/*
 * Copyright (c) 2005, 2018, 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/resolutionErrors.hpp"
#include "memory/resourceArea.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/safepoint.hpp"
#include "utilities/hashtable.inline.hpp"

// add new entry to the table
void ResolutionErrorTable::add_entry(int index, unsigned int hash,
                                     const constantPoolHandle& pool, int cp_index,
                                     Symbol* error, const char* message)
{
  assert_locked_or_safepoint(SystemDictionary_lock);
  assert(!pool.is_null() && error != NULL, "adding NULL obj");

  ResolutionErrorEntry* entry = new_entry(hash, pool(), cp_index, error, message);
  add_entry(index, entry);
}

// find entry in the table
ResolutionErrorEntry* ResolutionErrorTable::find_entry(int index, unsigned int hash,
                                                       const constantPoolHandle& pool, int cp_index)
{
  assert_locked_or_safepoint(SystemDictionary_lock);

  for (ResolutionErrorEntry *error_probe = bucket(index);
                         error_probe != NULL;
                         error_probe = error_probe->next()) {
  if (error_probe->hash() == hash && error_probe->pool() == pool()) {
      return error_probe;;
    }
  }
  return NULL;
}

void ResolutionErrorEntry::set_error(Symbol* e) {
  assert(e != NULL, "must set a value");
  _error = e;
  _error->increment_refcount();
}

void ResolutionErrorEntry::set_message(const char* c) {
  _message = c != NULL ? os::strdup(c) : NULL;
}

// create new error entry
ResolutionErrorEntry* ResolutionErrorTable::new_entry(int hash, ConstantPool* pool,
                                                      int cp_index, Symbol* error,
                                                      const char* message)
{
  ResolutionErrorEntry* entry = (ResolutionErrorEntry*)Hashtable<ConstantPool*, mtClass>::new_entry(hash, pool);
  entry->set_cp_index(cp_index);
  entry->set_error(error);
  entry->set_message(message);

  return entry;
}

void ResolutionErrorTable::free_entry(ResolutionErrorEntry *entry) {
  // decrement error refcount
  assert(entry->error() != NULL, "error should be set");
  entry->error()->decrement_refcount();
  if (entry->message() != NULL) {
    FREE_C_HEAP_ARRAY(char, entry->message());
  }
  Hashtable<ConstantPool*, mtClass>::free_entry(entry);
}


// create resolution error table
ResolutionErrorTable::ResolutionErrorTable(int table_size)
    : Hashtable<ConstantPool*, mtClass>(table_size, sizeof(ResolutionErrorEntry)) {
}

// RedefineClasses support - remove matching entry of a
// constant pool that is going away
void ResolutionErrorTable::delete_entry(ConstantPool* c) {
  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
  for (int i = 0; i < table_size(); i++) {
    for (ResolutionErrorEntry** p = bucket_addr(i); *p != NULL; ) {
      ResolutionErrorEntry* entry = *p;
      assert(entry->pool() != NULL, "resolution error table is corrupt");
      if (entry->pool() == c) {
        *p = entry->next();
        free_entry(entry);
      } else {
        p = entry->next_addr();
      }
    }
  }
}


// Remove unloaded entries from the table
void ResolutionErrorTable::purge_resolution_errors() {
  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
  for (int i = 0; i < table_size(); i++) {
    for (ResolutionErrorEntry** p = bucket_addr(i); *p != NULL; ) {
      ResolutionErrorEntry* entry = *p;
      assert(entry->pool() != (ConstantPool*)NULL, "resolution error table is corrupt");
      ConstantPool* pool = entry->pool();
      assert(pool->pool_holder() != NULL, "Constant pool without a class?");

      if (pool->pool_holder()->is_loader_alive()) {
        p = entry->next_addr();
      } else {
        *p = entry->next();
        free_entry(entry);
      }
    }
  }
}
