[PATCH 6/6] lib: Add "lastmod:" queries for filtering by last modification

[David Bremner]

From: Austin Clements <amdragon at mit.edu>

The implementation is essentially the same as the date range search
prior to Jani's fancy date parser.
---
 doc/man7/notmuch-search-terms.rst |  8 ++++++++
 lib/database-private.h            |  1 +
 lib/database.cc                   |  4 ++++
 test/T570-revision-tracking.sh    | 18 ++++++++++++++++++
 4 files changed, 31 insertions(+)

diff --git a/doc/man7/notmuch-search-terms.rst b/doc/man7/notmuch-search-terms.rst
index 1d27ac1..d9f213e 100644
--- a/doc/man7/notmuch-search-terms.rst
+++ b/doc/man7/notmuch-search-terms.rst
@@ -54,6 +54,8 @@ indicate user-supplied values):
 
 -  date:<since>..<until>
 
+-  lastmod:<since>..<until>
+
 The **from:** prefix is used to match the name or address of the sender
 of an email message.
 
@@ -124,6 +126,12 @@ The time range can also be specified using timestamps with a syntax of:
 Each timestamp is a number representing the number of seconds since
 1970-01-01 00:00:00 UTC.
 
+The **lastmod:** prefix can be used to restrict the result by the
+database revision number of when messages were last modified (tags
+were added/removed or filenames changed).  This is usually used in
+conjunction with the **--db-revision** argument to **notmuch search**
+to find messages that have changed since an earlier query.
+
 Operators
 ---------
 
diff --git a/lib/database-private.h b/lib/database-private.h
index 4e93257..3fb10f7 100644
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -176,6 +176,7 @@ struct _notmuch_database {
     Xapian::TermGenerator *term_gen;
     Xapian::ValueRangeProcessor *value_range_processor;
     Xapian::ValueRangeProcessor *date_range_processor;
+    Xapian::ValueRangeProcessor *last_mod_range_processor;
 };
 
 /* Prior to database version 3, features were implied by the database
diff --git a/lib/database.cc b/lib/database.cc
index ba8b8d9..a7daa44 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -986,6 +986,7 @@ notmuch_database_open_verbose (const char *path,
 	notmuch->term_gen->set_stemmer (Xapian::Stem ("english"));
 	notmuch->value_range_processor = new Xapian::NumberValueRangeProcessor (NOTMUCH_VALUE_TIMESTAMP);
 	notmuch->date_range_processor = new ParseTimeValueRangeProcessor (NOTMUCH_VALUE_TIMESTAMP);
+	notmuch->last_mod_range_processor = new Xapian::NumberValueRangeProcessor (NOTMUCH_VALUE_LAST_MOD, "lastmod:");
 
 	notmuch->query_parser->set_default_op (Xapian::Query::OP_AND);
 	notmuch->query_parser->set_database (*notmuch->xapian_db);
@@ -993,6 +994,7 @@ notmuch_database_open_verbose (const char *path,
 	notmuch->query_parser->set_stemming_strategy (Xapian::QueryParser::STEM_SOME);
 	notmuch->query_parser->add_valuerangeprocessor (notmuch->value_range_processor);
 	notmuch->query_parser->add_valuerangeprocessor (notmuch->date_range_processor);
+	notmuch->query_parser->add_valuerangeprocessor (notmuch->last_mod_range_processor);
 
 	for (i = 0; i < ARRAY_SIZE (BOOLEAN_PREFIX_EXTERNAL); i++) {
 	    prefix_t *prefix = &BOOLEAN_PREFIX_EXTERNAL[i];
@@ -1071,6 +1073,8 @@ notmuch_database_close (notmuch_database_t *notmuch)
     notmuch->value_range_processor = NULL;
     delete notmuch->date_range_processor;
     notmuch->date_range_processor = NULL;
+    delete notmuch->last_mod_range_processor;
+    notmuch->last_mod_range_processor = NULL;
 
     return status;
 }
diff --git a/test/T570-revision-tracking.sh b/test/T570-revision-tracking.sh
index bb09bf6..7ad8b2a 100755
--- a/test/T570-revision-tracking.sh
+++ b/test/T570-revision-tracking.sh
@@ -72,4 +72,22 @@ test_expect_success 'tag succeeds with correct db revision' \
 
 test_expect_code 1 'tag fails with incorrect db revision' \
 		 "notmuch show --db-revision=this-is-no-uuid '*' +test2"
+
+test_begin_subtest 'lastmod:0.. matches everything'
+total=$(notmuch count '*')
+modtotal=$(notmuch count lastmod:0..)
+test_expect_equal "$total" "$modtotal"
+
+test_begin_subtest 'lastmod:1000000.. matches nothing'
+modtotal=$(notmuch count lastmod:1000000..)
+test_expect_equal 0 "$modtotal"
+
+test_begin_subtest 'exclude one message using lastmod'
+lastmod=$(notmuch count --output=modifications '*' | cut -f2)
+total=$(notmuch count '*')
+notmuch tag +4EFC743A.3060609 at april.org id:4EFC743A.3060609 at april.org
+subtotal=$(notmuch count lastmod:..$lastmod)
+result=$(($subtotal == $total-1))
+test_expect_equal 1 "$result"
+
 test_done
-- 
2.1.4