message_filter.cc | Explore in Territory

/*
 * Copyright (C) 2021 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 "src/protozero/filtering/message_filter.h"

#include "perfetto/base/logging.h"
#include "perfetto/protozero/proto_utils.h"
#include "src/protozero/filtering/string_filter.h"

namespace protozero {

namespace {

// Inline helpers to append proto fields in output. They are the equivalent of
// the protozero::Message::AppendXXX() fields but don't require building and
// maintaining a full protozero::Message object or dealing with scattered
// output slices.
// All these functions assume there is enough space in the output buffer, which
// should be always the case assuming that we don't end up generating more
// output than input.

inline void AppendVarInt(uint32_t field_id, uint64_t value, uint8_t** out) { … }

// For fixed32 / fixed64.
template <typename INT_T /* uint32_t | uint64_t*/>
inline void AppendFixed(uint32_t field_id, INT_T value, uint8_t** out) { … }

// For length-delimited (string, bytes) fields. Note: this function appends only
// the proto preamble and the varint field that states the length of the payload
// not the payload itself.
// In the case of submessages, the caller needs to re-write the length at the
// end in the in the returned memory area.
// The problem here is that, because of filtering, the length of a submessage
// might be < original length (the original length is still an upper-bound).
// Returns a pair with: (1) the pointer where the final length should be written
// into, (2) the length of the size field.
// The caller must write a redundant varint to match the original size (i.e.
// needs to use WriteRedundantVarInt()).
inline std::pair<uint8_t*, uint32_t> AppendLenDelim(uint32_t field_id,
                                                    uint32_t len,
                                                    uint8_t** out) { … }
}  // namespace

MessageFilter::MessageFilter(Config config) : … { … }

MessageFilter::MessageFilter() : … { … }

MessageFilter::~MessageFilter() = default;

bool MessageFilter::Config::LoadFilterBytecode(const void* filter_data,
                                               size_t len) { … }

bool MessageFilter::Config::SetFilterRoot(
    std::initializer_list<uint32_t> field_ids) { … }

MessageFilter::FilteredMessage MessageFilter::FilterMessageFragments(
    const InputSlice* slices,
    size_t num_slices) { … }

void MessageFilter::FilterOneByte(uint8_t octet) { … }

void MessageFilter::SetUnrecoverableErrorState() { … }

void MessageFilter::IncrementCurrentFieldUsage(uint32_t field_id,
                                               bool allowed) { … }

}  // namespace protozero
chromium/third_party/perfetto/src/protozero/filtering/message_filter.cc
