| /* //device/libs/android_runtime/android_os_SystemProperties.cpp |
| ** |
| ** Copyright 2006, 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. |
| */ |
| |
| #define LOG_TAG "SysPropJNI" |
| |
| #include "android-base/logging.h" |
| #include "android-base/properties.h" |
| #include "cutils/properties.h" |
| #include "utils/misc.h" |
| #include <utils/Log.h> |
| #include "jni.h" |
| #include "core_jni_helpers.h" |
| #include <nativehelper/JNIHelp.h> |
| #include <nativehelper/ScopedPrimitiveArray.h> |
| #include <nativehelper/ScopedUtfChars.h> |
| |
| namespace android |
| { |
| |
| namespace { |
| |
| template <typename T, typename Handler> |
| T ConvertKeyAndForward(JNIEnv *env, jstring keyJ, T defJ, Handler handler) { |
| std::string key; |
| { |
| // Scope the String access. If the handler can throw an exception, |
| // releasing the string characters late would trigger an abort. |
| ScopedUtfChars key_utf(env, keyJ); |
| if (key_utf.c_str() == nullptr) { |
| return defJ; |
| } |
| key = key_utf.c_str(); // This will make a copy, but we can't avoid |
| // with the existing interface in |
| // android::base. |
| } |
| return handler(key, defJ); |
| } |
| |
| jstring SystemProperties_getSS(JNIEnv *env, jclass clazz, jstring keyJ, |
| jstring defJ) |
| { |
| // Using ConvertKeyAndForward is sub-optimal for copying the key string, |
| // but improves reuse and reasoning over code. |
| auto handler = [&](const std::string& key, jstring defJ) { |
| std::string prop_val = android::base::GetProperty(key, ""); |
| if (!prop_val.empty()) { |
| return env->NewStringUTF(prop_val.c_str()); |
| }; |
| if (defJ != nullptr) { |
| return defJ; |
| } |
| // This function is specified to never return null (or have an |
| // exception pending). |
| return env->NewStringUTF(""); |
| }; |
| return ConvertKeyAndForward(env, keyJ, defJ, handler); |
| } |
| |
| jstring SystemProperties_getS(JNIEnv *env, jclass clazz, jstring keyJ) |
| { |
| return SystemProperties_getSS(env, clazz, keyJ, nullptr); |
| } |
| |
| template <typename T> |
| T SystemProperties_get_integral(JNIEnv *env, jclass, jstring keyJ, |
| T defJ) |
| { |
| auto handler = [](const std::string& key, T defV) { |
| return android::base::GetIntProperty<T>(key, defV); |
| }; |
| return ConvertKeyAndForward(env, keyJ, defJ, handler); |
| } |
| |
| jboolean SystemProperties_get_boolean(JNIEnv *env, jclass, jstring keyJ, |
| jboolean defJ) |
| { |
| auto handler = [](const std::string& key, jboolean defV) -> jboolean { |
| bool result = android::base::GetBoolProperty(key, defV); |
| return result ? JNI_TRUE : JNI_FALSE; |
| }; |
| return ConvertKeyAndForward(env, keyJ, defJ, handler); |
| } |
| |
| void SystemProperties_set(JNIEnv *env, jobject clazz, jstring keyJ, |
| jstring valJ) |
| { |
| auto handler = [&](const std::string& key, bool) { |
| std::string val; |
| if (valJ != nullptr) { |
| ScopedUtfChars key_utf(env, valJ); |
| val = key_utf.c_str(); |
| } |
| return android::base::SetProperty(key, val); |
| }; |
| if (!ConvertKeyAndForward(env, keyJ, true, handler)) { |
| // Must have been a failure in SetProperty. |
| jniThrowException(env, "java/lang/RuntimeException", |
| "failed to set system property"); |
| } |
| } |
| |
| JavaVM* sVM = nullptr; |
| jclass sClazz = nullptr; |
| jmethodID sCallChangeCallbacks; |
| |
| void do_report_sysprop_change() { |
| //ALOGI("Java SystemProperties: VM=%p, Clazz=%p", sVM, sClazz); |
| if (sVM != nullptr && sClazz != nullptr) { |
| JNIEnv* env; |
| if (sVM->GetEnv((void **)&env, JNI_VERSION_1_4) >= 0) { |
| //ALOGI("Java SystemProperties: calling %p", sCallChangeCallbacks); |
| env->CallStaticVoidMethod(sClazz, sCallChangeCallbacks); |
| } |
| } |
| } |
| |
| void SystemProperties_add_change_callback(JNIEnv *env, jobject clazz) |
| { |
| // This is called with the Java lock held. |
| if (sVM == nullptr) { |
| env->GetJavaVM(&sVM); |
| } |
| if (sClazz == nullptr) { |
| sClazz = (jclass) env->NewGlobalRef(clazz); |
| sCallChangeCallbacks = env->GetStaticMethodID(sClazz, "callChangeCallbacks", "()V"); |
| add_sysprop_change_callback(do_report_sysprop_change, -10000); |
| } |
| } |
| |
| void SystemProperties_report_sysprop_change(JNIEnv /**env*/, jobject /*clazz*/) |
| { |
| report_sysprop_change(); |
| } |
| |
| } // namespace |
| |
| int register_android_os_SystemProperties(JNIEnv *env) |
| { |
| const JNINativeMethod method_table[] = { |
| { "native_get", "(Ljava/lang/String;)Ljava/lang/String;", |
| (void*) SystemProperties_getS }, |
| { "native_get", |
| "(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;", |
| (void*) SystemProperties_getSS }, |
| { "native_get_int", "(Ljava/lang/String;I)I", |
| (void*) SystemProperties_get_integral<jint> }, |
| { "native_get_long", "(Ljava/lang/String;J)J", |
| (void*) SystemProperties_get_integral<jlong> }, |
| { "native_get_boolean", "(Ljava/lang/String;Z)Z", |
| (void*) SystemProperties_get_boolean }, |
| { "native_set", "(Ljava/lang/String;Ljava/lang/String;)V", |
| (void*) SystemProperties_set }, |
| { "native_add_change_callback", "()V", |
| (void*) SystemProperties_add_change_callback }, |
| { "native_report_sysprop_change", "()V", |
| (void*) SystemProperties_report_sysprop_change }, |
| }; |
| return RegisterMethodsOrDie(env, "android/os/SystemProperties", |
| method_table, NELEM(method_table)); |
| } |
| |
| }; |