lib: Add per-message last modification tracking

[notmuch] / lib / database.cc

diff --git a/lib/database.cc b/lib/database.cc
index 6a15174959812cbb73455670038e55415b5a3105..52e2e8f16187bfc4dcd17b81c02473b95ebc2660 100644 (file)
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -101,6 +101,9 @@ typedef struct {
  *
  *     SUBJECT:        The value of the "Subject" header
  *
+ *     LAST_MOD:       The revision number as of the last tag or
+ *                     filename change.
+ *
  * In addition, terms from the content of the message are added with
  * "from", "to", "attachment", and "subject" prefixes for use by the
  * user in searching. Similarly, terms from the path of the mail
@@ -310,6 +313,8 @@ static const struct {
      * them. */
     { NOTMUCH_FEATURE_INDEXED_MIMETYPES,
       "indexed MIME types", "w"},
+    { NOTMUCH_FEATURE_LAST_MOD,
+      "modification tracking", "w"},
 };
 
 const char *
@@ -737,6 +742,23 @@ _notmuch_database_ensure_writable (notmuch_database_t *notmuch)
     return NOTMUCH_STATUS_SUCCESS;
 }
 
+/* Allocate a revision number for the next change. */
+unsigned long
+_notmuch_database_new_revision (notmuch_database_t *notmuch)
+{
+    unsigned long new_revision = notmuch->revision + 1;
+
+    /* If we're in an atomic section, hold off on updating the
+     * committed revision number until we commit the atomic section.
+     */
+    if (notmuch->atomic_nesting)
+       notmuch->atomic_dirty = TRUE;
+    else
+       notmuch->revision = new_revision;
+
+    return new_revision;
+}
+
 /* Parse a database features string from the given database version.
  * Returns the feature bit set.
  *
@@ -904,6 +926,7 @@ notmuch_database_open_verbose (const char *path,
     notmuch->atomic_nesting = 0;
     try {
        string last_thread_id;
+       string last_mod;
 
        if (mode == NOTMUCH_DATABASE_MODE_READ_WRITE) {
            notmuch->xapian_db = new Xapian::WritableDatabase (xapian_path,
@@ -962,6 +985,14 @@ notmuch_database_open_verbose (const char *path,
                INTERNAL_ERROR ("Malformed database last_thread_id: %s", str);
        }
 
+       /* Get current highest revision number. */
+       last_mod = notmuch->xapian_db->get_value_upper_bound (
+           NOTMUCH_VALUE_LAST_MOD);
+       if (last_mod.empty ())
+           notmuch->revision = 0;
+       else
+           notmuch->revision = Xapian::sortable_unserialise (last_mod);
+
        notmuch->query_parser = new Xapian::QueryParser;
        notmuch->term_gen = new Xapian::TermGenerator;
        notmuch->term_gen->set_stemmer (Xapian::Stem ("english"));
@@ -1369,7 +1400,8 @@ notmuch_database_upgrade (notmuch_database_t *notmuch,
 
     /* Figure out how much total work we need to do. */
     if (new_features &
-       (NOTMUCH_FEATURE_FILE_TERMS | NOTMUCH_FEATURE_BOOL_FOLDER)) {
+       (NOTMUCH_FEATURE_FILE_TERMS | NOTMUCH_FEATURE_BOOL_FOLDER |
+        NOTMUCH_FEATURE_LAST_MOD)) {
        notmuch_query_t *query = notmuch_query_create (notmuch, "");
        total += notmuch_query_count_messages (query);
        notmuch_query_destroy (query);
@@ -1396,7 +1428,8 @@ notmuch_database_upgrade (notmuch_database_t *notmuch,
 
     /* Perform per-message upgrades. */
     if (new_features &
-       (NOTMUCH_FEATURE_FILE_TERMS | NOTMUCH_FEATURE_BOOL_FOLDER)) {
+       (NOTMUCH_FEATURE_FILE_TERMS | NOTMUCH_FEATURE_BOOL_FOLDER |
+        NOTMUCH_FEATURE_LAST_MOD)) {
        notmuch_query_t *query = notmuch_query_create (notmuch, "");
        notmuch_messages_t *messages;
        notmuch_message_t *message;
@@ -1433,6 +1466,14 @@ notmuch_database_upgrade (notmuch_database_t *notmuch,
            if (new_features & NOTMUCH_FEATURE_BOOL_FOLDER)
                _notmuch_message_upgrade_folder (message);
 
+           /* Prior to NOTMUCH_FEATURE_LAST_MOD, messages did not
+            * track modification revisions.  Give all messages the
+            * next available revision; since we just started tracking
+            * revisions for this database, that will be 1.
+            */
+           if (new_features & NOTMUCH_FEATURE_LAST_MOD)
+               _notmuch_message_upgrade_last_mod (message);
+
            _notmuch_message_sync (message);
 
            notmuch_message_destroy (message);
@@ -1615,6 +1656,11 @@ notmuch_database_end_atomic (notmuch_database_t *notmuch)
        return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
 
+    if (notmuch->atomic_dirty) {
+       ++notmuch->revision;
+       notmuch->atomic_dirty = FALSE;
+    }
+
 DONE:
     notmuch->atomic_nesting--;
     return NOTMUCH_STATUS_SUCCESS;