[Patch v4 3/9] lib: add versions of n_q_count_{message, threads} with status return

[Jani Nikula]

On Sun, 27 Sep 2015, David Bremner <david at tethera.net> wrote:
> Although I think it's a pretty bad idea to continue using the old API,
> this allows both a more gentle transition for clients of the library,
> and allows us to break one monolithic change into a series

Mostly looks as good as it gets (who would say C makes error handling
like this look good?!), a few nitpicks inline below, up to your
discretion.

BR,
Jani.


> ---
>  lib/database.cc | 13 ++++++++++++-
>  lib/notmuch.h   | 48 ++++++++++++++++++++++++++++++++++++++++++------
>  lib/query.cc    | 47 +++++++++++++++++++++++++++++++++--------------
>  3 files changed, 87 insertions(+), 21 deletions(-)
>
> diff --git a/lib/database.cc b/lib/database.cc
> index dcfad8c..f39d448 100644
> --- a/lib/database.cc
> +++ b/lib/database.cc
> @@ -1410,8 +1410,15 @@ notmuch_database_upgrade (notmuch_database_t *notmuch,
>  	(NOTMUCH_FEATURE_FILE_TERMS | NOTMUCH_FEATURE_BOOL_FOLDER |
>  	 NOTMUCH_FEATURE_LAST_MOD)) {
>  	query = notmuch_query_create (notmuch, "");
> -	total += notmuch_query_count_messages (query);
> +	unsigned msg_count;
> +
> +	status = notmuch_query_count_messages_st (query, &msg_count);
> +	if (status)
> +	    goto DONE;
> +
> +	total += msg_count;
>  	notmuch_query_destroy (query);
> +	query = NULL;
>      }
>      if (new_features & NOTMUCH_FEATURE_DIRECTORY_DOCS) {
>  	t_end = db->allterms_end ("XTIMESTAMP");
> @@ -1492,6 +1499,7 @@ notmuch_database_upgrade (notmuch_database_t *notmuch,
>  	}
>  
>  	notmuch_query_destroy (query);
> +	query = NULL;
>      }
>  
>      /* Perform per-directory upgrades. */
> @@ -1612,6 +1620,9 @@ notmuch_database_upgrade (notmuch_database_t *notmuch,
>  	sigaction (SIGALRM, &action, NULL);
>      }
>  
> +    if (query)
> +	notmuch_query_destroy (query);
> +
>      talloc_free (local);
>      return status;
>  }
> diff --git a/lib/notmuch.h b/lib/notmuch.h
> index 8775683..2fb778b 100644
> --- a/lib/notmuch.h
> +++ b/lib/notmuch.h
> @@ -984,10 +984,26 @@ notmuch_threads_destroy (notmuch_threads_t *threads);
>   * This function performs a search and returns the number of matching
>   * messages.
>   *
> - * If a Xapian exception occurs, this function may return 0 (after
> - * printing a message).
> + * @returns
> + *
> + * NOTMUCH_STATUS_SUCCESS: query complete successfully.

complete_d_?

> + *
> + * NOTMUCH_STATUS_XAPIAN_EXCEPTION: a Xapian exception occured. The
> + *      value of *count is not defined.
>   */
> -unsigned
> +notmuch_status_t
> +notmuch_query_count_messages_st (notmuch_query_t *query, unsigned *count);

I'd use "unsigned int", but matter of style.

Do we care about documenting at which versions the new functions have
been introduced? Doxygen supports @since.

> +
> +/**
> + * like notmuch_query_count_messages_st, but without a status return

Period at the end.

> + *
> + * May return 0 in the case of errors.
> + *
> + * @deprecated Deprecated since libnotmuch 4.3 (notmuch 0.21). Please
> + * use notmuch_query_count_messages_st instead.
> + */
> +NOTMUCH_DEPRECATED(4,3)
> +unsigned int
>  notmuch_query_count_messages (notmuch_query_t *query);
>  
>  /**
> @@ -998,11 +1014,31 @@ notmuch_query_count_messages (notmuch_query_t *query);
>   * search.
>   *
>   * Note that this is a significantly heavier operation than
> - * notmuch_query_count_messages().
> + * notmuch_query_count_messages{_st}().

I think doxygen can do some hyperlinking here if you use the proper
function name(s). On output formats we don't use, but anyway...

> + *
> + * @returns
>   *
> - * If an error occurs, this function may return 0.
> + * NOTMUCH_STATUS_OUT_OF_MEMORY: Memory allocation failed. The value
> + *      of *count is not defined
> +
> + * NOTMUCH_STATUS_SUCCESS: query complete successfully.

complete_d_?

> + *
> + * NOTMUCH_STATUS_XAPIAN_EXCEPTION: a Xapian exception occured. The
> + *      value of *count is not defined.
>   */
> -unsigned
> +notmuch_status_t
> +notmuch_query_count_threads_st (notmuch_query_t *query, unsigned *count);
> +
> +/**
> + * like notmuch_query_count_threads, but without a status return.
> + *
> + * May return 0 in case of errors.
> + *
> + * @deprecated Deprecated as of libnotmuch 4.3 (notmuch 0.21). Please
> + * use notmuch_query_count_threads_st instead.
> + */
> +NOTMUCH_DEPRECATED(4,3)
> +unsigned int
>  notmuch_query_count_threads (notmuch_query_t *query);
>  
>  /**
> diff --git a/lib/query.cc b/lib/query.cc
> index 8cf0a07..e627bfc 100644
> --- a/lib/query.cc
> +++ b/lib/query.cc
> @@ -541,9 +541,19 @@ notmuch_threads_destroy (notmuch_threads_t *threads)
>      talloc_free (threads);
>  }
>  
> -unsigned
> +unsigned int
>  notmuch_query_count_messages (notmuch_query_t *query)
>  {
> +    notmuch_status_t status;
> +    unsigned int count;
> +
> +    status = notmuch_query_count_messages_st (query, &count);
> +    return status ? 0 : count;
> +}
> +
> +notmuch_status_t
> +notmuch_query_count_messages_st (notmuch_query_t *query, unsigned *count_out)
> +{
>      notmuch_database_t *notmuch = query->notmuch;
>      const char *query_string = query->query_string;
>      Xapian::doccount count = 0;
> @@ -605,35 +615,44 @@ notmuch_query_count_messages (notmuch_query_t *query)
>  			       "Query string was: %s\n",
>  			       error.get_msg().c_str(),
>  			       query->query_string);
> -
> +	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
>      }
>  
> -    return count;
> +    *count_out = count;
> +    return NOTMUCH_STATUS_SUCCESS;
>  }
>  
>  unsigned
>  notmuch_query_count_threads (notmuch_query_t *query)
>  {
> +    notmuch_status_t status;
> +    unsigned int count;
> +
> +    status = notmuch_query_count_threads_st (query, &count);
> +    return status ? 0 : count;
> +}
> +
> +notmuch_status_t
> +notmuch_query_count_threads_st (notmuch_query_t *query, unsigned *count)
> +{
>      notmuch_messages_t *messages;
>      GHashTable *hash;
> -    unsigned int count;
>      notmuch_sort_t sort;
> -    notmuch_status_t status;
> +    notmuch_status_t ret = NOTMUCH_STATUS_SUCCESS;
>  
>      sort = query->sort;
>      query->sort = NOTMUCH_SORT_UNSORTED;
> -    status = notmuch_query_search_messages_st (query, &messages);
> -    if (status)
> -	return 0;
> -
> +    ret = notmuch_query_search_messages_st (query, &messages);
> +    if (ret)
> +	return ret;
>      query->sort = sort;
>      if (messages == NULL)
> -	return 0;
> +	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
>  
>      hash = g_hash_table_new_full (g_str_hash, g_str_equal, NULL, NULL);
>      if (hash == NULL) {
>  	talloc_free (messages);
> -	return 0;
> +	return NOTMUCH_STATUS_OUT_OF_MEMORY;
>      }
>  
>      while (notmuch_messages_valid (messages)) {
> @@ -642,7 +661,7 @@ notmuch_query_count_threads (notmuch_query_t *query)
>  	char *thread_id_copy = talloc_strdup (messages, thread_id);
>  	if (unlikely (thread_id_copy == NULL)) {
>  	    notmuch_message_destroy (message);
> -	    count = 0;
> +	    ret = NOTMUCH_STATUS_OUT_OF_MEMORY;
>  	    goto DONE;
>  	}
>  	g_hash_table_insert (hash, thread_id_copy, NULL);
> @@ -650,13 +669,13 @@ notmuch_query_count_threads (notmuch_query_t *query)
>  	notmuch_messages_move_to_next (messages);
>      }
>  
> -    count = g_hash_table_size (hash);
> +    *count = g_hash_table_size (hash);
>  
>    DONE:
>      g_hash_table_unref (hash);
>      talloc_free (messages);
>  
> -    return count;
> +    return ret;
>  }
>  
>  notmuch_database_t *
> -- 
> 2.5.3
>
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