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/*
* Copyright (C) 2016 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 CHUNK_H_
#define CHUNK_H_
#include "android-base/logging.h"
#include "android-base/macros.h"
#include "utils/ByteOrder.h"
#ifdef _WIN32
#ifdef ERROR
#undef ERROR
#endif
#endif
#include "androidfw/ResourceTypes.h"
namespace android {
// Helpful wrapper around a ResChunk_header that provides getter methods
// that handle endianness conversions and provide access to the data portion
// of the chunk.
class Chunk {
public:
explicit Chunk(incfs::verified_map_ptr<ResChunk_header> chunk) : device_chunk_(chunk) {}
// Returns the type of the chunk. Caller need not worry about endianness.
inline int type() const { return dtohs(device_chunk_->type); }
// Returns the size of the entire chunk. This can be useful for skipping
// over the entire chunk. Caller need not worry about endianness.
inline size_t size() const { return dtohl(device_chunk_->size); }
// Returns the size of the header. Caller need not worry about endianness.
inline size_t header_size() const { return dtohs(device_chunk_->headerSize); }
template <typename T, size_t MinSize = sizeof(T)>
inline incfs::map_ptr<T> header() const {
return (header_size() >= MinSize) ? device_chunk_.convert<T>() : nullptr;
}
inline incfs::map_ptr<void> data_ptr() const {
return device_chunk_.offset(header_size());
}
inline size_t data_size() const { return size() - header_size(); }
private:
const incfs::verified_map_ptr<ResChunk_header> device_chunk_;
};
// Provides a Java style iterator over an array of ResChunk_header's.
// Validation is performed while iterating.
// The caller should check if there was an error during chunk validation
// by calling HadError() and GetLastError() to get the reason for failure.
// Example:
//
// ChunkIterator iter(data_ptr, data_len);
// while (iter.HasNext()) {
// const Chunk chunk = iter.Next();
// ...
// }
//
// if (iter.HadError()) {
// LOG(ERROR) << iter.GetLastError();
// }
//
class ChunkIterator {
public:
ChunkIterator(incfs::map_ptr<void> data, size_t len)
: next_chunk_(data.convert<ResChunk_header>()),
len_(len),
last_error_(nullptr) {
CHECK((bool) next_chunk_) << "data can't be null";
if (len_ != 0) {
VerifyNextChunk();
}
}
Chunk Next();
inline bool HasNext() const { return !HadError() && len_ != 0; };
// Returns whether there was an error and processing should stop
inline bool HadError() const { return last_error_ != nullptr; }
inline std::string GetLastError() const { return last_error_; }
// Returns whether there was an error and processing should stop. For legacy purposes,
// some errors are considered "non fatal". Fatal errors stop processing new chunks and
// throw away any chunks already processed. Non fatal errors also stop processing new
// chunks, but, will retain and use any valid chunks already processed.
inline bool HadFatalError() const { return HadError() && last_error_was_fatal_; }
private:
DISALLOW_COPY_AND_ASSIGN(ChunkIterator);
// Returns false if there was an error.
bool VerifyNextChunk();
// Returns false if there was an error. For legacy purposes.
bool VerifyNextChunkNonFatal();
incfs::map_ptr<ResChunk_header> next_chunk_;
size_t len_;
const char* last_error_;
bool last_error_was_fatal_ = true;
};
} // namespace android
#endif /* CHUNK_H_ */