Implement progress bar and multi-connection downloads

[ericcurtin]

For llama-server pulling

[JohannesGaessler]

FYI if you want a smoother/more compact progress bar you can use fractional blocks. Example implementation for training:

llama.cpp/ggml/src/ggml-opt.cpp

Lines 935 to 958 in 0889589

	// The progress bar consists of partially filled blocks, unicode has 8 separate fill levels.
	constexpr int64_t bar_length = 8;
	const int64_t ibatch8 = 8 * ibatch;
	for (int64_t j = 0; j < bar_length; ++j) {
	if (ibatch_max * (8*j + 8) / bar_length < ibatch8) {
	fprintf(stderr, "\u2588"); // full block
	} else if (ibatch_max * (8*j + 7) / bar_length < ibatch8) {
	fprintf(stderr, "\u2589"); // 7/8 filled
	} else if (ibatch_max * (8*j + 6) / bar_length < ibatch8) {
	fprintf(stderr, "\u258A"); // 6/8 filled
	} else if (ibatch_max * (8*j + 5) / bar_length < ibatch8) {
	fprintf(stderr, "\u258B"); // 5/8 filled
	} else if (ibatch_max * (8*j + 4) / bar_length < ibatch8) {
	fprintf(stderr, "\u258C"); // 4/8 filled
	} else if (ibatch_max * (8*j + 3) / bar_length < ibatch8) {
	fprintf(stderr, "\u258D"); // 3/8 filled
	} else if (ibatch_max * (8*j + 2) / bar_length < ibatch8) {
	fprintf(stderr, "\u258E"); // 2/8 filled
	} else if (ibatch_max * (8*j + 1) / bar_length < ibatch8) {
	fprintf(stderr, "\u258F"); // 1/8 filled
	} else {
	fprintf(stderr, " ");
	}
	}

[ericcurtin]

@JohannesGaessler was thinking docker-style because of portability, do you know if this works on Windows?

[angt]

Hey :)

I'm currently in the middle of a larger rework of this exact section, with the goal of removing the cURL dependency completely. You can see the work in progress here: #16185

And also made a very simple progressbar 😆

static void print_progress(size_t current, size_t total) { // TODO isatty
    if (!total) {
        return;
    }

    size_t width = 50;
    size_t pct = (100 * current) / total;
    size_t pos = (width * current) / total;

    std::cout << "["
              << std::string(pos, '=')
              << (pos < width ? ">" : "")
              << std::string(width - pos, ' ')
              << "] " << std::setw(3) << pct << "%  ("
              << current / (1024 * 1024) << " MB / "
              << total / (1024 * 1024) << " MB)\r";
    std::cout.flush();
}

To avoid us getting tangled in merge conflicts, how about we get my refactor merged first to create a clean base, and then we can circle back to integrate the improvements from your patch?

Let me know what you think

[ericcurtin]

#16185

Let me know when the PR is ready for review, would like to test and review.