/*
 * Copyright (C) 2009 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "modules/webgl/WebGLProgram.h"

#include "gpu/command_buffer/client/gles2_interface.h"
#include "modules/webgl/WebGLContextGroup.h"
#include "modules/webgl/WebGLRenderingContextBase.h"

namespace blink {

WebGLProgram* WebGLProgram::create(WebGLRenderingContextBase* ctx) {
  return new WebGLProgram(ctx);
}

WebGLProgram::WebGLProgram(WebGLRenderingContextBase* ctx)
    : WebGLSharedPlatform3DObject(ctx),
      m_linkStatus(false),
      m_linkCount(0),
      m_activeTransformFeedbackCount(0),
      m_vertexShader(this, nullptr),
      m_fragmentShader(this, nullptr),
      m_infoValid(true) {
  setObject(ctx->contextGL()->CreateProgram());
}

WebGLProgram::~WebGLProgram() {
  // These heap objects handle detachment on their own. Clear out
  // the references to prevent deleteObjectImpl() from trying to do
  // same, as we cannot safely access other heap objects from this
  // destructor.
  m_vertexShader = nullptr;
  m_fragmentShader = nullptr;

  // See the comment in WebGLObject::detachAndDeleteObject().
  detachAndDeleteObject();
}

void WebGLProgram::deleteObjectImpl(gpu::gles2::GLES2Interface* gl) {
  gl->DeleteProgram(m_object);
  m_object = 0;
  if (m_vertexShader) {
    m_vertexShader->onDetached(gl);
    m_vertexShader = nullptr;
  }
  if (m_fragmentShader) {
    m_fragmentShader->onDetached(gl);
    m_fragmentShader = nullptr;
  }
}

bool WebGLProgram::linkStatus(WebGLRenderingContextBase* context) {
  cacheInfoIfNeeded(context);
  return m_linkStatus;
}

void WebGLProgram::increaseLinkCount() {
  ++m_linkCount;
  m_infoValid = false;
}

void WebGLProgram::increaseActiveTransformFeedbackCount() {
  ++m_activeTransformFeedbackCount;
}

void WebGLProgram::decreaseActiveTransformFeedbackCount() {
  --m_activeTransformFeedbackCount;
}

WebGLShader* WebGLProgram::getAttachedShader(GLenum type) {
  switch (type) {
    case GL_VERTEX_SHADER:
      return m_vertexShader;
    case GL_FRAGMENT_SHADER:
      return m_fragmentShader;
    default:
      return 0;
  }
}

bool WebGLProgram::attachShader(WebGLShader* shader) {
  if (!shader || !shader->object())
    return false;
  switch (shader->type()) {
    case GL_VERTEX_SHADER:
      if (m_vertexShader)
        return false;
      m_vertexShader = shader;
      return true;
    case GL_FRAGMENT_SHADER:
      if (m_fragmentShader)
        return false;
      m_fragmentShader = shader;
      return true;
    default:
      return false;
  }
}

bool WebGLProgram::detachShader(WebGLShader* shader) {
  if (!shader || !shader->object())
    return false;
  switch (shader->type()) {
    case GL_VERTEX_SHADER:
      if (m_vertexShader != shader)
        return false;
      m_vertexShader = nullptr;
      return true;
    case GL_FRAGMENT_SHADER:
      if (m_fragmentShader != shader)
        return false;
      m_fragmentShader = nullptr;
      return true;
    default:
      return false;
  }
}

void WebGLProgram::visitChildDOMWrappers(
    v8::Isolate* isolate,
    const v8::Persistent<v8::Object>& wrapper) {
  DOMWrapperWorld::setWrapperReferencesInAllWorlds(wrapper, m_vertexShader,
                                                   isolate);
  DOMWrapperWorld::setWrapperReferencesInAllWorlds(wrapper, m_fragmentShader,
                                                   isolate);
}

void WebGLProgram::cacheInfoIfNeeded(WebGLRenderingContextBase* context) {
  if (m_infoValid)
    return;
  if (!m_object)
    return;
  gpu::gles2::GLES2Interface* gl = context->contextGL();
  m_linkStatus = 0;
  gl->GetProgramiv(m_object, GL_LINK_STATUS, &m_linkStatus);
  m_infoValid = true;
}

DEFINE_TRACE(WebGLProgram) {
  visitor->trace(m_vertexShader);
  visitor->trace(m_fragmentShader);
  WebGLSharedPlatform3DObject::trace(visitor);
}

DEFINE_TRACE_WRAPPERS(WebGLProgram) {
  visitor->traceWrappers(m_vertexShader);
  visitor->traceWrappers(m_fragmentShader);
  WebGLSharedPlatform3DObject::traceWrappers(visitor);
}

}  // namespace blink