src/trace_processor/util/gzip_decompressor.h

/*
 * Copyright (C) 2020 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef SRC_TRACE_PROCESSOR_UTIL_GZIP_DECOMPRESSOR_H_
#define SRC_TRACE_PROCESSOR_UTIL_GZIP_DECOMPRESSOR_H_

#include <cstddef>
#include <cstdint>
#include <memory>

#include "perfetto/base/build_config.h"
#include "src/trace_processor/util/stream_decompressor.h"

struct z_stream_s;

namespace perfetto::trace_processor::util {

// Returns whether gzip related functionality is supported with the current
// build flags.
constexpr bool IsGzipSupported() {
#if PERFETTO_BUILDFLAG(PERFETTO_ZLIB)
  return true;
#else
  return false;
#endif
}

// gzip/deflate StreamDecompressor. Prefer obtaining one through
// CreateDecompressor(); construct directly only when you need to pin
// the InputMode (e.g. raw deflate for zip entries). See stream_decompressor.h
// for the streaming usage contract.
class GzipDecompressor : public StreamDecompressor {
 public:
  enum class InputMode {
    // The input stream contains a gzip header. This is for the common case of
    // decompressing .gz files.
    kGzip = 0,

    // A raw deflate stream. This is for the case of uncompressing files from
    // a .zip archive, where the compression type is specified in the zip file
    // entry, rather than in the stream header.
    kRawDeflate = 1,
  };

  explicit GzipDecompressor(InputMode = InputMode::kGzip);

  void Feed(const uint8_t* data, size_t size) override;
  Result ExtractOutput(uint8_t* out, size_t out_capacity) override;
  void Reset() override;
  size_t AvailIn() const override;

 private:
  struct Deleter {
    void operator()(z_stream_s*) const;
  };
  std::unique_ptr<z_stream_s, Deleter> z_stream_;
};

}  // namespace perfetto::trace_processor::util

#endif  // SRC_TRACE_PROCESSOR_UTIL_GZIP_DECOMPRESSOR_H_