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).

1 files changed, 0 insertions, 46 deletions

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)