将用户数据分配给 x11/xcb 窗口 [英] Assign user data to x11/xcb window

问题描述

像 Windows 这样的平台允许我们将自定义数据分配给一个窗口.使用 WinAPI，可以调用 SetWindowLongPtr 将自定义数据分配给窗口.使用 AppKit，可以扩展他的 NSWindowDelegate 实现，它被分配给一个窗口，并带有所需的数据.

Platforms like Windows allow us to assign custom data to a window. With WinAPI, one can call SetWindowLongPtr to assign custom data to a window. With AppKit, one extends his implementation of NSWindowDelegate, which is assigned to a window, with the data required.

xcb 中是否有等价物?

到目前为止我尝试过...

So far I tried...

• 创建地图，将窗口 ID 映射到用户数据.
• 为窗口分配自定义属性/原子，其中包含指向我的数据的指针/索引.

我不认为任何一种方法都很好，因此我想知道是否有内置方法来实现我所需要的.尤其是后者，因为我不知道如何确保我的属性不会与 WM 定义的其他属性发生冲突.

I don't think either approach is good, thus I am wondering if there is built-in method to achieve what I need. Especially with latter, since I don't know how to make sure, that my properties do not collide with others, defined by the WM.

TL;DR:如何在 xcb 中使用自定义数据注释窗口?

TL;DR: How can I annotate a window with custom data in xcb?

推荐答案

我不知道 xcb 但我以前在 X windows 中做的事情是这样的.假设有一个存储数据的结构

I don't know about xcb but what I used to do in X windows is somethintg like this. Say there is a structure where the data is being stored

struct CustomData
{
     ...
} custom;

当您为标签中的指针分配空间时，添加 sizeof(void*).假设标签是 Fred.

When you allocate space for a pointer in the label, add sizeof(void*). Say the label is Fred.

const char* tag = "Fred";
size_t tag_len = strlen(tag) + 1;
Custom* custom_ptr = &custom;
size_t ptr_len = sizeof(Custom_ptr);
char* label = (char*) malloc(taglen + sizeof(void*));
strcpy(label, tag);
// Add pointer to custom
memcpy(&label[taglen], &custom_ptr, ptr_len);
XtSetValue(w, XtNLabel, label);

然后取回价值

char* label;
Arg warg[16];
XtSetArg(warg[0], XtNLabel, &label); 
XtGetValues(w, warg, 1);
size_t taglen = strlen(label) + 1;
Custom* custom_ptr;
memcpy(&custom_ptr, &label[taglen], sizeof(custom_ptr));

但那是在 80 年代中期，远在 STL 发明之前.现在，我只是按照@Ry 所说的去做 - 创建一个小部件 ID 和数据的映射.

but that was in the mid-80s, way before STL was invented. Nowadays, I'd just do as @Ry said - create a map of widget ids and data.

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