[PATCH 2/4] lib: add notmuch_database_reopen

[David Bremner <david@tethera.net>]

The main expected use is to recover from a Xapian::DatabaseChanged
exception.
---
 lib/database-private.h |  4 ++++
 lib/database.cc        | 23 +++++++++++++++++++++++
 lib/notmuch.h          | 12 ++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/lib/database-private.h b/lib/database-private.h
index 2fb60f5e..06882439 100644
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -207,6 +207,10 @@ struct _notmuch_database {
     unsigned long revision;
     const char *uuid;
 
+    /* Keep track of the number of times the database has been re-opened
+     * (or other global invalidations of notmuch's caching)
+     */
+    unsigned long view;
     Xapian::QueryParser *query_parser;
     Xapian::TermGenerator *term_gen;
     Xapian::ValueRangeProcessor *value_range_processor;
diff --git a/lib/database.cc b/lib/database.cc
index 386dcd17..1e958b65 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -951,6 +951,7 @@ notmuch_database_open_verbose (const char *path,
 
     notmuch->mode = mode;
     notmuch->atomic_nesting = 0;
+    notmuch->view = 1;
     try {
 	string last_thread_id;
 	string last_mod;
@@ -1133,6 +1134,28 @@ notmuch_database_close (notmuch_database_t *notmuch)
     return status;
 }
 
+notmuch_status_t
+notmuch_database_reopen (notmuch_database_t *notmuch)
+{
+    if (notmuch->mode != NOTMUCH_DATABASE_MODE_READ_ONLY)
+	return NOTMUCH_STATUS_UNSUPPORTED_OPERATION;
+
+    try {
+	notmuch->xapian_db->reopen ();
+    } catch (const Xapian::Error &error) {
+	if (! notmuch->exception_reported) {
+	    _notmuch_database_log (notmuch, "Error: A Xapian exception reopening database: %s\n",
+				   error.get_msg ().c_str ());
+	    notmuch->exception_reported = TRUE;
+	    return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
+	}
+    }
+
+    notmuch->view++;
+
+    return NOTMUCH_STATUS_SUCCESS;
+}
+
 static int
 unlink_cb (const char *path,
 	   unused (const struct stat *sb),
diff --git a/lib/notmuch.h b/lib/notmuch.h
index 16da8be9..e9ed01dd 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -363,6 +363,18 @@ notmuch_status_t
 notmuch_database_close (notmuch_database_t *database);
 
 /**
+ * Reopen a (read-only) database, synching the database view with that
+ * on disk.
+ *
+ * @returns
+ * - NOTMUCH_STATUS_UNSUPPORTED_OPERATION: database is not read only
+ * - NOTMUCH_STATUS_XAPIAN_EXCEPTION: a Xapian exception occured trying to
+ *   re-open the database.
+ */
+notmuch_status_t
+notmuch_database_reopen (notmuch_database_t *database);
+
+/**
  * A callback invoked by notmuch_database_compact to notify the user
  * of the progress of the compaction process.
  */
-- 
2.11.0