cef/libcef/browser/devtools/devtools_util.cc

142 lines
4.2 KiB
C++

// Copyright (c) 2020 The Chromium Embedded Framework 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 "libcef/browser/devtools/devtools_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
namespace devtools_util {
namespace {
bool IsValidDictionary(const std::string_view& str, bool allow_empty) {
return str.length() >= (allow_empty ? 2 : 3) && str[0] == '{' &&
str[str.length() - 1] == '}';
}
// Example:
// {"method":"Target.targetDestroyed","params":{"targetId":"1234..."}}
bool ParseEvent(const std::string_view& message,
std::string_view& method,
std::string_view& params) {
static const char kMethodStart[] = "{\"method\":\"";
static const char kMethodEnd[] = "\"";
static const char kParamsStart[] = ",\"params\":";
if (!base::StartsWith(message, kMethodStart)) {
return false;
}
const size_t method_start = sizeof(kMethodStart) - 1;
const size_t method_end = message.find(kMethodEnd, method_start);
if (method_end == std::string_view::npos) {
return false;
}
method = message.substr(method_start, method_end - method_start);
if (method.empty()) {
return false;
}
size_t remainder_start = method_end + sizeof(kMethodEnd) - 1;
if (remainder_start == message.size() - 1) {
// No more contents.
params = std::string_view();
} else {
const std::string_view& remainder = message.substr(remainder_start);
if (base::StartsWith(remainder, kParamsStart)) {
// Stop immediately before the message closing bracket.
remainder_start += sizeof(kParamsStart) - 1;
params =
message.substr(remainder_start, message.size() - 1 - remainder_start);
} else {
// Invalid format.
return false;
}
if (!IsValidDictionary(params, /*allow_empty=*/true)) {
return false;
}
}
return true;
}
// Examples:
// {"id":3,"result":{}}
// {"id":4,"result":{"debuggerId":"-2193881606781505058.81393575456727957"}}
// {"id":5,"error":{"code":-32000,"message":"Not supported"}}
bool ParseResult(const std::string_view& message,
int& message_id,
bool& success,
std::string_view& result) {
static const char kIdStart[] = "{\"id\":";
static const char kIdEnd[] = ",";
static const char kResultStart[] = "\"result\":";
static const char kErrorStart[] = "\"error\":";
if (!base::StartsWith(message, kIdStart)) {
return false;
}
const size_t id_start = sizeof(kIdStart) - 1;
const size_t id_end = message.find(kIdEnd, id_start);
if (id_end == std::string_view::npos) {
return false;
}
const std::string_view& id_str = message.substr(id_start, id_end - id_start);
if (id_str.empty() || !base::StringToInt(id_str, &message_id)) {
return false;
}
size_t remainder_start = id_end + sizeof(kIdEnd) - 1;
const std::string_view& remainder = message.substr(remainder_start);
if (base::StartsWith(remainder, kResultStart)) {
// Stop immediately before the message closing bracket.
remainder_start += sizeof(kResultStart) - 1;
result =
message.substr(remainder_start, message.size() - 1 - remainder_start);
success = true;
} else if (base::StartsWith(remainder, kErrorStart)) {
// Stop immediately before the message closing bracket.
remainder_start += sizeof(kErrorStart) - 1;
result =
message.substr(remainder_start, message.size() - 1 - remainder_start);
success = false;
} else {
// Invalid format.
return false;
}
if (!IsValidDictionary(result, /*allow_empty=*/true)) {
return false;
}
return true;
}
} // namespace
// static
bool ProtocolParser::IsValidMessage(const std::string_view& message) {
return IsValidDictionary(message, /*allow_empty=*/false);
}
bool ProtocolParser::Initialize(const std::string_view& message) {
if (status_ != UNINITIALIZED) {
return false;
}
if (ParseEvent(message, method_, params_)) {
status_ = EVENT;
} else if (ParseResult(message, message_id_, success_, params_)) {
status_ = RESULT;
} else {
status_ = FAILURE;
}
return true;
}
} // namespace devtools_util