// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "gpu/command_buffer/service/passthrough_discardable_manager.h"

#include <inttypes.h>

#include "base/strings/stringprintf.h"
#include "base/trace_event/memory_dump_manager.h"
#include "gpu/command_buffer/service/context_group.h"
#include "gpu/command_buffer/service/gles2_cmd_decoder_passthrough.h"
#include "gpu/command_buffer/service/service_discardable_manager.h"
#include "gpu/config/gpu_preferences.h"

namespace gpu {

PassthroughDiscardableManager::DiscardableCacheValue::DiscardableCacheValue() =
    default;
PassthroughDiscardableManager::DiscardableCacheValue::DiscardableCacheValue(
    const DiscardableCacheValue& other) = default;
PassthroughDiscardableManager::DiscardableCacheValue::DiscardableCacheValue(
    DiscardableCacheValue&& other) = default;
PassthroughDiscardableManager::DiscardableCacheValue&
PassthroughDiscardableManager::DiscardableCacheValue::operator=(
    const DiscardableCacheValue& other) = default;
PassthroughDiscardableManager::DiscardableCacheValue&
PassthroughDiscardableManager::DiscardableCacheValue::operator=(
    DiscardableCacheValue&& other) = default;
PassthroughDiscardableManager::DiscardableCacheValue::~DiscardableCacheValue() =
    default;

PassthroughDiscardableManager::PassthroughDiscardableManager(
    const GpuPreferences& preferences)
    : cache_(DiscardableCache::NO_AUTO_EVICT),
      cache_size_limit_(preferences.force_gpu_mem_discardable_limit_bytes
                            ? preferences.force_gpu_mem_discardable_limit_bytes
                            : DiscardableCacheSizeLimit()) {
  // In certain cases, SingleThreadTaskRunner::CurrentDefaultHandle isn't set
  // (Android Webview).  Don't register a dump provider in these cases.
  if (base::SingleThreadTaskRunner::HasCurrentDefault()) {
    base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
        this, "gpu::PassthroughDiscardableManager",
        base::SingleThreadTaskRunner::GetCurrentDefault());
  }
}

PassthroughDiscardableManager::~PassthroughDiscardableManager() {
  DCHECK(cache_.empty());
  base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
      this);
}

bool PassthroughDiscardableManager::OnMemoryDump(
    const base::trace_event::MemoryDumpArgs& args,
    base::trace_event::ProcessMemoryDump* pmd) {
  using base::trace_event::MemoryAllocatorDump;
  using base::trace_event::MemoryDumpLevelOfDetail;

  if (args.level_of_detail == MemoryDumpLevelOfDetail::kBackground) {
    std::string dump_name =
        base::StringPrintf("gpu/discardable_cache/cache_0x%" PRIXPTR,
                           reinterpret_cast<uintptr_t>(this));
    MemoryAllocatorDump* dump = pmd->CreateAllocatorDump(dump_name);
    dump->AddScalar(MemoryAllocatorDump::kNameSize,
                    MemoryAllocatorDump::kUnitsBytes, total_size_);

    if (!cache_.empty()) {
      MemoryAllocatorDump* dump_avg_size =
          pmd->CreateAllocatorDump(dump_name + "/avg_image_size");
      dump_avg_size->AddScalar("average_size", MemoryAllocatorDump::kUnitsBytes,
                               total_size_ / cache_.size());
    }

    // Early out, no need for more detail in a BACKGROUND dump.
    return true;
  }

  for (const auto& entry : cache_) {
    std::string dump_name = base::StringPrintf(
        "gpu/discardable_cache/cache_0x%" PRIXPTR "/entry_0x%" PRIXPTR,
        reinterpret_cast<uintptr_t>(this),
        reinterpret_cast<uintptr_t>(entry.second.unlocked_texture.get()));
    MemoryAllocatorDump* dump = pmd->CreateAllocatorDump(dump_name);
    dump->AddScalar(MemoryAllocatorDump::kNameSize,
                    MemoryAllocatorDump::kUnitsBytes, entry.second.size);
  }
  return true;
}

void PassthroughDiscardableManager::InitializeTexture(
    uint32_t client_id,
    const gles2::ContextGroup* context_group,
    size_t texture_size,
    ServiceDiscardableHandle handle) {
  DCHECK(cache_.Get({client_id, context_group}) == cache_.end());

  total_size_ += texture_size;

  DiscardableCacheValue entry;
  entry.handle = std::move(handle);
  entry.size = texture_size;

  cache_.Put(DiscardableCacheKey{client_id, context_group}, std::move(entry));
  EnforceCacheSizeLimit(cache_size_limit_);
}
bool PassthroughDiscardableManager::UnlockTexture(
    uint32_t client_id,
    const gles2::ContextGroup* context_group,
    gles2::TexturePassthrough** texture_to_unbind) {
  *texture_to_unbind = nullptr;

  auto iter = cache_.Get({client_id, context_group});
  if (iter == cache_.end())
    return false;

  iter->second.handle.Unlock();
  DCHECK(iter->second.lock_count > 0);
  if (--iter->second.lock_count == 0) {
    // Get the texture from this context group and store it.  Remove it from the
    // ID maps and tell the decoder to unbind it.
    gles2::PassthroughResources* resources =
        context_group->passthrough_resources();
    resources->texture_object_map.GetServiceID(client_id,
                                               &iter->second.unlocked_texture);
    resources->texture_id_map.RemoveClientID(client_id);
    resources->texture_object_map.RemoveClientID(client_id);
    *texture_to_unbind = iter->second.unlocked_texture.get();
  }

  return true;
}

bool PassthroughDiscardableManager::LockTexture(
    uint32_t client_id,
    const gles2::ContextGroup* context_group) {
  auto iter = cache_.Get({client_id, context_group});
  if (iter == cache_.end())
    return false;

  ++iter->second.lock_count;
  if (iter->second.unlocked_texture != nullptr) {
    scoped_refptr<gles2::TexturePassthrough> texture =
        std::move(iter->second.unlocked_texture);

    // Re-insert the texture back into the context group's ID maps.
    // If we've generated a replacement texture due to "bind generates
    // resource", behavior, just delete the resource being returned.
    gles2::PassthroughResources* resources =
        context_group->passthrough_resources();
    GLuint service_id = 0;
    if (!resources->texture_id_map.GetServiceID(client_id, &service_id)) {
      resources->texture_id_map.SetIDMapping(client_id, texture->service_id());
      resources->texture_object_map.SetIDMapping(client_id, std::move(texture));
    }
  }

  return true;
}

void PassthroughDiscardableManager::DeleteContextGroup(
    const gles2::ContextGroup* context_group,
    bool has_context) {
  DCHECK(context_group);

  DeleteTextures(context_group, has_context);
}

void PassthroughDiscardableManager::OnContextLost() {
  DeleteTextures(nullptr, false);
}

void PassthroughDiscardableManager::DeleteTextures(
    const gles2::ContextGroup* context_group,
    bool has_context) {
  auto iter = cache_.begin();
  while (iter != cache_.end()) {
    if (iter->first.second == context_group || !context_group) {
      iter->second.handle.ForceDelete();
      total_size_ -= iter->second.size;
      if (!has_context && iter->second.unlocked_texture)
        iter->second.unlocked_texture->MarkContextLost();
      iter = cache_.Erase(iter);
    } else {
      iter++;
    }
  }
}

void PassthroughDiscardableManager::DeleteTexture(
    uint32_t client_id,
    const gles2::ContextGroup* context_group) {
  auto iter = cache_.Get({client_id, context_group});
  if (iter == cache_.end())
    return;

  iter->second.handle.ForceDelete();
  total_size_ -= iter->second.size;
  cache_.Erase(iter);
}

void PassthroughDiscardableManager::UpdateTextureSize(
    uint32_t client_id,
    const gles2::ContextGroup* context_group,
    size_t new_size) {
  auto iter = cache_.Get({client_id, context_group});
  if (iter == cache_.end())
    return;

  total_size_ -= iter->second.size;
  iter->second.size = new_size;
  total_size_ += iter->second.size;

  EnforceCacheSizeLimit(cache_size_limit_);
}

void PassthroughDiscardableManager::HandleMemoryPressure(
    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
  size_t limit = DiscardableCacheSizeLimitForPressure(cache_size_limit_,
                                                      memory_pressure_level);
  EnforceCacheSizeLimit(limit);
}

bool PassthroughDiscardableManager::IsEntryLockedForTesting(
    uint32_t client_id,
    const gles2::ContextGroup* context_group) const {
  auto iter = cache_.Peek({client_id, context_group});
  CHECK(iter != cache_.end());
  return iter->second.unlocked_texture == nullptr;
}

bool PassthroughDiscardableManager::IsEntryTrackedForTesting(
    uint32_t client_id,
    const gles2::ContextGroup* context_group) const {
  return cache_.Peek({client_id, context_group}) != cache_.end();
}

scoped_refptr<gles2::TexturePassthrough>
PassthroughDiscardableManager::UnlockedTextureForTesting(
    uint32_t client_id,
    const gles2::ContextGroup* context_group) const {
  auto iter = cache_.Peek({client_id, context_group});
  CHECK(iter != cache_.end());
  return iter->second.unlocked_texture;
}

void PassthroughDiscardableManager::EnforceCacheSizeLimit(size_t limit) {
  for (auto it = cache_.rbegin(); it != cache_.rend();) {
    if (total_size_ <= limit) {
      return;
    }
    if (!it->second.handle.Delete()) {
      ++it;
      continue;
    }

    total_size_ -= it->second.size;

    GLuint client_id = it->first.first;
    const gles2::ContextGroup* context_group = it->first.second;
    gles2::PassthroughResources* resources =
        context_group->passthrough_resources();

    resources->texture_id_map.RemoveClientID(client_id);
    resources->texture_object_map.RemoveClientID(client_id);

    // Erase before calling texture_manager->RemoveTexture, to avoid attempting
    // to remove the texture from entries_ twice.
    it = cache_.Erase(it);
  }
}

}  // namespace gpu