X-Git-Url: https://git.notmuchmail.org/git?p=notmuch;a=blobdiff_plain;f=lib%2Fdatabase.cc;h=6842fafadad86967b4363abd5869a2aeaef345c2;hp=9cd46d4fcb7ca3c85b6d7be8340cc6b60a1a2c56;hb=14073b8851067db4dbf5727bf1f5547a66750934;hpb=e9bb90ba2c18ac6c36168ccb20099ef395d7dfb6 diff --git a/lib/database.cc b/lib/database.cc index 9cd46d4f..6842fafa 100644 --- a/lib/database.cc +++ b/lib/database.cc @@ -44,7 +44,8 @@ typedef struct { /* Here's the current schema for our database (for NOTMUCH_DATABASE_VERSION): * - * We currently have two different types of documents: mail and directory. + * We currently have two different types of documents (mail and + * directory) and also some metadata. * * Mail document * ------------- @@ -118,6 +119,49 @@ typedef struct { * * The data portion of a directory document contains the path of the * directory (relative to the database path). + * + * Database metadata + * ----------------- + * Xapian allows us to store arbitrary name-value pairs as + * "metadata". We currently use the following metadata names with the + * given meanings: + * + * version The database schema version, (which is distinct + * from both the notmuch package version (see + * notmuch --version) and the libnotmuch library + * version. The version is stored as an base-10 + * ASCII integer. The initial database version + * was 1, (though a schema existed before that + * were no "version" database value existed at + * all). Succesive versions are allocated as + * changes are made to the database (such as by + * indexing new fields). + * + * last_thread_id The last thread ID generated. This is stored + * as a 16-byte hexadecimal ASCII representation + * of a 64-bit unsigned integer. The first ID + * generated is 1 and the value will be + * incremented for each thread ID. + * + * thread_id_* A pre-allocated thread ID for a particular + * message. This is actually an arbitarily large + * family of metadata name. Any particular name + * is formed by concatenating "thread_id_" with a + * message ID. The value stored is a thread ID. + * + * These thread ID metadata values are stored + * whenever a message references a parent message + * that does not yet exist in the database. A + * thread ID will be allocated and stored, and if + * the message is later added, the stored thread + * ID will be used (and the metadata value will + * be cleared). + * + * Even before a message is added, it's + * pre-allocated thread ID is useful so that all + * descendant messages that reference this common + * parent can be recognized as belonging to the + * same thread. */ /* With these prefix values we follow the conventions published here: @@ -1152,36 +1196,41 @@ _resolve_message_id_to_thread_id (notmuch_database_t *notmuch, const char *message_id) { notmuch_message_t *message; - const char *ret = NULL; + string thread_id_string; + const char *thread_id; + char *metadata_key; + Xapian::WritableDatabase *db; message = notmuch_database_find_message (notmuch, message_id); - /* If we haven't seen that message yet then check if we have already - * generated a dummy id for it and stored it in the metadata. - * If not then we generate a new thread id. - * This ensures that we can thread messages even when we haven't received - * the root (yet?) - */ - if (message == NULL) { - Xapian::WritableDatabase *db = static_cast (notmuch->xapian_db); - char * metadata_key = _get_metadata_thread_id_key (ctx, message_id); - string thread_id = notmuch->xapian_db->get_metadata(metadata_key); - if (thread_id.empty()) { - ret = _notmuch_database_generate_thread_id(notmuch); - db->set_metadata(metadata_key, ret); - } else { - ret = thread_id.c_str(); - } - talloc_free (metadata_key); - goto DONE; - } - ret = talloc_steal (ctx, notmuch_message_get_thread_id (message)); + if (message) { + thread_id = talloc_steal (ctx, notmuch_message_get_thread_id (message)); - DONE: - if (message) notmuch_message_destroy (message); - return ret; + return thread_id; + } + + /* Message has not been seen yet. + * + * We may have seen a reference to it already, in which case, we + * can return the thread ID stored in the metadata. Otherwise, we + * generate a new thread ID and store it there. + */ + db = static_cast (notmuch->xapian_db); + metadata_key = _get_metadata_thread_id_key (ctx, message_id); + thread_id_string = notmuch->xapian_db->get_metadata (metadata_key); + + if (thread_id_string.empty()) { + thread_id = _notmuch_database_generate_thread_id (notmuch); + db->set_metadata (metadata_key, thread_id); + } else { + thread_id = thread_id_string.c_str(); + } + + talloc_free (metadata_key); + + return thread_id; } static notmuch_status_t @@ -1264,22 +1313,21 @@ _notmuch_database_link_message_to_parents (notmuch_database_t *notmuch, const char *parent_thread_id; parent_message_id = (char *) l->data; + + _notmuch_message_add_term (message, "reference", + parent_message_id); + parent_thread_id = _resolve_message_id_to_thread_id (notmuch, message, parent_message_id); - if (parent_thread_id == NULL) { - _notmuch_message_add_term (message, "reference", - parent_message_id); - } else { - if (*thread_id == NULL) { - *thread_id = talloc_strdup (message, parent_thread_id); - _notmuch_message_add_term (message, "thread", *thread_id); - } else if (strcmp (*thread_id, parent_thread_id)) { - ret = _merge_threads (notmuch, *thread_id, parent_thread_id); - if (ret) - goto DONE; - } + if (*thread_id == NULL) { + *thread_id = talloc_strdup (message, parent_thread_id); + _notmuch_message_add_term (message, "thread", *thread_id); + } else if (strcmp (*thread_id, parent_thread_id)) { + ret = _merge_threads (notmuch, *thread_id, parent_thread_id); + if (ret) + goto DONE; } } @@ -1343,18 +1391,27 @@ _notmuch_database_link_message_to_children (notmuch_database_t *notmuch, /* Given a (mostly empty) 'message' and its corresponding * 'message_file' link it to existing threads in the database. * - * We first look at 'message_file' and its link-relevant headers - * (References and In-Reply-To) for message IDs. We also look in the - * database for existing message that reference 'message'. In either - * case, we will assign to the current message the first thread_id + * The first check is in the metadata of the database to see if we + * have pre-allocated a thread_id in advance for this message, (which + * would have happened if a message was previously added that + * referenced this one). + * + * Second, we look at 'message_file' and its link-relevant headers + * (References and In-Reply-To) for message IDs. + * + * Finally, we look in the database for existing message that + * reference 'message'. + * + * In all cases, we assign to the current message the first thread_id * found (through either parent or child). We will also merge any * existing, distinct threads where this message belongs to both, * (which is not uncommon when mesages are processed out of order). * - * Finally, if not thread ID has been found through parent or child, - * we call _notmuch_message_generate_thread_id to generate a new - * generates a new thread ID if the message doesn't connect to any - * existing threads. + * Finally, if no thread ID has been found through parent or child, we + * call _notmuch_message_generate_thread_id to generate a new thread + * ID. This should only happen for new, top-level messages, (no + * References or In-Reply-To header in this message, and no previously + * added message refers to this message). */ static notmuch_status_t _notmuch_database_link_message (notmuch_database_t *notmuch, @@ -1362,17 +1419,27 @@ _notmuch_database_link_message (notmuch_database_t *notmuch, notmuch_message_file_t *message_file) { notmuch_status_t status; - const char *thread_id = NULL; - char *metadata_key = _get_metadata_thread_id_key (message, - notmuch_message_get_message_id (message)); + const char *message_id, *thread_id = NULL; + char *metadata_key; + string stored_id; + + message_id = notmuch_message_get_message_id (message); + metadata_key = _get_metadata_thread_id_key (message, message_id); + /* Check if we have already seen related messages to this one. * If we have then use the thread_id that we stored at that time. */ - string stored_id = notmuch->xapian_db->get_metadata (metadata_key); - if (!stored_id.empty()) { - Xapian::WritableDatabase *db = static_cast (notmuch->xapian_db); + stored_id = notmuch->xapian_db->get_metadata (metadata_key); + if (! stored_id.empty()) { + Xapian::WritableDatabase *db; + + db = static_cast (notmuch->xapian_db); + + /* Clear the metadata for this message ID. We don't need it + * anymore. */ db->set_metadata (metadata_key, ""); thread_id = stored_id.c_str(); + _notmuch_message_add_term (message, "thread", thread_id); } talloc_free (metadata_key);