blob: 9f13c3be8914a7498d666d306f6a3002c48ab2cd [file] [log] [blame]
/*
* Copyright (c) 2022 Project CHIP Authors
* All rights reserved.
*
* 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.
*
*/
#pragma once
#include "../common/CustomStringPrefix.h"
#include <json/json.h>
#include <lib/core/Optional.h>
#include <memory>
#include <sstream>
#include <string>
#include <vector>
class JsonParser
{
public:
// Returns whether the parse succeeded.
static bool ParseComplexArgument(const char * label, const char * json, Json::Value & value)
{
return Parse(label, json, /* strictRoot = */ true, value);
}
// Returns whether the parse succeeded.
static bool ParseCustomArgument(const char * label, const char * json, Json::Value & value)
{
return Parse(label, json, /* strictRoot = */ false, value);
}
private:
static bool Parse(const char * label, const char * json, bool strictRoot, Json::Value & value)
{
Json::CharReaderBuilder readerBuilder;
readerBuilder.settings_["strictRoot"] = strictRoot;
readerBuilder.settings_["allowSingleQuotes"] = true;
readerBuilder.settings_["failIfExtra"] = true;
readerBuilder.settings_["rejectDupKeys"] = true;
auto reader = std::unique_ptr<Json::CharReader>(readerBuilder.newCharReader());
std::string errors;
if (reader->parse(json, json + strlen(json), &value, &errors))
{
return true;
}
// The CharReader API allows us to set failIfExtra, unlike Reader, but does
// not allow us to get structured errors. We get to try to manually undo
// the work it did to create a string from the structured errors it had.
ChipLogError(chipTool, "Error parsing JSON for %s:", label);
// For each error "errors" has the following:
//
// 1) A line starting with "* " that has line/column info
// 2) A line with the error message.
// 3) An optional line with some extra info.
//
// We keep track of the last error column, in case the error message
// reporting needs it.
std::istringstream stream(errors);
std::string error;
chip::Optional<unsigned> errorColumn;
while (getline(stream, error))
{
if (error.rfind("* ", 0) == 0)
{
// Flush out any pending error location.
LogErrorLocation(errorColumn, json);
// The format of this line is:
//
// * Line N, Column M
//
// Unfortunately it does not indicate end of error, so we can only
// show its start.
unsigned errorLine; // ignored in practice
if (sscanf(error.c_str(), "* Line %u, Column %u", &errorLine, &errorColumn.Emplace()) != 2)
{
ChipLogError(chipTool, "Unexpected location string: %s\n", error.c_str());
// We don't know how to make sense of this thing anymore.
break;
}
if (errorColumn.Value() == 0)
{
ChipLogError(chipTool, "Expected error column to be at least 1");
// We don't know how to make sense of this thing anymore.
break;
}
// We are using our column numbers as offsets, so want them to be
// 0-based.
--errorColumn.Value();
}
else
{
ChipLogError(chipTool, " %s", error.c_str());
if (error == " Missing ',' or '}' in object declaration" && errorColumn.HasValue() && errorColumn.Value() > 0 &&
json[errorColumn.Value() - 1] == '0' && (json[errorColumn.Value()] == 'x' || json[errorColumn.Value()] == 'X'))
{
// Log the error location marker before showing the NOTE
// message.
LogErrorLocation(errorColumn, json);
ChipLogError(chipTool,
"NOTE: JSON does not allow hex syntax beginning with 0x for numbers. Try putting the hex number "
"in quotes (like {\"name\": \"0x100\"}).");
}
}
}
// Write out the marker for our last error.
LogErrorLocation(errorColumn, json);
return false;
}
private:
static void LogErrorLocation(chip::Optional<unsigned> & errorColumn, const char * json)
{
#if CHIP_ERROR_LOGGING
if (!errorColumn.HasValue())
{
return;
}
const char * sourceText = json;
unsigned error_start = errorColumn.Value();
// The whole JSON string might be too long to fit in our log
// messages. Just include 30 chars before the error.
constexpr ptrdiff_t kMaxContext = 30;
std::string errorMarker;
if (error_start > kMaxContext)
{
sourceText += (error_start - kMaxContext);
error_start = kMaxContext;
ChipLogError(chipTool, "... %s", sourceText);
// Add markers corresponding to the "... " above.
errorMarker += "----";
}
else
{
ChipLogError(chipTool, "%s", sourceText);
}
for (unsigned i = 0; i < error_start; ++i)
{
errorMarker += "-";
}
errorMarker += "^";
ChipLogError(chipTool, "%s", errorMarker.c_str());
errorColumn.ClearValue();
#endif // CHIP_ERROR_LOGGING
}
};