Fix segfault on exception log (#417)

samples/SkiaJvmSample/build.gradle.kts

@@ -56,6 +56,7 @@ val casualRun = tasks.named<JavaExec>("run") {
     systemProperty("skiko.win.exception.logger.enabled", "true")
     systemProperty("skiko.win.exception.handler.enabled", "true")
     jvmArgs?.add("-ea")
+    // jvmArgs?.add("-Xcheck:jni")
     // Use systemProperty("skiko.library.path", "/tmp") to test loader.
     System.getProperties().entries
         .associate {

skiko/src/jvmMain/cpp/common/interop.cc

@@ -99,6 +99,19 @@ namespace java {
                     return false;
             }
         }
+
+        namespace System {
+            jclass cls;
+            jmethodID getProperty;
+            void onLoad(JNIEnv* env) {
+                jclass local = env->FindClass("java/lang/System");
+                cls = static_cast<jclass>(env->NewGlobalRef(local));
+                getProperty = env->GetStaticMethodID(cls, "getProperty", "(Ljava/lang/String;)Ljava/lang/String;");
+            }
+            void onUnload(JNIEnv* env) {
+                env->DeleteGlobalRef(cls);
+            }
+        }
     }
 
     namespace util {
@@ -127,6 +140,7 @@ namespace java {
         lang::RuntimeException::onLoad(env);
         lang::String::onLoad(env);
         lang::Throwable::onLoad(env);
+        lang::System::onLoad(env);
         util::Iterator::onLoad(env);
     }
 
@@ -136,6 +150,7 @@ namespace java {
         lang::RuntimeException::onUnload(env);
         lang::Float::onUnload(env);
         lang::Boolean::onUnload(env);
+        lang::System::onUnload(env);
     }
 }
 

skiko/src/jvmMain/cpp/common/interop.hh

@@ -61,6 +61,13 @@ namespace java {
             void onLoad(JNIEnv* env);
             bool exceptionThrown(JNIEnv* env);
         }
+
+        namespace System {
+            extern jclass cls;
+            extern jmethodID getProperty;
+            void onLoad(JNIEnv* env);
+            void onUnload(JNIEnv* env);
+        }
     }
 
     namespace util {

skiko/src/jvmMain/cpp/windows/exceptions_handler.cc

 #if SK_BUILD_FOR_WIN
 
 #include "exceptions_handler.h"
-
-static JavaVM *jvm = NULL;
+#include "../common/interop.hh"
 
 bool isHandleException(JNIEnv *env)
 {
-    static jclass systemClass = NULL;
-    if (!systemClass)
-    {
-        systemClass = env->FindClass("java/lang/System");
-    }
-
-    static jmethodID getPropertyMethod = NULL;
-    if (!getPropertyMethod)
-    {
-        getPropertyMethod = env->GetStaticMethodID(systemClass, "getProperty", "(Ljava/lang/String;)Ljava/lang/String;");
-    }
-
     jstring propertyName = env->NewStringUTF("skiko.win.exception.handler.enabled");
-    jstring propertyString = (jstring)env->CallStaticObjectMethod(systemClass, getPropertyMethod, propertyName);
+    jstring propertyString = (jstring)env->CallStaticObjectMethod(java::lang::System::cls, java::lang::System::getProperty, propertyName);
     if (propertyString == 0)
     {
         return false;
@@ -81,29 +68,13 @@ const char *getDescription(DWORD code)
 
 void logJavaException(JNIEnv *env, const char *function, DWORD sehCode)
 {
-    char buffer[200];
-    int result = snprintf(
-        buffer, 200, "Native exception in [%s]:\nSEH description: %s\n", function, getDescription(sehCode));
-
-    if (jvm == NULL)
-    {
-        env->GetJavaVM(&jvm);
-    }
-
     if (isHandleException(env))
     {
-        static jclass logClass = NULL;
-        if (!logClass)
-        {
-            logClass = env->FindClass("org/jetbrains/skiko/RenderExceptionsHandler");
-        }
-
-        static jmethodID logMethod = NULL;
-        if (!logMethod)
-        {
-            logMethod = env->GetStaticMethodID(logClass, "logAndThrow", "(Ljava/lang/String;)V");
-        }
-
+        char buffer[200];
+        int result = snprintf(
+            buffer, sizeof(buffer) - 1, "Native exception in [%s]:\nSEH description: %s\n", function, getDescription(sehCode));
+        jclass logClass = env->FindClass("org/jetbrains/skiko/RenderExceptionsHandler");
+        jmethodID logMethod = env->GetStaticMethodID(logClass, "logAndThrow", "(Ljava/lang/String;)V");
         env->CallStaticVoidMethod(logClass, logMethod, env->NewStringUTF(buffer));
     }
 }