feat(desktop): gate Artist Pack browser on packaged backend

data/artist-packs/dev.sinty.desktop.artist-pack-install.policy

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE policyconfig PUBLIC "-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/PolicyKit/1/policyconfig.dtd">
+<policyconfig>
+  <vendor>Singularity</vendor>
+  <action id="dev.sinty.desktop.artist-pack-install">
+    <description>Install an Artist Pack</description>
+    <message>Authentication is required to install wallpaper packages</message>
+    <icon_name>preferences-desktop-wallpaper-symbolic</icon_name>
+    <defaults>
+      <allow_any>auth_admin</allow_any>
+      <allow_inactive>auth_admin</allow_inactive>
+      <allow_active>auth_admin_keep</allow_active>
+    </defaults>
+  </action>
+</policyconfig>

data/artist-packs/singularity-artist-pack-install

@@ -0,0 +1,35 @@
+#!/bin/sh
+# Usage: singularity-artist-pack-install PACKAGE SOURCE_URI (via pkexec).
+# Root has no dconf session, so apt's own policy must confirm SOURCE_URI.
+set -eu
+
+PACKAGE="${1:-}"
+SOURCE_URI="${2:-}"
+[ -n "$PACKAGE" ] && [ -n "$SOURCE_URI" ] || {
+    echo "usage: $0 PACKAGE SOURCE_URI" >&2
+    exit 2
+}
+case "$PACKAGE" in
+    *[!a-zA-Z0-9.+-]*|"")
+        echo "refusing: '$PACKAGE' is not a valid package name" >&2
+        exit 1
+        ;;
+esac
+
+command -v apt-cache >/dev/null 2>&1 && command -v apt-get >/dev/null 2>&1 || {
+    echo "apt is not available on this system" >&2
+    exit 1
+}
+
+POLICY=$(apt-cache policy "$PACKAGE" 2>/dev/null || true)
+CANDIDATE=$(printf '%s' "$POLICY" | awk '/Candidate:/{print $2; exit}')
+[ -n "$CANDIDATE" ] && [ "$CANDIDATE" != "(none)" ] || {
+    echo "refusing: '$PACKAGE' has no installation candidate" >&2
+    exit 1
+}
+printf '%s' "$POLICY" | grep -F "$SOURCE_URI" >/dev/null || {
+    echo "refusing: '$PACKAGE' candidate $CANDIDATE is not associated with source $SOURCE_URI" >&2
+    exit 1
+}
+
+exec apt-get install -y --no-install-recommends "$PACKAGE"

data/artist-packs/singularity-artist-pack-inventory

@@ -0,0 +1,68 @@
+#!/bin/sh
+# Unprivileged. Prints a JSON array of
+# {package,title,summary,version,source,installed} for every package the
+# dev.sinty.desktop artist-pack-apt-sources entries publish.
+set -eu
+
+json_escape() {
+    printf '%s' "$1" | sed -e 's/\\/\\\\/g' -e 's/"/\\"/g' -e ':a;N;$!ba;s/\n/\\n/g'
+}
+
+SOURCES_RAW=$(gsettings get dev.sinty.desktop artist-pack-apt-sources 2>/dev/null || printf '@as []')
+# gsettings prints a GVariant literal: ['deb https://...', ...]
+SOURCE_LINES=$(printf '%s\n' "$SOURCES_RAW" \
+    | sed -e "s/^@as //" -e "s/^\[//" -e "s/\]\s*$//" \
+    | tr ',' '\n' \
+    | sed -e "s/^[[:space:]]*'//" -e "s/'[[:space:]]*$//" \
+    | grep -v '^[[:space:]]*$' || true)
+
+[ -n "$SOURCE_LINES" ] || { printf '[]\n'; exit 0; }
+command -v apt-cache >/dev/null 2>&1 || { printf '[]\n'; exit 0; }
+command -v apt-get >/dev/null 2>&1 || { printf '[]\n'; exit 0; }
+
+first=1
+printf '['
+printf '%s\n' "$SOURCE_LINES" | while IFS= read -r source_line; do
+    [ -n "$source_line" ] || continue
+    uri=$(printf '%s' "$source_line" | awk '{print $2}')
+    suite=$(printf '%s' "$source_line" | awk '{print $3}')
+    [ -n "$uri" ] && [ -n "$suite" ] || continue
+
+    # Ask apt which index it resolved, rather than guessing the lists/ name.
+    index_file=$(apt-get indextargets --format '$(FILENAME)' \
+        "Repo-URI: $uri" "Codename: $suite" 2>/dev/null | head -1)
+    [ -n "$index_file" ] && [ -r "$index_file" ] || continue
+
+    pkg=""
+    version=""
+    summary=""
+    while IFS= read -r line; do
+        case "$line" in
+            "Package: "*) pkg=${line#Package: } ;;
+            "Version: "*) version=${line#Version: } ;;
+            "Description: "*|"Description-en: "*) summary=${line#*: } ;;
+            "")
+                [ -n "$pkg" ] || continue
+                installed=false
+                dpkg-query -W -f='${Status}' "$pkg" 2>/dev/null | grep -q '^install ok installed$' && installed=true
+                [ "$first" = 1 ] || printf ','
+                first=0
+                printf '{"package":"%s","title":"%s","summary":"%s","version":"%s","source":"%s","installed":%s}' \
+                    "$(json_escape "$pkg")" "$(json_escape "$pkg")" "$(json_escape "$summary")" \
+                    "$(json_escape "$version")" "$(json_escape "$uri")" "$installed"
+                pkg=""; version=""; summary=""
+                ;;
+        esac
+    done < "$index_file"
+    # A Packages file without a trailing blank line leaves the last stanza unflushed.
+    if [ -n "$pkg" ]; then
+        installed=false
+        dpkg-query -W -f='${Status}' "$pkg" 2>/dev/null | grep -q '^install ok installed$' && installed=true
+        [ "$first" = 1 ] || printf ','
+        first=0
+        printf '{"package":"%s","title":"%s","summary":"%s","version":"%s","source":"%s","installed":%s}' \
+            "$(json_escape "$pkg")" "$(json_escape "$pkg")" "$(json_escape "$summary")" \
+            "$(json_escape "$version")" "$(json_escape "$uri")" "$installed"
+    fi
+done
+printf ']\n'

meson.build

@@ -286,6 +286,7 @@ singularity_core_sources = files(
     'src/core/wallpaper_gallery.vala',
     'src/core/wallpaper_rotation_state.vala',
     'src/core/wallpaper_rotator.vala',
+    'src/core/artist_pack_manager.vala',
     'src/core/wallpaper_sidecar.vala',
     'src/core/wallpaper_ocs.vala',
     'src/core/wallpaper_browse_cache.vala',
@@ -490,6 +491,13 @@ install_data('data/fan-control/dev.sinty.FanControl.conf',
 install_data('data/fan-control/dev.sinty.fan-control.policy',
   install_dir: get_option('datadir') / 'polkit-1' / 'actions')
 
+install_data('data/artist-packs/singularity-artist-pack-inventory',
+  install_dir: '/usr/local/bin', install_mode: 'rwxr-xr-x')
+install_data('data/artist-packs/singularity-artist-pack-install',
+  install_dir: '/usr/local/bin', install_mode: 'rwxr-xr-x')
+install_data('data/artist-packs/dev.sinty.desktop.artist-pack-install.policy',
+  install_dir: get_option('datadir') / 'polkit-1' / 'actions')
+
 wallpaper_collections_test = executable('wallpaper-collections-test',
   sources: ['src/core/wallpaper_collections.vala', 'tests/wallpaper_collections_test.vala'],
   dependencies: [dependency('gobject-2.0'), dependency('glib-2.0'), dependency('gio-2.0'), gee_dep, json_dep],

src/components/sidebar/pages/desktop_page.vala

@@ -32,6 +32,10 @@ namespace Singularity {
         private int wallpaper_accent_generation = 0;
         private string cached_wallpaper_accent = "#3584e4";
         private static bool wallpaper_css_loaded = false;
+        private PreferencesGroup? artist_pack_group = null;
+        private int artist_pack_refresh_generation = 0;
+        // In-flight installs; survives the row teardown a refresh performs.
+        private HashSet<string> artist_packs_installing = new HashSet<string>();
 
         // Label for a stored rotate-interval that doesn't match a fixed
         // preset. Hours when it divides evenly, else minutes, else seconds
@@ -432,6 +436,19 @@ namespace Singularity {
 
             add_group(grid_group);
             GLib.Idle.add(() => { populate_grid(); return GLib.Source.REMOVE; });
+
+            if (ArtistPackManager.get_default().is_available()) {
+                artist_pack_group = new PreferencesGroup(
+                    _("Artist Packs"),
+                    _("Curated wallpaper packs, installed through the system package manager."));
+                var artist_pack_refresh_btn = new Button.from_icon_name("view-refresh-symbolic");
+                artist_pack_refresh_btn.has_frame = false;
+                artist_pack_refresh_btn.tooltip_text = _("Refresh");
+                artist_pack_refresh_btn.clicked.connect(() => { populate_artist_packs_async.begin(); });
+                artist_pack_group.add_header_suffix(artist_pack_refresh_btn);
+                add_group(artist_pack_group);
+                populate_artist_packs_async.begin();
+            }
             refresh_wallpaper_accent_async();
             update_preview_async();
             var wm = WallpaperManager.get_default();
@@ -2223,6 +2240,92 @@ namespace Singularity {
             }
         }
 
+        private async void populate_artist_packs_async() {
+            if (artist_pack_group == null) return;
+            int gen = ++artist_pack_refresh_generation;
+
+            artist_pack_group.clear();
+            var loading_row = new ActionRow(_("Loading..."));
+            loading_row.activatable = false;
+            artist_pack_group.add_row(loading_row);
+
+            Gee.ArrayList<ArtistPackInfo> packs;
+            try {
+                packs = yield ArtistPackManager.get_default().fetch_inventory_async();
+            } catch (Error e) {
+                if (gen != artist_pack_refresh_generation) return;
+                artist_pack_group.clear();
+                var error_row = new ActionRow(_("Could not list Artist Packs"), e.message, "dialog-error-symbolic");
+                error_row.activatable = false;
+                artist_pack_group.add_row(error_row);
+                return;
+            }
+            if (gen != artist_pack_refresh_generation) return;
+
+            artist_pack_group.clear();
+            if (packs.size == 0) {
+                var empty_row = new ActionRow(
+                    _("No Artist Packs available"),
+                    _("None of the configured apt sources currently offer one, or none are configured."));
+                empty_row.activatable = false;
+                artist_pack_group.add_row(empty_row);
+                return;
+            }
+
+            foreach (var pack in packs) {
+                var row = new ActionRow(pack.title, pack.summary);
+                row.activatable = false;
+                // A transaction started before this refresh is not yet in pack.installed.
+                bool installing = artist_packs_installing.contains(pack.package);
+                var install_btn = new Button.with_label(
+                    installing ? _("Installing...") : (pack.installed ? _("Installed") : _("Install")));
+                install_btn.sensitive = !installing && !pack.installed;
+                string captured_package = pack.package;
+                string captured_source = pack.source;
+                Button captured_btn = install_btn;
+                install_btn.clicked.connect(() => {
+                    start_artist_pack_install(captured_package, captured_source, captured_btn);
+                });
+                row.add_suffix(install_btn);
+                artist_pack_group.add_row(row);
+            }
+        }
+
+        private void start_artist_pack_install(string package, string source, Button btn) {
+            if (!artist_packs_installing.add(package)) return;
+            // A refresh mid-install detaches btn's row, so relabel only if gen holds.
+            int gen = artist_pack_refresh_generation;
+            btn.sensitive = false;
+            btn.label = _("Installing...");
+            ArtistPackManager.get_default().install_async.begin(package, source, null, (obj, res) => {
+                artist_packs_installing.remove(package);
+                bool row_alive = (gen == artist_pack_refresh_generation);
+                try {
+                    ArtistPackManager.get_default().install_async.end(res);
+                    if (row_alive) {
+                        btn.label = _("Installed");
+                    } else {
+                        populate_artist_packs_async.begin();
+                    }
+                    // The new pack's .collection file is only re-read here.
+                    populate_grid();
+                } catch (Error e) {
+                    warning("Artist Pack install of %s failed: %s", package, e.message);
+                    if (!row_alive) {
+                        populate_artist_packs_async.begin();
+                        return;
+                    }
+                    btn.label = _("Install Failed");
+                    GLib.Timeout.add_seconds(4, () => {
+                        if (gen != artist_pack_refresh_generation) return GLib.Source.REMOVE;
+                        btn.label = _("Install");
+                        btn.sensitive = true;
+                        return GLib.Source.REMOVE;
+                    });
+                }
+            });
+        }
+
         private void populate_grid() {
             int gen = ++wallpaper_grid_generation;
             wallpaper_grid.remove_all();