usm/installer/pm_emerge.sh

#!/bin/bash
# pm_emerge.sh - Portage (emerge) package manager implementation for Gentoo systems
#
# To add a new package manager, create a file named pm_<name>.sh with:
#  - pm_<name>_detect: Returns 0 if this PM is available, 1 otherwise
#  - pm_<name>_get_missing_deps: Prints space-separated list of missing packages
#  - pm_<name>_install_missing_deps: Installs the missing packages
#
# Gentoo notes:
#  - EMERGE_DEPS are Gentoo atoms mirroring the dnf/apt dependency sets
#    (vala, meson, ninja, pkgconf, gcc, glib, libsodium, json-glib,
#    libarchive, libgee, xz-utils, gobject-introspection). A stage3 already
#    carries gcc and friends; portageq skips whatever is present.
#  - Everything is compiled from source: this step can take a long time.
#  - USE flags are NOT modified. The stack's platform libraries (glib,
#    json-glib, libgee, ...) enable their introspection USE flag by default
#    and vala ships the platform .vapi bindings itself; only a system that
#    explicitly disabled introspection via package.use/make.conf will lack
#    .gir/.typelib/.vapi artifacts after install — re-enable the flag in
#    /etc/portage/package.use and re-emerge if the USM build needs them.

# Package atoms required by USM
EMERGE_DEPS="dev-lang/vala dev-build/meson dev-build/ninja dev-util/pkgconf sys-devel/gcc dev-libs/glib net-libs/glib-networking dev-libs/libsodium dev-libs/json-glib app-arch/libarchive dev-libs/libgee app-arch/xz-utils dev-libs/gobject-introspection"

# Check if this package manager is available
pm_emerge_detect() {
    command -v emerge &>/dev/null
}

# Get list of missing dependencies
pm_emerge_get_missing_deps() {
    local -a missing=()
    
    for pkg in $EMERGE_DEPS; do
        if ! portageq has_version / "$pkg" &>/dev/null; then
            missing+=("$pkg")
        fi
    done
    
    echo "${missing[*]}"
}

# Install missing dependencies
pm_emerge_install_missing_deps() {
    local missing=$(pm_emerge_get_missing_deps)
    
    if [[ -z "$missing" ]]; then
        log_info "All dependencies are already installed"
        return 0
    fi
    
    log_step "Installing packages via emerge: ${missing}"
    
    local sudo=""
    if ! is_root; then
        sudo=$(get_sudo)
    fi
    
    local emerge_opts="--ask=n --quiet=y"
    
    if [[ -n "$sudo" ]]; then
        $sudo emerge $emerge_opts $missing
    else
        emerge $emerge_opts $missing
    fi
}