// Copyright 2008, Google 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:
//
//    * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//    * 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.
//    * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "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 THE COPYRIGHT
// OWNER 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 "chrome/common/chrome_plugin_lib.h"

#include "base/command_line.h"
#include "base/histogram.h"
#include "base/path_service.h"
#include "base/perftimer.h"
#include "base/registry.h"
#include "base/string_util.h"
#include "chrome/common/chrome_counters.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/notification_service.h"
#include "chrome/common/chrome_paths.h"
#include "webkit/glue/plugins/plugin_list.h"

const TCHAR ChromePluginLib::kRegistryChromePlugins[] =
    _T("Software\\Google\\Chrome\\Plugins");
static const TCHAR kRegistryLoadOnStartup[] = _T("LoadOnStartup");
static const TCHAR kRegistryPath[] = _T("Path");

typedef stdext::hash_map<std::wstring, scoped_refptr<ChromePluginLib> >
    PluginMap;

// A map of all the instantiated plugins.
static PluginMap* g_loaded_libs;

// The thread plugins are loaded and used in, lazily initialized upon
// the first creation call.
static DWORD g_plugin_thread_id = 0;

static bool IsSingleProcessMode() {
  // We don't support ChromePlugins in single-process mode.
  CommandLine command_line;
  return command_line.HasSwitch(switches::kSingleProcess);
}

// static
ChromePluginLib* ChromePluginLib::Create(const std::wstring& filename,
                                         const CPBrowserFuncs* bfuncs) {
  // Keep a map of loaded plugins to ensure we only load each library once.
  if (!g_loaded_libs) {
    g_loaded_libs = new PluginMap();
    g_plugin_thread_id = ::GetCurrentThreadId();
  }
  DCHECK(IsPluginThread());

  // Lower case to match how PluginList::LoadPlugin stores the path.
  std::wstring filename_lc = StringToLowerASCII(filename);

  PluginMap::const_iterator iter = g_loaded_libs->find(filename_lc);
  if (iter != g_loaded_libs->end())
    return iter->second;

  scoped_refptr<ChromePluginLib> plugin(new ChromePluginLib(filename_lc));
  if (!plugin->CP_Initialize(bfuncs))
    return NULL;

  (*g_loaded_libs)[filename_lc] = plugin;
  return plugin;
}

// static
ChromePluginLib* ChromePluginLib::Find(const std::wstring& filename) {
  if (g_loaded_libs) {
    PluginMap::const_iterator iter = g_loaded_libs->find(filename);
    if (iter != g_loaded_libs->end())
      return iter->second;
  }
  return NULL;
}

// static
void ChromePluginLib::Destroy(const std::wstring& filename) {
  DCHECK(g_loaded_libs);
  PluginMap::iterator iter = g_loaded_libs->find(filename);
  if (iter != g_loaded_libs->end()) {
    iter->second->Unload();
    g_loaded_libs->erase(iter);
  }
}

// static
bool ChromePluginLib::IsPluginThread() {
  return ::GetCurrentThreadId() == g_plugin_thread_id;
}

// static
void ChromePluginLib::RegisterPluginsWithNPAPI() {
  // We don't support ChromePlugins in single-process mode.
  if (IsSingleProcessMode())
    return;

  std::wstring path;
  if (!PathService::Get(chrome::FILE_GEARS_PLUGIN, &path))
    return;
  // Note: we can only access the NPAPI list because the PluginService has done
  // the locking for us.  We should not touch it anywhere else.
  NPAPI::PluginList::AddExtraPluginPath(path);
}

static void LogPluginLoadTime(const TimeDelta &time) {
  UMA_HISTOGRAM_TIMES(L"Gears.LoadTime", time);
}

// static
void ChromePluginLib::LoadChromePlugins(const CPBrowserFuncs* bfuncs) {
  static bool loaded = false;
  if (loaded)
    return;
  loaded = true;

  // We don't support ChromePlugins in single-process mode.
  if (IsSingleProcessMode())
    return;

  std::wstring path;
  if (!PathService::Get(chrome::FILE_GEARS_PLUGIN, &path))
    return;

  PerfTimer timer;
  ChromePluginLib::Create(path, bfuncs);
  LogPluginLoadTime(timer.Elapsed());

  // TODO(mpcomplete): disabled loading of plugins from the registry until we
  // phase out registry keys from the gears installer.
#if 0
  for (RegistryKeyIterator iter(HKEY_CURRENT_USER, kRegistryChromePlugins);
       iter.Valid(); ++iter) {
    // Use the registry to gather plugin across the file system.
    std::wstring reg_path = kRegistryChromePlugins;
    reg_path.append(L"\\");
    reg_path.append(iter.Name());
    RegKey key(HKEY_CURRENT_USER, reg_path.c_str());

    DWORD is_persistent;
    if (key.ReadValueDW(kRegistryLoadOnStartup, &is_persistent) &&
        is_persistent) {
      std::wstring path;
      if (key.ReadValue(kRegistryPath, &path)) {
        ChromePluginLib::Create(path, bfuncs);
      }
    }
  }
#endif
}

// static
void ChromePluginLib::UnloadAllPlugins() {
  if (g_loaded_libs) {
    PluginMap::iterator it;
    for (PluginMap::iterator it = g_loaded_libs->begin();
         it != g_loaded_libs->end(); ++it) {
      it->second->Unload();
    }
    delete g_loaded_libs;
    g_loaded_libs = NULL;
  }
}

ChromePluginLib::ChromePluginLib(const std::wstring& filename)
    : filename_(filename),
      module_(0),
      initialized_(false),
      CP_VersionNegotiate_(NULL),
      CP_Initialize_(NULL) {
  memset((void*)&plugin_funcs_, 0, sizeof(plugin_funcs_));
}

ChromePluginLib::~ChromePluginLib() {
}

bool ChromePluginLib::CP_Initialize(const CPBrowserFuncs* bfuncs) {
  if (initialized_)
    return true;

  if (!Load())
    return false;

  if (CP_VersionNegotiate_) {
    uint16 selected_version = 0;
    CPError rv = CP_VersionNegotiate_(CP_VERSION, CP_VERSION,
                                      &selected_version);
    if ( (rv != CPERR_SUCCESS) || (selected_version != CP_VERSION))
      return false;
  }

  plugin_funcs_.size = sizeof(plugin_funcs_);
  CPError rv = CP_Initialize_(cpid(), bfuncs, &plugin_funcs_);
  initialized_ = (rv == CPERR_SUCCESS) &&
      (CP_GET_MAJOR_VERSION(plugin_funcs_.version) == CP_MAJOR_VERSION) &&
      (CP_GET_MINOR_VERSION(plugin_funcs_.version) <= CP_MINOR_VERSION);

  return initialized_;
}

void ChromePluginLib::CP_Shutdown() {
  DCHECK(initialized_);
  functions().shutdown();
  initialized_ = false;
  memset((void*)&plugin_funcs_, 0, sizeof(plugin_funcs_));
}

int ChromePluginLib::CP_Test(void* param) {
  DCHECK(initialized_);
  if (!CP_Test_)
    return -1;
  return CP_Test_(param);
}

bool ChromePluginLib::Load() {
  DCHECK(module_ == 0);
  module_ = LoadLibrary(filename_.c_str());
  if (module_ == 0)
    return false;

  // required initialization function
  CP_Initialize_ = reinterpret_cast<CP_InitializeFunc>
      (GetProcAddress(module_, "CP_Initialize"));

  if (!CP_Initialize_) {
    FreeLibrary(module_);
    module_ = 0;
    return false;
  }

  // optional version negotiation function
  CP_VersionNegotiate_ = reinterpret_cast<CP_VersionNegotiateFunc>
      (GetProcAddress(module_, "CP_VersionNegotiate"));

  // optional test function
  CP_Test_ = reinterpret_cast<CP_TestFunc>
      (GetProcAddress(module_, "CP_Test"));

  return true;
}

void ChromePluginLib::Unload() {
  NotificationService::current()->Notify(
      NOTIFY_CHROME_PLUGIN_UNLOADED,
      Source<ChromePluginLib>(this),
      NotificationService::NoDetails());

  if (initialized_)
    CP_Shutdown();

  if (module_) {
    FreeLibrary(module_);
    module_ = 0;
  }
}