Implement /theme apply <name> for themes currently in the in-memory
registry. The file-shadowing branch (read a .theme file from
${weechat_config_dir}/themes/ when no built-in matches) is added in
the next commit together with the parser.
Apply algorithm (theme_apply in core-theme.c):
- Look up the theme in the registry; abort with an error if unknown.
- If weechat.look.theme_backup is on and the target name does not
begin with "backup-", write a full snapshot of every themable
option to ${weechat_config_dir}/themes/backup-<timestamp>.theme
via theme_make_backup; abort the apply if the backup cannot be
written, so the user can always undo.
- Iterate the theme's overrides with theme_applying=1 so the
per-option config_change_color skips its gui refresh; for each
entry look up the option, refuse it if missing or non-themable
(warning to core buffer), otherwise call config_file_option_set.
- Perform a single gui_color_init_weechat + gui_window_ask_refresh
at the end.
- Persist the active label in weechat.look.theme and send signal
"theme_applied" with the name as data.
Add the new option weechat.look.theme_backup (boolean, default on)
which controls the backup-or-abort behaviour described above.
Wire the new /theme apply subcommand into core-command.c with the
existing /theme registration; update help text accordingly.
Introduce a new module (core-theme.{c,h}) holding the in-memory registry
of built-in themes used by the upcoming /theme command:
- struct t_theme stores name, description, date and weechat version
captured at registration time, plus a hashtable of overrides keyed by
full option name (file.section.option) -> value string.
- theme_register (name, overrides) creates a new theme or merges the
given overrides into an existing one (later calls override duplicate
keys); this is the API plugins and scripts will use to contribute
per-theme color values.
- theme_search and theme_list provide lookup and ordered enumeration.
- theme_init / theme_end are called from weechat_init / weechat_end.
The theme_applying flag is declared here but not yet consumed (it will
gate config_change_color in the next commit to avoid N redundant
window refreshes during /theme apply).
User theme files are not handled by this module: they are read
transiently inside /theme apply (a later commit) and never cached.