mu-cfind/contacts-cache: refactor matching in for_each

Move some of the code in from the command-line tool to contacts-cache, for
possible re-use. Clean up a bit while doing so.

lib/mu-contacts-cache.cc

@@ -285,7 +285,7 @@ struct ContactLessThan {
 };
 using ContactSet = std::set<std::reference_wrapper<const Contact>, ContactLessThan>;
 
-void
+Result<size_t>
 ContactsCache::for_each(const EachContactFunc& each_contact) const
 {
 	std::lock_guard<std::mutex> l_{priv_->mtx_};
@@ -296,10 +296,52 @@ ContactsCache::for_each(const EachContactFunc& each_contact) const
 		sorted.emplace(item.second);
 
 	// return in _reverse_ order, so we get the most relevant ones first.
+	size_t n{};
 	for (auto it = sorted.rbegin(); it != sorted.rend(); ++it) {
+		++n;
 		if (!each_contact(*it))
 			break;
 	}
+
+	return Ok(std::move(n));
+}
+
+Result<size_t>
+ContactsCache::for_each(const EachContactFunc& each_contact,
+			const std::string match_rx,
+			bool personal,
+			int64_t after,
+			size_t maxnum) const
+{
+	// get the pattern regex, if any.
+	const Result<Regex> rxres = match_rx.empty() ? Ok(Regex{}) :
+		Regex::make(match_rx, static_cast<GRegexCompileFlags>
+			    (G_REGEX_OPTIMIZE|G_REGEX_CASELESS));
+	if (!rxres)
+		return Err(rxres.error());
+
+	const Regex rx{*rxres};
+
+	size_t n{};
+	const auto res = for_each([&](const Contact& contact)->bool {
+		// filter for personal & "after"
+		if ((personal && !contact.personal) ||
+		    (after > contact.message_date))
+			return true; /* skip this contact */
+		// filter for regex, if any.
+		if (rx && !rx.matches(contact.name) && !rx.matches(contact.email))
+			return true; /* next */
+		// do we have enough matches?
+		if (maxnum != 0 && n >= maxnum)
+			return false; // terminate
+		++n;
+		return each_contact(contact);
+	});
+
+	if (res)
+		return Ok(std::move(n));
+	else
+		return Err(res.error());
 }
 
 static bool

lib/mu-contacts-cache.hh

@@ -1,5 +1,5 @@
 /*
-** Copyright (C) 2020-2022 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
@@ -158,9 +158,30 @@ public:
 	 * highest ranked contacts come first).
 	 *
 	 * @param each_contact function invoked for each contact
+	 *
+	 * @return The number of times the callback was invoked or some error
 	 */
-	void for_each(const EachContactFunc& each_contact) const;
+	Result<size_t> for_each(const EachContactFunc& each_contact) const;
 
+	/**
+	 * Invoke some callable for each contact, in _descending_ order of rank
+	 * (i.e., the highest ranked contacts come first).
+	 *
+	 * @param each_contact function invoked for each contact
+	 * @param match_rx string with regular expression or "" for none
+	 * @param personal if true, only include personal contacts
+	 *        (i.e., contacts seen in message in which a personal address
+	 *         was involved)
+	 * @param after only consider messages after this time_t (seconds since epoch)
+	 * @param maxnum maximum number of times the callback invoked
+	 *
+	 * @return The number of times the callback was invoked or some error
+	 */
+	Result<size_t> for_each(const EachContactFunc& each_contact,
+				const std::string match_rx,
+				bool personal = false,
+				int64_t after = 0,
+				size_t maxnum = 0) const;
 private:
 	struct Private;
 	std::unique_ptr<Private> priv_;

mu/mu-cmd-cfind.cc

@@ -1,5 +1,5 @@
 /*
-** Copyright (C) 2022-2023 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+** Copyright (C) 2022-2025 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
@@ -16,8 +16,6 @@
 ** Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 **
 */
-
-#include "config.h"
 #include "mu-cmd.hh"
 
 #include <cstdint>
@@ -260,64 +258,34 @@ Mu::mu_cmd_cfind(const Mu::Store& store, const Mu::Options& opts)
 	if (!output)
 		return Err(Error::Code::Internal,
 			   "missing output function");
-
-	// get the pattern regex, if any.
-	Regex rx{};
-	if (!opts.cfind.rx_pattern.empty()) {
-		if (auto&& res =  Regex::make(opts.cfind.rx_pattern,
-					      static_cast<GRegexCompileFlags>
-					      (G_REGEX_OPTIMIZE|G_REGEX_CASELESS)); !res)
-			return Err(std::move(res.error()));
-		else
-			rx = res.value();
-	}
-
 	nicks.clear();
-	store.contacts_cache().for_each([&](const Contact& contact)->bool {
 
-		if (opts.cfind.maxnum && num > *opts.cfind.maxnum)
-			return false; /* stop the loop */
-
-		if (!store.contacts_cache().is_valid(contact.email))
-			return true; /* next */
-
-		// filter for maxnum, personal  & "after"
-		if ((opts.cfind.personal && !contact.personal) ||
-		    (opts.cfind.after.value_or(0) > contact.message_date))
-			return true; /* next */
-
-		// filter for regex, if any.
-		if (rx) {
-			if (!rx.matches(contact.name) && !rx.matches(contact.email))
-				return true; /* next */
-		}
-
-		/* seems we have a match! display it. */
+	const auto res = store.contacts_cache().for_each([&](const Contact& contact)->bool {
 		const auto itype{num == 0 ? ItemType::Header : ItemType::Normal};
 		output(itype, contact, opts);
 		++num;
 		return true;
-	});
+	}, opts.cfind.rx_pattern, opts.cfind.personal,
+		opts.cfind.after.value_or(0),
+		opts.cfind.maxnum.value_or(0U));
 
-	if (num == 0)
+	if (!res)
+		return Err(res.error());
+	else if (*res == 0)
 		return Err(Error::Code::NoMatches, "no matching contacts found");
 
 	output(ItemType::Footer, Nothing, opts);
 	return Ok();
 }
 
-
-
-
 #ifdef BUILD_TESTS
 /*
  * Tests.
  *
  */
-
+#include "config.h"
 #include "utils/mu-test-utils.hh"
 
-
 static std::string test_mu_home;
 
 static void