add nix flake

Add functions debug, info, warning, critical which log to the mu logging
facilities.

NEWS.org

@@ -293,23 +293,31 @@
       property ~:hide-if-no-unread~, which hides the maildir/bookmark from the
       main-view if there are no unread messages which the corresponding query.
 
-   - 1.12.12: it now possible to create Emacs bookmarks for both messages
+    - 1.12.12: it now possible to create Emacs bookmarks for both messages
      (default) and queries. See the new variable ~mu4e-emacs-bookmark-policy~.
 
-   - 1.12.12: ~mu4e-get-mail-command~ which specifies the shell command to use for
-     getting mail, can now also be a function return that shell-command. This
-     makes it easier to use different shell commands in different situations.
+    - 1.12.12: ~mu4e-get-mail-command~ which specifies the shell command to use
+      for getting mail, can now also be a function return that shell-command.
+      This makes it easier to use different shell commands in different
+      situations.
+
+    - 1.12.13: with an SCM-enabled ~mu~, you can set ~mu4e-mu-scm-server~ to non-nil
+      and connect to the SCM REPL with ~M-x mu4e-mu-scm-repl~ after restart (see
+      their docstrings for details)
 
 *** scm
 
-   - 1.12.12: add new guile/scheme binding in ~scm/~. These are to replace the
-     long-deprecated ~guile/~ bindings. For now, this is all rather new and
-     experimental, but the basics are there.
+    - 1.12.12: add new guile/scheme binding in ~scm/~. These are to replace the
+      long-deprecated ~guile/~ bindings. For now, this is all rather new and
+      experimental, but the basics are there.
 
-     This requires a slightly newer gmime (3.2.8?) than the one ~mu~ requires.
+      This requires a slightly newer gmime (3.2.8?) than the one ~mu~ requires.
 
-  - 1.12.13: add the ~--listen~ flag for ~mu scm~, to start a REPL on a Unix domain
-    sockets. See the reference manual for details.
+    - 1.12.13: add the ~--listen~ flag for ~mu scm~ and ~mu server~, to start a REPL
+      on a Unix domain socket. See the reference manual for details.
+
+    - 1.12.13: ~mu scm~ also gained support for labels and logging; furthermore,
+      ~mfind~ was made much faster.
 
 *** Contributors
 

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1756125398,
+        "narHash": "sha256-XexyKZpf46cMiO5Vbj+dWSAXOnr285GHsMch8FBoHbc=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "3b9f00d7a7bf68acd4c4abb9d43695afb04e03a5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,72 @@
+{
+  description = "mu and mu4e email package for emacs";
+
+  inputs = { nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable"; };
+
+  outputs = { self, nixpkgs }: {
+
+    packages.x86_64-linux.default =
+      with import nixpkgs { system = "x86_64-linux"; };
+      stdenv.mkDerivation {
+        name = "mu4e";
+        src = self;
+
+        nativeBuildInputs = [
+          pkg-config
+          meson
+          ninja
+          texinfo
+          #installShellFiles
+          emacs
+          python3
+          #makeWrapper # need?
+          cmake
+          cld2
+        ];
+
+        buildInputs = [ glib gmime3 xapian ];
+
+        mesonFlags = [
+          # "--debug"
+          "-Dguile=disabled"
+          "-Dreadline=disabled"
+          "-Demacs=${emacs}/bin/emacs"
+        ];
+
+        # preConfigure = ''
+        #   echo "=== DEBUG: Environment before meson configure ==="
+        #   echo "PWD: $(pwd)"
+        #   echo "Python version:"
+        #   python3 --version || echo "python3 not available"
+        #   echo "Python path:"
+        #   #which python3 || echo "python3 not in PATH"
+        #   echo "PATH: $PATH"
+        #   echo "Meson version:"
+        #   meson --version
+        #   echo "Available files in current directory:"
+        #   ls -la
+        #   echo "Checking for Python scripts:"
+        #   find . -name "*.py" -type f | head -10
+        #   echo "=============================================="
+        # '';
+
+        meta = with lib; {
+          description = "Email indexer and Emacs client (mu4e)";
+          longDescription = ''
+            mu is a tool for dealing with email messages stored in the
+            Maildir-format. mu's purpose in life is to help you to quickly find the
+            messages you need; in addition, it allows you to view messages, extract
+            attachments, create new maildirs, and so on.
+
+            mu4e is an Emacs-based e-mail client that uses mu as its back-end.
+          '';
+          license = licenses.gpl3Plus;
+          homepage = "https://www.djcbsoftware.nl/code/mu/";
+          changelog = "https://github.com/djcb/mu/blob/v${version}/NEWS.org";
+          maintainers = with maintainers; [ antono chvp peterhoeg ];
+          platforms = platforms.unix;
+          mainProgram = "mu";
+        };
+      };
+  };
+}

lib/mu-server.cc

@@ -132,7 +132,8 @@ struct Server::Private {
 	{}
 
 	~Private() {
-		indexer().stop();
+		if (have_indexer_)
+			indexer().stop();
 		if (!tmp_dir_.empty())
 			remove_directory(tmp_dir_);
 	}
@@ -145,7 +146,7 @@ struct Server::Private {
 	// acccessors
 	Store&            store() { return store_; }
 	const Store&      store() const { return store_; }
-	Indexer&          indexer() { return store().indexer(); }
+	Indexer&          indexer() { have_indexer_ = true; return store().indexer(); }
 	void              do_index(const Indexer::Config& conf);
 	//CommandMap&       command_map() const { return command_map_; }
 
@@ -212,6 +213,8 @@ private:
 	const CommandHandler	command_handler_;
 	std::atomic<bool>       keep_going_{};
 	std::string		tmp_dir_;
+
+	bool have_indexer_{};
 };
 
 static void
@@ -1021,15 +1024,19 @@ Server::Private::ping_handler(const Command& cmd)
 	for (auto&& addr : store().config().get<Config::Id::PersonalAddresses>())
 		addrs.add(addr);
 
-	output_sexp(Sexp()
-		    .put_props(":pong", "mu")
-		    .put_props(":props",
-			       Sexp().put_props(
-				       ":version", VERSION,
-				       ":personal-addresses", std::move(addrs),
-				       ":database-path", store().path(),
-				       ":root-maildir", store().root_maildir(),
-				       ":doccount", storecount)));
+	Sexp props =  Sexp().put_props(
+		":version", VERSION,
+		":personal-addresses", std::move(addrs),
+		":database-path", store().path(),
+		":root-maildir", store().root_maildir(),
+		":doccount", storecount);
+
+	if (!options_.socket_path.empty())
+		props.put_props(
+			":scm-socket-path", options_.socket_path);
+
+	output_sexp(Sexp().put_props(":pong", "mu")
+		    .put_props(":props", std::move(props)));
 }
 
 void
@@ -1107,7 +1114,9 @@ Server::Private::view_mark_as_read(Store::Id docid, Message&& msg, bool rename)
 	if (rename)
 		move_opts |= Store::MoveOptions::ChangeName;
 
-	const auto ids{Store::id_vec(unwrap(store().move_message(docid, {}, nflags, move_opts)))};
+	const auto ids{Store::id_vec(
+			unwrap(store().move_message(docid, {},
+						    nflags, move_opts)))};
 	for (auto&& [id, moved_msg]: store().find_messages(ids))
 		output(mu_format("({} {})", id == docid ? ":view" : ":update",
 				 msg_sexp_str(moved_msg, id, {})));
@@ -1142,7 +1151,10 @@ Server::Private::view_handler(const Command& cmd)
 
 Server::Server(Store& store, const Server::Options& opts, Server::Output output)
     : priv_{std::make_unique<Private>(store, opts, output)}
-{}
+{
+	mu_message("created server with store @ {}; maildir @ {}",
+		   store.path(), store.root_maildir());
+}
 
 Server::~Server() = default;
 

lib/mu-server.hh

@@ -51,6 +51,7 @@ public:
 
 	struct Options {
 		bool allow_temp_file; /**< temp file optimization allowed? */
+		std::string socket_path; /**< Socket path or empty */
 	};
 
 	/**

man/mu-server.1.org

@@ -61,10 +61,16 @@ directly through the emacs process input/output. This is noticeably faster for
 commands with a lot of output, esp. when the the temp-file uses a in-memory
 file-system.
 
+** --listen
+If set, the server starts an SCM REPL as well, which listens on a Unix domain
+socket. This corresponds to the *--listen* options for *mu scm**.
+
+The store object (including the Xapian database) is shared between the server and the REPL.
+
 * PERFORMANCE
 
 As an indication for the relative performance, we can simulate something ~mu4e~
-does; we take overall time of 50 such requests:
+does. We take the overall time of 50 such requests:
 
 #+begin_src sh
 time build/mu/mu server --allow-temp-file --eval '(find :query "\"\"" :include-related t :threads t :maxnum 50000)' >/dev/null
@@ -78,7 +84,6 @@ time build/mu/mu server --allow-temp-file --eval '(find :query "\"\"" :include-r
 |          1.10 | 5.7s       |
 | 1.11 (master) | 2.8s       |
 
-
 #+include: "muhome.inc" :minlevel 2
 
 #+include: "common-options.inc" :minlevel 1
@@ -87,4 +92,5 @@ time build/mu/mu server --allow-temp-file --eval '(find :query "\"\"" :include-r
 
 * SEE ALSO
 
-{{{man-link(mu,1)}}}
+{{{man-link(mu,1)}}},
+{{{man-link(mu-scm,1)}}}

meson.build

@@ -165,6 +165,19 @@ else
   message('no wordexp, no command-line option expansion')
 endif
 
+pthread_setname_np_code = '''
+#include <pthread.h>
+int main() { return pthread_setname_np(pthread_self(), "test"); }
+'''
+pthread_setname_np_check = cxx.compiles(
+    pthread_setname_np_code,
+    name: 'pthread_setname_np check',
+    args: '-D_GNU_SOURCE'
+)
+if pthread_setname_np_check
+  config_h_data.set('HAVE_PTHREAD_SETNAME_NP', 1)
+endif
+
 if not get_option('tests').disabled()
   # only needed for tests
   cp=find_program('cp')

mu/mu-cmd-server.cc

@@ -1,5 +1,5 @@
 /*
-** Copyright (C) 2020-2023 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+** Copyright (C) 2020-2025 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
 **
 ** This program is free software; you can redistribute it and/or modify it
 ** under the terms of the GNU General Public License as published by the
@@ -29,6 +29,10 @@
 #include "mu-cmd.hh"
 #include "mu-server.hh"
 
+#if BUILD_SCM
+#include "scm/mu-scm.hh"
+#endif/*BUILD_SCM*/
+
 #include "utils/mu-utils.hh"
 #include "utils/mu-readline.hh"
 
@@ -60,6 +64,8 @@ install_sig_handler()
 }
 
 /*
+ * djcb@djcbsoftware.nl
+ *
  * Markers for/after the length cookie that precedes the expression we write to
  * output. We use octal 376, 377 (ie, 0xfe, 0xff) as they will never occur in
  * utf8
@@ -102,6 +108,46 @@ report_error(const Mu::Error& err) noexcept
 		      Server::OutputFlags::Flush);
 }
 
+static void
+maybe_setup_readline(const Mu::Options& opts)
+{
+	tty = ::isatty(::fileno(stdout));
+
+	// Note, the readline stuff is inactive unless on a tty.
+	const auto histpath{opts.runtime_path(RuntimePath::Cache) + "/history"};
+	setup_readline(histpath, 50);
+}
+
+// get the SCM socket path we're listening on, or empty if not listening
+static std::string
+maybe_listen_path(const Mu::Store& store, const Mu::Options& opts)
+{
+#ifdef BUILD_SCM
+	if (!opts.scm.socket_path)
+		return {};
+	const auto res = Mu::Scm::run(store, opts, false/*!block*/);
+	if (!res) {
+		mu_warning("failed to start scm socket: {}", res.error().what());
+		return {};
+	} else
+		return  *opts.scm.socket_path;
+#endif /*BUILD_SCM*/
+	return {};
+}
+
+static bool
+maybe_eval(Server& server, const Mu::Options& opts)
+{
+	const auto eval = std::string{opts.server.commands ?
+		"(help :full t)" : opts.server.eval};
+
+	if (!eval.empty()) {
+		server.invoke(eval);
+		return true;
+	} else
+		return false;
+}
+
 Result<void>
 Mu::mu_cmd_server(const Mu::Options& opts) try {
 
@@ -110,31 +156,23 @@ Mu::mu_cmd_server(const Mu::Options& opts) try {
 	if (!store)
 		return Err(store.error());
 
-	Server::Options sopts{};
-	sopts.allow_temp_file = opts.server.allow_temp_file;
+	// empty when we're not listening
+	const auto socket_path = maybe_listen_path(*store, opts);
 
+	Server::Options sopts{opts.server.allow_temp_file, socket_path};
 	Server server{*store, sopts, output_stdout};
-	mu_message("created server with store @ {}; maildir @ {}; debug-mode {};"
-		  "readline: {}",
-		   store->path(), store->root_maildir(),
-		   opts.debug ? "yes" : "no",
-		   have_readline() ? "yes" : "no");
 
-	tty = ::isatty(::fileno(stdout));
-	const auto eval = std::string{opts.server.commands ? "(help :full t)" : opts.server.eval};
-	if (!eval.empty()) {
-		server.invoke(eval);
+	if (maybe_eval(server, opts))
 		return Ok();
-	}
-
-	// Note, the readline stuff is inactive unless on a tty.
-	const auto histpath{opts.runtime_path(RuntimePath::Cache) + "/history"};
-	setup_readline(histpath, 50);
 
+	maybe_setup_readline(opts);
 	install_sig_handler();
-	mu_println(";; Welcome to the " PACKAGE_STRING " command-server{}\n"
-		   ";; Use (help) to get a list of commands, (quit) to quit.",
+
+	mu_println(";; Welcome to the " PACKAGE_STRING " command-server{}",
 		   opts.debug ? " (debug-mode)" : "");
+	if (!socket_path.empty())
+	mu_println(";; SCM socket listening on {}", socket_path);
+	mu_println(";; Use (help) to get a list of commands, (quit) to quit.");
 
 	bool do_quit{};
 	while (!MuTerminate && !do_quit) {
@@ -151,7 +189,6 @@ Mu::mu_cmd_server(const Mu::Options& opts) try {
 		mu_message ("shutting down due to signal {}", MuTerminate.load());
 
 	shutdown_readline();
-
 	return Ok();
 
 } catch (const Error& er) { /* note: user-level error, "OK" for mu */

mu/mu-cmd.cc

@@ -1,5 +1,5 @@
 /*
-** Copyright (C) 2010-2023 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+** Copyright (C) 2010-2025 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
 **
 ** This program is free software; you can redistribute it and/or modify it
 ** under the terms of the GNU General Public License as published by the
@@ -73,7 +73,7 @@ cmd_scm(const Store& store, const Options& opts)
 	return Err(Error::Code::InvalidArgument,
 		   "scm/guile is not available in this build");
 #else
-	return Mu::Scm::run(Mu::Scm::Config{store, opts});
+	return Mu::Scm::run(store, opts, true/*blocking*/);
 #endif /*BUILD_SCM*/
 }
 

mu/mu-options.cc

@@ -616,6 +616,24 @@ sub_remove(CLI::App& sub, Options& opts)
 		->type_name("<files>");
 }
 
+static std::string
+concoct_socket_path()
+{
+	return join_paths(g_get_user_runtime_dir(),
+			  mu_format("mu-scm-{}.sock", ::getpid()));
+}
+
+static void
+add_listen_flag(CLI::App& sub, Options& opts)
+{
+	sub.add_flag("--listen", opts.scm.listen,
+		     "Start SCM REPL on a domain socket");
+	sub.callback([&opts]{
+		if (opts.scm.listen)
+			opts.scm.socket_path = concoct_socket_path();
+	});
+}
+
 static void
 sub_server(CLI::App& sub, Options& opts)
 {
@@ -627,18 +645,23 @@ sub_server(CLI::App& sub, Options& opts)
 	sub.add_flag("--allow-temp-file", opts.server.allow_temp_file,
 		     "Allow for the temp-file optimization")
 		->excludes("--commands");
+
+#if BUILD_SCM
+	add_listen_flag(sub, opts);
+#endif/*BUILD_SCM*/
 }
 
 static void
 sub_scm(CLI::App& sub, Options& opts)
 {
-	sub.add_flag("--listen", opts.scm.listen,
-		       "Start listening on a domain socket");
+	add_listen_flag(sub, opts);
+
 	sub.add_option("script-path", opts.scm.script_path, "Path to script")
 		->type_name("<path>")
 		->excludes("--listen");
 	sub.add_option("script-args", opts.scm.params, "Parameters for script")
 		->type_name("<parameters>");
+
 }
 
 static void
@@ -787,7 +810,6 @@ AssocPairs<SubCommand, CommandInfo, Options::SubCommandNum> SubCommandInfos= {{
 	}};
 
 
-
 static ScriptInfos
 add_scripts(CLI::App& app, Options& opts)
 {

mu/mu-options.hh

@@ -46,13 +46,13 @@ struct Options {
 	/*
 	 * general options
 	 */
-	bool		quiet;				/**<  don't give any output */
-	bool		debug;				/**<  log debug-level info */
-	bool		version;			/**<  request mu version */
-	bool		log_stderr;			/**<  log to stderr */
-	bool		nocolor;			/**<  don't use use ansi-colors */
-	bool		verbose;			/**<  verbose output */
-	std::string	muhome;				/**<  alternative mu dir */
+	bool		quiet;			/**<  don't give any output */
+	bool		debug;			/**<  log debug-level info */
+	bool		version;		/**<  request mu version */
+	bool		log_stderr;		/**<  log to stderr */
+	bool		nocolor;		/**<  don't use use ansi-colors */
+	bool		verbose;		/**<  verbose output */
+	std::string	muhome;			/**<  alternative mu dir */
 
 	/**
 	 * Whether by default, we should show color
@@ -260,6 +260,8 @@ struct Options {
 		OptString script_path; /**< Path to script (optional) */
 		StringVec params;      /**< Parameters for script (after "--") */
 		bool listen; /**< Whether to start listening on a socket */
+		Option<std::string> socket_path; /**< path for the '--listen'
+						  * Unix domain socket */
 	} scm;
 
 

mu/mu.cc

@@ -77,6 +77,10 @@ handle_result(const Result<void>& res, const Mu::Options& opts)
 	return res.error().exit_code();
 }
 
+namespace {
+Options opts; // it's big, don't want it on the stack
+}
+
 int
 main(int argc, char* argv[]) try
 {
@@ -93,34 +97,36 @@ main(int argc, char* argv[]) try
 	/*
 	 * read command-line options
 	 */
-	const auto opts{Options::make(argc, argv)};
-	if (!opts) {
-		output_error(opts.error().what(), !Options::default_no_color());
-		return opts.error().exit_code();
-	} else if (!opts->sub_command) {
+	auto optsres{Options::make(argc, argv)};
+	if (!optsres) {
+		output_error(optsres.error().what(), !Options::default_no_color());
+		return optsres.error().exit_code();
+	} else if (!optsres->sub_command) {
 		// nothing more to do.
 		return 0;
 	}
 
+	opts = std::move(*optsres);
+
 	// setup logging
 	Logger::Options lopts{Logger::Options::None};
-	if (opts->log_stderr)
+	if (opts.log_stderr)
 		lopts |= Logger::Options::StdOutErr;
-	if (opts->debug)
+	if (opts.debug)
 		lopts |= Logger::Options::Debug;
 	if (!!g_getenv("MU_TEST"))
 		lopts |= Logger::Options::File;
 
-	const auto logger{Logger::make(opts->runtime_path(RuntimePath::LogFile), lopts)};
+	const auto logger{Logger::make(opts.runtime_path(RuntimePath::LogFile), lopts)};
 	if (!logger) {
-		output_error(logger.error().what(), !opts->nocolor);
+		output_error(logger.error().what(), !opts.nocolor);
 		return logger.error().exit_code();
 	}
 
 	/*
 	 * handle sub command
 	 */
-	return handle_result(mu_cmd_execute(*opts), *opts);
+	return handle_result(mu_cmd_execute(opts), opts);
 
 	// exceptions should have been handled earlier, but catch them here,
 	// just in case...

mu4e/mu4e-server.el

@@ -26,7 +26,6 @@
 
 (require 'mu4e-helpers)
 
-
 ;;; Configuration
 (defcustom mu4e-mu-home nil
   "Location of an alternate mu home directory.
@@ -93,6 +92,42 @@ stop/start mu4e."
   :group 'mu4e
   :safe  'booleanp)
 
+(defcustom mu4e-mu-scm-server nil
+  "Tell the mu server to start an SCM/Guile REPL.
+
+This starts the REPL on a Unix domain socket, which can be
+connected to using various tools. This only works if mu has been
+built with SCM support (if in doubt, check the output output of
+\"mu info\" for the line \"scm-support\"); see Info
+node `(mu-scm) Top' for details on mu-scm.
+
+The REPL uses the same server instance that mu4e uses.
+
+Changing this variable only affects the next time the mu4e
+server is started."
+  :type  'boolean
+  :group 'mu4e
+  :safe  'booleanp)
+
+(defun mu4e-mu-scm-repl ()
+  "Start a mu-scm REPL using geiser.
+
+See `mu4e-mu-scm-server' to enable this; and requires the
+`geiser-guile' package.
+
+The REPL uses the same server instance that mu4e uses.
+
+Note: this REPL is not to be confused with the mu REPL as per
+`mu4e-server-repl'."
+  (interactive)
+  (unless (require 'geiser-guile nil 'noerror)
+    (mu4e-error "geiser-guile not found; please install"))
+  (let ((sock (plist-get (mu4e-server-properties) :scm-socket-path)))
+    (unless sock
+      (mu4e-error "socket-path unavailable"))
+    (when (fboundp 'geiser-connect-local)
+      (geiser-connect-local 'guile sock))))
+
 ;; Cached data
 (defvar mu4e-maildir-list)
 
@@ -467,6 +502,7 @@ As per issue #2198."
               `(,(when mu4e-mu-debug "--debug")
                 "server"
                 ,(when mu4e-mu-allow-temp-file "--allow-temp-file")
+                ,(when mu4e-mu-scm-server "--listen")
                 ,(when mu4e-mu-home (format "--muhome=%s" mu4e-mu-home)))))
 
 (defun mu4e--version-check ()
@@ -491,12 +527,15 @@ As per issue #2198."
         (mu4e-message "Found mu version %s" version)))))
 
 (defun mu4e-server-repl ()
-  "Start a mu4e-server repl.
+  "Start a mu4e-server REPL.
 
-This is meant for debugging/testing - the repl is designed for
+This is meant for debugging/testing - the REPL is designed for
 machines, not for humans.
 
-You cannot run the repl when mu4e is running (or vice-versa)."
+You cannot run the REPL when mu4e is running (or vice-versa).
+
+Not to be confused with the SCM/Guile REPL, as per
+`mu4e-mu-scm-server'."
   (interactive)
   (if (mu4e-running-p)
       (mu4e-error "Cannot run repl when mu4e is running")

scm/mu-scm-message.cc

@@ -171,14 +171,13 @@ subr_cc_message_parts(SCM message_scm) try {
 		auto mime_part{GMIME_PART(part.mime_object().object())};
 		SCM mime_part_scm{to_scm(mime_part)};
 		SCM alist_scm{to_scm(idx, parts[idx])};
+		SCM item{scm_cons(mime_part_scm, alist_scm)};
 
-		parts_scm = scm_append_x(
-			scm_list_2(parts_scm,
-				   scm_list_1(
-					   scm_cons(mime_part_scm, alist_scm))));
+		parts_scm = scm_cons(item, parts_scm);
 	}
 
-	return parts_scm;
+	return scm_reverse_x(parts_scm, SCM_EOL);
+
 
 } catch (const ScmError& err) {
 	err.throw_scm();

scm/mu-scm-repl.scm

@@ -21,7 +21,8 @@
 ;; after printing UNIX-CONNECT:<socket-file>\n on stdout
 (let ((socket-path (getenv "MU_SCM_SOCKET_PATH")))
   (when socket-path
-    (format #t "UNIX-CONNECT:~a\n" socket-path)
+    (info "listening on domain socket ~a" socket-path)
+    (format #t "~a\n" socket-path)
     (run-server
      (make-unix-domain-server-socket #:path socket-path))))
 

scm/mu-scm-store.cc

@@ -127,7 +127,8 @@ to_sort_field_id(SCM field, const char *func, int pos)
 
 	const auto sym{from_scm<std::string>(scm_symbol_to_string(field), func, pos)};
 	if (const auto field_opt{field_from_name(sym)}; !field_opt) {
-		throw ScmError{ScmError::Id::WrongType, func, pos, field, "sort-field-symbol"};
+		throw ScmError{ScmError::Id::WrongType, func, pos, field,
+			"sort-field-symbol"};
 	} else
 		return field_opt->id;
 }
@@ -144,7 +145,8 @@ subr_cc_store_mfind(SCM store_scm, SCM query_scm, SCM related_scm, SCM skip_dups
 	const auto skip_dups(from_scm<bool>(skip_dups_scm, func, 4));
 
 	if (!scm_is_false(sort_field_scm) && !scm_is_symbol(sort_field_scm))
-		throw ScmError{ScmError::Id::WrongType, func, 5, sort_field_scm, "#f or sort-field-symbol"};
+		throw ScmError{ScmError::Id::WrongType, func, 5, sort_field_scm,
+			"#f or sort-field-symbol"};
 
 	const auto sort_field_id = to_sort_field_id(sort_field_scm, func, 5);
 	const auto reverse(from_scm<bool>(reverse_scm, func, 6));

scm/mu-scm.cc

@@ -16,23 +16,31 @@
 ** Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 **
 */
+#include "config.h"
 
 #include "mu-scm.hh"
 
+#include <thread>
 #include <unistd.h>
 #include <errno.h>
 
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
 #include "mu-utils.hh"
-#include "config.h"
 
 #include "mu-scm-types.hh"
 
+#ifdef HAVE_PTHREAD_SETNAME_NP
+#include <pthread.h>
+#endif
+
 using namespace Mu;
 using namespace Mu::Scm;
 
 namespace {
-static const Mu::Scm::Config *config{};
-static SCM mu_mod; // The mu module
+SCM mu_mod; // The mu module
 }
 
 /**
@@ -57,14 +65,45 @@ init_options(const Options& opts)
 }
 
 static void
-init_module_mu(void* _data)
+init_misc()
 {
-	init_options(config->options);
-	init_store(config->store);
-	init_message();
-	init_mime();
+	scm_define(make_symbol("level-critical"), to_scm(G_LOG_LEVEL_CRITICAL));
+	scm_define(make_symbol("level-warning"), to_scm(G_LOG_LEVEL_WARNING));
+	scm_define(make_symbol("level-info"), to_scm(G_LOG_LEVEL_INFO));
+	scm_define(make_symbol("level-debug"), to_scm(G_LOG_LEVEL_DEBUG));
 }
 
+static SCM
+subr_cc_log(SCM level_scm, SCM str_scm) try {
+	constexpr auto func{"cc-log"};
+
+	const auto level{static_cast<GLogLevelFlags>(from_scm<int>(level_scm, func, 1))};
+	if (level != G_LOG_LEVEL_CRITICAL && level != G_LOG_LEVEL_WARNING &&
+		level != G_LOG_LEVEL_INFO && level != G_LOG_LEVEL_DEBUG)
+		throw ScmError{ScmError::Id::WrongType, func, 1, level_scm, "level"};
+
+	const auto str{from_scm<std::string>(str_scm, func, 2)};
+
+	g_log("mu-scm", level, "%s", str.c_str());
+
+	return SCM_UNSPECIFIED;
+
+} catch (const ScmError& err) {
+	err.throw_scm();
+}
+
+static void
+init_subrs()
+{
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-function-type"
+	scm_c_define_gsubr("cc-log", 2/*req*/, 0/*opt*/, 0/*rst*/,
+			   reinterpret_cast<scm_t_subr>(subr_cc_log));
+#pragma GCC diagnostic pop
+}
+
+
+
 static const Result<std::string>
 make_mu_scm_path(const std::string& fname) {
 
@@ -84,23 +123,20 @@ make_mu_scm_path(const std::string& fname) {
 }
 
 namespace {
-static std::string mu_scm_path;
-static std::string mu_scm_repl_path;
-static std::string mu_scm_socket_path;
+std::string mu_scm_path;
+std::string mu_scm_repl_path;
+std::string mu_scm_socket_path;
 constexpr auto SOCKET_PATH_ENV = "MU_SCM_SOCKET_PATH";
+using StrVec = std::vector<std::string>;
+StrVec scm_args;
+std::thread scm_worker;
 }
 
 static Result<void>
-prepare_run(const Mu::Scm::Config& conf)
+prepare_run(const Mu::Options& opts)
 {
-	if (config)
-		return Err(Error{Error::Code::AccessDenied,
-				"already prepared"});
-	config = &conf;
-
 	// do a checks _before_ entering guile, so we get a bit more civilized
 	// error message.
-
 	if (const auto path = make_mu_scm_path("mu-scm.scm"); path)
 		mu_scm_path = *path;
 	else
@@ -111,8 +147,8 @@ prepare_run(const Mu::Scm::Config& conf)
 	else
 		return Err(path.error());
 
-	if (config->options.scm.script_path) {
-		const auto path{config->options.scm.script_path->c_str()};
+	if (opts.scm.script_path) {
+		const auto path{opts.scm.script_path->c_str()};
 		if (const auto res = ::access(path, R_OK); res != 0) {
 			return Err(Error::Code::InvalidArgument,
 				   "cannot read '{}': {}", path, ::strerror(errno));
@@ -122,71 +158,130 @@ prepare_run(const Mu::Scm::Config& conf)
 	return Ok();
 }
 
-// make a unique unix-socket path
-static std::string
-maybe_set_uds_path(bool set)
+static void
+prepare_script(const Options& opts, StrVec& args)
 {
-	if (set) {
-		GRand* grand{g_rand_new()};
-		auto path = join_paths(g_get_user_runtime_dir(),
-				       mu_format("mu-scm-socket-{:08x}",
-						 g_rand_int(grand)));
-		g_rand_free(grand);
-		g_setenv(SOCKET_PATH_ENV, path.c_str(), 1);
-		return path;
-	} else  {
-		g_unsetenv(SOCKET_PATH_ENV);
-		return {};
+	static std::string cmd; // keep alive
+
+	// XXX: couldn't get another combination of -l/-s/-e/-c to work
+	// a) invokes `main' with arguments, and
+	// b) exits (rather than drop to a shell)
+	// but, what works is to manually specify (main ....)
+	cmd = "(main " + quote(*opts.scm.script_path);
+	for (const auto& scriptarg : opts.scm.params)
+		cmd += " " + quote(scriptarg);
+	cmd += ")";
+
+	args.emplace_back("-l");
+	args.emplace_back(*opts.scm.script_path);
+	args.emplace_back("-c");
+	args.emplace_back(cmd);
+}
+
+static void
+maybe_remove_socket_path()
+{
+	struct stat statbuf{};
+	const auto sock{mu_scm_socket_path};
+
+	// opportunistic, so no real warnings, but be careful deleting!
+
+	if (const int res = ::stat(sock.c_str(), &statbuf); res != 0) {
+		mu_debug("can't stat '{}'; err={}", sock, -res);
+	} else if ((statbuf.st_mode & S_IFMT) != S_IFSOCK) {
+		mu_debug("{} is not a socket", sock);
+	} else if (const int ulres = ::unlink(sock.c_str()); ulres != 0) {
+		mu_debug("failed to unlink '{}'; err={}", sock, -ulres);
+	} else {
+		mu_debug("unlinked {}", sock);
 	}
 }
 
-
-Result<void>
-Mu::Scm::run(const Mu::Scm::Config& conf)
+static void
+prepare_shell(const Options& opts, StrVec& args)
 {
-	if (const auto res = prepare_run(conf); !res)
-		return Err(res.error());
+	// drop us into an interactive shell/repl or start listening on a domain socket.
+	if (opts.scm.listen && opts.scm.socket_path) {
+		mu_scm_socket_path = *opts.scm.socket_path;
+		g_setenv(SOCKET_PATH_ENV, mu_scm_socket_path.c_str(), 1);
+		mu_info("setting up socket-path {}", mu_scm_socket_path);
+		::atexit(maybe_remove_socket_path); //opportunistic cleanup
+	}
+	else
+		g_unsetenv(SOCKET_PATH_ENV);
 
-	scm_boot_guile(0, {}, [](void *data, int argc, char **argv) {
-		mu_mod = scm_c_define_module ("mu", init_module_mu, {});
-
-		std::vector<const char*> args {
-			"mu",
-			"-l", mu_scm_path.c_str(),
-		};
-		std::string cmd;
-		const auto opts{config->options.scm};
-		// if a script-path was specified, run a script
-		if (opts.script_path) {
-			// XXX: couldn't get another combination of -l/-s/-e/-c to work
-			// a) invokes `main' with arguments, and
-			// b) exits (rather than drop to a shell)
-			// but, what works is to manually specify (main ....)
-			cmd = "(main " + quote(*opts.script_path);
-			for (const auto& scriptarg : opts.params)
-				cmd += " " + quote(scriptarg);
-			cmd += ")";
-			for (const auto& arg: {
-					"-l", opts.script_path->c_str(),
-					"-c", cmd.c_str()})
-				args.emplace_back(arg);
-		} else {
-			// otherwise, drop us into an interactive shell/repl
-			// or start listening on a domain socket.
-			mu_scm_socket_path =
-				maybe_set_uds_path(config->options.scm.listen);
-			args.emplace_back("--no-auto-compile");
-			args.emplace_back("-l");
-			args.emplace_back(mu_scm_repl_path.c_str());
-		}
-		/* ahem...*/
-		scm_shell(std::size(args), const_cast<char**>(args.data()));
-	}, {}); // never returns.
-
-	return Ok();
+	args.emplace_back("--no-auto-compile");
+	args.emplace_back("-l");
+	args.emplace_back(mu_scm_repl_path);
 }
 
 
+struct ModMuData { const Mu::Store& store; const Mu::Options& opts; };
+
+static void
+init_module_mu(void* data)
+{
+	const ModMuData& conf{*reinterpret_cast<ModMuData*>(data)};
+
+	init_options(conf.opts);
+	init_misc();
+	init_subrs();
+
+	init_store(conf.store);
+	init_message();
+	init_mime();
+}
+
+static void
+run_scm(const Mu::Store& store, const Mu::Options& opts)
+{
+	static ModMuData mu_data{store, opts};
+
+	scm_boot_guile(0, {},
+		       [](auto _data, auto _argc, auto _argv) {
+			       mu_mod = scm_c_define_module ("mu", init_module_mu, &mu_data);
+		std::vector<char*> args;
+		std::transform(scm_args.begin(),
+			       scm_args.end(), std::back_inserter(args),
+			       [&](const std::string& strarg){
+				       /* ahem...*/
+				       return const_cast<char*>(strarg.c_str());
+		});
+		scm_shell(args.size(), args.data());
+
+	}, {}); // never returns.
+}
+
+Result<void>
+Mu::Scm::run(const Mu::Store& store, const Mu::Options& opts, bool blocking)
+{
+	if (const auto res = prepare_run(opts); !res)
+		return Err(res.error());
+
+	scm_args = {"mu", "-l", mu_scm_path};
+
+	// do env stuff _before_ starting guile / threads.
+	if (opts.scm.script_path)
+		prepare_script(opts, scm_args);
+	else
+		prepare_shell(opts, scm_args);
+
+	// in the non-blocking case, we start guile in a
+	// background thread; otherwise it will block.
+	if (!blocking) {
+		auto worker = std::thread([&](){
+#ifdef HAVE_PTHREAD_SETNAME_NP
+			pthread_setname_np(pthread_self(), "mu-scm");
+#endif /*HAVE_PTHREAD_SETNAME_NP*/
+			run_scm(store, opts);
+		});
+		worker.detach();
+	} else
+		run_scm(store, opts);
+
+	return Ok();
+
+}
 
 
 #ifdef BUILD_TESTS
@@ -199,7 +294,6 @@ Mu::Scm::run(const Mu::Scm::Config& conf)
 #include <mu-store.hh>
 #include "utils/mu-test-utils.hh"
 
-
 static void
 test_scm_script()
 {
@@ -233,13 +327,8 @@ test_scm_script()
 	Mu::Options opts{};
 	opts.scm.script_path = join_paths(MU_SCM_SRCDIR, "mu-scm-test.scm");
 
-	Mu::Scm::Config scm_conf {
-		/*.store =*/ *store,
-		/*.options =*/ opts
-	};
-
 	{
-		const auto res = Mu::Scm::run(scm_conf);
+		const auto res = Mu::Scm::run(*store, opts, false /*blocks*/);
 		assert_valid_result(res);
 	}
 }

scm/mu-scm.hh

@@ -39,28 +39,24 @@
  *
  */
 namespace Mu::Scm {
-
 	/**
-	 * Configuration object
+	 * Start a guile REPL or program
 	 *
-	 */
-	struct Config {
-		const Mu::Store& store;
-		const Options& options;
-	};
-
-	/**
-	 * Start a guile shell
-	 *
-	 * Initialize the Scm sub-system, then start a shell or run a script,
+	 * Initialize the Scm sub-system, then start a REPL or run a script,
 	 * based on the configuration.
 	 *
-	 * @param conf a Config object
+	 * Unless 'blocking' is false or there is some pre-guile error, this
+	 * method never returns. If blocking is false, it runs in the
+	 * background.
+	 *
+	 * @param store a Store object
+	 * @param opts options
+	 * @param blocking whether to block (or run in the background)
 	 *
 	 * @return Ok() or some error
 	 */
-	Result<void> run(const Config& conf);
-
+	Result<void> run(const Store& store, const Options& opts,
+			 bool blocking=true);
 
 	/**
 	 * Helpers
@@ -223,15 +219,18 @@ namespace Mu::Scm {
 			return scm_from_utf8_string(val);
 		else if constexpr (std::is_same_v<Type, std::vector<std::string>>) {
 			SCM lst{SCM_EOL};
-			for (const auto& s: val)
-				lst = scm_append_x(scm_list_2(lst,
-							      scm_list_1(to_scm(s))));
+			for (auto it = val.end(); it-- != val.begin();)
+				lst = scm_cons(to_scm(*it), lst);
 			return lst;
 		}
 		else if constexpr (std::is_same_v<Type, bool>)
 			return scm_from_bool(val);
 		else if constexpr (std::is_same_v<Type, size_t>)
 			return scm_from_size_t(val);
+		else if constexpr (std::is_same_v<Type, int>)
+			return scm_from_int(val);
+		else if constexpr (std::is_same_v<Type, GLogLevelFlags>)
+			return scm_from_int(static_cast<int>(val));
 		else if constexpr (std::is_same_v<Type, int64_t>)
 			return scm_from_int64(val);
 		else if constexpr (std::is_same_v<Type, uint64_t>)

scm/mu-scm.scm

@@ -21,6 +21,7 @@
   :use-module (system foreign)
   :use-module (rnrs bytevectors)
   :use-module (ice-9 optargs)
+  :use-module (ice-9 format)
   :use-module (ice-9 binary-ports)
   #:export (
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -100,11 +101,16 @@
 	    %options
 	    ;;	    %preferences
 
+	    ;; logging
+	    debug
+	    info
+	    warning
+	    critical
+
 	    ;; helpers
 	    string->time
 	    time->string))
 
-
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
 ;; Helpers
@@ -637,3 +643,43 @@ UTC time.
 	(let ((t (if utc? (gmtime time-t) (localtime time-t))))
 	  (strftime format t))
 	#f)))
+
+
+;; Logging to mu's log
+
+(define (mlog level frmstr . args)
+  "Log to the mu logger.
+
+LEVEL is the logging-level, a symbol one of:
+  debug, info, warning, critical
+
+FRMSTR is a format string like `(format)', and the ARGS are the parameters for
+that format string."
+  (let ((msg (if (null? args)
+		 frmstr
+		 (apply format #f frmstr args))))
+    (cc-log level msg)))
+
+(define (info frm . args)
+  "Log a message at info level to the mu logger.
+FRM is the format string and ARGS are its arguments, see `(format)' for details
+on the precise format."
+  (apply mlog level-info frm args))
+
+(define (warning frm . args)
+  "Log a message at warning level to the mu logger.
+FRM is the format string and ARGS are its arguments, see `(format)' for details
+on the precise format."
+  (apply mlog level-warning frm args))
+
+(define (critical frm . args)
+  "Log a message at critical level to the mu logger.
+FRM is the format string and ARGS are its arguments, see `(format)' for details
+on the precise format."
+  (apply mlog level-critical frm args))
+
+(define (debug frm . args)
+  "Log a message at debug level to the mu logger.
+FRM is the format string and ARGS are its arguments, see `(format)' for details
+on the precise format."
+  (apply mlog level-debug frm args))

scm/mu-scm.texi

@@ -107,6 +107,7 @@ Indices
 * Starting the REPL::
 * Listening on a Unix Domain Socket::
 * Hooking up with GNU/Emacs and Geiser::
+* Hooking up with Mu4e::
 @end menu
 
 This chapter walks you through the installation and basic setup.
@@ -183,19 +184,19 @@ REPL over a Unix domain socket, using the @t{--listen} flag.
 When you start @command{mu scm} with the @t{--listen} flag, it prints a
 (randomized) UNIX domain socket name and blocks after that; for instance:
 @example
-$mu scm --listen
-UNIX-CONNECT:/run/user/1000/mu-scm-socket-6ef6222e
+$ mu scm --listen
+/run/user/1000/mu-scm-15269.sock
 @end example
 
-You can connect to this with exernal tools, for instance with @command{socat}:
+You can connect to this with external tools, for instance with @command{socat}:
 @example
-socat - UNIX-CONNECT:/run/user/1000/mu-scm-socket-6ef6222e
+$ socat - UNIX-CONNECT:/run/user/1000/mu-scm-15269.sock
 GNU Guile 3.0.9
 Copyright (C) 1995-2023 Free Software Foundation, Inc.
 
-Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
-This program is free software, and you are welcome to redistribute it
-under certain conditions; type `,show c' for details.
+Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'. This
+program is free software, and you are welcome to redistribute it under certain
+conditions; type `,show c' for details.
 
 Enter `,help' for help.
 scheme@@(guile-user)>
@@ -216,7 +217,7 @@ domain socket, as discussed in @xref{Listening on a Unix Domain Socket}.
 Assuming you have installed the @t{guile-geiser} package, the following snippet
 makes that easy:
 @lisp
-(require 'guiser-guile)
+(require 'geiser-guile)
 
 (defvar mu-scm-listen-command "mu scm --listen"
   "mu command to start an scm repl listening on a socket.")
@@ -229,13 +230,32 @@ Connect to mu's scm (guile) interface through Geiser."
    :name "*mu-scm-repl*"
    :command `("sh" "-c"  ,mu-scm-listen-command)
    :filter (lambda (_proc chunk)
-             (when (string-match "^UNIX-CONNECT:\\(.*\\)$" chunk)
+             (when (stringng-match "^\\(mu-scm.*\\.sock\\)$" chunk)
                (geiser-connect-local 'guile (match-string 1 chunk))))))
 @end lisp
 
 After evaluating this, you can use @command{M-x mu-scm-geiser-connect} to start
 the REPL, with all the Geiser bells & whistles.
 
+@node Hooking up with Mu4e
+@section Hooking up with Mu4e
+@cindex Mu4e
+
+If you use @t{mu4e}, connecting to the SCM server is even easier than with
+``plain'' Emacs.
+
+First tell @t{mu4e} to starts it server with with @t{--listen} parameter:
+@lisp
+(setq mu4e-mu-scm-server t)
+@end lisp
+After that, (re)start @t{mu4e}.
+
+Now should be able to connect to the REPL using @t{M-x mu4e-mu-scm-repl}. Like
+@ref{Hooking up with GNU/Emacs and Geiser}, this depends on the @t{geiser-guile}
+package.
+
+The SCM instance uses the same database/store instance that @t{mu4e} uses.
+
 @node Shell
 @chapter Shell
 
@@ -919,6 +939,26 @@ their default values.
 @node Helpers
 @section Helpers
 
+@deffn {Scheme Procedure} debug frm . args
+@end deffn
+
+@deffn {Scheme Procedure} info frm . args
+@end deffn
+
+@deffn {Scheme Procedure} warning frm . args
+@end deffn
+
+@deffn {Scheme Procedure} critical frm . args
+@end deffn
+
+Log using @t{mu}'s logging facilities at the given level (debug, info, warning
+or critical). @code{frm} and @code{args} are expected to be a format string and
+its arguments, respectively, according to Guile's @code{format} function.
+
+Note: where the log output exactly appears (i.e., log-file, journal, console,
+nowhere) dependis on the particulars of the system and how mu was started; see
+the @t{mu (1)} man-page for details on the latter.
+
 @deffn {Scheme Procedure} string->time timestr [#:utc? (assoc-ref %preferences 'utc?)]
 @end deffn
 Convert some ISO-8601-style time-string to a seconds-since-epoch @t{time_t}