/*

 * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.

 * 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 "jni.h"

#include "classfile/symbolTable.hpp"

#include "classfile/systemDictionary.hpp"

#include "classfile/vmSymbols.hpp"

#include "jfr/jni/jfrJavaSupport.hpp"

#include "jfr/recorder/storage/jfrStorage.hpp"

#include "jfr/support/jfrThreadId.hpp"

#include "jfr/utilities/jfrTypes.hpp"

#include "jfr/writers/jfrJavaEventWriter.hpp"

#include "oops/instanceKlass.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/fieldDescriptor.inline.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/jniHandles.inline.hpp"

#include "runtime/thread.inline.hpp"

static int start_pos_offset = invalid_offset;

static int start_pos_address_offset = invalid_offset;

static int current_pos_offset = invalid_offset;

static int max_pos_offset = invalid_offset;

static int max_event_size_offset = invalid_offset;

static int notified_offset = invalid_offset;

static int thread_id_offset = invalid_offset;

static int valid_offset = invalid_offset;

static bool find_field(InstanceKlass* ik,

                       Symbol* name_symbol,

                       Symbol* signature_symbol,

                       fieldDescriptor* fd,

                       bool is_static = false,

                       bool allow_super = false) {

  if (allow_super || is_static) {

    return ik->find_field(name_symbol, signature_symbol, is_static, fd) != NULL;

  } else {

    return ik->find_local_field(name_symbol, signature_symbol, fd);

  }

}

static void compute_offset(int &dest_offset,

                           Klass* klass,

                           Symbol* name_symbol,

                           Symbol* signature_symbol,

                           bool is_static = false, bool allow_super = false) {

  fieldDescriptor fd;

  InstanceKlass* ik = InstanceKlass::cast(klass);

  if (!find_field(ik, name_symbol, signature_symbol, &fd, is_static, allow_super)) {

    assert(false, "invariant");

  }

  dest_offset = fd.offset();

}

static bool setup_event_writer_offsets(TRAPS) {

  const char class_name[] = "jdk/jfr/internal/EventWriter";

  Symbol* const k_sym = SymbolTable::new_symbol(class_name);

  assert(k_sym != NULL, "invariant");

  Klass* klass = SystemDictionary::resolve_or_fail(k_sym, true, CHECK_false);

  assert(klass != NULL, "invariant");

  const char start_pos_name[] = "startPosition";

  Symbol* const start_pos_sym = SymbolTable::new_symbol(start_pos_name);

  assert(start_pos_sym != NULL, "invariant");

  assert(invalid_offset == start_pos_offset, "invariant");

  compute_offset(start_pos_offset, klass, start_pos_sym, vmSymbols::long_signature());

  assert(start_pos_offset != invalid_offset, "invariant");

  const char start_pos_address_name[] = "startPositionAddress";

  Symbol* const start_pos_address_sym = SymbolTable::new_symbol(start_pos_address_name);

  assert(start_pos_address_sym != NULL, "invariant");

  assert(invalid_offset == start_pos_address_offset, "invariant");

  compute_offset(start_pos_address_offset, klass, start_pos_address_sym, vmSymbols::long_signature());

  assert(start_pos_address_offset != invalid_offset, "invariant");

  const char event_pos_name[] = "currentPosition";

  Symbol* const event_pos_sym = SymbolTable::new_symbol(event_pos_name);

  assert(event_pos_sym != NULL, "invariant");

  assert(invalid_offset == current_pos_offset, "invariant");

  compute_offset(current_pos_offset, klass, event_pos_sym,vmSymbols::long_signature());

  assert(current_pos_offset != invalid_offset, "invariant");

  const char max_pos_name[] = "maxPosition";

  Symbol* const max_pos_sym = SymbolTable::new_symbol(max_pos_name);

  assert(max_pos_sym != NULL, "invariant");

  assert(invalid_offset == max_pos_offset, "invariant");

  compute_offset(max_pos_offset, klass, max_pos_sym, vmSymbols::long_signature());

  assert(max_pos_offset != invalid_offset, "invariant");

  const char max_event_size_name[] = "maxEventSize";

  Symbol* const max_event_size_sym = SymbolTable::new_symbol(max_event_size_name);

  assert (max_event_size_sym != NULL, "invariant");

  assert(invalid_offset == max_event_size_offset, "invariant");

  compute_offset(max_event_size_offset, klass, max_event_size_sym, vmSymbols::int_signature());

  assert(max_event_size_offset != invalid_offset, "invariant");

  const char notified_name[] = "notified";

  Symbol* const notified_sym = SymbolTable::new_symbol(notified_name);

  assert (notified_sym != NULL, "invariant");

  assert(invalid_offset == notified_offset, "invariant");

  compute_offset(notified_offset, klass, notified_sym, vmSymbols::bool_signature());

  assert(notified_offset != invalid_offset, "invariant");

  const char valid_name[] = "valid";

  Symbol* const valid_sym = SymbolTable::new_symbol(valid_name);

  assert (valid_sym != NULL, "invariant");

  assert(invalid_offset == valid_offset, "invariant");

  compute_offset(valid_offset, klass, valid_sym, vmSymbols::bool_signature());

  assert(valid_offset != invalid_offset, "invariant");

  return true;

}

bool JfrJavaEventWriter::initialize() {

  static bool initialized = false;

  if (!initialized) {

  }

  return initialized;

}

jboolean JfrJavaEventWriter::flush(jobject writer, jint used, jint requested, JavaThread* jt) {

  DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt));

  assert(writer != NULL, "invariant");

  oop const w = JNIHandles::resolve_non_null(writer);

  assert(w != NULL, "invariant");

  JfrBuffer* const current = jt->jfr_thread_local()->java_buffer();

  assert(current != NULL, "invariant");

  JfrBuffer* const buffer = JfrStorage::flush(current, used, requested, false, jt);

  assert(buffer != NULL, "invariant");

  // "validity" is contextually defined here to mean

  // that some memory location was provided that is

  // large enough to accommodate the "requested size".

  const bool is_valid = buffer->free_size() >= (size_t)(used + requested);

  u1* const new_current_position = is_valid ? buffer->pos() + used : buffer->pos();

  w->long_field_put(start_pos_offset, (jlong)buffer->pos());

  w->long_field_put(current_pos_offset, (jlong)new_current_position);

  // only update java writer if underlying memory changed

  if (buffer != current) {

    w->long_field_put(start_pos_address_offset, (jlong)buffer->pos_address());

    w->long_field_put(max_pos_offset, (jlong)buffer->end());

  }

  if (!is_valid) {

    // mark writer as invalid for this write attempt

    w->release_bool_field_put(valid_offset, JNI_FALSE);

    return JNI_FALSE;

  }

  // An exclusive use of a leased buffer is treated equivalent to

  // holding a system resource. As such, it should be released as soon as possible.

  // Returning true here signals that the thread will need to call flush again

  // on EventWriter.endEvent() and that flush will return the lease.

  return buffer->lease() ? JNI_TRUE : JNI_FALSE;

}

class JfrJavaEventWriterNotificationClosure : public ThreadClosure {

 public:

   void do_thread(Thread* t) {

     if (t->is_Java_thread()) {

       JfrJavaEventWriter::notify((JavaThread*)t);

     }

   }

};

void JfrJavaEventWriter::notify() {

  assert(SafepointSynchronize::is_at_safepoint(), "invariant");

  JfrJavaEventWriterNotificationClosure closure;

  Threads::threads_do(&closure);

}

void JfrJavaEventWriter::notify(JavaThread* jt) {

  assert(jt != NULL, "invariant");

  assert(SafepointSynchronize::is_at_safepoint(), "invariant");

  if (jt->jfr_thread_local()->has_java_event_writer()) {

    oop buffer_writer = JNIHandles::resolve_non_null(jt->jfr_thread_local()->java_event_writer());

    assert(buffer_writer != NULL, "invariant");

    buffer_writer->release_bool_field_put(notified_offset, JNI_TRUE);

  }

}

static jobject create_new_event_writer(JfrBuffer* buffer, TRAPS) {

  assert(buffer != NULL, "invariant");

  DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));

  HandleMark hm(THREAD);

  static const char klass[] = "jdk/jfr/internal/EventWriter";

  static const char method[] = "<init>";

  static const char signature[] = "(JJJJZ)V";

  JavaValue result(T_OBJECT);

  JfrJavaArguments args(&result, klass, method, signature, CHECK_NULL);

  // parameters

  args.push_long((jlong)buffer->pos());

  args.push_long((jlong)buffer->end());

  args.push_long((jlong)buffer->pos_address());

  args.push_long((jlong)JFR_THREAD_ID(THREAD));

  args.push_int((int)JNI_TRUE);

  JfrJavaSupport::new_object_global_ref(&args, CHECK_NULL);

  return result.get_jobject();

}

jobject JfrJavaEventWriter::event_writer(Thread* t) {

  DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(t));

  JfrThreadLocal* const tl = t->jfr_thread_local();

  assert(tl->shelved_buffer() == NULL, "invariant");

  return tl->java_event_writer();

}

jobject JfrJavaEventWriter::new_event_writer(TRAPS) {

  DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));

  assert(event_writer(THREAD) == NULL, "invariant");

  JfrThreadLocal* const tl = THREAD->jfr_thread_local();

  assert(!tl->has_java_buffer(), "invariant");

  JfrBuffer* const buffer = tl->java_buffer();

  if (buffer == NULL) {

    JfrJavaSupport::throw_out_of_memory_error("OOME for thread local buffer", THREAD);

    return NULL;

  }

  jobject java_event_writer = create_new_event_writer(buffer, CHECK_NULL);

  tl->set_java_event_writer(java_event_writer);

  assert(tl->has_java_event_writer(), "invariant");

  return java_event_writer;

}