MEMORY64: GLFW drop function passes incorrect filename values

[oitel]

The onDrop function in libglfw.js has two different issues in the wasm64 version:

1. The drop callback's dyncall sets the filenames parameter to number, while on wasm64 it is BigInt.
2. The filenames array allocates 4 bytes per element, while on wasm64 it is 8.

Example output for 5 input files (running on Firefox 134):

Uncaught TypeError: can't convert 97048 to BigInt
    onloadend http://localhost:8000/main.js:5605
    onloadend http://localhost:8000/main.js:5605
    save http://localhost:8000/main.js:5595
    onDrop http://localhost:8000/main.js:5621
    _glfwInit http://localhost:8000/main.js:6110
    makeWrapper___PP http://localhost:8000/main.js:6257
    createExportWrapper http://localhost:8000/main.js:617
    callMain http://localhost:8000/main.js:6594
    doRun http://localhost:8000/main.js:6646
    run http://localhost:8000/main.js:6655
    setTimeout handler*run http://localhost:8000/main.js:6653
    removeRunDependency http://localhost:8000/main.js:572
    receiveInstance http://localhost:8000/main.js:726
    receiveInstantiationResult http://localhost:8000/main.js:744
    createWasm http://localhost:8000/main.js:767
    async* http://localhost:8000/main.js:6236

After applying a manual fix for the first issue:

Dropped file: /.glfw_dropped_files/test_0001.txt
Dropped file: /.glfw_dropped_files/test_0003.txt
Dropped file: /.glfw_dropped_files/test_0005.txt
Dropped file:
Uncaught RuntimeError: index out of bounds
    onloadend http://localhost:8000/main.js:5605
    onloadend http://localhost:8000/main.js:5605
    save http://localhost:8000/main.js:5595
    onDrop http://localhost:8000/main.js:5621
    _glfwInit http://localhost:8000/main.js:6110
    makeWrapper___PP http://localhost:8000/main.js:6257
    createExportWrapper http://localhost:8000/main.js:617
    callMain http://localhost:8000/main.js:6594
    doRun http://localhost:8000/main.js:6646
    run http://localhost:8000/main.js:6655
    setTimeout handler*run http://localhost:8000/main.js:6653
    removeRunDependency http://localhost:8000/main.js:572
    receiveInstance http://localhost:8000/main.js:726
    receiveInstantiationResult http://localhost:8000/main.js:744
    createWasm http://localhost:8000/main.js:767
    async* http://localhost:8000/main.js:6236

Version of emscripten/emsdk:
emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 4.0.0 (97c7c2a)
clang version 20.0.0git (https:/github.com/llvm/llvm-project 322eb1a92e6d4266184060346616fa0dbe39e731)
Target: wasm32-unknown-emscripten
Thread model: posix

Failing command line in full:
emcc -s ENVIRONMENT=web -s USE_GLFW=3 -s MEMORY64=1 main.cpp -o main.html

main.cpp:

#include <emscripten.h>
#include <GLFW/glfw3.h>
#include <iostream>

int main(int, char**)
{
    glfwInit();

    GLFWwindow* window = glfwCreateWindow(1280, 720, "GLFW example", nullptr, nullptr);

    glfwSetDropCallback(window, [](GLFWwindow* window, int count, const char** paths) {
        for (int i = 0; i < count; ++i) {
            std::cout << "Dropped file: " << paths[i] << std::endl;
        }
    });

    emscripten_set_main_loop(glfwPollEvents, 0, true);

    glfwDestroyWindow(window);
    glfwTerminate();

    return 0;
}

[kripken]

This works in Chrome, so it is likely a Firefox issue. Perhaps Firefox 134 has not updated to the final spec? You may want to check a Firefox nightly build.

[sbc100]

We have an interactive test called test_glfw_dropfile that I think we can you use test/verify this. You can run it in 64-bit mode using test/runner interactive64.test_glfw_dropfile

[oitel]

I've just checked it on Chromium version 133.0.6943.98 and got the same results (TypeError, then RuntimeError).
I don't know how does the test process dropping multiple files at once. Anyway I'll run it locally later and report to you.

[sbc100]

Fix is in #23676