// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/update_client/component_unpacker.h"

#include <stdint.h>
#include <string>
#include <utility>
#include <vector>

#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/files/scoped_file.h"
#include "base/functional/bind.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/numerics/safe_conversions.h"
#include "base/strings/string_number_conversions.h"
#include "base/task/sequenced_task_runner.h"
#include "components/crx_file/crx_verifier.h"
#include "components/update_client/component_patcher.h"
#include "components/update_client/patcher.h"
#include "components/update_client/unzipper.h"
#include "components/update_client/update_client.h"
#include "components/update_client/update_client_errors.h"
#include "components/update_client/utils.h"
#include "third_party/zlib/google/compression_utils.h"

namespace {

const base::FilePath::CharType kMetadataFolder[] =
    FILE_PATH_LITERAL("_metadata");

base::FilePath GetVerifiedContentsPath(const base::FilePath& extension_path) {
  return extension_path.Append(kMetadataFolder)
      .Append(FILE_PATH_LITERAL("verified_contents.json"));
}

}  // namespace

namespace update_client {

ComponentUnpacker::Result::Result() = default;

ComponentUnpacker::ComponentUnpacker(const std::vector<uint8_t>& pk_hash,
                                     const base::FilePath& path,
                                     scoped_refptr<CrxInstaller> installer,
                                     std::unique_ptr<Unzipper> unzipper,
                                     scoped_refptr<Patcher> patcher,
                                     crx_file::VerifierFormat crx_format)
    : pk_hash_(pk_hash),
      path_(path),
      is_delta_(false),
      installer_(installer),
      unzipper_(std::move(unzipper)),
      patcher_tool_(patcher),
      crx_format_(crx_format),
      error_(UnpackerError::kNone),
      extended_error_(0) {}

ComponentUnpacker::~ComponentUnpacker() = default;

void ComponentUnpacker::Unpack(Callback callback) {
  callback_ = std::move(callback);
  if (!Verify() || !BeginUnzipping())
    EndUnpacking();
}

bool ComponentUnpacker::Verify() {
  VLOG(1) << "Verifying component: " << path_.value();
  if (path_.empty()) {
    error_ = UnpackerError::kInvalidParams;
    return false;
  }
  std::vector<std::vector<uint8_t>> required_keys;
  if (!pk_hash_.empty())
    required_keys.push_back(pk_hash_);
  const crx_file::VerifierResult result = crx_file::Verify(
      path_, crx_format_, required_keys, std::vector<uint8_t>(), &public_key_,
      nullptr, &compressed_verified_contents_);
  if (result != crx_file::VerifierResult::OK_FULL &&
      result != crx_file::VerifierResult::OK_DELTA) {
    error_ = UnpackerError::kInvalidFile;
    extended_error_ = static_cast<int>(result);
    return false;
  }
  is_delta_ = result == crx_file::VerifierResult::OK_DELTA;
  VLOG(1) << "Verification successful: " << path_.value();
  return true;
}

bool ComponentUnpacker::BeginUnzipping() {
  // Mind the reference to non-const type, passed as an argument below.
  base::FilePath& destination = is_delta_ ? unpack_diff_path_ : unpack_path_;
  if (!base::CreateNewTempDirectory(
          FILE_PATH_LITERAL("chrome_ComponentUnpacker_BeginUnzipping"),
          &destination)) {
    VLOG(1) << "Unable to create temporary directory for unpacking.";
    error_ = UnpackerError::kUnzipPathError;
    return false;
  }
  VLOG(1) << "Unpacking in: " << destination.value();
  unzipper_->Unzip(path_, destination,
                   base::BindOnce(&ComponentUnpacker::EndUnzipping, this));
  return true;
}

void ComponentUnpacker::EndUnzipping(bool result) {
  if (!result) {
    VLOG(1) << "Unzipping failed.";
    error_ = UnpackerError::kUnzipFailed;
    EndUnpacking();
    return;
  }
  VLOG(1) << "Unpacked successfully";
  base::FilePath verified_contents_path =
      GetVerifiedContentsPath(is_delta_ ? unpack_diff_path_ : unpack_path_);
  // If the verified contents are already present in the _metadata folder, we
  // can ignore the verified contents in the header.
  if (compressed_verified_contents_.empty() ||
      base::PathExists(verified_contents_path)) {
    BeginPatching();
    return;
  }

  UncompressVerifiedContents();
}

void ComponentUnpacker::UncompressVerifiedContents() {
  std::string verified_contents;
  if (!compression::GzipUncompress(compressed_verified_contents_,
                                   &verified_contents)) {
    LOG(ERROR) << "Decompressing verified contents from header failed";
    BeginPatching();
    return;
  }

  StoreVerifiedContentsInExtensionDir(verified_contents);
}

void ComponentUnpacker::StoreVerifiedContentsInExtensionDir(
    const std::string& verified_contents) {
  base::FilePath extension_dir = is_delta_ ? unpack_diff_path_ : unpack_path_;
  base::FilePath metadata_path = extension_dir.Append(kMetadataFolder);
  if (!base::CreateDirectory(metadata_path)) {
    LOG(ERROR) << "Could not create metadata directory " << metadata_path;
    BeginPatching();
    return;
  }

  base::FilePath verified_contents_path =
      GetVerifiedContentsPath(extension_dir);

  // Cannot write the verified contents file.
  if (!base::WriteFile(verified_contents_path, verified_contents)) {
    LOG(ERROR) << "Could not write verified contents into file "
               << verified_contents_path;
    BeginPatching();
    return;
  }

  BeginPatching();
}

void ComponentUnpacker::BeginPatching() {
  if (is_delta_) {  // Package is a diff package.
    // Use a different temp directory for the patch output files.
    if (!base::CreateNewTempDirectory(
            FILE_PATH_LITERAL("chrome_ComponentUnpacker_BeginPatching"),
            &unpack_path_)) {
      base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
          FROM_HERE, base::BindOnce(&ComponentUnpacker::EndPatching, this,
                                    UnpackerError::kUnzipPathError, 0));
      return;
    }
    patcher_ = base::MakeRefCounted<ComponentPatcher>(
        unpack_diff_path_, unpack_path_, installer_, patcher_tool_);
    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
        FROM_HERE,
        base::BindOnce(&ComponentPatcher::Start, patcher_,
                       base::BindOnce(&ComponentUnpacker::EndPatching, this)));
  } else {
    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
        FROM_HERE, base::BindOnce(&ComponentUnpacker::EndPatching, this,
                                  UnpackerError::kNone, 0));
  }
}

void ComponentUnpacker::EndPatching(UnpackerError error, int extended_error) {
  error_ = error;
  extended_error_ = extended_error;
  patcher_ = nullptr;

  EndUnpacking();
}

void ComponentUnpacker::EndUnpacking() {
  if (!unpack_diff_path_.empty())
    base::DeletePathRecursively(unpack_diff_path_);
  if (error_ != UnpackerError::kNone && !unpack_path_.empty())
    base::DeletePathRecursively(unpack_path_);

  Result result;
  result.error = error_;
  result.extended_error = extended_error_;
  if (error_ == UnpackerError::kNone) {
    result.unpack_path = unpack_path_;
    result.public_key = public_key_;
  }

  base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
      FROM_HERE, base::BindOnce(std::move(callback_), result));
}

}  // namespace update_client