From: Carl Worth Date: Mon, 8 Feb 2010 19:33:33 +0000 (-0800) Subject: Switch from random to sequential thread identifiers. X-Git-Tag: 0.1~97 X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=9439b217c349478b3603d5368f534acb1cd23974;p=notmuch.git Switch from random to sequential thread identifiers. The sequential identifiers have the advantage of being guaranteed to be unique (until we overflow a 64-bit unsigned integer), and also take up half as much space in the "notmuch search" output (16 columns rather than 32). This change also has the side effect of fixing a bug where notmuch could block on /dev/random at startup (waiting for some entropy to appear). This bug was hit hard by the test suite, (which could easily exhaust the available entropy on common systems---resulting in large delays of the test suite). --- diff --git a/lib/database-private.h b/lib/database-private.h index 5891584e..5bb6e86c 100644 --- a/lib/database-private.h +++ b/lib/database-private.h @@ -27,14 +27,19 @@ struct _notmuch_database { notmuch_bool_t exception_reported; + char *path; + + notmuch_bool_t needs_upgrade; notmuch_database_mode_t mode; Xapian::Database *xapian_db; + + uint64_t last_thread_id; + Xapian::QueryParser *query_parser; Xapian::TermGenerator *term_gen; Xapian::ValueRangeProcessor *value_range_processor; - notmuch_bool_t needs_upgrade; }; /* Convert tags from Xapian internal format to notmuch format. diff --git a/lib/database.cc b/lib/database.cc index cce78478..86413215 100644 --- a/lib/database.cc +++ b/lib/database.cc @@ -533,6 +533,8 @@ notmuch_database_open (const char *path, notmuch->needs_upgrade = FALSE; notmuch->mode = mode; try { + string last_thread_id; + if (mode == NOTMUCH_DATABASE_MODE_READ_WRITE) { notmuch->xapian_db = new Xapian::WritableDatabase (xapian_path, Xapian::DB_CREATE_OR_OPEN); @@ -567,6 +569,20 @@ notmuch_database_open (const char *path, notmuch_path, version, NOTMUCH_DATABASE_VERSION); } } + + last_thread_id = notmuch->xapian_db->get_metadata ("last_thread_id"); + if (last_thread_id.empty ()) { + notmuch->last_thread_id = 0; + } else { + const char *str; + char *end; + + str = last_thread_id.c_str (); + notmuch->last_thread_id = strtoull (str, &end, 16); + if (*end != '\0') + INTERNAL_ERROR ("Malformed database last_thread_id: %s", str); + } + notmuch->query_parser = new Xapian::QueryParser; notmuch->term_gen = new Xapian::TermGenerator; notmuch->term_gen->set_stemmer (Xapian::Stem ("english")); @@ -1278,14 +1294,38 @@ _notmuch_database_link_message_to_children (notmuch_database_t *notmuch, return ret; } +static const char * +_notmuch_database_generate_thread_id (notmuch_database_t *notmuch) +{ + /* 16 bytes (+ terminator) for hexadecimal representation of + * a 64-bit integer. */ + static char thread_id[17]; + Xapian::WritableDatabase *db; + + db = static_cast (notmuch->xapian_db); + + notmuch->last_thread_id++; + + sprintf (thread_id, "%016llx", notmuch->last_thread_id); + + db->set_metadata ("last_thread_id", thread_id); + + return thread_id; +} + /* 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'. + * database for existing message that reference 'message'. In either + * case, we will 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). * - * The end result is to call _notmuch_message_ensure_thread_id which + * 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. */ @@ -1308,8 +1348,12 @@ _notmuch_database_link_message (notmuch_database_t *notmuch, if (status) return status; - if (thread_id == NULL) - _notmuch_message_ensure_thread_id (message); + /* If not part of any existing thread, generate a new thread ID. */ + if (thread_id == NULL) { + thread_id = _notmuch_database_generate_thread_id (notmuch); + + _notmuch_message_add_term (message, "thread", thread_id); + } return NOTMUCH_STATUS_SUCCESS; } diff --git a/lib/message.cc b/lib/message.cc index f0e905b7..01950505 100644 --- a/lib/message.cc +++ b/lib/message.cc @@ -42,13 +42,6 @@ struct _notmuch_message { Xapian::Document doc; }; -/* "128 bits of thread-id ought to be enough for anybody" */ -#define NOTMUCH_THREAD_ID_BITS 128 -#define NOTMUCH_THREAD_ID_DIGITS (NOTMUCH_THREAD_ID_BITS / 4) -typedef struct _thread_id { - char str[NOTMUCH_THREAD_ID_DIGITS + 1]; -} thread_id_t; - /* We end up having to call the destructor explicitly because we had * to use "placement new" in order to initialize C++ objects within a * block that we allocated with talloc. So C++ is making talloc @@ -557,45 +550,6 @@ _notmuch_message_set_date (notmuch_message_t *message, Xapian::sortable_serialise (time_value)); } -static void -thread_id_generate (thread_id_t *thread_id) -{ - static int seeded = 0; - FILE *dev_random; - uint32_t value; - char *s; - int i; - - if (! seeded) { - dev_random = fopen ("/dev/random", "r"); - if (dev_random == NULL) { - srand (time (NULL)); - } else { - fread ((void *) &value, sizeof (value), 1, dev_random); - srand (value); - fclose (dev_random); - } - seeded = 1; - } - - s = thread_id->str; - for (i = 0; i < NOTMUCH_THREAD_ID_DIGITS; i += 8) { - value = rand (); - sprintf (s, "%08x", value); - s += 8; - } -} - -void -_notmuch_message_ensure_thread_id (notmuch_message_t *message) -{ - /* If not part of any existing thread, generate a new thread_id. */ - thread_id_t thread_id; - - thread_id_generate (&thread_id); - _notmuch_message_add_term (message, "thread", thread_id.str); -} - /* Synchronize changes made to message->doc out into the database. */ void _notmuch_message_sync (notmuch_message_t *message) diff --git a/test/notmuch-test b/test/notmuch-test index 2e5eb245..7bc53eca 100755 --- a/test/notmuch-test +++ b/test/notmuch-test @@ -146,7 +146,7 @@ add_message () } NOTMUCH_IGNORED_OUTPUT_REGEXP='^Processed [0-9]*( total)? file|Found [0-9]* total file' -NOTMUCH_THREAD_ID_SQUELCH='s/thread:................................/thread:XXX/' +NOTMUCH_THREAD_ID_SQUELCH='s/thread:................/thread:XXX/' execute_expecting () { args=$1