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.

1 files changed, 55 insertions, 0 deletions

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