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Commit 37658383 authored by Peng Xu's avatar Peng Xu Committed by Android (Google) Code Review
Browse files

Merge "Intern Sensor object string using java String.intern()" into oc-dev

parents aca24656 3e132049

core/jni/android_hardware_SensorManager.cpp

+50 −64
Original line number Original line Diff line number Diff line
@@ -75,6 +75,12 @@ struct ListOffsets { 
    jmethodID   add;

    jmethodID   add;

} gListOffsets;

} gListOffsets;





struct StringOffsets {

    jclass      clazz;

    jmethodID   intern;

    jstring     emptyString;

} gStringOffsets;



/*

/*

 * nativeClassInit is not inteneded to be thread-safe. It should be called before other native...

 * nativeClassInit is not inteneded to be thread-safe. It should be called before other native...

 * functions (except nativeCreate).

 * functions (except nativeCreate).
@@ -84,75 +90,55 @@ nativeClassInit (JNIEnv *_env, jclass _this) 
{

{

    //android.hardware.Sensor

    //android.hardware.Sensor

    SensorOffsets& sensorOffsets = gSensorOffsets;

    SensorOffsets& sensorOffsets = gSensorOffsets;

    jclass sensorClass = (jclass) _env->NewGlobalRef(_env->FindClass("android/hardware/Sensor"));

    jclass sensorClass = (jclass)

            MakeGlobalRefOrDie(_env, FindClassOrDie(_env, "android/hardware/Sensor"));

    sensorOffsets.clazz = sensorClass;

    sensorOffsets.clazz = sensorClass;

    sensorOffsets.name        = _env->GetFieldID(sensorClass, "mName",      "Ljava/lang/String;");

    sensorOffsets.name = GetFieldIDOrDie(_env, sensorClass, "mName", "Ljava/lang/String;");

    sensorOffsets.vendor      = _env->GetFieldID(sensorClass, "mVendor",    "Ljava/lang/String;");

    sensorOffsets.vendor = GetFieldIDOrDie(_env, sensorClass, "mVendor", "Ljava/lang/String;");

    sensorOffsets.version     = _env->GetFieldID(sensorClass, "mVersion",   "I");

    sensorOffsets.version = GetFieldIDOrDie(_env, sensorClass, "mVersion", "I");

    sensorOffsets.handle      = _env->GetFieldID(sensorClass, "mHandle",    "I");

    sensorOffsets.handle = GetFieldIDOrDie(_env, sensorClass, "mHandle", "I");

    sensorOffsets.range       = _env->GetFieldID(sensorClass, "mMaxRange",  "F");

    sensorOffsets.range = GetFieldIDOrDie(_env, sensorClass, "mMaxRange", "F");

    sensorOffsets.resolution  = _env->GetFieldID(sensorClass, "mResolution","F");

    sensorOffsets.resolution = GetFieldIDOrDie(_env, sensorClass, "mResolution","F");

    sensorOffsets.power       = _env->GetFieldID(sensorClass, "mPower",     "F");

    sensorOffsets.power = GetFieldIDOrDie(_env, sensorClass, "mPower", "F");

    sensorOffsets.minDelay    = _env->GetFieldID(sensorClass, "mMinDelay",  "I");

    sensorOffsets.minDelay = GetFieldIDOrDie(_env, sensorClass, "mMinDelay", "I");

    sensorOffsets.fifoReservedEventCount =

    sensorOffsets.fifoReservedEventCount =

            _env->GetFieldID(sensorClass, "mFifoReservedEventCount",  "I");

            GetFieldIDOrDie(_env,sensorClass, "mFifoReservedEventCount", "I");

    sensorOffsets.fifoMaxEventCount = _env->GetFieldID(sensorClass, "mFifoMaxEventCount",  "I");

    sensorOffsets.fifoMaxEventCount = GetFieldIDOrDie(_env,sensorClass, "mFifoMaxEventCount", "I");

    sensorOffsets.stringType = _env->GetFieldID(sensorClass, "mStringType", "Ljava/lang/String;");

    sensorOffsets.stringType =

    sensorOffsets.requiredPermission = _env->GetFieldID(sensorClass, "mRequiredPermission",

            GetFieldIDOrDie(_env,sensorClass, "mStringType", "Ljava/lang/String;");

                                                        "Ljava/lang/String;");

    sensorOffsets.requiredPermission =

    sensorOffsets.maxDelay    = _env->GetFieldID(sensorClass, "mMaxDelay",  "I");

            GetFieldIDOrDie(_env,sensorClass, "mRequiredPermission", "Ljava/lang/String;");

    sensorOffsets.flags = _env->GetFieldID(sensorClass, "mFlags",  "I");

    sensorOffsets.maxDelay = GetFieldIDOrDie(_env,sensorClass, "mMaxDelay", "I");



    sensorOffsets.flags = GetFieldIDOrDie(_env,sensorClass, "mFlags", "I");

    sensorOffsets.setType = _env->GetMethodID(sensorClass, "setType", "(I)Z");



    sensorOffsets.setUuid = _env->GetMethodID(sensorClass, "setUuid", "(JJ)V");

    sensorOffsets.setType = GetMethodIDOrDie(_env,sensorClass, "setType", "(I)Z");

    sensorOffsets.init = _env->GetMethodID(sensorClass, "<init>", "()V");

    sensorOffsets.setUuid = GetMethodIDOrDie(_env,sensorClass, "setUuid", "(JJ)V");

    sensorOffsets.init = GetMethodIDOrDie(_env,sensorClass, "<init>", "()V");





    // java.util.List;

    // java.util.List;

    ListOffsets& listOffsets = gListOffsets;

    ListOffsets& listOffsets = gListOffsets;

    jclass listClass = (jclass) _env->NewGlobalRef(_env->FindClass("java/util/List"));

    jclass listClass = (jclass) MakeGlobalRefOrDie(_env, FindClassOrDie(_env, "java/util/List"));

    listOffsets.clazz = listClass;

    listOffsets.clazz = listClass;

    listOffsets.add = _env->GetMethodID(listClass, "add", "(Ljava/lang/Object;)Z");

    listOffsets.add = GetMethodIDOrDie(_env,listClass, "add", "(Ljava/lang/Object;)Z");

}





/**

    // initialize java.lang.String and empty string intern

 * A key comparator predicate.

    StringOffsets& stringOffsets = gStringOffsets;

 * It is used to intern strings associated with Sensor data.

    stringOffsets.clazz = MakeGlobalRefOrDie(_env, FindClassOrDie(_env, "java/lang/String"));

 * It defines a 'Strict weak ordering' for the interned strings.

    stringOffsets.intern =

 */

            GetMethodIDOrDie(_env, stringOffsets.clazz, "intern", "()Ljava/lang/String;");

class InternedStringCompare {

    ScopedLocalRef<jstring> empty(_env, _env->NewStringUTF(""));

public:

    stringOffsets.emptyString = (jstring)

    bool operator()(const String8* string1, const String8* string2) const {

            MakeGlobalRefOrDie(_env, _env->CallObjectMethod(empty.get(), stringOffsets.intern));

        if (string1 == NULL) {

            return string2 != NULL;

        }

        if (string2 == NULL) {

            return false;

        }

        return string1->compare(*string2) < 0;

}

}

};





/**

static jstring getJavaInternedString(JNIEnv *env, const String8 &string) {

 * A localized interning mechanism for Sensor strings.

    if (string == "") {

 * We implement our own interning to avoid the overhead of using java.lang.String#intern().

        return gStringOffsets.emptyString;

 * It is common that Vendor, StringType, and RequirePermission data is common between many of the

 * Sensors, by interning the memory usage to represent Sensors is optimized.

 */

static jstring

getInternedString(JNIEnv *env, const String8* string) {

    static std::map<const String8*, jstring, InternedStringCompare> internedStrings;



    jstring internedString;

    std::map<const String8*, jstring>::iterator iterator = internedStrings.find(string);

    if (iterator != internedStrings.end()) {

        internedString = iterator->second;

    } else {

        jstring localString = env->NewStringUTF(string->string());

        // we are implementing our own interning so expect these strings to be backed by global refs

        internedString = (jstring) env->NewGlobalRef(localString);

        internedStrings.insert(std::make_pair(string, internedString));

        env->DeleteLocalRef(localString);

    }

    }



    ScopedLocalRef<jstring> javaString(env, env->NewStringUTF(string.string()));

    jstring internedString = (jstring)

            env->CallObjectMethod(javaString.get(), gStringOffsets.intern);

    return internedString;

    return internedString;

}

}
@@ -174,10 +160,10 @@ translateNativeSensorToJavaSensor(JNIEnv *env, jobject sensor, const Sensor& nat 
    }

    }





    if (sensor != NULL) {

    if (sensor != NULL) {

        jstring name = env->NewStringUTF(nativeSensor.getName().string());

        jstring name = getJavaInternedString(env, nativeSensor.getName());

        jstring vendor = env->NewStringUTF(nativeSensor.getVendor().string());

        jstring vendor = getJavaInternedString(env, nativeSensor.getVendor());

        jstring requiredPermission =

        jstring requiredPermission =

                env->NewStringUTF(nativeSensor.getRequiredPermission().string());

                getJavaInternedString(env, nativeSensor.getRequiredPermission());





        env->SetObjectField(sensor, sensorOffsets.name,      name);

        env->SetObjectField(sensor, sensorOffsets.name,      name);

        env->SetObjectField(sensor, sensorOffsets.vendor,    vendor);

        env->SetObjectField(sensor, sensorOffsets.vendor,    vendor);
@@ -198,7 +184,7 @@ translateNativeSensorToJavaSensor(JNIEnv *env, jobject sensor, const Sensor& nat 




        if (env->CallBooleanMethod(sensor, sensorOffsets.setType, nativeSensor.getType())

        if (env->CallBooleanMethod(sensor, sensorOffsets.setType, nativeSensor.getType())

                == JNI_FALSE) {

                == JNI_FALSE) {

            jstring stringType = getInternedString(env, &nativeSensor.getStringType());

            jstring stringType = getJavaInternedString(env, nativeSensor.getStringType());

            env->SetObjectField(sensor, sensorOffsets.stringType, stringType);

            env->SetObjectField(sensor, sensorOffsets.stringType, stringType);

        }

        }