runtime_probe/probe_function.cc

// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "runtime_probe/probe_function.h"

#include <memory>

#include <base/check.h>
#include <base/json/json_reader.h>
#include <base/json/json_writer.h>
#include <base/logging.h>

#include "runtime_probe/helper_invoker_debugd_impl.h"
#include "runtime_probe/helper_invoker_direct_impl.h"

namespace runtime_probe {

using DataType = typename ProbeFunction::DataType;

std::unique_ptr<ProbeFunction> ProbeFunction::FromValue(const base::Value& dv) {
  if (!dv.is_dict()) {
    LOG(ERROR) << "ProbeFunction::FromValue takes a dictionary as parameter";
    return nullptr;
  }

  if (dv.DictSize() == 0) {
    LOG(ERROR) << "No function name found in the ProbeFunction dictionary";
    return nullptr;
  }

  if (dv.DictSize() > 1) {
    LOG(ERROR) << "More than 1 function names specified in the ProbeFunction"
                  " dictionary";
    return nullptr;
  }

  const auto& it = dv.DictItems().begin();

  // function_name is the only key exists in the dictionary */
  const auto& function_name = it->first;
  const auto& kwargs = it->second;

  if (registered_functions_.find(function_name) ==
      registered_functions_.end()) {
    // TODO(stimim): Should report an error.
    LOG(ERROR) << "Function \"" << function_name << "\" not found";
    return nullptr;
  }

  if (!kwargs.is_dict()) {
    // TODO(stimim): implement syntax sugar.
    LOG(ERROR) << "Function argument should be a dictionary";
    return nullptr;
  }

  std::unique_ptr<ProbeFunction> ret_value =
      registered_functions_[function_name](kwargs);
  ret_value->raw_value_ = dv.Clone();

  return ret_value;
}

bool ProbeFunction::InvokeHelper(std::string* result) const {
  std::string probe_statement_str;
  CHECK(raw_value_.has_value());
  base::JSONWriter::Write(*raw_value_, &probe_statement_str);

  // TODO(yhong): Stop hard-coding the underlying implementation so that
  //     unit-tests can mock it.
  if constexpr (USE_FACTORY_RUNTIME_PROBE) {
    return RuntimeProbeHelperInvokerDirectImpl().Invoke(probe_statement_str,
                                                        result);
  } else {
    return RuntimeProbeHelperInvokerDebugdImpl().Invoke(probe_statement_str,
                                                        result);
  }
}

base::Optional<base::Value> ProbeFunction::InvokeHelperToJSON() const {
  std::string raw_output;
  if (!InvokeHelper(&raw_output)) {
    return base::nullopt;
  }
  return base::JSONReader::Read(raw_output);
}

int ProbeFunction::EvalInHelper(std::string* output) const {
  return 0;
}

}  // namespace runtime_probe