feat: signal and slot principles; and moc principles (what is done)

signal 和 slot 原理；以及 moc 原理（做了什么内容）

DbSigSlot/CMakeLists.txt

@@ -3,4 +3,4 @@ project(DbSigSlot)
 
 set(CMAKE_CXX_STANDARD 14)
 
-add_executable(DbSigSlot main.cpp object.cpp object.h)
+add_executable(DbSigSlot main.cpp object.cpp object.h db_object.cpp)

DbSigSlot/db_object.cpp

@@ -0,0 +1,29 @@
+#include "object.h"
+
+//db_object: 是由 moc 编译器 将 object.cpp 展开的内容(此处手写表示)
+
+const char sig_names[] = "sig1()";
+const char slot_names[] = "slot1()";
+MetaObject Object::meta = {sig_names, slot_names};
+
+void Object::sig1()
+{
+    MetaObject::active(this, 0);
+}
+
+void Object::slot1()
+{
+    cout << "-----------> this is slot1()";
+}
+
+// 槽的索引==> 槽函数
+void Object::metacall(int idx)
+{
+    switch (idx) {
+    case 0:
+        slot1();
+        break;
+    default:
+        break;
+    }
+}

DbSigSlot/main.cpp

@@ -1,8 +1,19 @@
 #include <iostream>
+#include "object.h"
 using namespace std;
 
+// 目的：自行构造 moc 编译器，手动将 object.h --> db_bject.cpp (宏 和 moc 编译器处理的部分)
+// 时间：2021-003-26
+// 作者：偕臧  ifmet.cn
+// 下载：https://github.com/xmuli/QtExamples
+// 参考：https://blog.csdn.net/perfectguyipeng/article/details/78082360
+
 int main(int argc, char *argv[])
 {
+    Object *obj1 = new Object();
+    Object *obj2 = new Object();
 
+    Object::db_connet(obj1, "sig1()", obj2, "slot1()");
+    obj1->testSignal();
     return 0;
 }

DbSigSlot/object.cpp

@@ -1,6 +1,56 @@
 #include "object.h"
+#include <cstring>
+
+static int findSignalIndex(const char *str, const char *subStr)
+{
+    if (!str || !subStr || strlen(str) < strlen(subStr))
+        return -1;
+
+    int ret = strcmp(str, subStr);
+    if (ret == 0)
+        return ret;
+    else
+        return -1;
+
+}
+
+void Object::db_connet(Object *sender, const char *sig, Object *receiver, const char *slot)
+{
+    int sig_idx = findSignalIndex(sender->meta.sig_names, sig);
+    int slot_idx = findSignalIndex(receiver->meta.slot_names, slot);
+
+    if (sig_idx == -1 || slot_idx == -1) {
+        cout<<"signal or slot not found!";
+        return;
+    } else {
+        Connection c = {receiver, slot_idx};
+        sender->connectionsMap.insert(pair<int, Connection>(sig_idx, c));  // connectionsMap 私有成员
+    }
+}
+
+void Object::testSignal()
+{
+    db_emit sig1();
+}
 
 Object::Object()
 {
 
 }
+
+Object::~Object()
+{
+
+}
+
+// 通过 sender 的信号 idx ==> 槽函数
+void MetaObject::active(Object *sender, int idx)
+{
+    pair<ConnectionMapIt, ConnectionMapIt> ret;
+    ret = sender->connectionsMap.equal_range(idx);  // 寻找[idx,  )
+    for (ConnectionMapIt it = ret.first; it != ret.second; ++it) {
+        Connection c = (*it).second;
+        c.recviver->metacall(idx);
+    }
+
+}

DbSigSlot/object.h

@@ -1,11 +1,56 @@
 #ifndef OBJECT_H
 #define OBJECT_H
 
+#include <iostream>
+#include <map>
+using namespace std;
+
+#define db_signals protected
+#define db_slots
+#define db_emit
+
+class Object;
+struct MetaObject          // 元对象
+{
+    const char *sig_names;
+    const char *slot_names;
+
+    static void active(Object *sender, int idx);
+};
+
+struct Connection
+{
+    Object *recviver;
+    int method;
+};
+
+typedef multimap<int, Connection> ConnectionMap;
+typedef multimap<int, Connection>::iterator ConnectionMapIt;
 
 class Object
 {
+    static MetaObject meta;
+    void metacall(int idx);
+
+public:
+    static void db_connet(Object *sender, const char *sig, Object *receiver, const char *slot);
+    void testSignal();
+
 public:
     Object();
+    virtual ~Object();
+
+db_signals:
+    void sig1();
+//    void sig2();
+
+public db_slots:
+    void slot1();
+//    void slot2();
+
+friend class MetaObject;
+private:
+    ConnectionMap connectionsMap;
 };
 
-#endif // OBJECT_H
+#endif // OBJECT_H

README.md

@@ -156,10 +156,10 @@
 
 - [QtCreator设置代码美化 astyle 之 Artistic](https://blog.csdn.net/qq_33154343/article/details/101397429)
 - [Qt Creator 关闭.cpp文件右侧的黄色警告](https://blog.csdn.net/qq_33154343/article/details/102943623)
-
 - [小技巧：Design设计师里，无法拖拽action到toolbar里](https://blog.csdn.net/qq_33154343/article/details/100168170) 
 - [小技巧：设置`QToolBox`的每一页page的使用单独的布局（`QTabWidget`同理）](https://blog.csdn.net/qq_33154343/article/details/100185025) 
 - [小技巧：QtCreator用快捷键秒实现，声明在基类中重写的派生类(纯)虚函数](https://blog.csdn.net/qq_33154343/article/details/104457739) 
+- [VS2019调试Qt5时QString显示为内存地址而非字符串](https://xmuli.blog.csdn.net/article/details/116244865) 
 
 <br>
 
@@ -172,6 +172,7 @@
 - [如何给上游 Qt 提交 Bug 反馈和贡献代码 PATCH？](https://xmuli.blog.csdn.net/article/details/107220867) 
 - [Qt 项目用 doxygen 生成 .qch，嵌入文档到 Assistants](https://xmuli.blog.csdn.net/article/details/114580630) 
 - [修改 Doxygen 主题，生成 Qt 风格的文档](https://xmuli.blog.csdn.net/article/details/114591725) 
+- [QtCreator 中自定义项目例子置于“欢迎-实例”中](https://xmuli.blog.csdn.net/article/details/115049715)
 
 <br>
 
@@ -181,6 +182,7 @@
 - [Qt 项目(Cmake)设置国际化支持](https://xmuli.blog.csdn.net/article/details/114439385) 
 - [如何构建 QT5（5.15）](https://xmuli.blog.csdn.net/article/details/114259155) 
 - [在 Mac 编译成功运行 qt5.15 源码：debug 和 release 版本](https://xmuli.blog.csdn.net/article/details/114259186)
+- [Qt 信号和槽原理分析](https://xmuli.blog.csdn.net/article/details/115305903)
 
 <br>
 
@@ -252,7 +254,7 @@
 
 ## 作者：
 
-[偕藏 | xmuli ](https://ifmet.cn)
+[偕臧 | xmuli ](https://ifmet.cn)
 
 <br>