jsj_class.c

caffeine-monkey java实现的js模拟引擎

    if (!java_class) {
        jsj_UnexpectedJavaError(cx, jEnv, "Unable to reference Java class");
        goto error;
    }
    class_descriptor->java_class = java_class;

    if (!compute_java_class_signature(cx, jEnv, class_descriptor))
        goto error;

    class_descriptor->modifiers =
        (*jEnv)->CallIntMethod(jEnv, java_class, jlClass_getModifiers);
    class_descriptor->ref_count = 1;

    if (!JSJ_HashTableAdd(java_class_reflections, java_class, class_descriptor,
                          (void*)jEnv))
        goto error;

    return class_descriptor;

error:
    destroy_class_descriptor(cx, jEnv, class_descriptor);
    return NULL;
}

/* Trivial helper for jsj_DiscardJavaClassReflections(), below */
JS_STATIC_DLL_CALLBACK(JSIntn)
enumerate_remove_java_class(JSJHashEntry *he, JSIntn i, void *arg)
{
    JSJavaThreadState *jsj_env = (JSJavaThreadState *)arg;
    JavaClassDescriptor *class_descriptor;

    class_descriptor = (JavaClassDescriptor*)he->value;

    destroy_class_descriptor(jsj_env->cx, jsj_env->jEnv, class_descriptor);

    return HT_ENUMERATE_REMOVE;
}

/* This shutdown routine discards all JNI references to Java objects
   that have been reflected into JS, even if there are still references
   to them from JS. */
void
jsj_DiscardJavaClassReflections(JNIEnv *jEnv)
{
    JSJavaThreadState *jsj_env;
    char *err_msg;
    JSContext *cx;

    /* Get the per-thread state corresponding to the current Java thread */
    jsj_env = jsj_MapJavaThreadToJSJavaThreadState(jEnv, &err_msg);
    JS_ASSERT(jsj_env);
    if (!jsj_env)
        return;

    /* Get the JSContext that we're supposed to use for this Java thread */
    cx = jsj_env->cx;
    if (!cx) {
        /* We called spontaneously into JS from Java, rather than from JS into
           Java and back into JS.  Invoke a callback to obtain/create a
           JSContext for us to use. */
        if (JSJ_callbacks->map_jsj_thread_to_js_context) {
#ifdef OJI
            cx = JSJ_callbacks->map_jsj_thread_to_js_context(jsj_env,
                                                             NULL, /* FIXME: What should this argument be ? */
                                                             jEnv, &err_msg);
#else
            cx = JSJ_callbacks->map_jsj_thread_to_js_context(jsj_env,
                                                             jEnv, &err_msg);
#endif
            if (!cx)
                return;
        } else {
            err_msg = JS_smprintf("Unable to find/create JavaScript execution "
                                  "context for JNI thread 0x%08x", jEnv);
            jsj_LogError(err_msg);
            free(err_msg);
            return;
        }
    }

    if (java_class_reflections) {
        JSJ_HashTableEnumerateEntries(java_class_reflections,
                                      enumerate_remove_java_class,
                                      (void*)jsj_env);
        JSJ_HashTableDestroy(java_class_reflections);
        java_class_reflections = NULL;
    }
}

extern JavaClassDescriptor *
jsj_GetJavaClassDescriptor(JSContext *cx, JNIEnv *jEnv, jclass java_class)
{
    JavaClassDescriptor *class_descriptor = NULL;

#ifdef JSJ_THREADSAFE
    PR_EnterMonitor(java_class_reflections_monitor);
#endif

    if (java_class_reflections) {
        class_descriptor = JSJ_HashTableLookup(java_class_reflections,
                                               (const void *)java_class,
                                               (void*)jEnv);
    }
    if (!class_descriptor) {
        class_descriptor = new_class_descriptor(cx, jEnv, java_class);

#ifdef JSJ_THREADSAFE
        PR_ExitMonitor(java_class_reflections_monitor);
#endif
        return class_descriptor;
    }

#ifdef JSJ_THREADSAFE
    PR_ExitMonitor(java_class_reflections_monitor);
#endif

    JS_ASSERT(class_descriptor->ref_count > 0);
    class_descriptor->ref_count++;
    return class_descriptor;
}

void
jsj_ReleaseJavaClassDescriptor(JSContext *cx, JNIEnv *jEnv, JavaClassDescriptor *class_descriptor)
{
#if 0
    /* The ref-counting code doesn't work very well because cycles in the data
       structures routinely lead to uncollectible JavaClassDescriptor's.  Skip it. */
    JS_ASSERT(class_descriptor->ref_count >= 1);
    if (!--class_descriptor->ref_count) {
        JSJ_HashTableRemove(java_class_reflections,
                            class_descriptor->java_class, (void*)jEnv);
        destroy_class_descriptor(cx, jEnv, class_descriptor);
    }
#endif
}

#ifdef JSJ_THREADSAFE
static PRMonitor *java_reflect_monitor = NULL;
#endif

static JSBool
reflect_java_methods_and_fields(JSContext *cx,
                                JNIEnv *jEnv,
                                JavaClassDescriptor *class_descriptor,
                                JSBool reflect_statics_only)
{
    JavaMemberDescriptor *member_descriptor;
    JSBool success;

    success = JS_TRUE;  /* optimism */

#ifdef JSJ_THREADSAFE
    PR_EnterMonitor(java_reflect_monitor);
#endif

    /* See if we raced with another thread to reflect members of this class.
       If the status is REFLECT_COMPLETE, another thread beat us to it.  If
       the status is REFLECT_IN_PROGRESS, we've recursively called this
       function within a single thread.  Either way, we're done. */
    if (reflect_statics_only) {
        if (class_descriptor->static_members_reflected != REFLECT_NO)
            goto done;
        class_descriptor->static_members_reflected = REFLECT_IN_PROGRESS;
    } else {
        if (class_descriptor->instance_members_reflected != REFLECT_NO)
            goto done;
        class_descriptor->instance_members_reflected = REFLECT_IN_PROGRESS;
    }
    
    if (!jsj_ReflectJavaMethods(cx, jEnv, class_descriptor, reflect_statics_only))
        goto error;
    if (!jsj_ReflectJavaFields(cx, jEnv, class_descriptor, reflect_statics_only))
        goto error;

    if (reflect_statics_only) {
        member_descriptor = class_descriptor->static_members;
        while (member_descriptor) {
            class_descriptor->num_static_members++;
            member_descriptor = member_descriptor->next;
        }
        class_descriptor->static_members_reflected = REFLECT_COMPLETE;
    } else {
        member_descriptor = class_descriptor->instance_members;
        while (member_descriptor) {
            class_descriptor->num_instance_members++;
            member_descriptor = member_descriptor->next;
        }
        class_descriptor->instance_members_reflected = REFLECT_COMPLETE;
    }

done:
#ifdef JSJ_THREADSAFE
    PR_ExitMonitor(java_reflect_monitor);
#endif
    return success;

error:
    success = JS_FALSE;
    goto done;
}

JavaMemberDescriptor *
jsj_GetClassStaticMembers(JSContext *cx,
                          JNIEnv *jEnv,
                          JavaClassDescriptor *class_descriptor)
{
    if (class_descriptor->static_members_reflected != REFLECT_COMPLETE)
        reflect_java_methods_and_fields(cx, jEnv, class_descriptor, JS_TRUE);
    return class_descriptor->static_members;
}

JavaMemberDescriptor *
jsj_GetClassInstanceMembers(JSContext *cx,
                            JNIEnv *jEnv,
                            JavaClassDescriptor *class_descriptor)
{
    if (class_descriptor->instance_members_reflected != REFLECT_COMPLETE)
        reflect_java_methods_and_fields(cx, jEnv, class_descriptor, JS_FALSE);
    return class_descriptor->instance_members;
}

JavaMemberDescriptor *
jsj_LookupJavaStaticMemberDescriptorById(JSContext *cx,
                                         JNIEnv *jEnv,
                                         JavaClassDescriptor *class_descriptor,
                                         jsid id)
{
    JavaMemberDescriptor *member_descriptor;

    member_descriptor = jsj_GetClassStaticMembers(cx, jEnv, class_descriptor);
    while (member_descriptor) {
        if (id == member_descriptor->id)
            return member_descriptor;
        member_descriptor = member_descriptor->next;
    }
    return NULL;
}

JavaMemberDescriptor *
jsj_GetJavaStaticMemberDescriptor(JSContext *cx,
                                  JNIEnv *jEnv, 
                                  JavaClassDescriptor *class_descriptor,
                                  jstring member_name_jstr)
{
    JavaMemberDescriptor *member_descriptor;
    jsid id;

    if (!JavaStringToId(cx, jEnv, member_name_jstr, &id))
        return NULL;

    member_descriptor = jsj_LookupJavaStaticMemberDescriptorById(cx, jEnv, class_descriptor, id);
    if (member_descriptor)
        return member_descriptor;

    member_descriptor = JS_malloc(cx, sizeof(JavaMemberDescriptor));
    if (!member_descriptor)
        return NULL;
    memset(member_descriptor, 0, sizeof(JavaMemberDescriptor));

    member_descriptor->name = jsj_DupJavaStringUTF(cx, jEnv, member_name_jstr);
    if (!member_descriptor->name) {
        JS_free(cx, member_descriptor);
        return NULL;
    }
    member_descriptor->id = id;

    member_descriptor->next = class_descriptor->static_members;
    class_descriptor->static_members = member_descriptor;

    return member_descriptor;
}

JavaMemberDescriptor *
jsj_GetJavaClassConstructors(JSContext *cx,
                             JavaClassDescriptor *class_descriptor)
{
    JavaMemberDescriptor *member_descriptor;

    if (class_descriptor->constructors)
        return class_descriptor->constructors;

    member_descriptor = JS_malloc(cx, sizeof(JavaMemberDescriptor));
    if (!member_descriptor)
        return NULL;
    memset(member_descriptor, 0, sizeof(JavaMemberDescriptor));

    member_descriptor->name = JS_strdup(cx, "<init>");
    if (!member_descriptor->name) {
        JS_free(cx, member_descriptor);
        return NULL;
    }

    class_descriptor->constructors = member_descriptor;

    return member_descriptor;
}

JavaMemberDescriptor *
jsj_LookupJavaClassConstructors(JSContext *cx, JNIEnv *jEnv,
                                JavaClassDescriptor *class_descriptor)
{
    if (class_descriptor->static_members_reflected != REFLECT_COMPLETE)
        reflect_java_methods_and_fields(cx, jEnv, class_descriptor, JS_TRUE);
    return class_descriptor->constructors;
}

JavaMemberDescriptor *
jsj_LookupJavaMemberDescriptorById(JSContext *cx, JNIEnv *jEnv,
                                   JavaClassDescriptor *class_descriptor,
                                   jsid id)
{
    JavaMemberDescriptor *member_descriptor;

    member_descriptor = jsj_GetClassInstanceMembers(cx, jEnv, class_descriptor);
    while (member_descriptor) {
        if (id == member_descriptor->id)
            return member_descriptor;
        member_descriptor = member_descriptor->next;
    }
    return NULL;
}

JavaMemberDescriptor *
jsj_GetJavaMemberDescriptor(JSContext *cx,
                            JNIEnv *jEnv, 
                            JavaClassDescriptor *class_descriptor,
                            jstring member_name_jstr)
{
    JavaMemberDescriptor *member_descriptor;
    jsid id;

    if (!JavaStringToId(cx, jEnv, member_name_jstr, &id))
        return NULL;

    member_descriptor = jsj_LookupJavaMemberDescriptorById(cx, jEnv, class_descriptor, id);
    if (member_descriptor)
        return member_descriptor;

    member_descriptor = JS_malloc(cx, sizeof(JavaMemberDescriptor));
    if (!member_descriptor)
        return NULL;
    memset(member_descriptor, 0, sizeof(JavaMemberDescriptor));

    member_descriptor->name = jsj_DupJavaStringUTF(cx, jEnv, member_name_jstr);
    if (!member_descriptor->name) {
        JS_free(cx, member_descriptor);
        return NULL;
    }
    member_descriptor->id = id;

    member_descriptor->next = class_descriptor->instance_members;
    class_descriptor->instance_members = member_descriptor;

    return member_descriptor;
}

JSBool
jsj_InitJavaClassReflectionsTable()
{
    if (!java_class_reflections) {
        java_class_reflections =
            JSJ_NewHashTable(64, jsj_HashJavaObject, jsj_JavaObjectComparator,
                            NULL, NULL, NULL);

        if (!java_class_reflections)
            return JS_FALSE;

#ifdef JSJ_THREADSAFE
        java_class_reflections_monitor =
                (struct PRMonitor *) PR_NewMonitor();
        if (!java_class_reflections_monitor)
            return JS_FALSE;

        java_reflect_monitor =
                (struct PRMonitor *) PR_NewMonitor();
        if (!java_reflect_monitor)
            return JS_FALSE;
#endif
    }
    
    return JS_TRUE;
}