tools/aapt2/io/Data.h

/*
 * Copyright (C) 2015 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 AAPT_IO_DATA_H
#define AAPT_IO_DATA_H

#include <memory>

#include "android-base/macros.h"
#include "utils/FileMap.h"

namespace aapt {
namespace io {

/**
 * Interface for a block of contiguous memory. An instance of this interface
 * owns the data.
 */
class IData {
 public:
  virtual ~IData() = default;

  virtual const void* data() const = 0;
  virtual size_t size() const = 0;
};

class DataSegment : public IData {
 public:
  explicit DataSegment(std::unique_ptr<IData> data, size_t offset, size_t len)
      : data_(std::move(data)), offset_(offset), len_(len) {}

  const void* data() const override {
    return static_cast<const uint8_t*>(data_->data()) + offset_;
  }

  size_t size() const override { return len_; }

 private:
  DISALLOW_COPY_AND_ASSIGN(DataSegment);

  std::unique_ptr<IData> data_;
  size_t offset_;
  size_t len_;
};

/**
 * Implementation of IData that exposes a memory mapped file. The mmapped file
 * is owned by this
 * object.
 */
class MmappedData : public IData {
 public:
  explicit MmappedData(android::FileMap&& map)
      : map_(std::forward<android::FileMap>(map)) {}

  const void* data() const override { return map_.getDataPtr(); }

  size_t size() const override { return map_.getDataLength(); }

 private:
  android::FileMap map_;
};

/**
 * Implementation of IData that exposes a block of memory that was malloc'ed
 * (new'ed). The
 * memory is owned by this object.
 */
class MallocData : public IData {
 public:
  MallocData(std::unique_ptr<const uint8_t[]> data, size_t size)
      : data_(std::move(data)), size_(size) {}

  const void* data() const override { return data_.get(); }

  size_t size() const override { return size_; }

 private:
  std::unique_ptr<const uint8_t[]> data_;
  size_t size_;
};

/**
 * When mmap fails because the file has length 0, we use the EmptyData to
 * simulate data of length 0.
 */
class EmptyData : public IData {
 public:
  const void* data() const override {
    static const uint8_t d = 0;
    return &d;
  }

  size_t size() const override { return 0u; }
};

}  // namespace io
}  // namespace aapt

#endif /* AAPT_IO_DATA_H */