All of the code looks good to me (and improving error handling is
always a good thing). Some style nits are inline below.
The changes to _resolve_message_id_to_thread_id and
_notmuch_database_link_message_to_parents seem like just plain better
error handling and unrelated to the find_message API changes. Perhaps
these should be in a separate patch?
Quoth Ali Polatel on Oct 03 at 7:49 pm:
> Previously, the functions notmuch_database_find_message() and
> notmuch_database_find_message_by_filename() functions did not properly
> report error condition to the library user.
>
> For more information, read the thread on the notmuch mailing list
> starting with my mail "id:871uv2unfd.fsf@gmail.com"
>
> Make these functions accept a pointer to 'notmuch_message_t' as argument
> and return notmuch_status_t which may be used to check for any error
> condition.
>
> restore: Modify for the new notmuch_database_find_message()
> new: Modify for the new notmuch_database_find_message_by_filename()
> ---
> lib/database.cc | 90 ++++++++++++++++++++++++++++++++++------------------
> lib/message.cc | 6 ++--
> lib/notmuch.h | 61 +++++++++++++++++++++++++----------
> notmuch-new.c | 4 ++-
> notmuch-restore.c | 11 ++++--
> 5 files changed, 115 insertions(+), 57 deletions(-)
>
> diff --git a/lib/database.cc b/lib/database.cc
> index 9299c8d..1705232 100644
> --- a/lib/database.cc
> +++ b/lib/database.cc
> @@ -360,13 +360,17 @@ _message_id_compressed (void *ctx, const char *message_id)
> return compressed;
> }
>
> -notmuch_message_t *
> +notmuch_status_t
> notmuch_database_find_message (notmuch_database_t *notmuch,
> - const char *message_id)
> + const char *message_id,
> + notmuch_message_t **message)
Perhaps this should be message_ret to clearly distinguish it as an
out-argument?
> {
> notmuch_private_status_t status;
> unsigned int doc_id;
>
> + if (message == NULL)
> + return NOTMUCH_STATUS_NULL_POINTER;
> +
> if (strlen (message_id) > NOTMUCH_MESSAGE_ID_MAX)
> message_id = _message_id_compressed (notmuch, message_id);
>
> @@ -375,14 +379,21 @@ notmuch_database_find_message (notmuch_database_t *notmuch,
> message_id, &doc_id);
>
> if (status == NOTMUCH_PRIVATE_STATUS_NO_DOCUMENT_FOUND)
> - return NULL;
> + *message = NULL;
> + else {
> + *message = _notmuch_message_create (notmuch, notmuch, doc_id,
> + NULL);
> + if (*message == NULL)
> + return NOTMUCH_STATUS_OUT_OF_MEMORY;
> + }
>
> - return _notmuch_message_create (notmuch, notmuch, doc_id, NULL);
> + return NOTMUCH_STATUS_SUCCESS;
> } catch (const Xapian::Error &error) {
> fprintf (stderr, "A Xapian exception occurred finding message: %s.\n",
> error.get_msg().c_str());
> notmuch->exception_reported = TRUE;
> - return NULL;
> + *message = NULL;
> + return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
> }
> }
>
> @@ -1311,7 +1322,8 @@ _get_metadata_thread_id_key (void *ctx, const char *message_id)
>
> /* Find the thread ID to which the message with 'message_id' belongs.
> *
> - * Always returns a newly talloced string belonging to 'ctx'.
> + * Note: 'thread_id' must not be NULL!
> + * On success '*thread_id' is set to a newly talloced string belonging to 'ctx'.
> *
> * Note: If there is no message in the database with the given
> * 'message_id' then a new thread_id will be allocated for this
> @@ -1319,25 +1331,29 @@ _get_metadata_thread_id_key (void *ctx, const char *message_id)
> * thread ID can be looked up if the message is added to the database
> * later).
> */
> -static const char *
> +static notmuch_status_t
> _resolve_message_id_to_thread_id (notmuch_database_t *notmuch,
> void *ctx,
> - const char *message_id)
> + const char *message_id,
> + const char **thread_id)
thread_id_ret?
> {
> + notmuch_status_t status;
> notmuch_message_t *message;
> string thread_id_string;
> - const char *thread_id;
> char *metadata_key;
> Xapian::WritableDatabase *db;
>
> - message = notmuch_database_find_message (notmuch, message_id);
> + status = notmuch_database_find_message (notmuch, message_id, &message);
> +
> + if (status)
> + return status;
>
> if (message) {
> - thread_id = talloc_steal (ctx, notmuch_message_get_thread_id (message));
> + *thread_id = talloc_steal (ctx, notmuch_message_get_thread_id (message));
>
> notmuch_message_destroy (message);
>
> - return thread_id;
> + return NOTMUCH_STATUS_SUCCESS;
> }
>
> /* Message has not been seen yet.
> @@ -1351,15 +1367,15 @@ _resolve_message_id_to_thread_id (notmuch_database_t *notmuch,
> 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);
> + *thread_id = talloc_strdup (ctx, _notmuch_database_generate_thread_id (notmuch));
> + db->set_metadata (metadata_key, *thread_id);
> } else {
> - thread_id = thread_id_string.c_str();
> + *thread_id = talloc_strdup(ctx, thread_id_string.c_str());
Missing space after talloc_strdup.
> }
>
> talloc_free (metadata_key);
>
> - return talloc_strdup (ctx, thread_id);
> + return NOTMUCH_STATUS_SUCCESS;
> }
>
> static notmuch_status_t
> @@ -1446,9 +1462,12 @@ _notmuch_database_link_message_to_parents (notmuch_database_t *notmuch,
> _notmuch_message_add_term (message, "reference",
> parent_message_id);
>
> - parent_thread_id = _resolve_message_id_to_thread_id (notmuch,
> - message,
> - parent_message_id);
> + ret = _resolve_message_id_to_thread_id (notmuch,
> + message,
> + parent_message_id,
> + &parent_thread_id);
> + if (ret)
> + goto DONE;
>
> if (*thread_id == NULL) {
> *thread_id = talloc_strdup (message, parent_thread_id);
> @@ -1759,11 +1778,12 @@ notmuch_status_t
> notmuch_database_remove_message (notmuch_database_t *notmuch,
> const char *filename)
> {
> - notmuch_message_t *message =
> - notmuch_database_find_message_by_filename (notmuch, filename);
> - notmuch_status_t status = NOTMUCH_STATUS_SUCCESS;
> + notmuch_status_t status;
> + notmuch_message_t *message;
>
> - if (message) {
> + status = notmuch_database_find_message_by_filename (notmuch, filename, &message);
> +
> + if (status == NOTMUCH_STATUS_SUCCESS && message) {
> status = _notmuch_message_remove_filename (message, filename);
> if (status == NOTMUCH_STATUS_SUCCESS)
> _notmuch_message_delete (message);
This isn't a problem with your patch, but shouldn't this function be
notmuch_message_destroy'ing message?
> @@ -1774,24 +1794,27 @@ notmuch_database_remove_message (notmuch_database_t *notmuch,
> return status;
> }
>
> -notmuch_message_t *
> +notmuch_status_t
> notmuch_database_find_message_by_filename (notmuch_database_t *notmuch,
> - const char *filename)
> + const char *filename,
> + notmuch_message_t **message)
message_ret?
> {
> void *local;
> const char *prefix = _find_prefix ("file-direntry");
> char *direntry, *term;
> Xapian::PostingIterator i, end;
> - notmuch_message_t *message = NULL;
> notmuch_status_t status;
>
> + if (message == NULL)
> + return NOTMUCH_STATUS_NULL_POINTER;
> +
> local = talloc_new (notmuch);
>
> try {
> status = _notmuch_database_filename_to_direntry (local, notmuch,
> filename, &direntry);
> if (status)
> - return NULL;
> + goto DONE;
>
> term = talloc_asprintf (local, "%s%s", prefix, direntry);
>
> @@ -1800,19 +1823,24 @@ notmuch_database_find_message_by_filename (notmuch_database_t *notmuch,
> if (i != end) {
> notmuch_private_status_t private_status;
>
> - message = _notmuch_message_create (notmuch, notmuch,
> - *i, &private_status);
> + *message = _notmuch_message_create (notmuch, notmuch,
> + *i, &private_status);
> + if (*message == NULL)
> + status = NOTMUCH_STATUS_OUT_OF_MEMORY;
> }
> } catch (const Xapian::Error &error) {
> fprintf (stderr, "Error: A Xapian exception occurred finding message by filename: %s\n",
> error.get_msg().c_str());
> notmuch->exception_reported = TRUE;
> - message = NULL;
> + status = NOTMUCH_STATUS_OUT_OF_MEMORY;
> }
>
> + DONE:
> talloc_free (local);
>
> - return message;
> + if (status)
> + *message = NULL;
> + return status;
> }
>
> notmuch_string_list_t *
> diff --git a/lib/message.cc b/lib/message.cc
> index 531d304..2a85744 100644
> --- a/lib/message.cc
> +++ b/lib/message.cc
> @@ -216,11 +216,11 @@ _notmuch_message_create_for_message_id (notmuch_database_t *notmuch,
> unsigned int doc_id;
> char *term;
>
> - *status_ret = NOTMUCH_PRIVATE_STATUS_SUCCESS;
> -
> - message = notmuch_database_find_message (notmuch, message_id);
> + *status_ret = (notmuch_private_status_t) notmuch_database_find_message (notmuch, message_id, &message);
Long line, should probably be wrapped.
> if (message)
> return talloc_steal (notmuch, message);
> + else if (*status_ret)
> + return NULL;
>
> term = talloc_asprintf (NULL, "%s%s",
> _find_prefix ("id"), message_id);
> diff --git a/lib/notmuch.h b/lib/notmuch.h
> index 6d7a99f..08b4ce2 100644
> --- a/lib/notmuch.h
> +++ b/lib/notmuch.h
> @@ -347,35 +347,60 @@ notmuch_database_remove_message (notmuch_database_t *database,
>
> /* Find a message with the given message_id.
> *
> - * If the database contains a message with the given message_id, then
> - * a new notmuch_message_t object is returned. The caller should call
> - * notmuch_message_destroy when done with the message.
> + * If message with the given message_id is found then, on successful return
"If a message"
> + * (NOTMUCH_STATUS_SUCCESS) '*message' will be initialized to a message object.
> + * The user should call notmuch_message_destroy when done with the message.
Probably s/user/caller/, since "the user" is the person sitting at the
keyboard. (notmuch.h isn't very good about this, but it does use
"caller" more often than "user").
> - * This function returns NULL in the following situations:
> + * On any failure or when the message is not found, this function initializes
> + * '*message' to NULL. This means, when NOTMUCH_STATUS_SUCCESS is returned, the
> + * user is supposed to check '*message' for NULL to find out whether the
> + * message with the given message_id was found.
> *
> - * * No message is found with the given message_id
> - * * An out-of-memory situation occurs
> - * * A Xapian exception occurs
> + * Note: The argument 'message' must not be NULL!
Since it's clearly specified what happens if 'message' is NULL, this
note isn't necessary.
> + *
> + * Return value:
> + *
> + * NOTMUCH_STATUS_SUCCESS: Successful return, check '*message'.
> + *
> + * NOTMUCH_STATUS_NULL_POINTER: The given 'message' argument is NULL
> + *
> + * NOTMUCH_STATUS_OUT_OF_MEMORY: Out of memory, creating message object
> + *
> + * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred
> */
> -notmuch_message_t *
> +notmuch_status_t
> notmuch_database_find_message (notmuch_database_t *database,
> - const char *message_id);
> + const char *message_id,
> + notmuch_message_t **message);
>
> /* Find a message with the given filename.
> *
> - * If the database contains a message with the given filename, then a
> - * new notmuch_message_t object is returned. The caller should call
> - * notmuch_message_destroy when done with the message.
> + * If the database contains a message with the given filename then, on
> + * successful return (NOTMUCH_STATUS_SUCCESS) '*message' will be initialized to
> + * a message object. The user should call notmuch_message_destroy when done
> + * with the message.
Same comment about "user" as above.
> *
> - * This function returns NULL in the following situations:
> + * On any failure or when the message is not found, this function initializes
> + * '*message' to NULL. This means, when NOTMUCH_STATUS_SUCCESS is returned, the
> + * user is supposed to check '*message' for NULL to find out whether the
> + * message with the given filename is found.
> *
> - * * No message is found with the given filename
> - * * An out-of-memory situation occurs
> - * * A Xapian exception occurs
> + * Note: The argument 'message' must not be NULL!
Same comment about this note as above.
> + *
> + * Return value:
> + *
> + * NOTMUCH_STATUS_SUCCESS: Successful return, check '*message'
> + *
> + * NOTMUCH_STATUS_NULL_POINTER: The given 'message' argument is NULL
> + *
> + * NOTMUCH_STATUS_OUT_OF_MEMORY: Out of memory, creating the message object
> + *
> + * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred
> */
> -notmuch_message_t *
> +notmuch_status_t
> notmuch_database_find_message_by_filename (notmuch_database_t *notmuch,
> - const char *filename);
> + const char *filename,
> + notmuch_message_t **message);
>
> /* Return a list of all tags found in the database.
> *
> diff --git a/notmuch-new.c b/notmuch-new.c
> index e79593c..96a1e31 100644
> --- a/notmuch-new.c
> +++ b/notmuch-new.c
> @@ -743,7 +743,9 @@ remove_filename (notmuch_database_t *notmuch,
> status = notmuch_database_begin_atomic (notmuch);
> if (status)
> return status;
> - message = notmuch_database_find_message_by_filename (notmuch, path);
> + status = notmuch_database_find_message_by_filename (notmuch, path, &message);
> + if (status || message == NULL)
> + return status;
> status = notmuch_database_remove_message (notmuch, path);
> if (status == NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID) {
> add_files_state->renamed_messages++;
> diff --git a/notmuch-restore.c b/notmuch-restore.c
> index f095f64..e4a5355 100644
> --- a/notmuch-restore.c
> +++ b/notmuch-restore.c
> @@ -87,10 +87,13 @@ notmuch_restore_command (unused (void *ctx), int argc, char *argv[])
> file_tags = xstrndup (line + match[2].rm_so,
> match[2].rm_eo - match[2].rm_so);
>
> - message = notmuch_database_find_message (notmuch, message_id);
> - if (message == NULL) {
> - fprintf (stderr, "Warning: Cannot apply tags to missing message: %s\n",
> - message_id);
> + status = notmuch_database_find_message (notmuch, message_id, &message);
> + if (status || message == NULL) {
> + fprintf (stderr, "Warning: Cannot apply tags to %smessage: %s\n",
> + message ? "" : "missing ", message_id);
> + if (status)
> + fprintf (stderr, "%s\n",
> + notmuch_status_to_string(status));
> goto NEXT_LINE;
> }
>
--
Austin Clements MIT/'06/PhD/CSAIL
amdragon@mit.edu http://web.mit.edu/amdragon
Somewhere in the dream we call reality you will find me,
searching for the reality we call dreams.