// Copyright 2014 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 "ui/gl/gl_fence_arb.h"

#include "base/strings/stringprintf.h"
#include "ui/gl/gl_bindings.h"

namespace gfx {

namespace {

std::string GetGLErrors() {
  // Clears and logs all current gl errors.
  std::string accumulated_errors;
  GLenum error;
  while ((error = glGetError()) != GL_NO_ERROR) {
    accumulated_errors += base::StringPrintf("0x%x ", error);
  }
  return accumulated_errors;
}

}  // namespace

GLFenceARB::GLFenceARB() {
  sync_ = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
  DCHECK_EQ(GL_TRUE, glIsSync(sync_));
  glFlush();
}

bool GLFenceARB::HasCompleted() {
  // Handle the case where FenceSync failed.
  if (!sync_)
    return true;

  DCHECK_EQ(GL_TRUE, glIsSync(sync_));
  // We could potentially use glGetSynciv here, but it doesn't work
  // on OSX 10.7 (always says the fence is not signaled yet).
  // glClientWaitSync works better, so let's use that instead.
  GLenum result = glClientWaitSync(sync_, 0, 0);
  if (result == GL_WAIT_FAILED) {
    LOG(FATAL) << "Failed to wait for GLFence. error code:" << GetGLErrors();
  }
  return result != GL_TIMEOUT_EXPIRED;
}

void GLFenceARB::ClientWait() {
  DCHECK_EQ(GL_TRUE, glIsSync(sync_));
  GLenum result =
      glClientWaitSync(sync_, GL_SYNC_FLUSH_COMMANDS_BIT, GL_TIMEOUT_IGNORED);
  DCHECK_NE(static_cast<GLenum>(GL_TIMEOUT_EXPIRED), result);
  if (result == GL_WAIT_FAILED) {
    LOG(FATAL) << "Failed to wait for GLFence. error code:" << GetGLErrors();
  }
}

void GLFenceARB::ServerWait() {
  DCHECK_EQ(GL_TRUE, glIsSync(sync_));
  glWaitSync(sync_, 0, GL_TIMEOUT_IGNORED);
}

GLFenceARB::~GLFenceARB() {
  DCHECK_EQ(GL_TRUE, glIsSync(sync_));
  glDeleteSync(sync_);
}

}  // namespace gfx