| /* |
| * Copyright (C) 2019 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 "perfetto/base/build_config.h" |
| #if PERFETTO_BUILDFLAG(PERFETTO_TP_JSON) |
| |
| #include "src/trace_processor/importers/json/json_trace_tokenizer.h" |
| |
| #include <json/reader.h> |
| #include <json/value.h> |
| |
| #include "src/trace_processor/importers/json/json_trace_utils.h" |
| #include "src/trace_processor/stats.h" |
| #include "src/trace_processor/trace_blob_view.h" |
| #include "src/trace_processor/trace_sorter.h" |
| |
| namespace perfetto { |
| namespace trace_processor { |
| |
| // Parses at most one JSON dictionary and returns a pointer to the end of it, |
| // or nullptr if no dict could be detected. |
| // This is to avoid decoding the full trace in memory and reduce heap traffic. |
| // E.g. input: { a:1 b:{ c:2, d:{ e:3 } } } , { a:4, ... }, |
| // output: [ only this is parsed ] ^return value points here. |
| ReadDictRes ReadOneJsonDict(const char* start, |
| const char* end, |
| Json::Value* value, |
| const char** next) { |
| int braces = 0; |
| int square_brackets = 0; |
| const char* dict_begin = nullptr; |
| bool in_string = false; |
| bool is_escaping = false; |
| for (const char* s = start; s < end; s++) { |
| if (isspace(*s) || *s == ',') |
| continue; |
| if (*s == '"' && !is_escaping) { |
| in_string = !in_string; |
| continue; |
| } |
| if (in_string) { |
| // If we're in a string and we see a backslash and the last character was |
| // not a backslash the next character is escaped: |
| is_escaping = *s == '\\' && !is_escaping; |
| // If we're currently parsing a string we should ignore otherwise special |
| // characters: |
| continue; |
| } |
| if (*s == '{') { |
| if (braces == 0) |
| dict_begin = s; |
| braces++; |
| continue; |
| } |
| if (*s == '}') { |
| if (braces <= 0) |
| return kEndOfTrace; |
| if (--braces > 0) |
| continue; |
| Json::Reader reader; |
| if (!reader.parse(dict_begin, s + 1, *value, /*collectComments=*/false)) { |
| PERFETTO_ELOG("JSON error: %s", |
| reader.getFormattedErrorMessages().c_str()); |
| return kFatalError; |
| } |
| *next = s + 1; |
| return kFoundDict; |
| } |
| if (*s == '[') { |
| square_brackets++; |
| continue; |
| } |
| if (*s == ']') { |
| if (square_brackets == 0) { |
| // We've reached the end of [traceEvents] array. |
| // There might be other top level keys in the json (e.g. metadata) |
| // after. |
| // TODO(dproy): Handle trace metadata importing. |
| return kEndOfTrace; |
| } |
| square_brackets--; |
| } |
| } |
| return kNeedsMoreData; |
| } |
| |
| JsonTraceTokenizer::JsonTraceTokenizer(TraceProcessorContext* ctx) |
| : context_(ctx) {} |
| JsonTraceTokenizer::~JsonTraceTokenizer() = default; |
| |
| util::Status JsonTraceTokenizer::Parse(std::unique_ptr<uint8_t[]> data, |
| size_t size) { |
| buffer_.insert(buffer_.end(), data.get(), data.get() + size); |
| const char* buf = buffer_.data(); |
| const char* next = buf; |
| const char* end = buf + buffer_.size(); |
| |
| if (offset_ == 0) { |
| // Trace could begin in any of these ways: |
| // {"traceEvents":[{ |
| // { "traceEvents": [{ |
| // [{ |
| // Skip up to the first '[' |
| while (next != end && *next != '[') { |
| next++; |
| } |
| if (next == end) |
| return util::ErrStatus("Failed to parse: first chunk missing opening ["); |
| next++; |
| } |
| |
| auto* trace_sorter = context_->sorter.get(); |
| |
| while (next < end) { |
| std::unique_ptr<Json::Value> value(new Json::Value()); |
| const auto res = ReadOneJsonDict(next, end, value.get(), &next); |
| if (res == kFatalError) |
| return util::ErrStatus("Encountered fatal error while parsing JSON"); |
| if (res == kEndOfTrace || res == kNeedsMoreData) |
| break; |
| |
| base::Optional<int64_t> opt_ts = |
| json_trace_utils::CoerceToNs((*value)["ts"]); |
| if (!opt_ts.has_value()) { |
| context_->storage->IncrementStats(stats::json_tokenizer_failure); |
| continue; |
| } |
| int64_t ts = opt_ts.value(); |
| |
| trace_sorter->PushJsonValue(ts, std::move(value)); |
| } |
| |
| offset_ += static_cast<uint64_t>(next - buf); |
| buffer_.erase(buffer_.begin(), buffer_.begin() + (next - buf)); |
| return util::OkStatus(); |
| } |
| |
| } // namespace trace_processor |
| } // namespace perfetto |
| |
| #endif // PERFETTO_BUILDFLAG(PERFETTO_TP_JSON) |