/*
 * Copyright (C) 2010 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 "third_party/blink/renderer/core/fileapi/file_reader_loader.h"

#include <limits>
#include <memory>
#include <utility>

#include "base/memory/scoped_refptr.h"
#include "mojo/public/cpp/system/wait.h"
#include "third_party/blink/public/platform/web_url_request.h"
#include "third_party/blink/renderer/core/execution_context/execution_context.h"
#include "third_party/blink/renderer/core/fileapi/blob.h"
#include "third_party/blink/renderer/core/fileapi/file_reader_loader_client.h"
#include "third_party/blink/renderer/core/html/parser/text_resource_decoder.h"
#include "third_party/blink/renderer/core/loader/threadable_loader.h"
#include "third_party/blink/renderer/core/loader/threadable_loader_client.h"
#include "third_party/blink/renderer/core/typed_arrays/dom_array_buffer.h"
#include "third_party/blink/renderer/platform/blob/blob_registry.h"
#include "third_party/blink/renderer/platform/blob/blob_url.h"
#include "third_party/blink/renderer/platform/histogram.h"
#include "third_party/blink/renderer/platform/loader/fetch/fetch_initiator_type_names.h"
#include "third_party/blink/renderer/platform/loader/fetch/resource_error.h"
#include "third_party/blink/renderer/platform/loader/fetch/resource_loader_options.h"
#include "third_party/blink/renderer/platform/loader/fetch/resource_request.h"
#include "third_party/blink/renderer/platform/loader/fetch/resource_response.h"
#include "third_party/blink/renderer/platform/loader/fetch/text_resource_decoder_options.h"
#include "third_party/blink/renderer/platform/wtf/std_lib_extras.h"
#include "third_party/blink/renderer/platform/wtf/text/base64.h"
#include "third_party/blink/renderer/platform/wtf/text/string_builder.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"
#include "v8/include/v8.h"

namespace blink {

// static
std::unique_ptr<FileReaderLoader> FileReaderLoader::Create(
    ReadType read_type,
    FileReaderLoaderClient* client) {
  return std::make_unique<FileReaderLoader>(read_type, client);
}

FileReaderLoader::FileReaderLoader(ReadType read_type,
                                   FileReaderLoaderClient* client)
    : read_type_(read_type),
      client_(client),
      // TODO(hajimehoshi): Pass an appropriate task runner to SimpleWatcher
      // constructor.
      handle_watcher_(FROM_HERE, mojo::SimpleWatcher::ArmingPolicy::AUTOMATIC),
      binding_(this),
      weak_factory_(this) {}

FileReaderLoader::~FileReaderLoader() {
  Cleanup();
  UnadjustReportedMemoryUsageToV8();
}

void FileReaderLoader::Start(scoped_refptr<BlobDataHandle> blob_data) {
#if DCHECK_IS_ON()
  DCHECK(!started_loading_) << "FileReaderLoader can only be used once";
  started_loading_ = true;
#endif  // DCHECK_IS_ON()

  mojo::ScopedDataPipeProducerHandle producer_handle;
  MojoResult result =
      CreateDataPipe(nullptr, &producer_handle, &consumer_handle_);
  if (result != MOJO_RESULT_OK) {
    Failed(FileError::kNotReadableErr);
    return;
  }

  mojom::blink::BlobReaderClientPtr client_ptr;
  binding_.Bind(MakeRequest(&client_ptr));
  blob_data->ReadAll(std::move(producer_handle), std::move(client_ptr));

  if (IsSyncLoad()) {
    // Wait for OnCalculatedSize, which will also synchronously drain the data
    // pipe.
    binding_.WaitForIncomingMethodCall();
    if (received_on_complete_)
      return;
    if (!received_all_data_) {
      Failed(FileError::kNotReadableErr);
      return;
    }

    // Wait for OnComplete
    binding_.WaitForIncomingMethodCall();
    if (!received_on_complete_)
      Failed(FileError::kNotReadableErr);
  }
}

void FileReaderLoader::Cancel() {
  error_code_ = FileError::kAbortErr;
  Cleanup();
}

DOMArrayBuffer* FileReaderLoader::ArrayBufferResult() {
  DCHECK_EQ(read_type_, kReadAsArrayBuffer);
  if (array_buffer_result_)
    return array_buffer_result_;

  // If the loading is not started or an error occurs, return an empty result.
  if (!raw_data_ || error_code_)
    return nullptr;

  DOMArrayBuffer* result = DOMArrayBuffer::Create(raw_data_->ToArrayBuffer());
  if (finished_loading_) {
    array_buffer_result_ = result;
    AdjustReportedMemoryUsageToV8(
        -1 * static_cast<int64_t>(raw_data_->ByteLength()));
    raw_data_.reset();
  }
  return result;
}

String FileReaderLoader::StringResult() {
  DCHECK_NE(read_type_, kReadAsArrayBuffer);
  DCHECK_NE(read_type_, kReadByClient);

  if (!raw_data_ || error_code_ || is_raw_data_converted_)
    return string_result_;

  switch (read_type_) {
    case kReadAsArrayBuffer:
      // No conversion is needed.
      return string_result_;
    case kReadAsBinaryString:
      SetStringResult(raw_data_->ToString());
      break;
    case kReadAsText:
      SetStringResult(ConvertToText());
      break;
    case kReadAsDataURL:
      // Partial data is not supported when reading as data URL.
      if (finished_loading_)
        SetStringResult(ConvertToDataURL());
      break;
    default:
      NOTREACHED();
  }

  if (finished_loading_) {
    DCHECK(is_raw_data_converted_);
    AdjustReportedMemoryUsageToV8(
        -1 * static_cast<int64_t>(raw_data_->ByteLength()));
    raw_data_.reset();
  }
  return string_result_;
}

void FileReaderLoader::SetEncoding(const String& encoding) {
  if (!encoding.IsEmpty())
    encoding_ = WTF::TextEncoding(encoding);
}

void FileReaderLoader::Cleanup() {
  handle_watcher_.Cancel();
  consumer_handle_.reset();

  // If we get any error, we do not need to keep a buffer around.
  if (error_code_) {
    raw_data_.reset();
    string_result_ = "";
    is_raw_data_converted_ = true;
    decoder_.reset();
    array_buffer_result_ = nullptr;
    UnadjustReportedMemoryUsageToV8();
  }
}

void FileReaderLoader::Failed(FileError::ErrorCode error_code) {
  // If an error was already reported, don't report this error again.
  if (error_code_ != FileError::kOK)
    return;
  error_code_ = error_code;
  Cleanup();
  if (client_)
    client_->DidFail(error_code_);
}

void FileReaderLoader::OnStartLoading(uint64_t total_bytes) {
  total_bytes_ = total_bytes;

  DCHECK(!raw_data_);

  if (read_type_ != kReadByClient) {
    // Check that we can cast to unsigned since we have to do
    // so to call ArrayBuffer's create function.
    // FIXME: Support reading more than the current size limit of ArrayBuffer.
    if (total_bytes > std::numeric_limits<unsigned>::max()) {
      Failed(FileError::kNotReadableErr);
      return;
    }

    raw_data_ = std::make_unique<ArrayBufferBuilder>(total_bytes);
    if (!raw_data_->IsValid()) {
      Failed(FileError::kNotReadableErr);
      return;
    }
    raw_data_->SetVariableCapacity(false);
  }

  if (client_)
    client_->DidStartLoading();
}

void FileReaderLoader::OnReceivedData(const char* data, unsigned data_length) {
  DCHECK(data);

  // Bail out if we already encountered an error.
  if (error_code_)
    return;

  if (read_type_ == kReadByClient) {
    bytes_loaded_ += data_length;

    if (client_)
      client_->DidReceiveDataForClient(data, data_length);
    return;
  }

  unsigned bytes_appended = raw_data_->Append(data, data_length);
  if (!bytes_appended) {
    raw_data_.reset();
    bytes_loaded_ = 0;
    Failed(FileError::kNotReadableErr);
    return;
  }
  bytes_loaded_ += bytes_appended;
  is_raw_data_converted_ = false;
  AdjustReportedMemoryUsageToV8(bytes_appended);

  if (client_)
    client_->DidReceiveData();
}

void FileReaderLoader::OnFinishLoading() {
  if (read_type_ != kReadByClient && raw_data_) {
    raw_data_->ShrinkToFit();
    is_raw_data_converted_ = false;
  }

  finished_loading_ = true;

  Cleanup();
  if (client_)
    client_->DidFinishLoading();
}

void FileReaderLoader::OnCalculatedSize(uint64_t total_size,
                                        uint64_t expected_content_size) {
  auto weak_this = weak_factory_.GetWeakPtr();
  OnStartLoading(expected_content_size);
  // OnStartLoading calls out to our client, which could delete |this|, so bail
  // out if that happened.
  if (!weak_this)
    return;

  if (expected_content_size == 0) {
    received_all_data_ = true;
    return;
  }

  if (IsSyncLoad()) {
    OnDataPipeReadable(MOJO_RESULT_OK);
  } else {
    handle_watcher_.Watch(
        consumer_handle_.get(), MOJO_HANDLE_SIGNAL_READABLE,
        WTF::BindRepeating(&FileReaderLoader::OnDataPipeReadable,
                           WTF::Unretained(this)));
  }
}

void FileReaderLoader::OnComplete(int32_t status, uint64_t data_length) {
  DEFINE_THREAD_SAFE_STATIC_LOCAL(SparseHistogram,
                                  file_reader_loader_read_errors_histogram,
                                  ("Storage.Blob.FileReaderLoader.ReadError"));
  if (status != net::OK || data_length != total_bytes_) {
    net_error_ = status;
    if (net_error_ != net::OK)
      file_reader_loader_read_errors_histogram.Sample(std::max(0, -net_error_));
    Failed(status == net::ERR_FILE_NOT_FOUND ? FileError::kNotFoundErr
                                             : FileError::kNotReadableErr);
    return;
  }

  received_on_complete_ = true;
  if (received_all_data_)
    OnFinishLoading();
}

void FileReaderLoader::OnDataPipeReadable(MojoResult result) {
  if (result != MOJO_RESULT_OK) {
    if (!received_all_data_)
      Failed(FileError::kNotReadableErr);
    return;
  }

  while (true) {
    uint32_t num_bytes;
    const void* buffer;
    MojoResult result = consumer_handle_->BeginReadData(
        &buffer, &num_bytes, MOJO_READ_DATA_FLAG_NONE);
    if (result == MOJO_RESULT_SHOULD_WAIT) {
      if (!IsSyncLoad())
        return;

      result = mojo::Wait(consumer_handle_.get(), MOJO_HANDLE_SIGNAL_READABLE);
      if (result == MOJO_RESULT_OK)
        continue;
    }
    if (result == MOJO_RESULT_FAILED_PRECONDITION) {
      // Pipe closed.
      if (!received_all_data_)
        Failed(FileError::kNotReadableErr);
      return;
    }
    if (result != MOJO_RESULT_OK) {
      Failed(FileError::kNotReadableErr);
      return;
    }
    OnReceivedData(static_cast<const char*>(buffer), num_bytes);
    consumer_handle_->EndReadData(num_bytes);
    if (BytesLoaded() >= total_bytes_) {
      received_all_data_ = true;
      if (received_on_complete_)
        OnFinishLoading();
      return;
    }
  }
}

void FileReaderLoader::AdjustReportedMemoryUsageToV8(int64_t usage) {
  if (!usage)
    return;
  memory_usage_reported_to_v8_ += usage;
  v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(usage);
  DCHECK_GE(memory_usage_reported_to_v8_, 0);
}

void FileReaderLoader::UnadjustReportedMemoryUsageToV8() {
  if (!memory_usage_reported_to_v8_)
    return;
  v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(
      -memory_usage_reported_to_v8_);
  memory_usage_reported_to_v8_ = 0;
}

String FileReaderLoader::ConvertToText() {
  if (!bytes_loaded_)
    return "";

  // Decode the data.
  // The File API spec says that we should use the supplied encoding if it is
  // valid. However, we choose to ignore this requirement in order to be
  // consistent with how WebKit decodes the web content: always has the BOM
  // override the provided encoding.
  // FIXME: consider supporting incremental decoding to improve the perf.
  StringBuilder builder;
  if (!decoder_) {
    decoder_ = TextResourceDecoder::Create(TextResourceDecoderOptions(
        TextResourceDecoderOptions::kPlainTextContent,
        encoding_.IsValid() ? encoding_ : UTF8Encoding()));
  }
  builder.Append(decoder_->Decode(static_cast<const char*>(raw_data_->Data()),
                                  raw_data_->ByteLength()));

  if (finished_loading_)
    builder.Append(decoder_->Flush());

  return builder.ToString();
}

String FileReaderLoader::ConvertToDataURL() {
  StringBuilder builder;
  builder.Append("data:");

  if (!bytes_loaded_)
    return builder.ToString();

  builder.Append(data_type_);
  builder.Append(";base64,");

  Vector<char> out;
  Base64Encode(static_cast<const char*>(raw_data_->Data()),
               raw_data_->ByteLength(), out);
  out.push_back('\0');
  builder.Append(out.data());

  return builder.ToString();
}

void FileReaderLoader::SetStringResult(const String& result) {
  AdjustReportedMemoryUsageToV8(
      -1 * static_cast<int64_t>(string_result_.CharactersSizeInBytes()));
  is_raw_data_converted_ = true;
  string_result_ = result;
  AdjustReportedMemoryUsageToV8(string_result_.CharactersSizeInBytes());
}

}  // namespace blink