src/dawn/native/X11Functions.cpp

// Copyright 2021 The Dawn & Tint Authors
//
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#include "dawn/native/X11Functions.h"

#include <memory>

#include "dawn/common/Log.h"

namespace dawn::native {

X11Functions::X11Functions() {
    if (!mX11Lib.Open("libX11.so.6") || !mX11Lib.GetProc(&xSetErrorHandler, "XSetErrorHandler") ||
        !mX11Lib.GetProc(&xGetWindowAttributes, "XGetWindowAttributes") ||
        !mX11Lib.GetProc(&xSynchronize, "XSynchronize")) {
        mX11Lib.Close();
    }

    if (!mX11XcbLib.Open("libX11-xcb.so.1") ||
        !mX11XcbLib.GetProc(&xGetXCBConnection, "XGetXCBConnection")) {
        mX11XcbLib.Close();
    }
}
X11Functions::~X11Functions() = default;

bool X11Functions::IsX11Loaded() const {
    return mX11Lib.Valid();
}

bool X11Functions::IsX11XcbLoaded() const {
    return mX11XcbLib.Valid();
}

struct DebugX11 {
    static DebugX11* sDebug;
    static void Init(Display* display) {
        if (sDebug == nullptr) {
            auto debug = std::make_unique<DebugX11>();
            if (!debug->x.IsX11Loaded()) {
                return;
            }

            debug->previousHandler = debug->x.xSetErrorHandler(&HandleError);
            sDebug = debug.release();
        }

        // Make all X11 calls synchronous so that the error handler is called immediately.
        sDebug->x.xSynchronize(display, true);
    }

    static int HandleError(Display* d, XErrorEvent* e) {
        dawn::ErrorLog()
            << "An X11 error happened, triggering a breakpoint, the culprit will be in the stack.";
        dawn::BreakPoint();

        int result = sDebug->previousHandler(d, e);
        return result;
    }

    X11Functions x;
    XErrorHandler previousHandler = nullptr;
};
DebugX11* DebugX11::sDebug = nullptr;

void SynchronouslyDebugX11(Display* display) {
    DebugX11::Init(display);
}

}  // namespace dawn::native