/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "logging/log.hpp"

#include "memory/iterator.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/jniHandles.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/thread.inline.hpp"

#include "trace/traceMacros.hpp"

#include "utilities/align.hpp"

#if INCLUDE_ALL_GCS

#include "gc/g1/g1SATBCardTableModRefBS.hpp"

#endif

jobject JNIHandles::make_local(oop obj) {

  if (obj == NULL) {

    return NULL;                // ignore null handles

  } else {

    Thread* thread = Thread::current();

    assert(!current_thread_in_native(), "must not be in native");

    return thread->active_handles()->allocate_handle(obj);

  }

}

// optimized versions

jobject JNIHandles::make_local(Thread* thread, oop obj) {

  if (obj == NULL) {

    return NULL;                // ignore null handles

  } else {

    assert(thread->is_Java_thread(), "not a Java thread");

    assert(!current_thread_in_native(), "must not be in native");

    return thread->active_handles()->allocate_handle(obj);

  }

}

jobject JNIHandles::make_local(JNIEnv* env, oop obj) {

  if (obj == NULL) {

    return NULL;                // ignore null handles

  } else {

    JavaThread* thread = JavaThread::thread_from_jni_environment(env);

    assert(!current_thread_in_native(), "must not be in native");

    return thread->active_handles()->allocate_handle(obj);

  }

}

  assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC");

  assert(!current_thread_in_native(), "must not be in native");

  jobject res = NULL;

  if (!obj.is_null()) {

    // ignore null handles

  } else {

    CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());

  }

  return res;

}

  assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC");

  assert(!current_thread_in_native(), "must not be in native");

  jobject res = NULL;

  if (!obj.is_null()) {

    // ignore null handles

    }

  } else {

    CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());

  }

  return res;

}

oop JNIHandles::resolve_jweak(jweak handle) {

  assert(is_jweak(handle), "precondition");

  oop result = jweak_ref(handle);

#if INCLUDE_ALL_GCS

  if (result != NULL && UseG1GC) {

    G1SATBCardTableModRefBS::enqueue(result);

  }

#endif // INCLUDE_ALL_GCS

  return result;

}

bool JNIHandles::is_global_weak_cleared(jweak handle) {

  assert(is_jweak(handle), "not a weak handle");

}

void JNIHandles::destroy_global(jobject handle) {

  if (handle != NULL) {

  }

}

void JNIHandles::destroy_weak_global(jobject handle) {

  if (handle != NULL) {

  }

}

void JNIHandles::oops_do(OopClosure* f) {

  _global_handles->oops_do(f);

}

void JNIHandles::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {

  _weak_global_handles->weak_oops_do(is_alive, f);

}

void JNIHandles::weak_oops_do(OopClosure* f) {

}

void JNIHandles::initialize() {

}

bool JNIHandles::is_local_handle(Thread* thread, jobject handle) {

  JNIHandleBlock* block = thread->active_handles();

  // Look back past possible native calls to jni_PushLocalFrame.

  while (block != NULL) {

    if (block->chain_contains(handle)) {

      return true;

    }

    block = block->pop_frame_link();

  }

  return false;

}

// Determine if the handle is somewhere in the current thread's stack.

// We easily can't isolate any particular stack frame the handle might

// come from, so we'll check the whole stack.

bool JNIHandles::is_frame_handle(JavaThread* thr, jobject obj) {

  // If there is no java frame, then this must be top level code, such

  // as the java command executable, in which case, this type of handle

  // is not permitted.

  return (thr->has_last_Java_frame() &&

         (void*)obj < (void*)thr->stack_base() &&

         (void*)obj >= (void*)thr->last_Java_sp());

}

bool JNIHandles::is_global_handle(jobject handle) {

}

bool JNIHandles::is_weak_global_handle(jobject handle) {

}

// We assume this is called at a safepoint: no lock is needed.

void JNIHandles::print_on(outputStream* st) {

  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");

  assert(_global_handles != NULL && _weak_global_handles != NULL,

         "JNIHandles not initialized");

  st->cr();

  st->flush();

}

public:

  virtual void do_oop(oop* root) {

    (*root)->verify();

  }

  virtual void do_oop(narrowOop* root) { ShouldNotReachHere(); }

};

void JNIHandles::verify() {

  oops_do(&verify_handle);

  weak_oops_do(&verify_handle);

}

// This method is implemented here to avoid circular includes between

// jniHandles.hpp and thread.hpp.

bool JNIHandles::current_thread_in_native() {

  Thread* thread = Thread::current();

  return (thread->is_Java_thread() &&

          JavaThread::current()->thread_state() == _thread_in_native);

}

void jni_handles_init() {

  JNIHandles::initialize();

}

int             JNIHandleBlock::_blocks_allocated     = 0;

JNIHandleBlock* JNIHandleBlock::_block_free_list      = NULL;

#ifndef PRODUCT

JNIHandleBlock* JNIHandleBlock::_block_list           = NULL;

#endif

#ifdef ASSERT

void JNIHandleBlock::zap() {

  // Zap block values

  _top = 0;

  for (int index = 0; index < block_size_in_oops; index++) {

    _handles[index] = NULL;

  }

}

#endif // ASSERT

JNIHandleBlock* JNIHandleBlock::allocate_block(Thread* thread)  {

  assert(thread == NULL || thread == Thread::current(), "sanity check");

  JNIHandleBlock* block;

  // Check the thread-local free list for a block so we don't

  // have to acquire a mutex.

  if (thread != NULL && thread->free_handle_block() != NULL) {

    block = thread->free_handle_block();

    thread->set_free_handle_block(block->_next);

  }

  else {

    // locking with safepoint checking introduces a potential deadlock:

    // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock

    // - another would hold Threads_lock (jni_AttachCurrentThread) and then

    //   JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block)

    MutexLockerEx ml(JNIHandleBlockFreeList_lock,

                     Mutex::_no_safepoint_check_flag);

    if (_block_free_list == NULL) {

      // Allocate new block

      block = new JNIHandleBlock();

      _blocks_allocated++;

      block->zap();

      #ifndef PRODUCT

      // Link new block to list of all allocated blocks

      block->_block_list_link = _block_list;

      _block_list = block;

      #endif

    } else {

      // Get block from free list

      block = _block_free_list;

      _block_free_list = _block_free_list->_next;

    }

  }

  block->_top = 0;

  block->_next = NULL;

  block->_pop_frame_link = NULL;

  block->_planned_capacity = block_size_in_oops;

  // _last, _free_list & _allocate_before_rebuild initialized in allocate_handle

  debug_only(block->_last = NULL);

  debug_only(block->_free_list = NULL);

  debug_only(block->_allocate_before_rebuild = -1);

  return block;

}

void JNIHandleBlock::release_block(JNIHandleBlock* block, Thread* thread) {

  assert(thread == NULL || thread == Thread::current(), "sanity check");

  JNIHandleBlock* pop_frame_link = block->pop_frame_link();

  // Put returned block at the beginning of the thread-local free list.

  // Note that if thread == NULL, we use it as an implicit argument that

  // we _don't_ want the block to be kept on the free_handle_block.

  // See for instance JavaThread::exit().

  if (thread != NULL ) {

    block->zap();

    JNIHandleBlock* freelist = thread->free_handle_block();

    block->_pop_frame_link = NULL;

    thread->set_free_handle_block(block);

    // Add original freelist to end of chain

    if ( freelist != NULL ) {

      while ( block->_next != NULL ) block = block->_next;

      block->_next = freelist;

    }

    block = NULL;

  }

  if (block != NULL) {

    // Return blocks to free list

    // locking with safepoint checking introduces a potential deadlock:

    // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock

    // - another would hold Threads_lock (jni_AttachCurrentThread) and then

    //   JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block)

    MutexLockerEx ml(JNIHandleBlockFreeList_lock,

                     Mutex::_no_safepoint_check_flag);

    while (block != NULL) {

      block->zap();

      JNIHandleBlock* next = block->_next;

      block->_next = _block_free_list;

      _block_free_list = block;

      block = next;

    }

  }

  if (pop_frame_link != NULL) {

    // As a sanity check we release blocks pointed to by the pop_frame_link.

    // This should never happen (only if PopLocalFrame is not called the

    // correct number of times).

    release_block(pop_frame_link, thread);

  }

}

void JNIHandleBlock::oops_do(OopClosure* f) {

  JNIHandleBlock* current_chain = this;

  // Iterate over chain of blocks, followed by chains linked through the

  // pop frame links.

  while (current_chain != NULL) {

    for (JNIHandleBlock* current = current_chain; current != NULL;

         current = current->_next) {

      assert(current == current_chain || current->pop_frame_link() == NULL,

        "only blocks first in chain should have pop frame link set");

      for (int index = 0; index < current->_top; index++) {

        oop* root = &(current->_handles)[index];

        oop value = *root;

        // traverse heap pointers only, not deleted handles or free list

        // pointers

        if (value != NULL && Universe::heap()->is_in_reserved(value)) {

          f->do_oop(root);

        }

      }

      // the next handle block is valid only if current block is full

      if (current->_top < block_size_in_oops) {

        break;

      }

    }

    current_chain = current_chain->pop_frame_link();

  }

}

jobject JNIHandleBlock::allocate_handle(oop obj) {

  assert(Universe::heap()->is_in_reserved(obj), "sanity check");

  if (_top == 0) {

    // This is the first allocation or the initial block got zapped when

    // entering a native function. If we have any following blocks they are

    // not valid anymore.

    for (JNIHandleBlock* current = _next; current != NULL;

         current = current->_next) {

      assert(current->_last == NULL, "only first block should have _last set");

      assert(current->_free_list == NULL,

             "only first block should have _free_list set");

      if (current->_top == 0) {

        // All blocks after the first clear trailing block are already cleared.

#ifdef ASSERT

        for (current = current->_next; current != NULL; current = current->_next) {

          assert(current->_top == 0, "trailing blocks must already be cleared");

        }

#endif

        break;

      }

      current->_top = 0;

      current->zap();

    }

    // Clear initial block

    _free_list = NULL;

    _allocate_before_rebuild = 0;

    _last = this;

    zap();

  }

  // Try last block

  if (_last->_top < block_size_in_oops) {

    oop* handle = &(_last->_handles)[_last->_top++];

    *handle = obj;

    return (jobject) handle;

  }

  // Try free list

  if (_free_list != NULL) {

    oop* handle = _free_list;

    _free_list = (oop*) *_free_list;

    *handle = obj;

    return (jobject) handle;

  }

  // Check if unused block follow last

  if (_last->_next != NULL) {

    // update last and retry

    _last = _last->_next;

    return allocate_handle(obj);

  }

  // No space available, we have to rebuild free list or expand

  if (_allocate_before_rebuild == 0) {

      rebuild_free_list();        // updates _allocate_before_rebuild counter

  } else {