// Copyright (c) 2013 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 "chrome/common/extensions/extension_file_util.h"

#include <map>
#include <vector>

#include "base/file_util.h"
#include "base/files/file_enumerator.h"
#include "base/files/file_path.h"
#include "base/files/scoped_temp_dir.h"
#include "base/json/json_file_value_serializer.h"
#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "base/path_service.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/thread_restrictions.h"
#include "chrome/common/chrome_paths.h"
#include "chrome/common/extensions/api/extension_action/action_info.h"
#include "chrome/common/extensions/extension_icon_set.h"
#include "chrome/common/extensions/extension_l10n_util.h"
#include "chrome/common/extensions/extension_messages.h"
#include "chrome/common/extensions/manifest_handlers/icons_handler.h"
#include "chrome/common/extensions/manifest_handlers/theme_handler.h"
#include "chrome/common/extensions/message_bundle.h"
#include "extensions/common/constants.h"
#include "extensions/common/extension.h"
#include "extensions/common/extension_resource.h"
#include "extensions/common/install_warning.h"
#include "extensions/common/manifest.h"
#include "extensions/common/manifest_constants.h"
#include "extensions/common/manifest_handler.h"
#include "grit/generated_resources.h"
#include "net/base/file_stream.h"
#include "ui/base/l10n/l10n_util.h"

using extensions::Extension;
using extensions::ExtensionResource;
using extensions::Manifest;

namespace errors = extensions::manifest_errors;

namespace {

const base::FilePath::CharType kTempDirectoryName[] = FILE_PATH_LITERAL("Temp");

// Add the image paths contained in the |icon_set| to |image_paths|.
void AddPathsFromIconSet(const ExtensionIconSet& icon_set,
                         std::set<base::FilePath>* image_paths) {
  // TODO(viettrungluu): These |FilePath::FromUTF8Unsafe()| indicate that we're
  // doing something wrong.
  for (ExtensionIconSet::IconMap::const_iterator iter = icon_set.map().begin();
       iter != icon_set.map().end(); ++iter) {
    image_paths->insert(base::FilePath::FromUTF8Unsafe(iter->second));
  }
}

}  // namespace

namespace extension_file_util {

base::FilePath InstallExtension(const base::FilePath& unpacked_source_dir,
                                const std::string& id,
                                const std::string& version,
                                const base::FilePath& extensions_dir) {
  base::FilePath extension_dir = extensions_dir.AppendASCII(id);
  base::FilePath version_dir;

  // Create the extension directory if it doesn't exist already.
  if (!base::PathExists(extension_dir)) {
    if (!base::CreateDirectory(extension_dir))
      return base::FilePath();
  }

  // Get a temp directory on the same file system as the profile.
  base::FilePath install_temp_dir = GetInstallTempDir(extensions_dir);
  base::ScopedTempDir extension_temp_dir;
  if (install_temp_dir.empty() ||
      !extension_temp_dir.CreateUniqueTempDirUnderPath(install_temp_dir)) {
    LOG(ERROR) << "Creating of temp dir under in the profile failed.";
    return base::FilePath();
  }
  base::FilePath crx_temp_source =
      extension_temp_dir.path().Append(unpacked_source_dir.BaseName());
  if (!base::Move(unpacked_source_dir, crx_temp_source)) {
    LOG(ERROR) << "Moving extension from : " << unpacked_source_dir.value()
               << " to : " << crx_temp_source.value() << " failed.";
    return base::FilePath();
  }

  // Try to find a free directory. There can be legitimate conflicts in the case
  // of overinstallation of the same version.
  const int kMaxAttempts = 100;
  for (int i = 0; i < kMaxAttempts; ++i) {
    base::FilePath candidate = extension_dir.AppendASCII(
        base::StringPrintf("%s_%u", version.c_str(), i));
    if (!base::PathExists(candidate)) {
      version_dir = candidate;
      break;
    }
  }

  if (version_dir.empty()) {
    LOG(ERROR) << "Could not find a home for extension " << id << " with "
               << "version " << version << ".";
    return base::FilePath();
  }

  if (!base::Move(crx_temp_source, version_dir)) {
    LOG(ERROR) << "Installing extension from : " << crx_temp_source.value()
               << " into : " << version_dir.value() << " failed.";
    return base::FilePath();
  }

  return version_dir;
}

void UninstallExtension(const base::FilePath& extensions_dir,
                        const std::string& id) {
  // We don't care about the return value. If this fails (and it can, due to
  // plugins that aren't unloaded yet), it will get cleaned up by
  // ExtensionService::GarbageCollectExtensions.
  base::DeleteFile(extensions_dir.AppendASCII(id), true);  // recursive.
}

scoped_refptr<Extension> LoadExtension(const base::FilePath& extension_path,
                                       Manifest::Location location,
                                       int flags,
                                       std::string* error) {
  return LoadExtension(extension_path, std::string(), location, flags, error);
}

scoped_refptr<Extension> LoadExtension(const base::FilePath& extension_path,
                                       const std::string& extension_id,
                                       Manifest::Location location,
                                       int flags,
                                       std::string* error) {
  scoped_ptr<base::DictionaryValue> manifest(
      LoadManifest(extension_path, error));
  if (!manifest.get())
    return NULL;
  if (!extension_l10n_util::LocalizeExtension(extension_path, manifest.get(),
                                              error)) {
    return NULL;
  }

  scoped_refptr<Extension> extension(Extension::Create(extension_path,
                                                       location,
                                                       *manifest,
                                                       flags,
                                                       extension_id,
                                                       error));
  if (!extension.get())
    return NULL;

  std::vector<extensions::InstallWarning> warnings;
  if (!ValidateExtension(extension.get(), error, &warnings))
    return NULL;
  extension->AddInstallWarnings(warnings);

  return extension;
}

base::DictionaryValue* LoadManifest(const base::FilePath& extension_path,
                                    std::string* error) {
  base::FilePath manifest_path =
      extension_path.Append(extensions::kManifestFilename);
  if (!base::PathExists(manifest_path)) {
    *error = l10n_util::GetStringUTF8(IDS_EXTENSION_MANIFEST_UNREADABLE);
    return NULL;
  }

  JSONFileValueSerializer serializer(manifest_path);
  scoped_ptr<base::Value> root(serializer.Deserialize(NULL, error));
  if (!root.get()) {
    if (error->empty()) {
      // If |error| is empty, than the file could not be read.
      // It would be cleaner to have the JSON reader give a specific error
      // in this case, but other code tests for a file error with
      // error->empty().  For now, be consistent.
      *error = l10n_util::GetStringUTF8(IDS_EXTENSION_MANIFEST_UNREADABLE);
    } else {
      *error = base::StringPrintf("%s  %s",
                                  errors::kManifestParseError,
                                  error->c_str());
    }
    return NULL;
  }

  if (!root->IsType(base::Value::TYPE_DICTIONARY)) {
    *error = l10n_util::GetStringUTF8(IDS_EXTENSION_MANIFEST_INVALID);
    return NULL;
  }

  return static_cast<base::DictionaryValue*>(root.release());
}

std::vector<base::FilePath> FindPrivateKeyFiles(
    const base::FilePath& extension_dir) {
  std::vector<base::FilePath> result;
  // Pattern matching only works at the root level, so filter manually.
  base::FileEnumerator traversal(extension_dir, /*recursive=*/true,
                                 base::FileEnumerator::FILES);
  for (base::FilePath current = traversal.Next(); !current.empty();
       current = traversal.Next()) {
    if (!current.MatchesExtension(extensions::kExtensionKeyFileExtension))
      continue;

    std::string key_contents;
    if (!base::ReadFileToString(current, &key_contents)) {
      // If we can't read the file, assume it's not a private key.
      continue;
    }
    std::string key_bytes;
    if (!Extension::ParsePEMKeyBytes(key_contents, &key_bytes)) {
      // If we can't parse the key, assume it's ok too.
      continue;
    }

    result.push_back(current);
  }
  return result;
}

bool ValidateFilePath(const base::FilePath& path) {
  int64 size = 0;
  if (!base::PathExists(path) ||
      !base::GetFileSize(path, &size) ||
      size == 0) {
    return false;
  }

  return true;
}

bool ValidateExtensionIconSet(const ExtensionIconSet& icon_set,
                              const Extension* extension,
                              int error_message_id,
                              std::string* error) {
  for (ExtensionIconSet::IconMap::const_iterator iter = icon_set.map().begin();
       iter != icon_set.map().end();
       ++iter) {
    const base::FilePath path =
        extension->GetResource(iter->second).GetFilePath();
    if (!ValidateFilePath(path)) {
      *error = l10n_util::GetStringFUTF8(error_message_id,
                                         UTF8ToUTF16(iter->second));
      return false;
    }
  }
  return true;
}

bool ValidateExtension(const Extension* extension,
                       std::string* error,
                       std::vector<extensions::InstallWarning>* warnings) {
  // Ask registered manifest handlers to validate their paths.
  if (!extensions::ManifestHandler::ValidateExtension(
          extension, error, warnings))
    return false;

  // Check children of extension root to see if any of them start with _ and is
  // not on the reserved list. We only warn, and do not block the loading of the
  // extension.
  std::string warning;
  if (!CheckForIllegalFilenames(extension->path(), &warning))
    warnings->push_back(extensions::InstallWarning(warning));

  // Check that extensions don't include private key files.
  std::vector<base::FilePath> private_keys =
      FindPrivateKeyFiles(extension->path());
  if (extension->creation_flags() & Extension::ERROR_ON_PRIVATE_KEY) {
    if (!private_keys.empty()) {
      // Only print one of the private keys because l10n_util doesn't have a way
      // to translate a list of strings.
      *error = l10n_util::GetStringFUTF8(
          IDS_EXTENSION_CONTAINS_PRIVATE_KEY,
          private_keys.front().LossyDisplayName());
      return false;
    }
  } else {
    for (size_t i = 0; i < private_keys.size(); ++i) {
      warnings->push_back(extensions::InstallWarning(
          l10n_util::GetStringFUTF8(
              IDS_EXTENSION_CONTAINS_PRIVATE_KEY,
              private_keys[i].LossyDisplayName())));
    }
    // Only warn; don't block loading the extension.
  }
  return true;
}

std::set<base::FilePath> GetBrowserImagePaths(const Extension* extension) {
  std::set<base::FilePath> image_paths;

  AddPathsFromIconSet(extensions::IconsInfo::GetIcons(extension), &image_paths);

  // Theme images
  const base::DictionaryValue* theme_images =
      extensions::ThemeInfo::GetImages(extension);
  if (theme_images) {
    for (base::DictionaryValue::Iterator it(*theme_images); !it.IsAtEnd();
         it.Advance()) {
      base::FilePath::StringType path;
      if (it.value().GetAsString(&path))
        image_paths.insert(base::FilePath(path));
    }
  }

  const extensions::ActionInfo* page_action =
      extensions::ActionInfo::GetPageActionInfo(extension);
  if (page_action && !page_action->default_icon.empty())
    AddPathsFromIconSet(page_action->default_icon, &image_paths);

  const extensions::ActionInfo* browser_action =
      extensions::ActionInfo::GetBrowserActionInfo(extension);
  if (browser_action && !browser_action->default_icon.empty())
    AddPathsFromIconSet(browser_action->default_icon, &image_paths);

  return image_paths;
}

void GarbageCollectExtensions(
    const base::FilePath& install_directory,
    const std::multimap<std::string, base::FilePath>& extension_paths) {
  // Nothing to clean up if it doesn't exist.
  if (!base::DirectoryExists(install_directory))
    return;

  DVLOG(1) << "Garbage collecting extensions...";
  base::FileEnumerator enumerator(install_directory,
                                  false,  // Not recursive.
                                  base::FileEnumerator::DIRECTORIES);
  base::FilePath extension_path;
  for (extension_path = enumerator.Next(); !extension_path.value().empty();
       extension_path = enumerator.Next()) {
    std::string extension_id;

    base::FilePath basename = extension_path.BaseName();
    // Clean up temporary files left if Chrome crashed or quit in the middle
    // of an extension install.
    if (basename.value() == kTempDirectoryName) {
      base::DeleteFile(extension_path, true);  // Recursive
      continue;
    }

    // Parse directory name as a potential extension ID.
    if (IsStringASCII(basename.value())) {
      extension_id = UTF16ToASCII(basename.LossyDisplayName());
      if (!Extension::IdIsValid(extension_id))
        extension_id.clear();
    }

    // Delete directories that aren't valid IDs.
    if (extension_id.empty()) {
      DLOG(WARNING) << "Invalid extension ID encountered in extensions "
                       "directory: " << basename.value();
      DVLOG(1) << "Deleting invalid extension directory "
               << extension_path.value() << ".";
      base::DeleteFile(extension_path, true);  // Recursive.
      continue;
    }

    typedef std::multimap<std::string, base::FilePath>::const_iterator Iter;
    std::pair<Iter, Iter> iter_pair = extension_paths.equal_range(extension_id);

    // If there is no entry in the prefs file, just delete the directory and
    // move on. This can legitimately happen when an uninstall does not
    // complete, for example, when a plugin is in use at uninstall time.
    if (iter_pair.first == iter_pair.second) {
      DVLOG(1) << "Deleting unreferenced install for directory "
               << extension_path.LossyDisplayName() << ".";
      base::DeleteFile(extension_path, true);  // Recursive.
      continue;
    }

    // Clean up old version directories.
    base::FileEnumerator versions_enumerator(
        extension_path,
        false,  // Not recursive.
        base::FileEnumerator::DIRECTORIES);
    for (base::FilePath version_dir = versions_enumerator.Next();
         !version_dir.value().empty();
         version_dir = versions_enumerator.Next()) {
      bool knownVersion = false;
      for (Iter it = iter_pair.first; it != iter_pair.second; ++it)
        if (version_dir.BaseName() == it->second.BaseName()) {
          knownVersion = true;
          break;
        }
      if (!knownVersion) {
        DVLOG(1) << "Deleting old version for directory "
                 << version_dir.LossyDisplayName() << ".";
        base::DeleteFile(version_dir, true);  // Recursive.
      }
    }
  }
}

extensions::MessageBundle* LoadMessageBundle(
    const base::FilePath& extension_path,
    const std::string& default_locale,
    std::string* error) {
  error->clear();
  // Load locale information if available.
  base::FilePath locale_path = extension_path.Append(extensions::kLocaleFolder);
  if (!base::PathExists(locale_path))
    return NULL;

  std::set<std::string> locales;
  if (!extension_l10n_util::GetValidLocales(locale_path, &locales, error))
    return NULL;

  if (default_locale.empty() ||
      locales.find(default_locale) == locales.end()) {
    *error = l10n_util::GetStringUTF8(
        IDS_EXTENSION_LOCALES_NO_DEFAULT_LOCALE_SPECIFIED);
    return NULL;
  }

  extensions::MessageBundle* message_bundle =
      extension_l10n_util::LoadMessageCatalogs(
          locale_path,
          default_locale,
          extension_l10n_util::CurrentLocaleOrDefault(),
          locales,
          error);

  return message_bundle;
}

SubstitutionMap* LoadMessageBundleSubstitutionMap(
    const base::FilePath& extension_path,
    const std::string& extension_id,
    const std::string& default_locale) {
  SubstitutionMap* returnValue = new SubstitutionMap();
  if (!default_locale.empty()) {
    // Touch disk only if extension is localized.
    std::string error;
    scoped_ptr<extensions::MessageBundle> bundle(
        LoadMessageBundle(extension_path, default_locale, &error));

    if (bundle.get())
      *returnValue = *bundle->dictionary();
  }

  // Add @@extension_id reserved message here, so it's available to
  // non-localized extensions too.
  returnValue->insert(
      std::make_pair(extensions::MessageBundle::kExtensionIdKey, extension_id));

  return returnValue;
}

bool CheckForIllegalFilenames(const base::FilePath& extension_path,
                              std::string* error) {
  // Reserved underscore names.
  static const base::FilePath::CharType* reserved_names[] = {
    extensions::kLocaleFolder,
    extensions::kPlatformSpecificFolder,
    FILE_PATH_LITERAL("__MACOSX"),
  };
  CR_DEFINE_STATIC_LOCAL(
      std::set<base::FilePath::StringType>, reserved_underscore_names,
      (reserved_names, reserved_names + arraysize(reserved_names)));

  // Enumerate all files and directories in the extension root.
  // There is a problem when using pattern "_*" with FileEnumerator, so we have
  // to cheat with find_first_of and match all.
  const int kFilesAndDirectories =
      base::FileEnumerator::DIRECTORIES | base::FileEnumerator::FILES;
  base::FileEnumerator all_files(extension_path, false, kFilesAndDirectories);

  base::FilePath file;
  while (!(file = all_files.Next()).empty()) {
    base::FilePath::StringType filename = file.BaseName().value();
    // Skip all that don't start with "_".
    if (filename.find_first_of(FILE_PATH_LITERAL("_")) != 0) continue;
    if (reserved_underscore_names.find(filename) ==
        reserved_underscore_names.end()) {
      *error = base::StringPrintf(
          "Cannot load extension with file or directory name %s. "
          "Filenames starting with \"_\" are reserved for use by the system.",
          filename.c_str());
      return false;
    }
  }

  return true;
}

base::FilePath GetInstallTempDir(const base::FilePath& extensions_dir) {
  // We do file IO in this function, but only when the current profile's
  // Temp directory has never been used before, or in a rare error case.
  // Developers are not likely to see these situations often, so do an
  // explicit thread check.
  base::ThreadRestrictions::AssertIOAllowed();

  // Create the temp directory as a sub-directory of the Extensions directory.
  // This guarantees it is on the same file system as the extension's eventual
  // install target.
  base::FilePath temp_path = extensions_dir.Append(kTempDirectoryName);
  if (base::PathExists(temp_path)) {
    if (!base::DirectoryExists(temp_path)) {
      DLOG(WARNING) << "Not a directory: " << temp_path.value();
      return base::FilePath();
    }
    if (!base::PathIsWritable(temp_path)) {
      DLOG(WARNING) << "Can't write to path: " << temp_path.value();
      return base::FilePath();
    }
    // This is a directory we can write to.
    return temp_path;
  }

  // Directory doesn't exist, so create it.
  if (!base::CreateDirectory(temp_path)) {
    DLOG(WARNING) << "Couldn't create directory: " << temp_path.value();
    return base::FilePath();
  }
  return temp_path;
}

void DeleteFile(const base::FilePath& path, bool recursive) {
  base::DeleteFile(path, recursive);
}

}  // namespace extension_file_util