/*

 * Copyright (C) 2009 Martin Willi

 *

 * Copyright (C) secunet Security Networks AG

 *

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

 * under the terms of the GNU General Public License as published by the

 * Free Software Foundation; either version 2 of the License, or (at your

 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.

 *

 * This program 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

 * for more details.

 */

#include "cred_encoding.h"

#include <stdint.h>

#include <collections/linked_list.h>

#include <collections/hashtable.h>

#include <threading/rwlock.h>

typedef struct private_cred_encoding_t private_cred_encoding_t;

/**

 * Private data of an cred_encoding_t object.

 */

struct private_cred_encoding_t {

  /**

   * Public cred_encoding_t interface.

   */

  cred_encoding_t public;

  /**

   * cached encodings, a table for each encoding_type_t, containing chunk_t*

   */

  hashtable_t *cache[CRED_ENCODING_MAX];

  /**

   * Registered encoding functions, cred_encoder_t

   */

  linked_list_t *encoders;

  /**

   * lock to access cache/encoders

   */

  rwlock_t *lock;

};

/**

 * See header.

 */

bool cred_encoding_args(va_list args, ...)

{

  va_list parts, copy;

  bool failed = FALSE;

  va_start(parts, args);

  while (!failed)

  {

    cred_encoding_part_t current, target;

    chunk_t *out, data;

    /* get the part we are looking for */

    target = va_arg(parts, cred_encoding_part_t);

    if (target == CRED_PART_END)

    {

      break;

    }

    out = va_arg(parts, chunk_t*);

    va_copy(copy, args);

    while (!failed)

    {

      current = va_arg(copy, cred_encoding_part_t);

      if (current == CRED_PART_END)

      {

        failed = TRUE;

        break;

      }

      data = va_arg(copy, chunk_t);

      if (current == target)

      {

        *out = data;

        break;

      }

    }

    va_end(copy);

  }

  va_end(parts);

  return !failed;

}

METHOD(cred_encoding_t, get_cache, bool,

  private_cred_encoding_t *this, cred_encoding_type_t type, void *cache,

  chunk_t *encoding)

{

  chunk_t *chunk;

  if (type >= CRED_ENCODING_MAX || (int)type < 0)

  {

    return FALSE;

  }

  this->lock->read_lock(this->lock);

  chunk = this->cache[type]->get(this->cache[type], cache);

  if (chunk)

  {

    *encoding = *chunk;

  }

  this->lock->unlock(this->lock);

  return !!chunk;

}

METHOD(cred_encoding_t, cache, void,

  private_cred_encoding_t *this, cred_encoding_type_t type, void *cache,

  chunk_t *encoding)

{

  chunk_t *chunk;

  if (type >= CRED_ENCODING_MAX || (int)type < 0)

  {

    free(encoding->ptr);

    return;

  }

  this->lock->write_lock(this->lock);

  chunk = this->cache[type]->get(this->cache[type], cache);

  if (chunk)

  {

    free(encoding->ptr);

    *encoding = *chunk;

  }

  else

  {

    chunk = malloc_thing(chunk_t);

    *chunk = *encoding;

    this->cache[type]->put(this->cache[type], cache, chunk);

  }

  this->lock->unlock(this->lock);

}

/**

 * Implementation of cred_encoding_t.encode

 */

static bool encode(private_cred_encoding_t *this, cred_encoding_type_t type,

           void *cache, chunk_t *encoding, ...)

{

  enumerator_t *enumerator;

  va_list args, copy;

  cred_encoder_t encode;

  bool success = FALSE;

  chunk_t *chunk;

  if (type >= CRED_ENCODING_MAX || (int)type < 0)

  {

    return FALSE;

  }

  this->lock->read_lock(this->lock);

  if (cache)

  {

    chunk = this->cache[type]->get(this->cache[type], cache);

    if (chunk)

    {

      *encoding = *chunk;

      this->lock->unlock(this->lock);

      return TRUE;

    }

  }

  va_start(args, encoding);

  enumerator = this->encoders->create_enumerator(this->encoders);

  while (enumerator->enumerate(enumerator, &encode))

  {

    va_copy(copy, args);

    success = encode(type, encoding, copy);

    va_end(copy);

    if (success)

    {

      break;

    }

  }

  enumerator->destroy(enumerator);

  this->lock->unlock(this->lock);

  va_end(args);

  if (success && cache)

  {

    _cache(this, type, cache, encoding);

  }

  return success;

}

METHOD(cred_encoding_t, clear_cache, void,

  private_cred_encoding_t *this, void *cache)

{

  cred_encoding_type_t type;

  chunk_t *chunk;

  this->lock->write_lock(this->lock);

  for (type = 0; type < CRED_ENCODING_MAX; type++)

  {

    chunk = this->cache[type]->remove(this->cache[type], cache);

    if (chunk)

    {

      chunk_free(chunk);

      free(chunk);

    }

  }

  this->lock->unlock(this->lock);

}

METHOD(cred_encoding_t, add_encoder, void,

  private_cred_encoding_t *this, cred_encoder_t encoder)

{

  this->lock->write_lock(this->lock);

  this->encoders->insert_last(this->encoders, encoder);

  this->lock->unlock(this->lock);

}

METHOD(cred_encoding_t, remove_encoder, void,

  private_cred_encoding_t *this, cred_encoder_t encoder)

{

  this->lock->write_lock(this->lock);

  this->encoders->remove(this->encoders, encoder, NULL);

  this->lock->unlock(this->lock);

}

METHOD(cred_encoding_t, destroy, void,

  private_cred_encoding_t *this)

{

  cred_encoding_type_t type;

  for (type = 0; type < CRED_ENCODING_MAX; type++)

  {

    /* We explicitly do not free remaining encodings. All creds should

     * have gone now, and they are responsible for cleaning out their

     * cache entries. Not flushing here allows the leak detective to

     * complain if a credential did not flush cached encodings. */

    this->cache[type]->destroy(this->cache[type]);

  }

  this->encoders->destroy(this->encoders);

  this->lock->destroy(this->lock);

  free(this);

}

/**

 * See header

 */

cred_encoding_t *cred_encoding_create()

{

  private_cred_encoding_t *this;

  cred_encoding_type_t type;

  INIT(this,

    .public = {

      .encode = (bool(*)(cred_encoding_t*, cred_encoding_type_t type, void *cache, chunk_t *encoding, ...))encode,

      .get_cache = _get_cache,

      .cache = _cache,

      .clear_cache = _clear_cache,

      .add_encoder = _add_encoder,

      .remove_encoder = _remove_encoder,

      .destroy = _destroy,

    },

    .encoders = linked_list_create(),

    .lock = rwlock_create(RWLOCK_TYPE_DEFAULT),

  );

  for (type = 0; type < CRED_ENCODING_MAX; type++)

  {

    this->cache[type] = hashtable_create(hashtable_hash_ptr,

                       hashtable_equals_ptr, 8);

  }

  return &this->public;

}