Merge changes from topic "property-handle" (54543bb4) · Commits · e / os / android_frameworks_base

core/java/android/os/SystemProperties.java

+99 −13

Original line number	Diff line number	Diff line
		@@ -26,6 +26,9 @@ import android.util.MutableInt;

		import com.android.internal.annotations.GuardedBy;

		import dalvik.annotation.optimization.CriticalNative;
		import dalvik.annotation.optimization.FastNative;

		import libcore.util.HexEncoding;

		import java.nio.charset.StandardCharsets;
		@@ -93,18 +96,43 @@ public class SystemProperties {
		}
		}

		// The one-argument version of native_get used to be a regular native function. Nowadays,
		// we use the two-argument form of native_get all the time, but we can't just delete the
		// one-argument overload: apps use it via reflection, as the UnsupportedAppUsage annotation
		// indicates. Let's just live with having a Java function with a very unusual name.
		@UnsupportedAppUsage
		private static native String native_get(String key);
		private static String native_get(String key) {
		return native_get(key, "");
		}

		@FastNative
		@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
		private static native String native_get(String key, String def);
		@FastNative
		@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
		private static native int native_get_int(String key, int def);
		@FastNative
		@UnsupportedAppUsage
		private static native long native_get_long(String key, long def);
		@FastNative
		@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
		private static native boolean native_get_boolean(String key, boolean def);

		@FastNative
		private static native long native_find(String name);
		@FastNative
		private static native String native_get(long handle);
		@CriticalNative
		private static native int native_get_int(long handle, int def);
		@CriticalNative
		private static native long native_get_long(long handle, long def);
		@CriticalNative
		private static native boolean native_get_boolean(long handle, boolean def);

		// _NOT_ FastNative: native_set performs IPC and can block
		@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
		private static native void native_set(String key, String def);

		@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
		private static native void native_add_change_callback();
		private static native void native_report_sysprop_change();
		@@ -229,27 +257,29 @@ public class SystemProperties {

		@SuppressWarnings("unused") // Called from native code.
		private static void callChangeCallbacks() {
		ArrayList<Runnable> callbacks = null;
		synchronized (sChangeCallbacks) {
		//Log.i("foo", "Calling " + sChangeCallbacks.size() + " change callbacks!");
		if (sChangeCallbacks.size() == 0) {
		return;
		}
		ArrayList<Runnable> callbacks = new ArrayList<Runnable>(sChangeCallbacks);
		callbacks = new ArrayList<Runnable>(sChangeCallbacks);
		}
		final long token = Binder.clearCallingIdentity();
		try {
		for (int i = 0; i < callbacks.size(); i++) {
		try {
		callbacks.get(i).run();
		} catch (Throwable t) {
		Log.wtf(TAG, "Exception in SystemProperties change callback", t);
		// Ignore and try to go on.
		// Ignore and try to go on. Don't use wtf here: that
		// will cause the process to exit on some builds and break tests.
		Log.e(TAG, "Exception in SystemProperties change callback", t);
		}
		}
		} finally {
		Binder.restoreCallingIdentity(token);
		}
		}
		}

		/**
		* Notifies listeners that a system property has changed
		@@ -284,4 +314,60 @@ public class SystemProperties {
		@UnsupportedAppUsage
		private SystemProperties() {
		}

		/**
		* Look up a property location by name.
		* @name name of the property
		* @return property handle or {@code null} if property isn't set
		* @hide
		*/
		@Nullable public static Handle find(@NonNull String name) {
		long nativeHandle = native_find(name);
		if (nativeHandle == 0) {
		return null;
		}
		return new Handle(nativeHandle);
		}

		/**
		* Handle to a pre-located property. Looking up a property handle in advance allows
		* for optimal repeated lookup of a single property.
		* @hide
		*/
		public static final class Handle {

		private final long mNativeHandle;

		/**
		* @return Value of the property
		*/
		@NonNull public String get() {
		return native_get(mNativeHandle);
		}
		/**
		* @param def default value
		* @return value or {@code def} on parse error
		*/
		public int getInt(int def) {
		return native_get_int(mNativeHandle, def);
		}
		/**
		* @param def default value
		* @return value or {@code def} on parse error
		*/
		public long getLong(long def) {
		return native_get_long(mNativeHandle, def);
		}
		/**
		* @param def default value
		* @return value or {@code def} on parse error
		*/
		public boolean getBoolean(boolean def) {
		return native_get_boolean(mNativeHandle, def);
		}

		private Handle(long nativeHandle) {
		mNativeHandle = nativeHandle;
		}
		}
		}

core/jni/android_os_SystemProperties.cpp

+157 −58

Original line number	Diff line number	Diff line
		@@ -17,9 +17,13 @@

		#define LOG_TAG "SysPropJNI"

		#include <utility>
		#include <optional>

		#include "android-base/logging.h"
		#include "android-base/parsebool.h"
		#include "android-base/parseint.h"
		#include "android-base/properties.h"
		#include "cutils/properties.h"
		#include "utils/misc.h"
		#include <utils/Log.h>
		#include "jni.h"
		@@ -28,86 +32,171 @@
		#include <nativehelper/ScopedPrimitiveArray.h>
		#include <nativehelper/ScopedUtfChars.h>

		namespace android
		{
		#if defined(__BIONIC__)
		# include <sys/system_properties.h>
		#else
		struct prop_info;
		#endif

		namespace android {
		namespace {

		template <typename T, typename Handler>
		T ConvertKeyAndForward(JNIEnv *env, jstring keyJ, T defJ, Handler handler) {
		std::string key;
		using android::base::ParseBoolResult;

		template<typename Functor>
		void ReadProperty(const prop_info* prop, Functor&& functor)
		{
		// 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;
		#if defined(__BIONIC__)
		auto thunk = [](void* cookie,
		const char* /name/,
		const char* value,
		uint32_t /serial/) {
		std::forward<Functor>(static_cast<Functor>(cookie))(value);
		};
		__system_property_read_callback(prop, thunk, &functor);
		#else
		LOG(FATAL) << "fast property access supported only on device";
		#endif
		}
		key = key_utf.c_str(); // This will make a copy, but we can't avoid
		// with the existing interface in
		// android::base.

		template<typename Functor>
		void ReadProperty(JNIEnv* env, jstring keyJ, Functor&& functor)
		{
		ScopedUtfChars key(env, keyJ);
		if (!key.c_str()) {
		return;
		}
		#if defined(__BIONIC__)
		const prop_info* prop = __system_property_find(key.c_str());
		if (!prop) {
		return;
		}
		return handler(key, defJ);
		ReadProperty(prop, std::forward<Functor>(functor));
		#else
		std::forward<Functor>(functor)(
		android::base::GetProperty(key.c_str(), "").c_str());
		#endif
		}

		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;
		jstring ret = defJ;
		ReadProperty(env, keyJ, [&](const char* value) {
		if (value[0]) {
		ret = env->NewStringUTF(value);
		}
		// This function is specified to never return null (or have an
		// exception pending).
		return env->NewStringUTF("");
		};
		return ConvertKeyAndForward(env, keyJ, defJ, handler);
		});
		if (ret == nullptr && !env->ExceptionCheck()) {
		ret = env->NewStringUTF(""); // Legacy behavior
		}

		jstring SystemProperties_getS(JNIEnv *env, jclass clazz, jstring keyJ)
		{
		return SystemProperties_getSS(env, clazz, keyJ, nullptr);
		return ret;
		}

		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);
		T ret = defJ;
		ReadProperty(env, keyJ, [&](const char* value) {
		android::base::ParseInt<T>(value, &ret);
		});
		return ret;
		}

		static jboolean jbooleanFromParseBoolResult(ParseBoolResult parseResult, jboolean defJ) {
		jboolean ret;
		switch (parseResult) {
		case ParseBoolResult::kError:
		ret = defJ;
		break;
		case ParseBoolResult::kFalse:
		ret = JNI_FALSE;
		break;
		case ParseBoolResult::kTrue:
		ret = JNI_TRUE;
		break;
		}
		return ret;
		}

		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);
		ParseBoolResult parseResult;
		ReadProperty(env, keyJ, [&](const char* value) {
		parseResult = android::base::ParseBool(value);
		});
		return jbooleanFromParseBoolResult(parseResult, defJ);
		}

		jlong SystemProperties_find(JNIEnv* env, jclass, jstring keyJ)
		{
		#if defined(__BIONIC__)
		ScopedUtfChars key(env, keyJ);
		if (!key.c_str()) {
		return 0;
		}
		const prop_info* prop = __system_property_find(key.c_str());
		return reinterpret_cast<jlong>(prop);
		#else
		LOG(FATAL) << "fast property access supported only on device";
		__builtin_unreachable(); // Silence warning
		#endif
		}

		jstring SystemProperties_getH(JNIEnv* env, jclass clazz, jlong propJ)
		{
		jstring ret;
		auto prop = reinterpret_cast<const prop_info*>(propJ);
		ReadProperty(prop, [&](const char* value) {
		ret = env->NewStringUTF(value);
		});
		return ret;
		}

		template <typename T>
		T SystemProperties_get_integralH(CRITICAL_JNI_PARAMS_COMMA jlong propJ, T defJ)
		{
		T ret = defJ;
		auto prop = reinterpret_cast<const prop_info*>(propJ);
		ReadProperty(prop, [&](const char* value) {
		android::base::ParseInt<T>(value, &ret);
		});
		return ret;
		}

		jboolean SystemProperties_get_booleanH(CRITICAL_JNI_PARAMS_COMMA jlong propJ, jboolean defJ)
		{
		ParseBoolResult parseResult;
		auto prop = reinterpret_cast<const prop_info*>(propJ);
		ReadProperty(prop, [&](const char* value) {
		parseResult = android::base::ParseBool(value);
		});
		return jbooleanFromParseBoolResult(parseResult, defJ);
		}

		void SystemProperties_set(JNIEnv *env, jobject clazz, jstring keyJ,
		jstring valJ)
		{
		auto handler = [&](const std::string& key, bool) {
		std::string val;
		ScopedUtfChars key(env, keyJ);
		if (!key.c_str()) {
		return;
		}
		std::optional<ScopedUtfChars> value;
		if (valJ != nullptr) {
		ScopedUtfChars key_utf(env, valJ);
		val = key_utf.c_str();
		value.emplace(env, valJ);
		if (!value->c_str()) {
		return;
		}
		return android::base::SetProperty(key, val);
		};
		if (!ConvertKeyAndForward(env, keyJ, true, handler)) {
		// Must have been a failure in SetProperty.
		}
		bool success;
		#if defined(__BIONIC__)
		success = !__system_property_set(key.c_str(), value ? value->c_str() : "");
		#else
		success = android::base::SetProperty(key.c_str(), value ? value->c_str() : "");
		#endif
		if (!success) {
		jniThrowException(env, "java/lang/RuntimeException",
		"failed to set system property (check logcat for reason)");
		}
		@@ -157,8 +246,6 @@ void SystemProperties_report_sysprop_change(JNIEnv /*env/, jobject /clazz/)
		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 },
		@@ -168,6 +255,18 @@ int register_android_os_SystemProperties(JNIEnv *env)
		(void*) SystemProperties_get_integral<jlong> },
		{ "native_get_boolean", "(Ljava/lang/String;Z)Z",
		(void*) SystemProperties_get_boolean },
		{ "native_find",
		"(Ljava/lang/String;)J",
		(void*) SystemProperties_find },
		{ "native_get",
		"(J)Ljava/lang/String;",
		(void*) SystemProperties_getH },
		{ "native_get_int", "(JI)I",
		(void*) SystemProperties_get_integralH<jint> },
		{ "native_get_long", "(JJ)J",
		(void*) SystemProperties_get_integralH<jlong> },
		{ "native_get_boolean", "(JZ)Z",
		(void*) SystemProperties_get_booleanH },
		{ "native_set", "(Ljava/lang/String;Ljava/lang/String;)V",
		(void*) SystemProperties_set },
		{ "native_add_change_callback", "()V",
		@@ -179,4 +278,4 @@ int register_android_os_SystemProperties(JNIEnv *env)
		method_table, NELEM(method_table));
		}

		};
		} // namespace android

core/tests/systemproperties/src/android/os/SystemPropertiesTest.java

+21 −0

Original line number	Diff line number	Diff line
		@@ -92,6 +92,27 @@ public class SystemPropertiesTest extends TestCase {
		assertEquals(expected, value);
		}

		@SmallTest
		private static void testHandle() throws Exception {
		String value;
		SystemProperties.Handle handle = SystemProperties.find("doesnotexist_2341431");
		assertNull(handle);
		SystemProperties.set(KEY, "abc");
		handle = SystemProperties.find(KEY);
		assertNotNull(handle);
		value = handle.get();
		assertEquals("abc", value);
		SystemProperties.set(KEY, "blarg");
		value = handle.get();
		assertEquals("blarg", value);
		SystemProperties.set(KEY, "1");
		assertEquals(1, handle.getInt(-1));
		assertEquals(1, handle.getLong(-1));
		assertEquals(true, handle.getBoolean(false));
		SystemProperties.set(KEY, "");
		assertEquals(12345, handle.getInt(12345));
		}

		@SmallTest
		public void testIntegralProperties() throws Exception {
		testInt("", 123, 123);