added a JniCache objectet for caching jclass, jmethodID, and jfieldID objects

java/jni/ZT1_jnicache.cpp

@@ -0,0 +1,242 @@
+/*
+ * ZeroTier One - Network Virtualization Everywhere
+ * Copyright (C) 2011-2015  ZeroTier, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * --
+ *
+ * ZeroTier may be used and distributed under the terms of the GPLv3, which
+ * are available at: http://www.gnu.org/licenses/gpl-3.0.html
+ *
+ * If you would like to embed ZeroTier into a commercial application or
+ * redistribute it in a modified binary form, please contact ZeroTier Networks
+ * LLC. Start here: http://www.zerotier.com/
+ */
+
+#include "ZT1_jnicache.h"
+#include "ZT1_jniutils.h"
+
+JniCache::JniCache()
+    : m_jvm(NULL)
+    , m_classes()
+    , m_fields()
+    , m_staticFields()
+    , m_methods()
+    , m_staticMethods()
+{
+    LOGD("JNI Cache Created");
+}
+
+JniCache::JniCache(JavaVM *jvm)
+    : m_jvm(jvm)
+    , m_classes()
+    , m_fields()
+    , m_staticFields()
+    , m_methods()
+    , m_staticMethods()
+{
+    LOGD("JNI Cache Created");
+}
+
+JniCache::~JniCache()
+{
+    LOGD("JNI Cache Destroyed");
+    clearCache();
+}
+
+void JniCache::clearCache()
+{
+    if(m_jvm)
+    {
+        JNIEnv *env = NULL;
+        if(m_jvm->GetEnv((void**)&env, JNI_VERSION_1_6) != JNI_OK)
+            return;
+
+        for(ClassMap::iterator iter = m_classes.begin(), end = m_classes.end();
+            iter != end; ++iter)
+        {
+            env->DeleteGlobalRef(iter->second);
+        }
+    }
+
+    m_classes.clear();
+    m_fields.clear();
+    m_staticFields.clear();
+    m_methods.clear();
+    m_staticMethods.clear();
+}
+
+void JniCache::setJavaVM(JavaVM *jvm)
+{ 
+    LOGD("Assigned JVM to object");
+    m_jvm = jvm; 
+}
+
+
+jclass JniCache::findClass(const std::string &name)
+{
+    if(!m_jvm)
+        return NULL;
+
+    ClassMap::iterator found = m_classes.find(name);
+
+    if(found == m_classes.end())
+    {
+        // get the class from the JVM
+        JNIEnv *env = NULL;
+        if(m_jvm->GetEnv((void**)&env, JNI_VERSION_1_6) != JNI_OK)
+        {
+            LOGE("Error retreiving JNI Environment");
+            return NULL;
+        }
+
+        jclass localCls = env->FindClass(name.c_str());
+        if(env->ExceptionCheck())
+        {
+            LOGE("Error finding class: %s", name.c_str());
+            return NULL;
+        }
+
+        jclass cls = (jclass)env->NewGlobalRef(localCls);
+
+        m_classes.insert(std::make_pair(name, cls));
+
+        return cls;
+    }
+
+    LOGD("Returning cached %s", name.c_str());
+    return found->second;
+}
+
+
+jmethodID JniCache::findMethod(jclass cls, const std::string &methodName, const std::string &methodSig)
+{
+    if(!m_jvm)
+        return NULL;
+
+    std::string id = methodName + methodSig;
+
+    MethodMap::iterator found = m_methods.find(id);
+    if(found == m_methods.end())
+    {
+        JNIEnv *env = NULL;
+        if(m_jvm->GetEnv((void**)&env, JNI_VERSION_1_6) != JNI_OK)
+        {
+            return NULL;
+        }
+
+        jmethodID mid = env->GetMethodID(cls, methodName.c_str(), methodSig.c_str());
+        if(env->ExceptionCheck())
+        {
+            return NULL;
+        }
+
+        m_methods.insert(std::make_pair(id, mid));
+
+        return mid;
+    }
+
+    return found->second;
+}
+
+jmethodID JniCache::findStaticMethod(jclass cls, const std::string &methodName, const std::string &methodSig)
+{
+    if(!m_jvm)
+        return NULL;
+
+    std::string id = methodName + methodSig;
+
+    MethodMap::iterator found = m_staticMethods.find(id);
+    if(found == m_staticMethods.end())
+    {
+        JNIEnv *env = NULL;
+        if(m_jvm->GetEnv((void**)&env, JNI_VERSION_1_6) != JNI_OK)
+        {
+            return NULL;
+        }
+
+        jmethodID mid = env->GetStaticMethodID(cls, methodName.c_str(), methodSig.c_str());
+        if(env->ExceptionCheck())
+        {
+            return NULL;
+        }
+
+        m_staticMethods.insert(std::make_pair(id, mid));
+
+        return mid;
+    }
+
+    return found->second;
+}
+
+jfieldID JniCache::findField(jclass cls, const std::string &fieldName, const std::string &typeStr)
+{
+    if(!m_jvm)
+        return NULL;
+
+    std::string id = fieldName + typeStr;
+
+    FieldMap::iterator found = m_fields.find(id);
+    if(found == m_fields.end())
+    {
+        JNIEnv *env = NULL;
+        if(m_jvm->GetEnv((void**)&env, JNI_VERSION_1_6) != JNI_OK)
+        {
+            return NULL;
+        }
+
+        jfieldID fid = env->GetFieldID(cls, fieldName.c_str(), typeStr.c_str());
+        if(env->ExceptionCheck())
+        {
+            return NULL;
+        }
+
+        m_fields.insert(std::make_pair(id, fid));
+
+        return fid;
+    }
+
+    return found->second;
+}
+
+jfieldID JniCache::findStaticField(jclass cls, const std::string &fieldName, const std::string &typeStr)
+{
+    if(!m_jvm)
+        return NULL;
+
+    std::string id = fieldName + typeStr;
+
+    FieldMap::iterator found = m_staticFields.find(id);
+    if(found == m_staticFields.end())
+    {
+        JNIEnv *env = NULL;
+        if(m_jvm->GetEnv((void**)&env, JNI_VERSION_1_6) != JNI_OK)
+        {
+            return NULL;
+        }
+
+        jfieldID fid = env->GetStaticFieldID(cls, fieldName.c_str(), typeStr.c_str());
+        if(env->ExceptionCheck())
+        {
+            return NULL;
+        }
+
+        m_staticFields.insert(std::make_pair(id, fid));
+
+        return fid;
+    }
+
+    return found->second;
+}