[Patch v5 02/11] lib: optionally support single argument date: queries

[David Bremner <david@tethera.net>]

This relies on the FieldProcessor API, which is only present in xapian
>= 1.3.
---
 doc/man7/notmuch-search-terms.rst | 22 +++++++++++++++++++---
 lib/database-private.h            |  3 +++
 lib/database.cc                   |  6 ++++++
 lib/parse-time-vrp.cc             | 21 +++++++++++++++++++++
 lib/parse-time-vrp.h              |  5 +++++
 test/T500-search-date.sh          |  6 ++++++
 6 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/doc/man7/notmuch-search-terms.rst b/doc/man7/notmuch-search-terms.rst
index 2fbc16d..adedf5a 100644
--- a/doc/man7/notmuch-search-terms.rst
+++ b/doc/man7/notmuch-search-terms.rst
@@ -281,9 +281,10 @@ matches from the beginning of January to the end of February.
 date:<expr>..! can be used as a shorthand for date:<expr>..<expr>. The
 expansion takes place before interpretation, and thus, for example,
 date:monday..! matches from the beginning of Monday until the end of
-Monday. (Note that entering date:<expr> without "..", for example
-date:yesterday, won't work, as it's not interpreted as a range
-expression at all. Again, use date:yesterday..!)
+Monday.
+With **Xapian Field Processor** support (see below), non-range
+date queries such as date:yesterday will work, but otherwise
+will give unexpected results; if in doubt use date:yesterday..!
 
 Currently, we do not support spaces in range expressions. You can
 replace the spaces with '\_', or (in most cases) '-', or (in some cases)
@@ -370,6 +371,21 @@ Time zones
 
 Some time zone codes, e.g. UTC, EET.
 
+XAPIAN FIELD PROCESSORS
+=======================
+
+Certain optional features of the notmuch query processor rely on the
+presence of the Xapian field processor API. You can determine if your
+notmuch was built against a sufficiently recent version of Xapian by running
+
+::
+
+  % notmuch config get built_with.field_processor
+
+Currently the following features require field processor support:
+
+- non-range date queries, e.g. "date:today"
+
 SEE ALSO
 ========
 
diff --git a/lib/database-private.h b/lib/database-private.h
index 3fb10f7..e1962f4 100644
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -176,6 +176,9 @@ struct _notmuch_database {
     Xapian::TermGenerator *term_gen;
     Xapian::ValueRangeProcessor *value_range_processor;
     Xapian::ValueRangeProcessor *date_range_processor;
+#if HAVE_XAPIAN_FIELD_PROCESSOR
+    Xapian::FieldProcessor *date_field_processor;
+#endif
     Xapian::ValueRangeProcessor *last_mod_range_processor;
 };
 
diff --git a/lib/database.cc b/lib/database.cc
index c8c5e26..ebe019f 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -1000,6 +1000,12 @@ 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);
+#if HAVE_XAPIAN_FIELD_PROCESSOR
+	/* This currently relies on the query parser to pass anything
+	 * with a .. to the range processor */
+	notmuch->date_field_processor = new DateFieldProcessor();
+	notmuch->query_parser->add_boolean_prefix("date", notmuch->date_field_processor);
+#endif
 	notmuch->last_mod_range_processor = new Xapian::NumberValueRangeProcessor (NOTMUCH_VALUE_LAST_MOD, "lastmod:");
 
 	notmuch->query_parser->set_default_op (Xapian::Query::OP_AND);
diff --git a/lib/parse-time-vrp.cc b/lib/parse-time-vrp.cc
index 03804cf..b15b77c 100644
--- a/lib/parse-time-vrp.cc
+++ b/lib/parse-time-vrp.cc
@@ -64,3 +64,24 @@ ParseTimeValueRangeProcessor::operator() (std::string &begin, std::string &end)
 
     return valno;
 }
+
+#if HAVE_XAPIAN_FIELD_PROCESSOR
+/* XXX TODO: is throwing an exception the right thing to do here? */
+Xapian::Query DateFieldProcessor::operator()(const std::string & str) {
+    time_t from, to, now;
+
+    /* Use the same 'now' for begin and end. */
+    if (time (&now) == (time_t) -1)
+	throw Xapian::QueryParserError("Unable to get current time");
+
+    if (parse_time_string (str.c_str (), &from, &now, PARSE_TIME_ROUND_DOWN))
+	throw Xapian::QueryParserError ("Didn't understand date specification '" + str + "'");
+
+    if (parse_time_string (str.c_str (), &to, &now, PARSE_TIME_ROUND_UP_INCLUSIVE))
+	throw Xapian::QueryParserError ("Didn't understand date specification '" + str + "'");
+
+    return Xapian::Query(Xapian::Query::OP_AND,
+			 Xapian::Query(Xapian::Query::OP_VALUE_GE, 0, Xapian::sortable_serialise ((double) from)),
+			 Xapian::Query(Xapian::Query::OP_VALUE_LE, 0, Xapian::sortable_serialise ((double) to)));
+}
+#endif
diff --git a/lib/parse-time-vrp.h b/lib/parse-time-vrp.h
index 094c4f8..3bd12bf 100644
--- a/lib/parse-time-vrp.h
+++ b/lib/parse-time-vrp.h
@@ -37,4 +37,9 @@ public:
     Xapian::valueno operator() (std::string &begin, std::string &end);
 };
 
+#if HAVE_XAPIAN_FIELD_PROCESSOR
+class DateFieldProcessor : public Xapian::FieldProcessor {
+    Xapian::Query operator()(const std::string & str);
+};
+#endif
 #endif /* NOTMUCH_PARSE_TIME_VRP_H */
diff --git a/test/T500-search-date.sh b/test/T500-search-date.sh
index f5cea42..198a2e6 100755
--- a/test/T500-search-date.sh
+++ b/test/T500-search-date.sh
@@ -12,6 +12,12 @@ test_begin_subtest "Absolute date range with 'same' operator"
 output=$(notmuch search date:2010-12-16..! | notmuch_search_sanitize)
 test_expect_equal "$output" "thread:XXX   2010-12-16 [1/1] Olivier Berger; Essai accentué (inbox unread)"
 
+if [ "${NOTMUCH_HAVE_XAPIAN_FIELD_PROCESSOR}" = "1" ]; then
+    test_begin_subtest "Absolute date field"
+    output=$(notmuch search date:2010-12-16 | notmuch_search_sanitize)
+    test_expect_equal "$output" "thread:XXX   2010-12-16 [1/1] Olivier Berger; Essai accentué (inbox unread)"
+fi
+
 test_begin_subtest "Absolute time range with TZ"
 notmuch search date:18-Nov-2009_02:19:26-0800..2009-11-18_04:49:52-06:00 | notmuch_search_sanitize > OUTPUT
 cat <<EOF >EXPECTED
-- 
2.8.1