Re: [PATCH 2/4] lib: add notmuch_database_reopen

[Jani Nikula <jani@nikula.org>]

On Fri, 24 Feb 2017, David Bremner <david@tethera.net> wrote:
> The main expected use is to recover from a Xapian::DatabaseChanged
> exception.

I guess the main question here is if this should be exposed from the
library or not. If the intention is to recover *within* the library, why
add new API?

> ---
>  lib/database-private.h |  4 ++++
>  lib/database.cc        | 23 +++++++++++++++++++++++
>  lib/notmuch.h          | 12 ++++++++++++
>  3 files changed, 39 insertions(+)
>
> diff --git a/lib/database-private.h b/lib/database-private.h
> index 2fb60f5e..06882439 100644
> --- a/lib/database-private.h
> +++ b/lib/database-private.h
> @@ -207,6 +207,10 @@ struct _notmuch_database {
>      unsigned long revision;
>      const char *uuid;
>  
> +    /* Keep track of the number of times the database has been re-opened
> +     * (or other global invalidations of notmuch's caching)
> +     */
> +    unsigned long view;
>      Xapian::QueryParser *query_parser;
>      Xapian::TermGenerator *term_gen;
>      Xapian::ValueRangeProcessor *value_range_processor;
> diff --git a/lib/database.cc b/lib/database.cc
> index 386dcd17..1e958b65 100644
> --- a/lib/database.cc
> +++ b/lib/database.cc
> @@ -951,6 +951,7 @@ notmuch_database_open_verbose (const char *path,
>  
>      notmuch->mode = mode;
>      notmuch->atomic_nesting = 0;
> +    notmuch->view = 1;
>      try {
>  	string last_thread_id;
>  	string last_mod;
> @@ -1133,6 +1134,28 @@ notmuch_database_close (notmuch_database_t *notmuch)
>      return status;
>  }
>  
> +notmuch_status_t
> +notmuch_database_reopen (notmuch_database_t *notmuch)
> +{
> +    if (notmuch->mode != NOTMUCH_DATABASE_MODE_READ_ONLY)
> +	return NOTMUCH_STATUS_UNSUPPORTED_OPERATION;
> +
> +    try {
> +	notmuch->xapian_db->reopen ();
> +    } catch (const Xapian::Error &error) {
> +	if (! notmuch->exception_reported) {
> +	    _notmuch_database_log (notmuch, "Error: A Xapian exception reopening database: %s\n",
> +				   error.get_msg ().c_str ());
> +	    notmuch->exception_reported = TRUE;
> +	    return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
> +	}

Move the above return out of the if block?

> +    }
> +
> +    notmuch->view++;
> +
> +    return NOTMUCH_STATUS_SUCCESS;
> +}
> +
>  static int
>  unlink_cb (const char *path,
>  	   unused (const struct stat *sb),
> diff --git a/lib/notmuch.h b/lib/notmuch.h
> index 16da8be9..e9ed01dd 100644
> --- a/lib/notmuch.h
> +++ b/lib/notmuch.h
> @@ -363,6 +363,18 @@ notmuch_status_t
>  notmuch_database_close (notmuch_database_t *database);
>  
>  /**
> + * Reopen a (read-only) database, synching the database view with that
> + * on disk.
> + *
> + * @returns
> + * - NOTMUCH_STATUS_UNSUPPORTED_OPERATION: database is not read only
> + * - NOTMUCH_STATUS_XAPIAN_EXCEPTION: a Xapian exception occured trying to
> + *   re-open the database.
> + */
> +notmuch_status_t
> +notmuch_database_reopen (notmuch_database_t *database);
> +
> +/**
>   * A callback invoked by notmuch_database_compact to notify the user
>   * of the progress of the compaction process.
>   */
> -- 
> 2.11.0
>
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