Implement 'notmuch dump'.

This is a fairly big milestone for notmuch. It's our first command
to do anything besides building the index, so it proves we can
actually read valid results out from the index.

It also puts in place almost all of the API and infrastructure we
will need to allow searching of the database.

Finally, with this change we are now using talloc inside of notmuch
which is truly a delight to use. And now that I figured out how
to use C++ objects with talloc allocation, (it requires grotty
parts of C++ such as "placement new" and "explicit destructors"),
we are valgrind-clean for "notmuch dump", (as in "no leaks are
possible").

1 files changed, 137 insertions, 0 deletions

diff --git a/query.cc b/query.cc
new file mode 100644
index 0000000..d3614dc
--- /dev/null
+++ b/query.cc
@@ -0,0 +1,137 @@
+/* query.cc - Support for searching a notmuch database
+ *
+ * Copyright © 2009 Carl Worth
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see http://www.gnu.org/licenses/ .
+ *
+ * Author: Carl Worth <cworth@cworth.org>
+ */
+
+#include "notmuch-private.h"
+#include "database-private.h"
+
+#include <xapian.h>
+
+const char *NOTMUCH_QUERY_ALL = "";
+
+struct _notmuch_query {
+    notmuch_database_t *notmuch;
+    const char *query_string;
+    notmuch_sort_t sort;
+};
+
+struct _notmuch_results {
+    notmuch_database_t *notmuch;
+    Xapian::PostingIterator iterator;
+    Xapian::PostingIterator iterator_end;
+};
+
+notmuch_query_t *
+notmuch_query_create (notmuch_database_t *notmuch,
+		      const char *query_string)
+{
+    notmuch_query_t *query;
+
+    query = talloc (NULL, notmuch_query_t);
+    if (unlikely (query == NULL))
+	return NULL;
+
+    query->notmuch = notmuch;
+
+    /* Special-case NOTMUCH_QUERY_ALL so we see it and not a copy. */
+    if (query_string == NOTMUCH_QUERY_ALL)
+	query->query_string = query_string;
+    else
+	query->query_string = talloc_strdup (query, query_string);
+
+    query->sort = NOTMUCH_SORT_DATE_OLDEST_FIRST;
+
+    return query;
+}
+
+void
+notmuch_query_set_sort (notmuch_query_t *query, notmuch_sort_t sort)
+{
+    query->sort = sort;
+}
+
+static int
+_notmuch_results_destroy (notmuch_results_t *results)
+{
+    results->iterator.~PostingIterator ();
+    results->iterator_end.~PostingIterator ();
+
+    return 0;
+}
+
+notmuch_results_t *
+notmuch_query_search (notmuch_query_t *query)
+{
+    notmuch_results_t *results;
+
+    results = talloc (query, notmuch_results_t);
+    if (unlikely (results == NULL))
+	return NULL;
+
+    try {
+	if (query->query_string != NOTMUCH_QUERY_ALL) {
+	    fprintf (stderr, "Error: Arbitrary search strings are not supported yet. Come back soon!\n");
+	    exit (1);
+	}
+
+	results->notmuch = query->notmuch;
+	new (&results->iterator) Xapian::PostingIterator ();
+	new (&results->iterator_end) Xapian::PostingIterator ();
+
+	talloc_set_destructor (results, _notmuch_results_destroy);
+
+	results->iterator = query->notmuch->xapian_db->postlist_begin ("");
+	results->iterator_end = query->notmuch->xapian_db->postlist_end ("");
+
+    } catch (const Xapian::Error &error) {
+	fprintf (stderr, "A Xapian exception occurred: %s\n",
+		 error.get_msg().c_str());
+    }
+
+    return results;
+}
+
+void
+notmuch_query_destroy (notmuch_query_t *query)
+{
+    talloc_free (query);
+}
+
+notmuch_bool_t
+notmuch_results_has_more (notmuch_results_t *results)
+{
+    return (results->iterator != results->iterator_end);
+}
+
+notmuch_message_t *
+notmuch_results_get (notmuch_results_t *results)
+{
+    Xapian::docid doc_id;
+
+    doc_id = *results->iterator;
+
+    return _notmuch_message_create (results,
+				    results->notmuch, doc_id);
+}
+
+void
+notmuch_results_advance (notmuch_results_t *results)
+{
+    results->iterator++;
+}