412 lines
12 KiB
C++
412 lines
12 KiB
C++
#ifndef EXCEPTION_BASE_H
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#define EXCEPTION_BASE_H
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#include <exception>
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#include <string>
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#include <cstring>
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#include <memory>
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#include <source_location>
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#include <sstream>
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#include <type_traits>
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/**
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* @brief 通用异常基类
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*
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* 特性：
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* 1. 完整的错误信息管理（错误码、消息、位置信息）
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* 2. 支持异常链（嵌套异常）
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* 3. 多态支持（clone、自定义消息）
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* 4. 线程安全的 what() 缓存
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* 5. 支持 C++20 source_location
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*/
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class ExceptionBase : public std::exception {
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public:
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// ============ 构造函数 ============
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explicit ExceptionBase(
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int code = 0,
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const std::string& message = "",
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const std::source_location& location = std::source_location::current()
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) noexcept
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: m_code(code)
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, m_message(message)
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, m_file(location.file_name())
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, m_line(location.line())
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, m_function(location.function_name())
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, m_what_cache()
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{
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}
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// 支持从字符串字面量构造
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explicit ExceptionBase(
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const std::string& message,
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const std::source_location& location = std::source_location::current()
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) noexcept
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: m_code(0)
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, m_message(message)
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, m_file(location.file_name())
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, m_line(location.line())
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, m_function(location.function_name())
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, m_what_cache()
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{
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}
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// ============ 拷贝和移动 ============
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ExceptionBase(const ExceptionBase& other) noexcept
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: std::exception(other)
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, m_code(other.m_code)
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, m_message(other.m_message)
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, m_file(other.m_file)
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, m_line(other.m_line)
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, m_function(other.m_function)
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, m_nested(other.m_nested ? other.m_nested->clone() : nullptr)
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, m_what_cache()
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{
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}
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ExceptionBase(ExceptionBase&& other) noexcept
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: std::exception(std::move(other))
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, m_code(other.m_code)
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, m_message(std::move(other.m_message))
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, m_file(std::move(other.m_file))
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, m_line(other.m_line)
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, m_function(std::move(other.m_function))
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, m_nested(std::move(other.m_nested))
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, m_what_cache(std::move(other.m_what_cache))
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{
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other.m_code = 0;
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other.m_line = 0;
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}
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virtual ~ExceptionBase() noexcept = default;
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// ============ 赋值运算符 ============
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ExceptionBase& operator=(const ExceptionBase& other) noexcept {
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if (this != &other) {
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m_code = other.m_code;
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m_message = other.m_message;
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m_file = other.m_file;
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m_line = other.m_line;
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m_function = other.m_function;
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m_nested = other.m_nested ? other.m_nested->clone() : nullptr;
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m_what_cache.clear();
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}
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return *this;
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}
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ExceptionBase& operator=(ExceptionBase&& other) noexcept {
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if (this != &other) {
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m_code = other.m_code;
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m_message = std::move(other.m_message);
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m_file = std::move(other.m_file);
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m_line = other.m_line;
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m_function = std::move(other.m_function);
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m_nested = std::move(other.m_nested);
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m_what_cache = std::move(other.m_what_cache);
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other.m_code = 0;
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other.m_line = 0;
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}
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return *this;
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}
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// ============ 访问器 ============
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int code() const noexcept { return m_code; }
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const std::string& message() const noexcept { return m_message; }
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const std::string& file() const noexcept { return m_file; }
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int line() const noexcept { return m_line; }
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const std::string& function() const noexcept { return m_function; }
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const ExceptionBase* nested() const noexcept { return m_nested.get(); }
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// ============ 异常链操作 ============
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void set_nested(std::unique_ptr<ExceptionBase> nested) noexcept {
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m_nested = std::move(nested);
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m_what_cache.clear();
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}
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template<typename ExType>
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void set_nested(const ExType& nested_ex) noexcept {
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static_assert(std::is_base_of<ExceptionBase, ExType>::value,
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"ExType must inherit from ExceptionBase");
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m_nested = std::make_unique<ExType>(nested_ex);
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m_what_cache.clear();
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}
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// ============ std::exception 接口 ============
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const char* what() const noexcept override {
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if (m_what_cache.empty()) {
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build_what_message();
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}
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return m_what_cache.c_str();
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}
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// ============ 多态支持 ============
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virtual std::unique_ptr<ExceptionBase> clone() const {
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return std::make_unique<ExceptionBase>(*this);
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}
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// ============ 重新抛出 ============
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[[noreturn]] void rethrow() const {
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throw *this;
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}
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protected:
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// ============ 可重写的消息构建方法 ============
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virtual std::string build_message() const {
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std::string result;
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// 错误码
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if (m_code != 0) {
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result += "[Error " + std::to_string(m_code) + "] ";
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}
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// 错误消息
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result += m_message;
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/* ===== 以下「位置信息」与「嵌套异常」暂时以注释方式保留 =====
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* 原因：黑盒检测发现 what() 的返回值会透传到 HTTP 响应体，
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* 导致泄露源码文件路径、行号、C++ 模板类型签名（函数名），
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* 便于攻击者定位代码、确认技术栈、构造针对性 payload（P0-3）。
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* 排障：完整信息仍由各 handler 通过 std::cerr 输出到服务端日志。
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* 恢复：如需调试可临时取消下方注释；生产环境必须保持注释状态，
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* 并确保 what() 不直接进入客户端响应。
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* ====================================================================
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// 位置信息
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if (!m_file.empty()) {
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result += " (at " + m_file;
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if (m_line > 0) {
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result += ":" + std::to_string(m_line);
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}
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if (!m_function.empty()) {
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result += " in " + m_function;
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}
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result += ")";
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}
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// 嵌套异常
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if (m_nested) {
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result += "\n Caused by: " + std::string(m_nested->what());
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}
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* ==================================================================== */
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return result;
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}
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private:
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// ============ 内部方法 ============
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void build_what_message() const noexcept {
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try {
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m_what_cache = build_message();
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} catch (...) {
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// 降级处理
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m_what_cache = "Exception: " + m_message;
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}
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}
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private:
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// ============ 成员变量 ============
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int m_code;
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std::string m_message;
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std::string m_file;
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int m_line;
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std::string m_function;
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std::unique_ptr<ExceptionBase> m_nested;
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mutable std::string m_what_cache;
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};
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// ============================================================================
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// 宏定义 - 方案二完整版
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// ============================================================================
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/**
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* @brief 抛出指定类型的异常（自动添加 source_location）
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*
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* 适用场景：子类构造函数与 ExceptionBase 相同
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*
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* 使用示例：
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* THROW_EX(NetworkException, 404, "Server not found")
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* THROW_EX(DatabaseException, 100, "Connection timeout")
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*/
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#define THROW_EX(ExType, code, msg) \
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throw ExType(code, msg, std::source_location::current())
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/**
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* @brief 抛出异常（仅消息，不传错误码）
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*
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* 适用场景：子类支持只传消息的构造函数
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*
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* 使用示例：
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* THROW_EX_MSG(ValidationException, "Invalid input data")
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*/
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#define THROW_EX_MSG(ExType, msg) \
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throw ExType(msg, std::source_location::current())
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/**
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* @brief 抛出异常（支持任意构造函数参数）
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*
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* 适用场景：子类有额外的构造函数参数
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*
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* 使用示例：
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* // 子类定义
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* class FileException : public ExceptionBase {
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* public:
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* FileException(int code, const std::string& msg,
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* const std::string& filename,
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* const std::source_location& loc = std::source_location::current())
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* : ExceptionBase(code, msg, loc), m_filename(filename) {}
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* };
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*
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* // 使用
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* THROW_EX_CUSTOM(FileException, 404, "File not found", "/etc/config.txt")
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*/
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#define THROW_EX_CUSTOM(ExType, ...) \
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throw ExType(__VA_ARGS__, std::source_location::current())
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/**
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* @brief 抛出异常并携带嵌套异常
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*
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* 适用场景：需要保留原始异常信息
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*
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* 使用示例：
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* try {
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* connect_to_server();
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* } catch (const NetworkException& e) {
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* THROW_EX_NESTED(ServiceException, 500, "Service failed", e)
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* }
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*/
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#define THROW_EX_NESTED(ExType, code, msg, nested_ex) \
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do { \
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auto ex = ExType(code, msg, std::source_location::current()); \
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ex.set_nested(nested_ex); \
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throw ex; \
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} while(0)
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/**
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* @brief 抛出异常并携带嵌套异常（支持自定义参数）
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*
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* 使用示例：
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* THROW_EX_NESTED_CUSTOM(FileException, 500, "Read failed",
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* original_ex, "/data/file.txt")
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*/
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#define THROW_EX_NESTED_CUSTOM(ExType, code, msg, nested_ex, ...) \
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do { \
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auto ex = ExType(code, msg, __VA_ARGS__, std::source_location::current()); \
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ex.set_nested(nested_ex); \
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throw ex; \
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} while(0)
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/**
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* @brief 检查条件，失败则抛出异常
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*
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* 使用示例：
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* THROW_IF(ptr == nullptr, NullPointerException, 100, "Pointer is null")
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* THROW_IF(data.empty(), ValidationException, 200, "Data cannot be empty")
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*/
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#define THROW_IF(cond, ExType, code, msg) \
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do { \
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if (cond) { \
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THROW_EX(ExType, code, msg); \
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} \
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} while(0)
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/**
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* @brief 检查条件，失败则抛出异常（仅消息）
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*/
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#define THROW_IF_MSG(cond, ExType, msg) \
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do { \
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if (cond) { \
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THROW_EX_MSG(ExType, msg); \
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} \
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} while(0)
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/**
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* @brief 检查条件，失败则抛出异常（自定义参数）
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*/
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#define THROW_IF_CUSTOM(cond, ExType, ...) \
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do { \
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if (cond) { \
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THROW_EX_CUSTOM(ExType, __VA_ARGS__); \
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} \
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} while(0)
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/**
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* @brief 检查条件，失败则抛出异常（带嵌套异常）
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*/
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#define THROW_IF_NESTED(cond, ExType, code, msg, nested_ex) \
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do { \
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if (cond) { \
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THROW_EX_NESTED(ExType, code, msg, nested_ex); \
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} \
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} while(0)
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/**
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* @brief 检查条件，失败则抛出异常（带嵌套异常和自定义参数）
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*/
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#define THROW_IF_NESTED_CUSTOM(cond, ExType, code, msg, nested_ex, ...) \
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do { \
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if (cond) { \
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THROW_EX_NESTED_CUSTOM(ExType, code, msg, nested_ex, __VA_ARGS__); \
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} \
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} while(0)
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// ============================================================================
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// 辅助宏 - 用于格式化错误消息
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// ============================================================================
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/**
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* @brief 格式化错误消息（使用流式语法）
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*
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* 使用示例：
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* THROW_EX_FMT(NetworkException, 404, "Failed to connect to " << host << ":" << port)
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*/
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#define THROW_EX_FMT(ExType, code, msg_expr) \
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do { \
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std::ostringstream _oss; \
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_oss << msg_expr; \
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THROW_EX(ExType, code, _oss.str()); \
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} while(0)
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/**
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* @brief 格式化错误消息（使用 printf 风格）
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*
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* 使用示例：
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* THROW_EX_PRINTF(NetworkException, 404, "Failed to connect to %s:%d", host.c_str(), port)
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*/
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#define THROW_EX_PRINTF(ExType, code, fmt, ...) \
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do { \
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char _buf[1024]; \
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snprintf(_buf, sizeof(_buf), fmt, __VA_ARGS__); \
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THROW_EX(ExType, code, std::string(_buf)); \
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} while(0)
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/**
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* @brief 条件检查 + 格式化消息
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*/
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#define THROW_IF_FMT(cond, ExType, code, msg_expr) \
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do { \
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if (cond) { \
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THROW_EX_FMT(ExType, code, msg_expr); \
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} \
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} while(0)
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/**
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* @brief 条件检查 + printf 风格格式化
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*/
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#define THROW_IF_PRINTF(cond, ExType, code, fmt, ...) \
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do { \
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if (cond) { \
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THROW_EX_PRINTF(ExType, code, fmt, __VA_ARGS__); \
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} \
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} while(0)
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#endif // EXCEPTION_BASE_H
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