/**

 * WinPR: Windows Portable Runtime

 * Object Pool

 *

 * Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include <winpr/config.h>

#include <winpr/crt.h>

#include <winpr/wlog.h>

#include <winpr/collections.h>

#include "../stream.h"

#include "../log.h"

#define XTAG WINPR_TAG("utils.streampool")

struct s_StreamPoolEntry

{

#if defined(WITH_STREAMPOOL_DEBUG)

  char** msg;

  size_t lines;

#endif

  wStream* s;

};

struct s_wStreamPool

{

  size_t aSize;

  size_t aCapacity;

  struct s_StreamPoolEntry* aArray;

  size_t uSize;

  size_t uCapacity;

  struct s_StreamPoolEntry* uArray;

  CRITICAL_SECTION lock;

  BOOL synchronized;

  size_t defaultSize;

  wLog* log;

};

static void discard_entry(struct s_StreamPoolEntry* entry, BOOL discardStream)

{

  if (!entry)

    return;

#if defined(WITH_STREAMPOOL_DEBUG)

  free((void*)entry->msg);

#endif

  if (discardStream && entry->s)

    Stream_Free(entry->s, entry->s->isAllocatedStream);

  const struct s_StreamPoolEntry empty = WINPR_C_ARRAY_INIT;

  *entry = empty;

}

static struct s_StreamPoolEntry add_entry(wStream* s)

{

  struct s_StreamPoolEntry entry = WINPR_C_ARRAY_INIT;

#if defined(WITH_STREAMPOOL_DEBUG)

  void* stack = winpr_backtrace(20);

  if (stack)

    entry.msg = winpr_backtrace_symbols(stack, &entry.lines);

  winpr_backtrace_free(stack);

#endif

  entry.s = s;

  return entry;

}

/**

 * Lock the stream pool

 */

static inline void StreamPool_Lock(wStreamPool* pool)

{

  WINPR_ASSERT(pool);

  if (pool->synchronized)

    EnterCriticalSection(&pool->lock);

}

/**

 * Unlock the stream pool

 */

static inline void StreamPool_Unlock(wStreamPool* pool)

{

  WINPR_ASSERT(pool);

  if (pool->synchronized)

    LeaveCriticalSection(&pool->lock);

}

static BOOL StreamPool_EnsureCapacity(wStreamPool* pool, size_t count, BOOL usedOrAvailable)

{

  WINPR_ASSERT(pool);

  size_t* cap = (usedOrAvailable) ? &pool->uCapacity : &pool->aCapacity;

  size_t* size = (usedOrAvailable) ? &pool->uSize : &pool->aSize;

  struct s_StreamPoolEntry** array = (usedOrAvailable) ? &pool->uArray : &pool->aArray;

  size_t new_cap = 0;

  if (*cap == 0)

    new_cap = *size + count;

  else if (*size + count > *cap)

    new_cap = (*size + count + 2) / 2 * 3;

  else if ((*size + count) < *cap / 3)

    new_cap = *cap / 2;

  if (new_cap > 0)

  {

    struct s_StreamPoolEntry* new_arr = nullptr;

    if (*cap < *size + count)

      *cap += count;

    new_arr =

        (struct s_StreamPoolEntry*)realloc(*array, sizeof(struct s_StreamPoolEntry) * new_cap);

    if (!new_arr)

      return FALSE;

    *cap = new_cap;

    *array = new_arr;

  }

  return TRUE;

}

/**

 * Methods

 */

static void StreamPool_ShiftUsed(wStreamPool* pool, size_t index)

{

  WINPR_ASSERT(pool);

  const size_t pcount = 1;

  const size_t off = index + pcount;

  if (pool->uSize >= off)

  {

    for (size_t x = 0; x < pcount; x++)

    {

      struct s_StreamPoolEntry* cur = &pool->uArray[index + x];

      discard_entry(cur, FALSE);

    }

    MoveMemory(&pool->uArray[index], &pool->uArray[index + pcount],

               (pool->uSize - index - pcount) * sizeof(struct s_StreamPoolEntry));

    pool->uSize -= pcount;

  }

}

/**

 * Adds a used stream to the pool.

 */

static void StreamPool_AddUsed(wStreamPool* pool, wStream* s)

{

  StreamPool_EnsureCapacity(pool, 1, TRUE);

  pool->uArray[pool->uSize] = add_entry(s);

  pool->uSize++;

}

/**

 * Removes a used stream from the pool.

 */

static void StreamPool_RemoveUsed(wStreamPool* pool, wStream* s)

{

  WINPR_ASSERT(pool);

  for (size_t index = 0; index < pool->uSize; index++)

  {

    struct s_StreamPoolEntry* cur = &pool->uArray[index];

    if (cur->s == s)

    {

      StreamPool_ShiftUsed(pool, index);

      break;

    }

  }

}

static void StreamPool_ShiftAvailable(wStreamPool* pool, size_t index)

{

  WINPR_ASSERT(pool);

  const size_t pcount = 1;

  const size_t off = index + pcount;

  if (pool->aSize >= off)

  {

    for (size_t x = 0; x < pcount; x++)

    {

      struct s_StreamPoolEntry* cur = &pool->aArray[index + x];

      discard_entry(cur, FALSE);

    }

    MoveMemory(&pool->aArray[index], &pool->aArray[index + pcount],

               (pool->aSize - index - pcount) * sizeof(struct s_StreamPoolEntry));

    pool->aSize -= pcount;

  }

}

/**

 * Gets a stream from the pool.

 */

wStream* StreamPool_Take(wStreamPool* pool, size_t size)

{

  BOOL found = FALSE;

  size_t foundIndex = 0;

  wStream* s = nullptr;

  StreamPool_Lock(pool);

  if (size == 0)

    size = pool->defaultSize;

  for (size_t index = 0; index < pool->aSize; index++)

  {

    struct s_StreamPoolEntry* cur = &pool->aArray[index];

    s = cur->s;

    if (Stream_Capacity(s) >= size)

    {

      found = TRUE;

      foundIndex = index;

      break;

    }

  }

  if (!found)

  {

    s = Stream_New(nullptr, size);

    if (!s)

      goto out_fail;

  }

  else if (s)

  {

    Stream_ResetPosition(s);

    if (!Stream_SetLength(s, Stream_Capacity(s)))

      goto out_fail;

    StreamPool_ShiftAvailable(pool, foundIndex);

  }

  if (s)

  {

    s->pool = pool;

    s->count = 1;

    StreamPool_AddUsed(pool, s);

  }

out_fail:

  StreamPool_Unlock(pool);

  return s;

}

/**

 * Returns an object to the pool.

 */

static void StreamPool_Remove(wStreamPool* pool, wStream* s)

{

  StreamPool_EnsureCapacity(pool, 1, FALSE);

  Stream_EnsureValidity(s);

  for (size_t x = 0; x < pool->aSize; x++)

  {

    wStream* cs = pool->aArray[x].s;

    if (cs == s)

      return;

  }

  pool->aArray[(pool->aSize)++] = add_entry(s);

  StreamPool_RemoveUsed(pool, s);

}

static void StreamPool_ReleaseOrReturn(wStreamPool* pool, wStream* s)

{

  StreamPool_Lock(pool);

  StreamPool_Remove(pool, s);

  StreamPool_Unlock(pool);

}

void StreamPool_Return(wStreamPool* pool, wStream* s)

{

  WINPR_ASSERT(pool);

  if (!s)

    return;

  StreamPool_Lock(pool);

  StreamPool_Remove(pool, s);

  StreamPool_Unlock(pool);

}

/**

 * Increment stream reference count

 */

void Stream_AddRef(wStream* s)

{

  WINPR_ASSERT(s);

  s->count++;

}

/**

 * Decrement stream reference count

 */

void Stream_Release(wStream* s)

{

  WINPR_ASSERT(s);

  if (s->count > 0)

    s->count--;

  if (s->count == 0)

  {

    if (s->pool)

      StreamPool_ReleaseOrReturn(s->pool, s);

    else

      Stream_Free(s, TRUE);

  }

}

/**

 * Find stream in pool using pointer inside buffer

 */

wStream* StreamPool_Find(wStreamPool* pool, const BYTE* ptr)

{

  wStream* s = nullptr;

  StreamPool_Lock(pool);

  for (size_t index = 0; index < pool->uSize; index++)

  {

    struct s_StreamPoolEntry* cur = &pool->uArray[index];

    if ((ptr >= Stream_Buffer(cur->s)) &&

        (ptr < (Stream_Buffer(cur->s) + Stream_Capacity(cur->s))))

    {

      s = cur->s;

      break;

    }

  }

  StreamPool_Unlock(pool);

  return s;

}

/**

 * Releases the streams currently cached in the pool.

 */

void StreamPool_Clear(wStreamPool* pool)

{

  StreamPool_Lock(pool);

  for (size_t x = 0; x < pool->aSize; x++)

  {

    struct s_StreamPoolEntry* cur = &pool->aArray[x];

    discard_entry(cur, TRUE);

  }

  pool->aSize = 0;

  if (pool->uSize > 0)

  {

    WLog_Print(pool->log, WLOG_WARN,

               "Clearing StreamPool, but there are %" PRIuz " streams currently in use",

               pool->uSize);

    for (size_t x = 0; x < pool->uSize; x++)

    {

      struct s_StreamPoolEntry* cur = &pool->uArray[x];

      discard_entry(cur, TRUE);

    }

    pool->uSize = 0;

  }

  StreamPool_Unlock(pool);

}

size_t StreamPool_UsedCount(wStreamPool* pool)

{

  StreamPool_Lock(pool);

  size_t usize = pool->uSize;

  StreamPool_Unlock(pool);

  return usize;

}

/**

 * Construction, Destruction

 */

wStreamPool* StreamPool_New(BOOL synchronized, size_t defaultSize)

{

  wStreamPool* pool = calloc(1, sizeof(wStreamPool));

  if (!pool)

    return nullptr;

  pool->log = WLog_Create(XTAG, WLog_GetRoot());

  if (!pool->log)

    goto fail;

  pool->synchronized = synchronized;

  pool->defaultSize = defaultSize;

  if (!StreamPool_EnsureCapacity(pool, 32, FALSE))

    goto fail;

  if (!StreamPool_EnsureCapacity(pool, 32, TRUE))

    goto fail;

  if (!InitializeCriticalSectionAndSpinCount(&pool->lock, 4000))

    goto fail;

  return pool;

fail:

  WINPR_PRAGMA_DIAG_PUSH

  WINPR_PRAGMA_DIAG_IGNORED_MISMATCHED_DEALLOC

  StreamPool_Free(pool);

  WINPR_PRAGMA_DIAG_POP

  return nullptr;

}

void StreamPool_Free(wStreamPool* pool)

{

  if (!pool)

    return;

  StreamPool_Clear(pool);

  DeleteCriticalSection(&pool->lock);

  free(pool->aArray);

  free(pool->uArray);

  WLog_Discard(pool->log);

  free(pool);

}

char* StreamPool_GetStatistics(wStreamPool* pool, char* buffer, size_t size)

{

  WINPR_ASSERT(pool);

  if (!buffer || (size < 1))

    return nullptr;

  size_t used = 0;

  int offset = _snprintf(buffer, size - 1,

                         "aSize    =%" PRIuz ", uSize    =%" PRIuz ", aCapacity=%" PRIuz

                         ", uCapacity=%" PRIuz,

                         pool->aSize, pool->uSize, pool->aCapacity, pool->uCapacity);

  if ((offset > 0) && ((size_t)offset < size))

    used += (size_t)offset;

#if defined(WITH_STREAMPOOL_DEBUG)

  StreamPool_Lock(pool);

  offset = _snprintf(&buffer[used], size - 1 - used, "\n-- dump used array take locations --\n");

  if ((offset > 0) && ((size_t)offset < size - used))

    used += (size_t)offset;

  for (size_t x = 0; x < pool->uSize; x++)

  {

    const struct s_StreamPoolEntry* cur = &pool->uArray[x];

    WINPR_ASSERT(cur->msg || (cur->lines == 0));

    for (size_t y = 0; y < cur->lines; y++)

    {

      offset = _snprintf(&buffer[used], size - 1 - used, "[%" PRIuz " | %" PRIuz "]: %s\n", x,

                         y, cur->msg[y]);

      if ((offset > 0) && ((size_t)offset < size - used))

        used += (size_t)offset;

    }

  }

  offset = _snprintf(&buffer[used], size - 1 - used, "\n-- statistics called from --\n");

  if ((offset > 0) && ((size_t)offset < size - used))

    used += (size_t)offset;

  struct s_StreamPoolEntry entry = WINPR_C_ARRAY_INIT;

  void* stack = winpr_backtrace(20);

  if (stack)

    entry.msg = winpr_backtrace_symbols(stack, &entry.lines);

  winpr_backtrace_free(stack);

  for (size_t x = 0; x < entry.lines; x++)

  {

    const char* msg = entry.msg[x];

    offset = _snprintf(&buffer[used], size - 1 - used, "[%" PRIuz "]: %s\n", x, msg);

    if ((offset > 0) && ((size_t)offset < size - used))

      used += (size_t)offset;

  }

  free((void*)entry.msg);

  StreamPool_Unlock(pool);

#endif

  buffer[used] = '\0';

  return buffer;

}

BOOL StreamPool_WaitForReturn(wStreamPool* pool, UINT32 timeoutMS)

{

  /* HACK: We disconnected the transport above, now wait without a read or write lock until all

   * streams in use have been returned to the pool. */

  while (timeoutMS > 0)

  {

    const size_t used = StreamPool_UsedCount(pool);

    if (used == 0)

      return TRUE;

    WLog_Print(pool->log, WLOG_DEBUG, "%" PRIuz " streams still in use, sleeping...", used);

    char buffer[4096] = WINPR_C_ARRAY_INIT;

    StreamPool_GetStatistics(pool, buffer, sizeof(buffer));

    WLog_Print(pool->log, WLOG_TRACE, "Pool statistics: %s", buffer);

    UINT32 diff = 10;

    if (timeoutMS != INFINITE)

    {

      diff = timeoutMS > 10 ? 10 : timeoutMS;

      timeoutMS -= diff;

    }

    Sleep(diff);

  }

  return FALSE;

}