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// This file implements the EffectHelper class.

#include "command_buffer/common/cross/cmd_buffer_format.h"
#include "command_buffer/client/cross/cmd_buffer_helper.h"
#include "command_buffer/client/cross/effect_helper.h"
#include "command_buffer/client/cross/fenced_allocator.h"
#include "command_buffer/client/cross/id_allocator.h"

// TODO: write a unit test.

namespace o3d {
namespace command_buffer {

bool EffectHelper::CreateEffectParameters(ResourceId effect_id,
                                          std::vector<EffectParamDesc> *descs) {
  using effect_param::Desc;
  DCHECK_NE(effect_id, kInvalidResource);
  DCHECK(descs);
  descs->clear();

  // Get the param count.
  Uint32 *retval = shm_allocator_->AllocTyped<Uint32>(1);
  helper_->GetParamCount(effect_id, sizeof(*retval),
                         shm_id_, shm_allocator_->GetOffset(retval));
  // Finish has to be called to get the result.
  helper_->Finish();

  // We could have failed if the effect_id is invalid.
  if (helper_->interface()->GetParseError() !=
      BufferSyncInterface::kParseNoError) {
    shm_allocator_->Free(retval);
    return false;
  }
  unsigned int param_count = *retval;

  shm_allocator_->Free(retval);
  unsigned int max_buffer_size = shm_allocator_->GetLargestFreeOrPendingSize();
  if (max_buffer_size < sizeof(Desc)) {  // NOLINT
    // Not enough memory to get at least 1 param desc.
    return false;
  }
  descs->resize(param_count);
  for (unsigned int i = 0; i < param_count; ++i) {
    EffectParamDesc *desc = &((*descs)[i]);
    desc->id = param_id_allocator_->AllocateID();
    helper_->CreateParam(desc->id, effect_id, i);
  }

  // Read param descriptions in batches. We use as much shared memory as
  // possible so that we only call Finish as little as possible.
  unsigned int max_param_per_batch =
      std::min(static_cast<unsigned>(param_count),
      static_cast<unsigned>(max_buffer_size / sizeof(Desc)));  // NOLINT
  Desc *raw_descs = shm_allocator_->AllocTyped<Desc>(max_param_per_batch);
  DCHECK(raw_descs);
  for (unsigned int i = 0; i < param_count; i += max_param_per_batch) {
    unsigned int count = std::min(param_count - i, max_param_per_batch);
    for (unsigned int j = 0 ; j < count; ++j) {
      EffectParamDesc *desc = &((*descs)[i + j]);
      Desc *raw_desc = raw_descs + j;
      helper_->GetParamDesc(desc->id, sizeof(*raw_desc),
                            shm_id_,
                            shm_allocator_->GetOffset(raw_desc));
    }
    // Finish to get the results.
    helper_->Finish();
    DCHECK_EQ(helper_->interface()->GetParseError(),
              BufferSyncInterface::kParseNoError);
    for (unsigned int j = 0 ; j < count; ++j) {
      EffectParamDesc *desc = &((*descs)[i + j]);
      Desc *raw_desc = raw_descs + j;
      desc->data_type = raw_desc->data_type;
      desc->data_size = raw_desc->data_size;
      desc->num_elements = raw_desc->num_elements;
      desc->cmd_desc_size = raw_desc->size;
    }
  }
  shm_allocator_->Free(raw_descs);
  return true;
}

bool EffectHelper::GetParamStrings(EffectParamDesc *desc) {
  using effect_param::Desc;
  DCHECK(desc);
  DCHECK_NE(desc->id, kInvalidResource);
  // desc may not have come directly from CreateEffectParameters, so it may be
  // less than the minimum required size.
  unsigned int size = std::max(static_cast<unsigned>(desc->cmd_desc_size),
      static_cast<unsigned>(sizeof(Desc)));  // NOLINT
  Desc *raw_desc = static_cast<Desc *>(shm_allocator_->Alloc(size));
  if (!raw_desc) {
    // Not enough memory to get the param desc.
    return false;
  }
  helper_->GetParamDesc(desc->id, size,
                        shm_id_,
                        shm_allocator_->GetOffset(raw_desc));

  // Finish to get the results.
  helper_->Finish();

  // We could have failed if the param ID is invalid.
  if (helper_->interface()->GetParseError() !=
      BufferSyncInterface::kParseNoError) {
    shm_allocator_->Free(raw_desc);
    return false;
  }

  if (raw_desc->size > size) {
    // We had not allocated enough memory the first time (e.g. if the
    // EffectParamDesc didn't come from CreateEffectParameters, so the user had
    // no way of knowing what size was needed for the strings), so re-allocate
    // and try again.
    size = raw_desc->size;
    desc->cmd_desc_size = size;
    shm_allocator_->Free(raw_desc);
    raw_desc = static_cast<Desc *>(shm_allocator_->Alloc(size));
    if (!raw_desc) {
      // Not enough memory to get the param desc.
      return false;
    }
    helper_->GetParamDesc(desc->id, size,
                          shm_id_,
                          shm_allocator_->GetOffset(raw_desc));
    // Finish to get the results.
    helper_->Finish();
    DCHECK_EQ(helper_->interface()->GetParseError(),
              BufferSyncInterface::kParseNoError);
    DCHECK_EQ(raw_desc->size, size);
  }

  const char *raw_desc_string = reinterpret_cast<char *>(raw_desc);
  if (raw_desc->name_offset) {
    DCHECK_LE(raw_desc->name_offset + raw_desc->name_size, raw_desc->size);
    DCHECK_GT(raw_desc->name_size, 0U);
    DCHECK_EQ(raw_desc_string[raw_desc->name_offset + raw_desc->name_size - 1],
              0);
    desc->name = String(raw_desc_string + raw_desc->name_offset,
                        raw_desc->name_size - 1);
  } else {
    desc->name.clear();
  }
  if (raw_desc->semantic_offset) {
    DCHECK_LE(raw_desc->semantic_offset + raw_desc->semantic_size,
              raw_desc->size);
    DCHECK_GT(raw_desc->semantic_size, 0U);
    DCHECK_EQ(raw_desc_string[raw_desc->semantic_offset +
                              raw_desc->semantic_size - 1],
              0);
    desc->semantic = String(raw_desc_string + raw_desc->semantic_offset,
                            raw_desc->semantic_size - 1);
  } else {
    desc->semantic.clear();
  }
  shm_allocator_->Free(raw_desc);
  return true;
}

void EffectHelper::DestroyEffectParameters(
    const std::vector<EffectParamDesc> &descs) {
  for (unsigned int i = 0; i < descs.size(); ++i) {
    const EffectParamDesc &desc = descs[i];
    helper_->DestroyParam(desc.id);
    param_id_allocator_->FreeID(desc.id);
  }
}

bool EffectHelper::GetEffectStreams(ResourceId effect_id,
                                    std::vector<EffectStreamDesc> *descs) {
  using effect_stream::Desc;
  DCHECK_NE(effect_id, kInvalidResource);

  // Get the param count.
  Uint32 *retval = shm_allocator_->AllocTyped<Uint32>(1);
  helper_->GetStreamCount(effect_id, sizeof(*retval),
                          shm_id_,
                          shm_allocator_->GetOffset(retval));
  // Finish has to be called to get the result.
  helper_->Finish();

  // We could have failed if the effect_id is invalid.
  if (helper_->interface()->GetParseError() !=
      BufferSyncInterface::kParseNoError) {
    shm_allocator_->Free(retval);
    return false;
  }
  unsigned int stream_count = *retval;
  shm_allocator_->Free(retval);
  unsigned int max_buffer_size = shm_allocator_->GetLargestFreeOrPendingSize();
  if (max_buffer_size < sizeof(Desc)) {  // NOLINT
    // Not enough memory to get at least 1 stream desc.
    return false;
  }
  descs->resize(stream_count);

  // Read stream descriptions in batches. We use as much shared memory as
  // possible so that we only call Finish as little as possible.
  unsigned int max_stream_per_batch =
      std::min(static_cast<unsigned>(stream_count),
      static_cast<unsigned>(max_buffer_size / sizeof(Desc)));  // NOLINT
  Desc *raw_descs = shm_allocator_->AllocTyped<Desc>(max_stream_per_batch);
  DCHECK(raw_descs);
  for (unsigned int i = 0; i < stream_count; i += max_stream_per_batch) {
    unsigned int count = std::min(stream_count - i, max_stream_per_batch);
    for (unsigned int j = 0 ; j < count; ++j) {
      EffectStreamDesc *desc = &((*descs)[i + j]);
      Desc *raw_desc = raw_descs + j;
      helper_->GetStreamDesc(effect_id, i + j, sizeof(*raw_desc),
                             shm_id_,
                             shm_allocator_->GetOffset(raw_desc));
    }
    // Finish to get the results.
    helper_->Finish();
    DCHECK_EQ(helper_->interface()->GetParseError(),
              BufferSyncInterface::kParseNoError);
    for (unsigned int j = 0 ; j < count; ++j) {
      EffectStreamDesc *desc = &((*descs)[i + j]);
      Desc *raw_desc = raw_descs + j;
      desc->semantic = static_cast<vertex_struct::Semantic>(raw_desc->semantic);
      desc->semantic_index = raw_desc->semantic_index;
    }
  }
  shm_allocator_->Free(raw_descs);
  return true;
}
}  // namespace command_buffer
}  // namespace o3d