python: provide batch iteration / filters

[Jannik2099]

Turns out iterating over ~ 30k packages with 5 depend exprs each is really slow as pybind has to bind each iterator object, and throw a C++ exception for each iteration end.

We need some kind of API akin to "find ebuilds where dependency expr contains ..."

A quick "revdep at home":

C++:

#include "pms-utils/atom/atom.hpp"
#include "pms-utils/depend/depend.hpp"
#include "pms-utils/repo/repo.hpp"

#include <boost/variant/static_visitor.hpp>
#include <format>
#include <iostream>

bool contains_expr(const pms_utils::depend::DependExpr &dependExpr,
                   const pms_utils::atom::PackageExpr &packageExpr) {
    for (const auto &expr : dependExpr) {
        class visitor : public boost::static_visitor<bool> {
        public:
            const pms_utils::atom::PackageExpr &packageExpr;
            visitor(const pms_utils::atom::PackageExpr &packageExpr) : packageExpr{packageExpr} {}
            bool operator()(const pms_utils::atom::PackageExpr &expr) const {
                return expr.category == packageExpr.category && expr.name == packageExpr.name;
            }
            bool operator()(const pms_utils::depend::DependExpr &expr) const {
                return contains_expr(expr, packageExpr);
            }
        };
        if (boost::apply_visitor(visitor(packageExpr), expr)) {
            return true;
        }
    }
    return false;
}

int main() {
    pms_utils::repo::Repository repo{"/var/db/repos/gentoo"};

    for (const auto &category : repo) {
        for (const auto &package : category) {
            for (const auto &ebuild : package) {
                bool found = false;
                for (const auto &depends :
                     {ebuild.metadata().BDEPEND, ebuild.metadata().DEPEND, ebuild.metadata().IDEPEND,
                      ebuild.metadata().PDEPEND, ebuild.metadata().RDEPEND}) {
                    if (contains_expr(depends, pms_utils::atom::PackageExpr{.category = {"net-dns"},
                                                                            .name = {"avahi"}})) {
                        found = true;
                    }
                }
                if (found) {
                    std::cout << std::format("found in ebuild {}\n", std::string{ebuild.name});
                }
            }
        }
    }
}

./revdep 0.68s user 0.40s system 99% cpu 1.081 total

Python:

import pms_utils
from pathlib import Path

repo = pms_utils.repo.Repository(Path("/var/db/repos/gentoo"))
profile = pms_utils.profile.Profile(Path("/etc/portage/make.profile"))


def contains_expr(
    depend_expr: pms_utils.depend.DependExpr, package_expr: pms_utils.atom.Atom
) -> bool:
    for expr in depend_expr:
        if (
            type(expr) == pms_utils.atom.Atom
            and expr.category == package_expr.category
            and expr.name == package_expr.name
        ):
            return True
        if type(expr) == pms_utils.depend.DependExpr:
            if contains_expr(expr, package_expr):
                return True
    return False


for category in repo:
    for package in category:
        for ebuild in package:
            found = False
            for depends in [
                ebuild.metadata.BDEPEND,
                ebuild.metadata.IDEPEND,
                ebuild.metadata.RDEPEND,
                ebuild.metadata.DEPEND,
                ebuild.metadata.PDEPEND,
            ]:
                if contains_expr(depends, pms_utils.atom.Atom("net-dns/avahi")):
                    found = True
            if found:
                print(f"found in ebuild {ebuild.name}")

python revdep.py 4.35s user 0.48s system 99% cpu 4.858 total