X11: クリップボードからUTF-8テキストを取得する

x11-get-clipboard-text.cpp

// g++ -std=c++0x x11clipboard.cpp -lX11
// http://tools.suckless.org/sselp
#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <string>
#include <climits>

std::string getClipboardText() {
    std::string result;
    Display* d = XOpenDisplay(nullptr);
    if(d) {
        Window wParent = DefaultRootWindow(d);
        Window w = XCreateSimpleWindow(
            d, wParent, 0, 0, 1, 1, 0, CopyFromParent, CopyFromParent);
        Atom target = XInternAtom(d, "UTF8_STRING", False);
        XConvertSelection(d, XA_PRIMARY, target, None, w, CurrentTime);
        XFlush(d);

        for(unsigned long offset = 0;;) {
            XEvent ev;
            XNextEvent(d, &ev);
            if(SelectionNotify == ev.type
               && None != ev.xselection.property
            ) {
                Atom actual_type_return = None;
                int actual_format_return = 0;
                unsigned long nitems_return = 0;
                unsigned long bytes_after_return = 0;
                unsigned char* prop_return = nullptr;
                XGetWindowProperty(
                    d, w, ev.xselection.property, offset, INT_MAX
                    , False, AnyPropertyType, &actual_type_return
                    , &actual_format_return, &nitems_return
                    , &bytes_after_return, &prop_return);
                if(nitems_return) {
                    result.append(reinterpret_cast<const char*>(prop_return)
                                  , nitems_return);
                    offset += nitems_return;
                }
                XDeleteProperty(d, w, ev.xselection.property);
                if(!bytes_after_return) {
                    break;
                }
            }
        }
        XDestroyWindow(d, w);
        XCloseDisplay(d);
    }
    return result;
}

int main(int argc, const char* argv[]) {
    std::string utf8 = getClipboardText();
    printf("CLIPBOARD[%s]\n", utf8.c_str());
    return 0;
}