
+    return res;
+}
+
+static inline jfieldID GetStaticFieldIDOrDie(JNIEnv* env, jclass clazz, const char* field_name,
+                                             const char* field_signature) {
+    jfieldID res = env->GetStaticFieldID(clazz, field_name, field_signature);
+    LOG_ALWAYS_FATAL_IF(res == NULL, "Unable to find static field %s", field_name);
+    return res;
+}
+
+static inline jmethodID GetStaticMethodIDOrDie(JNIEnv* env, jclass clazz, const char* method_name,
+                                               const char* method_signature) {
+    jmethodID res = env->GetStaticMethodID(clazz, method_name, method_signature);
+    LOG_ALWAYS_FATAL_IF(res == NULL, "Unable to find static method %s", method_name);
+    return res;
+}
+
+template <typename T>
+static inline T MakeGlobalRefOrDie(JNIEnv* env, T in) {
+    jobject res = env->NewGlobalRef(in);
+    LOG_ALWAYS_FATAL_IF(res == NULL, "Unable to create global reference.");
+    return static_cast<T>(res);
+}
+
+static inline int RegisterMethodsOrDie(JNIEnv* env, const char* className,
+                                       const JNINativeMethod* gMethods, int numMethods) {
+    int res = jniRegisterNativeMethods(env, className, gMethods, numMethods);
+    LOG_ALWAYS_FATAL_IF(res < 0, "Unable to register native methods.");
+    return res;
+}
+
+/**
+ * Read the specified field from jobject, and convert to std::string.
+ * If the field cannot be obtained, return defaultValue.
+ */
+static inline std::string getStringField(JNIEnv* env, jobject obj, jfieldID fieldId,
+        const char* defaultValue) {
+    ScopedLocalRef<jstring> strObj(env, jstring(env->GetObjectField(obj, fieldId)));
+    if (strObj != nullptr) {
+        ScopedUtfChars chars(env, strObj.get());
+        return std::string(chars.c_str());
+    }
+    return std::string(defaultValue);
+}
+
+}  // namespace android
+
+#endif  // GRAPHICS_JNI_HELPERS