// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// 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/query_manager.h"

#include <stddef.h>
#include <stdint.h>

#include "base/atomicops.h"
#include "base/bind.h"
#include "base/logging.h"
#include "base/memory/shared_memory.h"
#include "base/numerics/safe_math.h"
#include "base/synchronization/lock.h"
#include "base/time/time.h"
#include "gpu/command_buffer/common/gles2_cmd_format.h"
#include "gpu/command_buffer/service/error_state.h"
#include "gpu/command_buffer/service/feature_info.h"
#include "gpu/command_buffer/service/gles2_cmd_decoder.h"
#include "ui/gl/gl_bindings.h"
#include "ui/gl/gl_context.h"
#include "ui/gl/gl_fence.h"
#include "ui/gl/gpu_timing.h"

namespace gpu {
namespace gles2 {

class AbstractIntegerQuery : public QueryManager::Query {
 public:
  AbstractIntegerQuery(QueryManager* manager,
                       GLenum target,
                       int32_t shm_id,
                       uint32_t shm_offset);
  bool Begin() override;
  bool End(base::subtle::Atomic32 submit_count) override;
  bool QueryCounter(base::subtle::Atomic32 submit_count) override;
  void Pause() override;
  void Resume() override;
  void Destroy(bool have_context) override;

 protected:
  ~AbstractIntegerQuery() override;
  bool AreAllResultsAvailable();

  // Service side query ids.
  std::vector<GLuint> service_ids_;
};

AbstractIntegerQuery::AbstractIntegerQuery(QueryManager* manager,
                                           GLenum target,
                                           int32_t shm_id,
                                           uint32_t shm_offset)
    : Query(manager, target, shm_id, shm_offset) {
  GLuint service_id = 0;
  glGenQueries(1, &service_id);
  DCHECK_NE(0u, service_id);
  service_ids_.push_back(service_id);
}

bool AbstractIntegerQuery::Begin() {
  MarkAsActive();
  // Delete all but the first one when beginning a new query.
  if (service_ids_.size() > 1) {
    glDeleteQueries(service_ids_.size() - 1, &service_ids_[1]);
    service_ids_.resize(1);
  }
  BeginQueryHelper(target(), service_ids_.back());
  return true;
}

bool AbstractIntegerQuery::End(base::subtle::Atomic32 submit_count) {
  EndQueryHelper(target());
  return AddToPendingQueue(submit_count);
}

bool AbstractIntegerQuery::QueryCounter(base::subtle::Atomic32 submit_count) {
  NOTREACHED();
  return false;
}

void AbstractIntegerQuery::Pause() {
  MarkAsPaused();
  EndQueryHelper(target());
}

void AbstractIntegerQuery::Resume() {
  MarkAsActive();

  GLuint service_id = 0;
  glGenQueries(1, &service_id);
  DCHECK_NE(0u, service_id);
  service_ids_.push_back(service_id);
  BeginQueryHelper(target(), service_ids_.back());
}

void AbstractIntegerQuery::Destroy(bool have_context) {
  if (have_context && !IsDeleted()) {
    glDeleteQueries(service_ids_.size(), &service_ids_[0]);
    service_ids_.clear();
    MarkAsDeleted();
  }
}

AbstractIntegerQuery::~AbstractIntegerQuery() {
}

bool AbstractIntegerQuery::AreAllResultsAvailable() {
  GLuint available = 0;
  glGetQueryObjectuiv(
      service_ids_.back(), GL_QUERY_RESULT_AVAILABLE_EXT, &available);
  return !!available;
}

class BooleanQuery : public AbstractIntegerQuery {
 public:
  BooleanQuery(QueryManager* manager,
               GLenum target,
               int32_t shm_id,
               uint32_t shm_offset);
  bool Process(bool did_finish) override;

 protected:
  ~BooleanQuery() override;
};

BooleanQuery::BooleanQuery(QueryManager* manager,
                           GLenum target,
                           int32_t shm_id,
                           uint32_t shm_offset)
    : AbstractIntegerQuery(manager, target, shm_id, shm_offset) {}

BooleanQuery::~BooleanQuery() {
}

bool BooleanQuery::Process(bool did_finish) {
  if (!AreAllResultsAvailable()) {
    // Must return true to avoid generating an error at the command
    // buffer level.
    return true;
  }
  for (const GLuint& service_id : service_ids_) {
    GLuint result = 0;
    glGetQueryObjectuiv(service_id, GL_QUERY_RESULT_EXT, &result);
    if (result != 0)
      return MarkAsCompleted(1);
  }
  return MarkAsCompleted(0);
}

class SummedIntegerQuery : public AbstractIntegerQuery {
 public:
  SummedIntegerQuery(QueryManager* manager,
                     GLenum target,
                     int32_t shm_id,
                     uint32_t shm_offset);
  bool Process(bool did_finish) override;

 protected:
  ~SummedIntegerQuery() override;
};

SummedIntegerQuery::SummedIntegerQuery(QueryManager* manager,
                                       GLenum target,
                                       int32_t shm_id,
                                       uint32_t shm_offset)
    : AbstractIntegerQuery(manager, target, shm_id, shm_offset) {}

SummedIntegerQuery::~SummedIntegerQuery() {
}

bool SummedIntegerQuery::Process(bool did_finish) {
  if (!AreAllResultsAvailable()) {
    // Must return true to avoid generating an error at the command
    // buffer level.
    return true;
  }
  GLuint summed_result = 0;
  for (const GLuint& service_id : service_ids_) {
    GLuint result = 0;
    glGetQueryObjectuiv(service_id, GL_QUERY_RESULT_EXT, &result);
    summed_result += result;
  }
  return MarkAsCompleted(summed_result);
}

class CommandsIssuedQuery : public QueryManager::Query {
 public:
  CommandsIssuedQuery(QueryManager* manager,
                      GLenum target,
                      int32_t shm_id,
                      uint32_t shm_offset);

  bool Begin() override;
  bool End(base::subtle::Atomic32 submit_count) override;
  bool QueryCounter(base::subtle::Atomic32 submit_count) override;
  void Pause() override;
  void Resume() override;
  bool Process(bool did_finish) override;
  void Destroy(bool have_context) override;

 protected:
  ~CommandsIssuedQuery() override;

 private:
  base::TimeTicks begin_time_;
};

CommandsIssuedQuery::CommandsIssuedQuery(QueryManager* manager,
                                         GLenum target,
                                         int32_t shm_id,
                                         uint32_t shm_offset)
    : Query(manager, target, shm_id, shm_offset) {}

bool CommandsIssuedQuery::Begin() {
  MarkAsActive();
  begin_time_ = base::TimeTicks::Now();
  return true;
}

void CommandsIssuedQuery::Pause() {
  MarkAsPaused();
}

void CommandsIssuedQuery::Resume() {
  MarkAsActive();
}

bool CommandsIssuedQuery::End(base::subtle::Atomic32 submit_count) {
  const base::TimeDelta elapsed = base::TimeTicks::Now() - begin_time_;
  MarkAsPending(submit_count);
  return MarkAsCompleted(elapsed.InMicroseconds());
}

bool CommandsIssuedQuery::QueryCounter(base::subtle::Atomic32 submit_count) {
  NOTREACHED();
  return false;
}

bool CommandsIssuedQuery::Process(bool did_finish) {
  NOTREACHED();
  return true;
}

void CommandsIssuedQuery::Destroy(bool /* have_context */) {
  if (!IsDeleted()) {
    MarkAsDeleted();
  }
}

CommandsIssuedQuery::~CommandsIssuedQuery() {
}

class CommandLatencyQuery : public QueryManager::Query {
 public:
  CommandLatencyQuery(QueryManager* manager,
                      GLenum target,
                      int32_t shm_id,
                      uint32_t shm_offset);

  bool Begin() override;
  bool End(base::subtle::Atomic32 submit_count) override;
  bool QueryCounter(base::subtle::Atomic32 submit_count) override;
  void Pause() override;
  void Resume() override;
  bool Process(bool did_finish) override;
  void Destroy(bool have_context) override;

 protected:
  ~CommandLatencyQuery() override;
};

CommandLatencyQuery::CommandLatencyQuery(QueryManager* manager,
                                         GLenum target,
                                         int32_t shm_id,
                                         uint32_t shm_offset)
    : Query(manager, target, shm_id, shm_offset) {}

bool CommandLatencyQuery::Begin() {
  MarkAsActive();
  return true;
}

void CommandLatencyQuery::Pause() {
  MarkAsPaused();
}

void CommandLatencyQuery::Resume() {
  MarkAsActive();
}

bool CommandLatencyQuery::End(base::subtle::Atomic32 submit_count) {
    base::TimeDelta now = base::TimeTicks::Now() - base::TimeTicks();
    MarkAsPending(submit_count);
    return MarkAsCompleted(now.InMicroseconds());
}

bool CommandLatencyQuery::QueryCounter(base::subtle::Atomic32 submit_count) {
  NOTREACHED();
  return false;
}

bool CommandLatencyQuery::Process(bool did_finish) {
  NOTREACHED();
  return true;
}

void CommandLatencyQuery::Destroy(bool /* have_context */) {
  if (!IsDeleted()) {
    MarkAsDeleted();
  }
}

CommandLatencyQuery::~CommandLatencyQuery() {
}


class AsyncReadPixelsCompletedQuery
    : public QueryManager::Query,
      public base::SupportsWeakPtr<AsyncReadPixelsCompletedQuery> {
 public:
  AsyncReadPixelsCompletedQuery(QueryManager* manager,
                                GLenum target,
                                int32_t shm_id,
                                uint32_t shm_offset);

  bool Begin() override;
  bool End(base::subtle::Atomic32 submit_count) override;
  bool QueryCounter(base::subtle::Atomic32 submit_count) override;
  void Pause() override;
  void Resume() override;
  bool Process(bool did_finish) override;
  void Destroy(bool have_context) override;

 protected:
  void Complete();
  ~AsyncReadPixelsCompletedQuery() override;

 private:
  bool complete_result_;
};

AsyncReadPixelsCompletedQuery::AsyncReadPixelsCompletedQuery(
    QueryManager* manager,
    GLenum target,
    int32_t shm_id,
    uint32_t shm_offset)
    : Query(manager, target, shm_id, shm_offset), complete_result_(false) {}

bool AsyncReadPixelsCompletedQuery::Begin() {
  MarkAsActive();
  return true;
}

void AsyncReadPixelsCompletedQuery::Pause() {
  MarkAsPaused();
}

void AsyncReadPixelsCompletedQuery::Resume() {
  MarkAsActive();
}

bool AsyncReadPixelsCompletedQuery::End(base::subtle::Atomic32 submit_count) {
  if (!AddToPendingQueue(submit_count)) {
    return false;
  }
  manager()->decoder()->WaitForReadPixels(
      base::Bind(&AsyncReadPixelsCompletedQuery::Complete,
                 AsWeakPtr()));

  return Process(false);
}

bool AsyncReadPixelsCompletedQuery::QueryCounter(
    base::subtle::Atomic32 submit_count) {
  NOTREACHED();
  return false;
}

void AsyncReadPixelsCompletedQuery::Complete() {
  complete_result_ = MarkAsCompleted(1);
}

bool AsyncReadPixelsCompletedQuery::Process(bool did_finish) {
  return !IsFinished() || complete_result_;
}

void AsyncReadPixelsCompletedQuery::Destroy(bool /* have_context */) {
  if (!IsDeleted()) {
    MarkAsDeleted();
  }
}

AsyncReadPixelsCompletedQuery::~AsyncReadPixelsCompletedQuery() {
}


class GetErrorQuery : public QueryManager::Query {
 public:
  GetErrorQuery(QueryManager* manager,
                GLenum target,
                int32_t shm_id,
                uint32_t shm_offset);

  bool Begin() override;
  bool End(base::subtle::Atomic32 submit_count) override;
  bool QueryCounter(base::subtle::Atomic32 submit_count) override;
  void Pause() override;
  void Resume() override;
  bool Process(bool did_finish) override;
  void Destroy(bool have_context) override;

 protected:
  ~GetErrorQuery() override;

 private:
};

GetErrorQuery::GetErrorQuery(QueryManager* manager,
                             GLenum target,
                             int32_t shm_id,
                             uint32_t shm_offset)
    : Query(manager, target, shm_id, shm_offset) {}

bool GetErrorQuery::Begin() {
  MarkAsActive();
  return true;
}

void GetErrorQuery::Pause() {
  MarkAsPaused();
}

void GetErrorQuery::Resume() {
  MarkAsActive();
}

bool GetErrorQuery::End(base::subtle::Atomic32 submit_count) {
  MarkAsPending(submit_count);
  return MarkAsCompleted(manager()->decoder()->GetErrorState()->GetGLError());
}

bool GetErrorQuery::QueryCounter(base::subtle::Atomic32 submit_count) {
  NOTREACHED();
  return false;
}

bool GetErrorQuery::Process(bool did_finish) {
  NOTREACHED();
  return true;
}

void GetErrorQuery::Destroy(bool /* have_context */) {
  if (!IsDeleted()) {
    MarkAsDeleted();
  }
}

GetErrorQuery::~GetErrorQuery() {
}

class CommandsCompletedQuery : public QueryManager::Query {
 public:
  CommandsCompletedQuery(QueryManager* manager,
                         GLenum target,
                         int32_t shm_id,
                         uint32_t shm_offset);

  // Overridden from QueryManager::Query:
  bool Begin() override;
  bool End(base::subtle::Atomic32 submit_count) override;
  bool QueryCounter(base::subtle::Atomic32 submit_count) override;
  void Pause() override;
  void Resume() override;
  bool Process(bool did_finish) override;
  void Destroy(bool have_context) override;

 protected:
  ~CommandsCompletedQuery() override;

 private:
  std::unique_ptr<gl::GLFence> fence_;
  base::TimeTicks begin_time_;
};

CommandsCompletedQuery::CommandsCompletedQuery(QueryManager* manager,
                                               GLenum target,
                                               int32_t shm_id,
                                               uint32_t shm_offset)
    : Query(manager, target, shm_id, shm_offset) {}

bool CommandsCompletedQuery::Begin() {
  MarkAsActive();
  begin_time_ = base::TimeTicks::Now();
  return true;
}

void CommandsCompletedQuery::Pause() {
  MarkAsPaused();
}

void CommandsCompletedQuery::Resume() {
  MarkAsActive();
}

bool CommandsCompletedQuery::End(base::subtle::Atomic32 submit_count) {
  if (fence_ && fence_->ResetSupported()) {
    fence_->ResetState();
  }
  else {
    fence_.reset(gl::GLFence::Create());
  }
  DCHECK(fence_);
  return AddToPendingQueue(submit_count);
}

bool CommandsCompletedQuery::QueryCounter(base::subtle::Atomic32 submit_count) {
  NOTREACHED();
  return false;
}

bool CommandsCompletedQuery::Process(bool did_finish) {
  // Note: |did_finish| guarantees that the GPU has passed the fence but
  // we cannot assume that GLFence::HasCompleted() will return true yet as
  // that's not guaranteed by all GLFence implementations.
  if (!did_finish && fence_ && !fence_->HasCompleted())
    return true;

  const base::TimeDelta elapsed = base::TimeTicks::Now() - begin_time_;
  return MarkAsCompleted(elapsed.InMicroseconds());
}

void CommandsCompletedQuery::Destroy(bool have_context) {
  if (have_context && !IsDeleted()) {
    fence_.reset();
    MarkAsDeleted();
  }
}

CommandsCompletedQuery::~CommandsCompletedQuery() {}

class TimeElapsedQuery : public QueryManager::Query {
 public:
  TimeElapsedQuery(QueryManager* manager,
                   GLenum target,
                   int32_t shm_id,
                   uint32_t shm_offset);

  // Overridden from QueryManager::Query:
  bool Begin() override;
  bool End(base::subtle::Atomic32 submit_count) override;
  bool QueryCounter(base::subtle::Atomic32 submit_count) override;
  void Pause() override;
  void Resume() override;
  bool Process(bool did_finish) override;
  void Destroy(bool have_context) override;

 protected:
  ~TimeElapsedQuery() override;

 private:
  std::unique_ptr<gl::GPUTimer> gpu_timer_;
};

TimeElapsedQuery::TimeElapsedQuery(QueryManager* manager,
                                   GLenum target,
                                   int32_t shm_id,
                                   uint32_t shm_offset)
    : Query(manager, target, shm_id, shm_offset),
      gpu_timer_(manager->CreateGPUTimer(true)) {}

bool TimeElapsedQuery::Begin() {
  // Reset the disjoint value before the query begins if it is safe.
  SafelyResetDisjointValue();
  MarkAsActive();
  gpu_timer_->Start();
  return true;
}

bool TimeElapsedQuery::End(base::subtle::Atomic32 submit_count) {
  gpu_timer_->End();
  return AddToPendingQueue(submit_count);
}

bool TimeElapsedQuery::QueryCounter(base::subtle::Atomic32 submit_count) {
  NOTREACHED();
  return false;
}

void TimeElapsedQuery::Pause() {
  MarkAsPaused();
}

void TimeElapsedQuery::Resume() {
  MarkAsActive();
}

bool TimeElapsedQuery::Process(bool did_finish) {
  if (!gpu_timer_->IsAvailable())
    return true;

  // Make sure disjoint value is up to date. This disjoint check is the only one
  // that needs to be done to validate that this query is valid. If a disjoint
  // occurs before the client checks the query value we will just hide the
  // disjoint state since it did not affect this query.
  UpdateDisjointValue();

  const uint64_t nano_seconds = gpu_timer_->GetDeltaElapsed() *
                                base::Time::kNanosecondsPerMicrosecond;
  return MarkAsCompleted(nano_seconds);
}

void TimeElapsedQuery::Destroy(bool have_context) {
  gpu_timer_->Destroy(have_context);
}

TimeElapsedQuery::~TimeElapsedQuery() {}

class TimeStampQuery : public QueryManager::Query {
 public:
  TimeStampQuery(QueryManager* manager,
                 GLenum target,
                 int32_t shm_id,
                 uint32_t shm_offset);

  // Overridden from QueryManager::Query:
  bool Begin() override;
  bool End(base::subtle::Atomic32 submit_count) override;
  bool QueryCounter(base::subtle::Atomic32 submit_count) override;
  void Pause() override;
  void Resume() override;
  bool Process(bool did_finish) override;
  void Destroy(bool have_context) override;

 protected:
  ~TimeStampQuery() override;

 private:
  std::unique_ptr<gl::GPUTimer> gpu_timer_;
};

TimeStampQuery::TimeStampQuery(QueryManager* manager,
                               GLenum target,
                               int32_t shm_id,
                               uint32_t shm_offset)
    : Query(manager, target, shm_id, shm_offset),
      gpu_timer_(manager->CreateGPUTimer(false)) {}

bool TimeStampQuery::Begin() {
  NOTREACHED();
  return false;
}

bool TimeStampQuery::End(base::subtle::Atomic32 submit_count) {
  NOTREACHED();
  return false;
}

void TimeStampQuery::Pause() {
  MarkAsPaused();
}

void TimeStampQuery::Resume() {
  MarkAsActive();
}

bool TimeStampQuery::QueryCounter(base::subtle::Atomic32 submit_count) {
  // Reset the disjoint value before the query begins if it is safe.
  SafelyResetDisjointValue();
  MarkAsActive();
  // After a timestamp has begun, we will want to continually detect
  // the disjoint value every frame until the context is destroyed.
  BeginContinualDisjointUpdate();

  gpu_timer_->QueryTimeStamp();
  return AddToPendingQueue(submit_count);
}

bool TimeStampQuery::Process(bool did_finish) {
  if (!gpu_timer_->IsAvailable())
    return true;

  // Make sure disjoint value is up to date. This disjoint check is the only one
  // that needs to be done to validate that this query is valid. If a disjoint
  // occurs before the client checks the query value we will just hide the
  // disjoint state since it did not affect this query.
  UpdateDisjointValue();

  int64_t start = 0;
  int64_t end = 0;
  gpu_timer_->GetStartEndTimestamps(&start, &end);
  DCHECK(start == end);

  const uint64_t nano_seconds = start * base::Time::kNanosecondsPerMicrosecond;
  return MarkAsCompleted(nano_seconds);
}

void TimeStampQuery::Destroy(bool have_context) {
  if (gpu_timer_.get()) {
    gpu_timer_->Destroy(have_context);
    gpu_timer_.reset();
  }
}

TimeStampQuery::~TimeStampQuery() {}

QueryManager::QueryManager(
    GLES2Decoder* decoder,
    FeatureInfo* feature_info)
    : decoder_(decoder),
      use_arb_occlusion_query2_for_occlusion_query_boolean_(
          feature_info->feature_flags(
            ).use_arb_occlusion_query2_for_occlusion_query_boolean),
      use_arb_occlusion_query_for_occlusion_query_boolean_(
          feature_info->feature_flags(
            ).use_arb_occlusion_query_for_occlusion_query_boolean),
      update_disjoints_continually_(false),
      disjoint_notify_shm_id_(-1),
      disjoint_notify_shm_offset_(0),
      disjoints_notified_(0),
      query_count_(0) {
  DCHECK(!(use_arb_occlusion_query_for_occlusion_query_boolean_ &&
           use_arb_occlusion_query2_for_occlusion_query_boolean_));
  DCHECK(decoder);
  gl::GLContext* context = decoder_->GetGLContext();
  if (context) {
    gpu_timing_client_ = context->CreateGPUTimingClient();
  } else {
    gpu_timing_client_ = new gl::GPUTimingClient();
  }
}

QueryManager::~QueryManager() {
  DCHECK(queries_.empty());

  // If this triggers, that means something is keeping a reference to
  // a Query belonging to this.
  CHECK_EQ(query_count_, 0u);
}

void QueryManager::Destroy(bool have_context) {
  active_queries_.clear();
  pending_queries_.clear();
  pending_transfer_queries_.clear();
  active_queries_.clear();
  while (!queries_.empty()) {
    Query* query = queries_.begin()->second.get();
    query->Destroy(have_context);
    queries_.erase(queries_.begin());
  }
}

error::Error QueryManager::SetDisjointSync(int32_t shm_id,
                                           uint32_t shm_offset) {
  if (disjoint_notify_shm_id_ != -1 || shm_id == -1)
    return error::kInvalidArguments;

  DisjointValueSync* sync = decoder_->GetSharedMemoryAs<DisjointValueSync*>(
      shm_id, shm_offset, sizeof(*sync));
  if (!sync)
    return error::kOutOfBounds;

  sync->Reset();
  disjoints_notified_ = 0;

  disjoint_notify_shm_id_ = shm_id;
  disjoint_notify_shm_offset_ = shm_offset;
  return error::kNoError;
}

QueryManager::Query* QueryManager::CreateQuery(GLenum target,
                                               GLuint client_id,
                                               int32_t shm_id,
                                               uint32_t shm_offset) {
  scoped_refptr<Query> query;
  switch (target) {
    case GL_COMMANDS_ISSUED_CHROMIUM:
      query = new CommandsIssuedQuery(this, target, shm_id, shm_offset);
      break;
    case GL_LATENCY_QUERY_CHROMIUM:
      query = new CommandLatencyQuery(this, target, shm_id, shm_offset);
      break;
    case GL_ASYNC_PIXEL_PACK_COMPLETED_CHROMIUM:
      query = new AsyncReadPixelsCompletedQuery(
          this, target, shm_id, shm_offset);
      break;
    case GL_GET_ERROR_QUERY_CHROMIUM:
      query = new GetErrorQuery(this, target, shm_id, shm_offset);
      break;
    case GL_COMMANDS_COMPLETED_CHROMIUM:
      query = new CommandsCompletedQuery(this, target, shm_id, shm_offset);
      break;
    case GL_TIME_ELAPSED:
      query = new TimeElapsedQuery(this, target, shm_id, shm_offset);
      break;
    case GL_TIMESTAMP:
      query = new TimeStampQuery(this, target, shm_id, shm_offset);
      break;
    case GL_ANY_SAMPLES_PASSED:
    case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
      query = new BooleanQuery(this, target, shm_id, shm_offset);
      break;
    case GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN:
      query = new SummedIntegerQuery(this, target, shm_id, shm_offset);
      break;
    default: {
      NOTREACHED();
    }
  }
  std::pair<QueryMap::iterator, bool> result =
      queries_.insert(std::make_pair(client_id, query));
  DCHECK(result.second);
  return query.get();
}

std::unique_ptr<gl::GPUTimer> QueryManager::CreateGPUTimer(bool elapsed_time) {
  return gpu_timing_client_->CreateGPUTimer(elapsed_time);
}

bool QueryManager::GPUTimingAvailable() {
  return gpu_timing_client_->IsAvailable();
}

void QueryManager::GenQueries(GLsizei n, const GLuint* queries) {
  DCHECK_GE(n, 0);
  for (GLsizei i = 0; i < n; ++i) {
    generated_query_ids_.insert(queries[i]);
  }
}

bool QueryManager::IsValidQuery(GLuint id) {
  GeneratedQueryIds::iterator it = generated_query_ids_.find(id);
  return it != generated_query_ids_.end();
}

QueryManager::Query* QueryManager::GetQuery(GLuint client_id) {
  QueryMap::iterator it = queries_.find(client_id);
  return it != queries_.end() ? it->second.get() : nullptr;
}

QueryManager::Query* QueryManager::GetActiveQuery(GLenum target) {
  ActiveQueryMap::iterator it = active_queries_.find(target);
  return it != active_queries_.end() ? it->second.get() : nullptr;
}

void QueryManager::RemoveQuery(GLuint client_id) {
  QueryMap::iterator it = queries_.find(client_id);
  if (it != queries_.end()) {
    Query* query = it->second.get();

    // Remove from active query map if it is active.
    ActiveQueryMap::iterator active_it = active_queries_.find(query->target());
    bool is_active = (active_it != active_queries_.end() &&
                      query == active_it->second.get());
    DCHECK(is_active == query->IsActive());
    if (is_active)
      active_queries_.erase(active_it);

    query->Destroy(true);
    RemovePendingQuery(query);
    query->MarkAsDeleted();
    queries_.erase(it);
  }
  generated_query_ids_.erase(client_id);
}

void QueryManager::StartTracking(QueryManager::Query* /* query */) {
  ++query_count_;
}

void QueryManager::StopTracking(QueryManager::Query* /* query */) {
  --query_count_;
}

GLenum QueryManager::AdjustTargetForEmulation(GLenum target) {
  switch (target) {
    case GL_ANY_SAMPLES_PASSED_CONSERVATIVE_EXT:
    case GL_ANY_SAMPLES_PASSED_EXT:
      if (use_arb_occlusion_query2_for_occlusion_query_boolean_) {
        // ARB_occlusion_query2 does not have a
        // GL_ANY_SAMPLES_PASSED_CONSERVATIVE_EXT
        // target.
        target = GL_ANY_SAMPLES_PASSED_EXT;
      } else if (use_arb_occlusion_query_for_occlusion_query_boolean_) {
        // ARB_occlusion_query does not have a
        // GL_ANY_SAMPLES_PASSED_EXT
        // target.
        target = GL_SAMPLES_PASSED_ARB;
      }
      break;
    default:
      break;
  }
  return target;
}

void QueryManager::BeginQueryHelper(GLenum target, GLuint id) {
  target = AdjustTargetForEmulation(target);
  glBeginQuery(target, id);
}

void QueryManager::EndQueryHelper(GLenum target) {
  target = AdjustTargetForEmulation(target);
  glEndQuery(target);
}

void QueryManager::UpdateDisjointValue() {
  if (disjoint_notify_shm_id_ != -1) {
    if (gpu_timing_client_->CheckAndResetTimerErrors()) {
      disjoints_notified_++;

      DisjointValueSync* sync = decoder_->GetSharedMemoryAs<DisjointValueSync*>(
          disjoint_notify_shm_id_, disjoint_notify_shm_offset_, sizeof(*sync));
      if (!sync) {
        // Shared memory does not seem to be valid, ignore the shm id/offset.
        disjoint_notify_shm_id_ = -1;
        disjoint_notify_shm_offset_ = 0;
      } else {
        sync->SetDisjointCount(disjoints_notified_);
      }
    }
  }
}

void QueryManager::SafelyResetDisjointValue() {
  // It is only safe to reset the disjoint value is there is no active
  // elapsed timer and we are not continually updating the disjoint value.
  if (!update_disjoints_continually_ && !GetActiveQuery(GL_TIME_ELAPSED)) {
    // Reset the error state without storing the result.
    gpu_timing_client_->CheckAndResetTimerErrors();
  }
}

QueryManager::Query::Query(QueryManager* manager,
                           GLenum target,
                           int32_t shm_id,
                           uint32_t shm_offset)
    : manager_(manager),
      target_(target),
      shm_id_(shm_id),
      shm_offset_(shm_offset),
      submit_count_(0),
      query_state_(kQueryState_Initialize),
      deleted_(false) {
  DCHECK(manager);
  manager_->StartTracking(this);
}

void QueryManager::Query::RunCallbacks() {
  for (size_t i = 0; i < callbacks_.size(); i++) {
    callbacks_[i].Run();
  }
  callbacks_.clear();
}

void QueryManager::Query::AddCallback(base::Closure callback) {
  if (query_state_ == kQueryState_Pending) {
    callbacks_.push_back(callback);
  } else {
    callback.Run();
  }
}

QueryManager::Query::~Query() {
  // The query is getting deleted, either by the client or
  // because the context was lost. Call any outstanding
  // callbacks to avoid leaks.
  RunCallbacks();
  if (manager_) {
    manager_->StopTracking(this);
    manager_ = NULL;
  }
}

bool QueryManager::Query::MarkAsCompleted(uint64_t result) {
  UnmarkAsPending();
  QuerySync* sync = manager_->decoder_->GetSharedMemoryAs<QuerySync*>(
      shm_id_, shm_offset_, sizeof(*sync));
  if (!sync) {
    return false;
  }

  sync->result = result;
  base::subtle::Release_Store(&sync->process_count, submit_count_);

  return true;
}

bool QueryManager::ProcessPendingQueries(bool did_finish) {
  while (!pending_queries_.empty()) {
    Query* query = pending_queries_.front().get();
    if (!query->Process(did_finish)) {
      return false;
    }
    if (query->IsPending()) {
      break;
    }
    query->RunCallbacks();
    pending_queries_.pop_front();
  }
  // If glFinish() has been called, all of our queries should be completed.
  DCHECK(!did_finish || pending_queries_.empty());

  return true;
}

bool QueryManager::HavePendingQueries() {
  return !pending_queries_.empty();
}

bool QueryManager::ProcessPendingTransferQueries() {
  while (!pending_transfer_queries_.empty()) {
    Query* query = pending_transfer_queries_.front().get();
    if (!query->Process(false)) {
      return false;
    }
    if (query->IsPending()) {
      break;
    }
    query->RunCallbacks();
    pending_transfer_queries_.pop_front();
  }

  return true;
}

bool QueryManager::HavePendingTransferQueries() {
  return !pending_transfer_queries_.empty();
}

void QueryManager::ProcessFrameBeginUpdates() {
  if (update_disjoints_continually_)
    UpdateDisjointValue();
}

bool QueryManager::AddPendingQuery(Query* query,
                                   base::subtle::Atomic32 submit_count) {
  DCHECK(query);
  DCHECK(!query->IsDeleted());
  if (!RemovePendingQuery(query)) {
    return false;
  }
  query->MarkAsPending(submit_count);
  pending_queries_.push_back(query);
  return true;
}

bool QueryManager::AddPendingTransferQuery(
    Query* query,
    base::subtle::Atomic32 submit_count) {
  DCHECK(query);
  DCHECK(!query->IsDeleted());
  if (!RemovePendingQuery(query)) {
    return false;
  }
  query->MarkAsPending(submit_count);
  pending_transfer_queries_.push_back(query);
  return true;
}

bool QueryManager::RemovePendingQuery(Query* query) {
  DCHECK(query);
  if (query->IsPending()) {
    // TODO(gman): Speed this up if this is a common operation. This would only
    // happen if you do being/end begin/end on the same query without waiting
    // for the first one to finish.
    for (QueryQueue::iterator it = pending_queries_.begin();
         it != pending_queries_.end(); ++it) {
      if (it->get() == query) {
        pending_queries_.erase(it);
        break;
      }
    }
    for (QueryQueue::iterator it = pending_transfer_queries_.begin();
         it != pending_transfer_queries_.end(); ++it) {
      if (it->get() == query) {
        pending_transfer_queries_.erase(it);
        break;
      }
    }
    if (!query->MarkAsCompleted(0)) {
      return false;
    }
  }
  return true;
}

bool QueryManager::BeginQuery(Query* query) {
  DCHECK(query);
  if (!RemovePendingQuery(query)) {
    return false;
  }
  if (query->Begin()) {
    active_queries_[query->target()] = query;
    return true;
  }

  return false;
}

bool QueryManager::EndQuery(Query* query, base::subtle::Atomic32 submit_count) {
  DCHECK(query);
  if (!RemovePendingQuery(query)) {
    return false;
  }

  // Remove from active query map if it is active.
  ActiveQueryMap::iterator active_it = active_queries_.find(query->target());
  DCHECK(active_it != active_queries_.end());
  DCHECK(query == active_it->second.get());
  active_queries_.erase(active_it);

  return query->End(submit_count);
}

bool QueryManager::QueryCounter(
    Query* query, base::subtle::Atomic32 submit_count) {
  DCHECK(query);
  return query->QueryCounter(submit_count);
}

void QueryManager::PauseQueries() {
  for (std::pair<const GLenum, scoped_refptr<Query> >& it : active_queries_) {
    if (it.second->IsActive()) {
      it.second->Pause();
      DCHECK(it.second->IsPaused());
    }
  }
}

void QueryManager::ResumeQueries() {
  for (std::pair<const GLenum, scoped_refptr<Query> >& it : active_queries_) {
    if (it.second->IsPaused()) {
      it.second->Resume();
      DCHECK(it.second->IsActive());
    }
  }
}

}  // namespace gles2
}  // namespace gpu