/*
 * Copyright (c) 2012, 2020, 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 "classfile/classFileStream.hpp"
#include "classfile/dictionary.hpp"
#include "classfile/javaClasses.inline.hpp"
#include "classfile/klassFactory.hpp"
#include "classfile/systemDictionaryShared.hpp"
#include "classfile/vmSymbols.hpp"
#include "memory/lambdaFormInvokers.hpp"
#include "memory/allocation.hpp"
#include "logging/log.hpp"
#include "memory/oopFactory.hpp"
#include "memory/metaspaceShared.hpp"
#include "memory/resourceArea.hpp"
#include "oops/instanceKlass.hpp"
#include "oops/klass.hpp"
#include "oops/objArrayKlass.hpp"
#include "oops/objArrayOop.hpp"
#include "oops/oop.inline.hpp"
#include "oops/typeArrayKlass.hpp"
#include "oops/typeArrayOop.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/os.hpp"
#include "runtime/signature.hpp"
#include "utilities/exceptions.hpp"

GrowableArray<char*>* LambdaFormInvokers::_lambdaform_lines = NULL;
GrowableArray<Klass*>* LambdaFormInvokers::_replacement_holder_classes = NULL;

void LambdaFormInvokers::append(char* line) {
  if (_lambdaform_lines == NULL) {
    _lambdaform_lines = new GrowableArray<char*>(100);
    _replacement_holder_classes = new (ResourceObj::C_HEAP, mtClassShared) GrowableArray<Klass*>(12, mtClassShared);
  }
  _lambdaform_lines->append(line);
}

void LambdaFormInvokers::regenerate_holder_classes(TRAPS) {
  assert(_lambdaform_lines != NULL, "Bad List");
  ResourceMark rm(THREAD);

  Symbol* helper_name  = vmSymbols::java_lang_invoke_GenerateJLIClassesHelper();
  Klass*  helper_klass = SystemDictionary::resolve_or_null(helper_name, THREAD);
  guarantee(helper_klass != NULL, "java/lang/invoke/GenerateJLIClassesHelper exist!");

  int len = _lambdaform_lines->length();
  objArrayHandle list_lines = oopFactory::new_objArray_handle(SystemDictionary::String_klass(), len, CHECK);
  for (int i = 0; i < len; i++) {
    char* record = _lambdaform_lines->at(i);
    record += strlen(lambda_form_invoker_tag()) + 1; // @lambda_form_invoker [...]
    Handle h_line = java_lang_String::create_from_str(record, CHECK);
    list_lines->obj_at_put(i, h_line());
  }

  //
  // Object[] InvokerBytecodeGeneratorHelper.generateMethodHandleHolderClasses(String[] lines)
  // the returned Object[] layout:
  //   name, byte[], name, byte[] ....
  Symbol* method = vmSymbols::generateMethodHandleHolderClasses();
  Symbol* signrs = vmSymbols::generateMethodHandleHolderClasses_signature();

  JavaValue result(T_OBJECT);
  JavaCalls::call_static(&result, helper_klass, method, signrs, list_lines, THREAD);
  objArrayHandle h_array(THREAD, (objArrayOop)result.get_jobject());
  if (!HAS_PENDING_EXCEPTION) {
    if (h_array() == NULL) {
      log_info(cds)("Failed call to %s.%s", helper_name->as_C_string(), method->as_C_string());
      return;
    }
  } else {
    log_info(cds)("Exception happened: %s", PENDING_EXCEPTION->klass()->name()->as_C_string());
    CLEAR_PENDING_EXCEPTION;
    return;
  }

  int sz = h_array->length();
  assert(sz % 2 == 0 && sz >= 2, "Must be even size of length");
  for (int i = 0; i < sz; i+= 2) {
    Handle h_name(THREAD, h_array->obj_at(i));
    typeArrayHandle h_bytes(THREAD, (typeArrayOop)h_array->obj_at(i+1));
    assert(h_name != NULL, "Class name is NULL");
    assert(h_bytes != NULL, "Class bytes is NULL");
    reload_class(h_name, h_bytes, THREAD);
  }

}

// the format maybe of "/java.base/package/class_name.class"
char* get_full_class_name(char* path_name) {
  char* end = strstr(path_name, ".class");
  if (end == NULL) {
   end = path_name + strlen(path_name);
  }
  char* start = strstr(path_name, "/java.base/");
 if (start == NULL) {
    start = path_name;
  } else {
    start = path_name + strlen("/java.base/");
  }
  assert(start < end, "Sanity check");
  size_t size = end - start + 1;

  char* full_name = (char*)os::malloc(size, mtInternal);
  size_t i = 0;
  while (i < size) {
    full_name[i++] = *start++;
  }
  full_name[size - 1] = '\0';
  return full_name;
}

// class_handle - the class full name, bytes_handle - the class bytes
void LambdaFormInvokers::reload_class(Handle name_handle, typeArrayHandle bytes_handle, TRAPS) {
  char* path_name = java_lang_String::as_utf8_string(name_handle());
  char* class_name = get_full_class_name(path_name);
  Symbol* sym = SymbolTable::probe((const char*)class_name, (int)strlen(class_name));
  assert(sym != NULL, "The class should be loaded already");
  // the class must exist
  Klass* klass = SystemDictionary::resolve_or_null(sym, THREAD);
  if (klass == NULL) {
    log_info(cds)("Class %s not present, skip", class_name);
    return;
  }

  int len = bytes_handle->length();
  // make a copy of class bytes so GC will not affect us.
  char *buf = resource_allocate_bytes(THREAD, len);
  memcpy(buf, (char*)bytes_handle->byte_at_addr(0), len);
  ClassFileStream st((u1*)buf, len, NULL, ClassFileStream::verify);
  ClassLoaderData* cld = ClassLoaderData::the_null_class_loader_data();
  Handle protection_domain;
  ClassLoadInfo cl_info(protection_domain);

  Klass* result = KlassFactory::create_from_stream(&st,
                                                   sym,
                                                   cld,
                                                   cl_info,
                                                   CHECK);

  // free buf
  resource_free_bytes(buf, len); 
  if (HAS_PENDING_EXCEPTION) {
    log_info(cds)("Exception happened: %s", PENDING_EXCEPTION->klass()->name()->as_C_string());
    log_info(cds)("Could not create InstanceKlass for class %s", class_name);
    CLEAR_PENDING_EXCEPTION;
    return;
  }

  // add to hierarchy and set state to loaded.
  {
    MutexLocker mu_r(THREAD, Compile_lock); // add_shared_to_hierarchy asserts this.
    SystemDictionaryShared::add_shared_to_hierarchy(InstanceKlass::cast(result), THREAD);
  }
  // new class not linked yet.
  MetaspaceShared::try_link_class(InstanceKlass::cast(result), THREAD);
  assert(!HAS_PENDING_EXCEPTION, "Invariant");

  assert(_replacement_holder_classes != NULL, "Should be created already");
  _replacement_holder_classes->append(result);

  // exclude the existing class from dump list
  Klass* old = cld->find_class(sym);
  assert(old->is_instance_klass(), "Invariant");
  SystemDictionaryShared::set_excluded(InstanceKlass::cast(old));
  log_info(cds)("Replace class %s, old: %p  new: %p", class_name, old, result);
}