From 53f8cc565126db4a003dbfc02850d2bf3b260636 Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Fri, 20 Nov 2009 23:15:07 -0800
Subject: Add 'notmuch count' command to show the count of matching messages

Getting the count of matching threads or messages is a fairly
expensive operation. Xapian provides a very efficient mechanism that
returns an approximate value, so use that for this new command.

This returns the number of matching messages, not threads, as that is
cheap to compute.

Signed-off-by: Keith Packard <keithp@keithp.com>
---
 lib/query.cc | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

(limited to 'lib/query.cc')

diff --git a/lib/query.cc b/lib/query.cc
index 86167352..686d75f9 100644
--- a/lib/query.cc
+++ b/lib/query.cc
@@ -279,3 +279,55 @@ notmuch_threads_destroy (notmuch_threads_t *threads)
 {
     talloc_free (threads);
 }
+
+unsigned
+notmuch_query_count_messages (notmuch_query_t *query)
+{
+    notmuch_database_t *notmuch = query->notmuch;
+    const char *query_string = query->query_string;
+    Xapian::doccount count;
+
+    try {
+	Xapian::Enquire enquire (*notmuch->xapian_db);
+	Xapian::Query mail_query (talloc_asprintf (query, "%s%s",
+						   _find_prefix ("type"),
+						   "mail"));
+	Xapian::Query string_query, final_query;
+	Xapian::MSet mset;
+	unsigned int flags = (Xapian::QueryParser::FLAG_BOOLEAN |
+			      Xapian::QueryParser::FLAG_PHRASE |
+			      Xapian::QueryParser::FLAG_LOVEHATE |
+			      Xapian::QueryParser::FLAG_BOOLEAN_ANY_CASE |
+			      Xapian::QueryParser::FLAG_WILDCARD |
+			      Xapian::QueryParser::FLAG_PURE_NOT);
+
+	if (strcmp (query_string, "") == 0) {
+	    final_query = mail_query;
+	} else {
+	    string_query = notmuch->query_parser->
+		parse_query (query_string, flags);
+	    final_query = Xapian::Query (Xapian::Query::OP_AND,
+					 mail_query, string_query);
+	}
+
+	enquire.set_weighting_scheme(Xapian::BoolWeight());
+	enquire.set_docid_order(Xapian::Enquire::ASCENDING);
+
+#if DEBUG_QUERY
+	fprintf (stderr, "Final query is:\n%s\n", final_query.get_description().c_str());
+#endif
+
+	enquire.set_query (final_query);
+
+	mset = enquire.get_mset (0, notmuch->xapian_db->get_doccount ());
+
+	count = mset.get_matches_estimated();
+
+    } catch (const Xapian::Error &error) {
+	fprintf (stderr, "A Xapian exception occurred: %s\n",
+		 error.get_msg().c_str());
+	fprintf (stderr, "Query string was: %s\n", query->query_string);
+    }
+
+    return count;
+}
-- 
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