lib/parse-sexp: parse single terms and the empty list.

There is not much of a parser here yet, but it already does some
useful error reporting. Most functionality sketched in the
documentation is not implemented yet; detailed documentation will
follow with the implementation.

4 files changed, 66 insertions, 7 deletions

diff --git a/lib/Makefile.local b/lib/Makefile.local
index e2d4b91d..1378a74b 100644
--- a/lib/Makefile.local
+++ b/lib/Makefile.local
@@ -63,7 +63,8 @@ libnotmuch_cxx_srcs =		\
 	$(dir)/features.cc	\
 	$(dir)/prefix.cc	\
 	$(dir)/open.cc		\
-	$(dir)/init.cc
+	$(dir)/init.cc		\
+	$(dir)/parse-sexp.cc
 
 libnotmuch_modules := $(libnotmuch_c_srcs:.c=.o) $(libnotmuch_cxx_srcs:.cc=.o)
 
diff --git a/lib/database-private.h b/lib/database-private.h
index 9706c17e..f206efaf 100644
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -300,4 +300,11 @@ _notmuch_database_setup_standard_query_fields (notmuch_database_t *notmuch);
 notmuch_status_t
 _notmuch_database_setup_user_query_fields (notmuch_database_t *notmuch);
 
+#if __cplusplus
+/* parse-sexp.cc */
+notmuch_status_t
+_notmuch_sexp_string_to_xapian_query (notmuch_database_t *notmuch, const char *querystr,
+				      Xapian::Query &output);
+#endif
+
 #endif
diff --git a/lib/parse-sexp.cc b/lib/parse-sexp.cc
new file mode 100644
index 00000000..66dbdb41
--- /dev/null
+++ b/lib/parse-sexp.cc
@@ -0,0 +1,55 @@
+#include <xapian.h>
+#include "notmuch-private.h"
+
+#if HAVE_SFSEXP
+#include "sexp.h"
+
+
+/* _sexp is used for file scope symbols to avoid clashing with
+ * definitions from sexp.h */
+
+/* Here we expect the s-expression to be a proper list, with first
+ * element defining and operation, or as a special case the empty
+ * list */
+
+static notmuch_status_t
+_sexp_to_xapian_query (notmuch_database_t *notmuch, const sexp_t *sx,
+		       Xapian::Query &output)
+{
+
+    if (sx->ty == SEXP_VALUE) {
+	output = Xapian::Query (Xapian::Unicode::tolower (sx->val));
+	return NOTMUCH_STATUS_SUCCESS;
+    }
+
+    /* Empty list */
+    if (! sx->list) {
+	output = Xapian::Query::MatchAll;
+	return NOTMUCH_STATUS_SUCCESS;
+    }
+
+    if (sx->list->ty == SEXP_VALUE)
+	_notmuch_database_log (notmuch, "unknown prefix '%s'\n", sx->list->val);
+    else
+	_notmuch_database_log (notmuch, "unexpected list in field/operation position\n",
+			       sx->list->val);
+
+    return NOTMUCH_STATUS_BAD_QUERY_SYNTAX;
+}
+
+notmuch_status_t
+_notmuch_sexp_string_to_xapian_query (notmuch_database_t *notmuch, const char *querystr,
+				      Xapian::Query &output)
+{
+    const sexp_t *sx = NULL;
+    char *buf = talloc_strdup (notmuch, querystr);
+
+    sx = parse_sexp (buf, strlen (querystr));
+    if (! sx) {
+	_notmuch_database_log (notmuch, "invalid s-expression: '%s'\n", querystr);
+	return NOTMUCH_STATUS_BAD_QUERY_SYNTAX;
+    }
+
+    return _sexp_to_xapian_query (notmuch, sx, output);
+}
+#endif
diff --git a/lib/query.cc b/lib/query.cc
index a3fe3793..435f7229 100644
--- a/lib/query.cc
+++ b/lib/query.cc
@@ -23,10 +23,6 @@
 
 #include <glib.h> /* GHashTable, GPtrArray */
 
-#if HAVE_SFSEXP
-#include "sexp.h"
-#endif
-
 struct _notmuch_query {
     notmuch_database_t *notmuch;
     const char *query_string;
@@ -210,8 +206,8 @@ _notmuch_query_ensure_parsed_sexpr (notmuch_query_t *query)
     if (query->parsed)
 	return NOTMUCH_STATUS_SUCCESS;
 
-    query->xapian_query = Xapian::Query::MatchAll;
-    return NOTMUCH_STATUS_SUCCESS;
+    return _notmuch_sexp_string_to_xapian_query (query->notmuch, query->query_string,
+						 query->xapian_query);
 }
 
 static notmuch_status_t