aosp12/art/libdexfile/dex/dex_file_exception_helpers.cc

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2023-01-09 17:11:35 +08:00
/*
* Copyright (C) 2017 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.
*/
#include "dex_file_exception_helpers.h"
#include "code_item_accessors-inl.h"
#include "dex_file_structs.h"
namespace art {
CatchHandlerIterator::CatchHandlerIterator(const CodeItemDataAccessor& accessor, uint32_t address) {
handler_.address_ = -1;
int32_t offset = -1;
// Short-circuit the overwhelmingly common cases.
switch (accessor.TriesSize()) {
case 0:
break;
case 1: {
const dex::TryItem* tries = accessor.TryItems().begin();
uint32_t start = tries->start_addr_;
if (address >= start) {
uint32_t end = start + tries->insn_count_;
if (address < end) {
offset = tries->handler_off_;
}
}
break;
}
default: {
const dex::TryItem* try_item = accessor.FindTryItem(address);
offset = try_item != nullptr ? try_item->handler_off_ : -1;
break;
}
}
Init(accessor, offset);
}
CatchHandlerIterator::CatchHandlerIterator(const CodeItemDataAccessor& accessor,
const dex::TryItem& try_item) {
handler_.address_ = -1;
Init(accessor, try_item.handler_off_);
}
void CatchHandlerIterator::Init(const CodeItemDataAccessor& accessor, int32_t offset) {
if (offset >= 0) {
Init(accessor.GetCatchHandlerData(offset));
} else {
// Not found, initialize as empty
current_data_ = nullptr;
remaining_count_ = -1;
catch_all_ = false;
DCHECK(!HasNext());
}
}
void CatchHandlerIterator::Init(const uint8_t* handler_data) {
current_data_ = handler_data;
remaining_count_ = DecodeSignedLeb128(&current_data_);
// If remaining_count_ is non-positive, then it is the negative of
// the number of catch types, and the catches are followed by a
// catch-all handler.
if (remaining_count_ <= 0) {
catch_all_ = true;
remaining_count_ = -remaining_count_;
} else {
catch_all_ = false;
}
Next();
}
void CatchHandlerIterator::Next() {
if (remaining_count_ > 0) {
handler_.type_idx_ = dex::TypeIndex(DecodeUnsignedLeb128(&current_data_));
handler_.address_ = DecodeUnsignedLeb128(&current_data_);
remaining_count_--;
return;
}
if (catch_all_) {
handler_.type_idx_ = dex::TypeIndex(DexFile::kDexNoIndex16);
handler_.address_ = DecodeUnsignedLeb128(&current_data_);
catch_all_ = false;
return;
}
// no more handler
remaining_count_ = -1;
}
} // namespace art