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Added "no projects" label to lash_panel, updated manual 

git-svn-id: svn://svn.savannah.nongnu.org/lash/trunk@12 1de19dc7-4e3f-0410-a61d-eddf686bf0b7
This commit is contained in:
Dave Robillard 2005-09-19 09:34:23 +00:00
parent 596df7ded5
commit 18c04faec9
3 changed files with 277 additions and 240 deletions
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25
clients/panel/panel.c
View File

@ -108,6 +108,9 @@ event_project_add(panel_t * panel, lash_event_t * event)
printf("Add project: %s\n", name);
if (panel->num_projects == 0)
gtk_label_set_text(GTK_LABEL(panel->no_projects_label), "");
gtk_list_store_append(panel->projects, &iter);
project = project_create(panel->lash_client, name);
@ -115,12 +118,11 @@ event_project_add(panel_t * panel, lash_event_t * event)
gtk_list_store_set(panel->projects, &iter,
PROJECT_PROJECT_COLUMN, project, -1);
/*gtk_widget_unparent(project->box); */
project->page_number =
gtk_notebook_append_page(GTK_NOTEBOOK(panel->project_notebook),
project->box, project->tab_label);
panel->num_projects++;
}
void
@ -133,6 +135,10 @@ event_project_remove(panel_t * panel, lash_event_t * event)
printf("Remove project: %s\n", name);
if (panel->num_projects == 1)
gtk_label_set_text(GTK_LABEL(panel->no_projects_label),
"(No projects open. Start a LASH client, or load a project from the File menu)");
if (project != NULL)
if (gtk_tree_model_get_iter_first(tree_model, &iter))
do {
@ -148,6 +154,8 @@ event_project_remove(panel_t * panel, lash_event_t * event)
break;
}
} while (gtk_tree_model_iter_next(tree_model, &iter));
panel->num_projects--;
}
void
@ -342,6 +350,7 @@ panel_create(lash_client_t * lash_client)
panel->lash_client = lash_client;
panel->projects = gtk_list_store_new(PROJECT_NUM_COLUMNS, G_TYPE_POINTER);
panel->num_projects = 0;
panel->window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_title(GTK_WINDOW(panel->window), WINDOW_TITLE);
@ -410,9 +419,15 @@ panel_create(lash_client_t * lash_client)
gtk_notebook_set_tab_pos(GTK_NOTEBOOK(panel->project_notebook),
GTK_POS_TOP);
gtk_widget_show(panel->project_notebook);
gtk_box_pack_start(GTK_BOX(main_box), panel->project_notebook, TRUE, TRUE,
0);
gtk_box_pack_start(GTK_BOX(main_box), panel->project_notebook, TRUE, TRUE, 0);
/*
* "no project" label (shown instead of a notebook tab when no projects are present)
*/
panel->no_projects_label = gtk_label_new("(No projects open. Start a LASH client, or load a project from the File menu)");
gtk_widget_show(panel->no_projects_label);
gtk_box_pack_start(GTK_BOX(main_box), panel->no_projects_label, TRUE, TRUE, 0);
/*
* status bar
*/

2
clients/panel/panel.h
View File

@ -36,11 +36,13 @@ struct _panel
{
lash_client_t* lash_client;
size_t num_projects;
GtkListStore* projects;
GtkWidget* window;
GtkWidget* status_bar;
GtkWidget* project_notebook;
GtkWidget* no_projects_label;
};
panel_t* panel_create (lash_client_t * client);

490
docs/lash-manual.texi
View File

@ -73,31 +73,33 @@ Appendicies
@comment node-name, next, previous, up
@chapter Introduction
LASH stands for LASH Audio Session Handler.
It is a session management system for audio applications on GNU/Linux. It
understands the JACK low latency audio API and the ALSA MIDI sequencer
interface. The system is comprised of a server program, @command{lashd},
an application library, @code{liblash}, and a command line control program,
@command{laddca_control}. The server and clients communicate over TCP
sockets. There are three kinds of clients: normal clients (audio
applications), user interfaces for the server, and connection patchbays.
LASH stands for LASH Audio Session Handler. It is a session management
system for audio applications on GNU/Linux. It understands the
JACK low latency audio API and the ALSA MIDI sequencer interface. The
system is comprised of a server program, @command{lashd}, an application
library, @code{liblash}, and a control program - either the command-line
@command{lash_control} or the GTK @command{lash_panel}. The server and
clients communicate over TCP sockets. There are three kinds of clients:
normal clients (audio applications), user interfaces for the server,
and connection patchbays.
@section Nomenclature
In order to describe the system, we should introduce some terminology.
In order to describe the system, we should introduce some terminology.
First of all, the @dfn{server} is the @command{lashd} server program, an
omni-present marshaller and database for storing arbitrary application data.
The @dfn{library} is the @samp{liblash} shared library. It contains all
the functions that an application uses to communicate with the server and
take part in the system. Such an application is called a @dfn{client}.
omni-present marshaller and database for storing arbitrary application
data. The @dfn{library} is the @samp{liblash} shared library.
It contains all the functions that an application uses to communicate
with the server and take part in the system. Such an application is
called a @dfn{client}.
The server deals with things in terms of collections of clients, called
@dfn{projects}. A project has a unique string name, a current directory
and a list of clients that are in that project. The server can have one
client that is a @dfn{server interface} that allows the user to control the
server. There are two server interface included with the system, the
@command{lash_control} command-line interface, and the @command{lash_panel}
GTK interface.
The server deals with things in terms of collections of clients,
called @dfn{projects}. A project has a unique string name, a current
directory and a list of clients that are in that project. The server
can have one client that is a @dfn{server interface} that allows the
user to control the server. There are two server interface included
with the system, the @command{lash_control} command-line interface,
and the @command{lash_panel} GTK interface.
@ -106,23 +108,25 @@ GTK interface.
@comment node-name, next, previous, up
@chapter Copying LASH
LASH is distributed under the GNU General Public License. A copy of the
license text is provided in the file @file{COPYING} along with the software
source code, or you can get a copy by writing to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
LASH is distributed under the GNU General Public License. A copy of
the license text is provided in the file @file{COPYING} along with
the software source code, or you can get a copy by writing to the
Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
MA 02110-1301 USA.
In plain english, the GPL basically restricts you from restricting other
people's use of the LASH source code (ie, all of LASH), and any additions you make to
the code, including linking with the LASH library. If you use code from this
software, your software must be relased under the GPL. If you modify this
software and release it, your modifications must be released under the GPL. If
you release software linked against the LASH library, your software must be
released under the GPL.
people's use of the LASH source code (ie, all of LASH), and any additions
you make to the code, including linking with the LASH library. If you
use code from this software, your software must be relased under the GPL.
If you modify this software and release it, your modifications must be
released under the GPL. If you release software linked against the LASH
library, your software must be released under the GPL.
Note that this in no way restricts those people who want to release non-free
LASH clients. LASH operates using a well defined protocol over TCP
sockets. The high-level protocol is described within this document and
the lower-level bit-wise protocol can be garnered from the source itself.
Note that this in no way restricts those people who want to release
non-free LASH clients. LASH operates using a well defined protocol
over TCP sockets. The high-level protocol is described within this
document and the lower-level bit-wise protocol can be garnered from the
source itself.
@ -134,99 +138,100 @@ This chapter describes how to get LASH installed on your system.
@section Dependencies
LASH depends on the ALSA library, the JACK library, a unique ID library
called libuuid and the XML library libxml2. You need these installed before attempting to install
LASH.
called libuuid and the XML library libxml2. You need these installed
before attempting to install LASH.
ALSA is available from @url{http://www.alsa-project.org/}.
ALSA is available from @url{http://www.alsa-project.org/}.
JACK is available from @url{http://jackit.sf.net/}.
The libuuid library is included with the ubiquitous e2fsprogs package,
but if this is not installed on your system, it is available from
@url{http://e2fsprogs.sf.net/}.
The libxml2 library is available from @url{http://www.xmlsoft.org/}.
@url{http://e2fsprogs.sf.net/}. The libxml2 library is available from
@url{http://www.xmlsoft.org/}.
The LASH Control client depends on the GNU Readline library,
available from @url{ftp://ftp.gnu.org/pub/gnu/readline/}.
The LASH Control client depends on the GNU Readline library, available
from @url{ftp://ftp.gnu.org/pub/gnu/readline/}.
The LASH GTK Test Client, LASH Save Button 2, and LASH Panel all depend
on the GTK+ 2 toolkit, available from @url{ftp://ftp.gtk.org/pub/gtk/v2.0/}.
The LASH Synth client has an optional GUI which also uses the GTK+ 2 toolkit.
The LASH GTK Test Client, LASH Save Button 2, and LASH Panel all depend on
the GTK+ 2 toolkit, available from @url{ftp://ftp.gtk.org/pub/gtk/v2.0/}.
The LASH Synth client has an optional GUI which also uses the GTK+
2 toolkit.
The LASH Save Button client depends on the GTK+ 1.2 toolkit, also
available from @url{ftp://ftp.gtk.org/pub/gtk/v1.2/}.
available from @url{ftp://ftp.gtk.org/pub/gtk/v1.2/}.
@section Installation
First off, you need to download the package. It is available from the
LASH webpage, @url{http://www.nongnu.org/lash}. After you have
downloaded it, unpack the tarball into a directory using @command{tar -xzf
/where/ever/you/put/lash-0.5.0.tar.gz} and change into the source directory
with @command{cd lash-0.5.0}.
First off, you need to download the package. It is available from
the LASH webpage, @url{http://www.nongnu.org/lash}. After you have
downloaded it, unpack the tarball into a directory using @command{tar
-xzf /where/ever/you/put/lash-0.5.0.tar.gz} and change into the source
directory with @command{cd lash-0.5.0}.
The package uses the GNU autotools for configuration and makefile creation.
In order to install the package, you must complete three steps:
The package uses the GNU autotools for configuration and makefile
creation. In order to install the package, you must complete three steps:
configuration; building; and installing.
@subsection Configuration
To configure the package, there is a shell script named @file{configure} in the
top source directory. It is a standard GNU autoconf configure script, and
so accepts the standard GNU configuration options (such as
@option{--prefix}, @option{--datadir}, etc.) To run it type
@command{./configure} and add any options. The non-standard options that
the script recognises are described below.
@subsection Configuration To configure the package, there is a shell
script named @file{configure} in the top source directory. It is a
standard GNU autoconf configure script, and so accepts the standard GNU
configuration options (such as @option{--prefix}, @option{--datadir},
etc.) To run it type @command{./configure} and add any options.
The non-standard options that the script recognises are described below.
Running the script with the @option{--help} option will also provide a
quick summary of the recognised options.
@subsubsection Configure script options
@table @option
@item --disable-gtk2
Prevents the configure script from checking for the presence of the
GTK+ 2 toolkit and disables the building of any code that relies on it. The
LASH Save Button 2 and LASH GTK Test Client both rely on GTK+ 2.
@item --disable-gtk2 Prevents the configure script from
checking for the presence of the GTK+ 2 toolkit and disables the building
of any code that relies on it. The LASH Save Button 2 and LASH GTK Test
Client both rely on GTK+ 2.
@item --disable-gtk
Prevents the configure script from checking for the presence of the
GTK+ 1.2 toolkit and disables the building of any code that relies on it.
The LASH Save Button client relies on GTK+ 1.2.
@item --disable-gtk Prevents the configure script from checking for the
presence of the GTK+ 1.2 toolkit and disables the building of any code
that relies on it. The LASH Save Button client relies on GTK+ 1.2.
@item --enable-debug
Causes the library, server and clients to be built with debugging output.
This is not very useful and only recommended for developers working on the
LASH code itself.
@item --enable-debug Causes the library, server and clients to be built
with debugging output. This is not very useful and only recommended
for developers working on the LASH code itself.
@item --with-default-dir=DIR
Specifies the default directory, relative to \$HOME under which the server will create new project
directories. Without this option, the value defaults to @file{audio-projects}.
@item --with-default-dir=DIR Specifies the default directory, relative
to \$HOME under which the server will create new project directories.
Without this option, the value defaults to @file{audio-projects}.
@item --disable-serv-inst
The LASH server and library look up port addresses for the LASH service
using standard system calls that refer to the @file{/etc/services} database.
If @file{/etc/services} does not contain a valid entry, an error will result.
By default, the installation routine will install a service entry if one does not
exist. This flag disables that action.
@item --disable-serv-inst The LASH server and library look up port
addresses for the LASH service using standard system calls that
refer to the @file{/etc/services} database. If @file{/etc/services}
does not contain a valid entry, an error will result. By default, the
installation routine will install a service entry if one does not exist.
This flag disables that action.
@end table
@subsection Building
To build the package, simply type @command{make} in the top source
directory. This will build the server, the library and the clients that are
compatible with the resources found by the configure script.
To build the package, simply type @command{make}
in the top source directory. This will build the server, the library
and the clients that are compatible with the resources found by the
configure script.
@subsection Installing
To install the package, type @command{make install} in the top source
directory. By default the package installation prefix is @file{/usr/local} but
the @option{--prefix} option to the configure script will change this. The
@command{lashd} server and the clients that were built are installed in
@file{@var{prefix}/bin}. The @code{liblash} client library is installed
in @file{@var{prefix}/lib}. The C header files for the client library are
installed under @file{@var{prefix}/include}. This manual is installed under
To install the package, type @command{make install}
in the top source directory. By default the package installation
prefix is @file{/usr/local} but the @option{--prefix} option to the
configure script will change this. The @command{lashd} server and
the clients that were built are installed in @file{@var{prefix}/bin}.
The @code{liblash} client library is installed in @file{@var{prefix}/lib}.
The C header files for the client library are installed under
@file{@var{prefix}/include}. This manual is installed under
@file{@var{prefix}/info}.
With @command{make install}, the package is installed with debugging symbols in the object
files. To save space, you can install with @command{make install-strip} to
install the object files without debugging symbols.
With @command{make install}, the package is installed with debugging
symbols in the object files. To save space, you can install with
@command{make install-strip} to install the object files without
debugging symbols.
@ -247,6 +252,7 @@ For a command line interface, run the command @command{lashd_control}.
There is a @command{help} command.
For a graphical interface, run the command @command{lash_panel}.
It should be relatively self-explanatory.
@ -266,142 +272,154 @@ programmers of LASH clients.
@section Operational overview
In this section we give an overview of how the LASH system operates,
describing the server and client objects and operations that make it work. The
@command{lashd} server must be running in order for clients to participate
in the system; clients cannot interoperate soley between themselves. The
server maintains a list of connected clients and a list of projects with
which these clients are associated.
describing the server and client objects and operations that make it
work. The @command{lashd} server must be running in order for clients
to participate in the system; clients cannot interoperate soley between
themselves. The server maintains a list of connected clients and a list
of projects with which these clients are associated.
The server and clients exchange events and configs over their connections. There
is one, and only one, bi-directional connection between a client and
the server. The transport for this connection is currently TCP.
The server and clients exchange events and configs over their connections.
There is one, and only one, bi-directional connection between a client
and the server. The transport for this connection is currently TCP.
An @dfn{event} is a very simple object having two relevant properties: a type and an
optional arbitrary character string. The type defines what the event means to the recipient,
and the string allows additional information to be included with it. For
example, if a client wishes the server to save the current project, it sends a
@code{LASH_Save} event to the server. While saving the project, the server
may wish to tell a client to save its data in a certain directory. To so,
it sends a @code{LASH_Save_File} event to the client with a string containing the
name of a directory into which the client should save its data files.
An @dfn{event} is a very simple object having two relevant properties:
a type and an optional arbitrary character string. The type defines
what the event means to the recipient, and the string allows additional
information to be included with it. For example, if a client wishes
the server to save the current project, it sends a @code{LASH_Save}
event to the server. While saving the project, the server may wish to
tell a client to save its data in a certain directory. To so, it sends
a @code{LASH_Save_File} event to the client with a string containing
the name of a directory into which the client should save its data files.
Clients can save data on the server if they wish. To do this, the
client declares that it wants to save data on the server when it initialises the server connection
and then later sends one or more @dfn{config}s to the server. A config is
also a very simple object. It has a client-unique character string key, and
a value of arbitrary size and type (well, almost arbitrary; its size must
be able to be described by a @code{uint32_t} integer due to byte-order conversions
client declares that it wants to save data on the server when it
initialises the server connection and then later sends one or more
@dfn{config}s to the server. A config is also a very simple object.
It has a client-unique character string key, and a value of arbitrary
size and type (well, almost arbitrary; its size must be able to be
described by a @code{uint32_t} integer due to byte-order conversions
done when sending data over the network.)
@subsection Session example
In this section we will examine a typical session in some detail, describing
the server and client operations that take place. In the session, the
server is started, a number of clients connect, the session is saved and
then restored.
In this section we will examine a typical session in some detail,
describing the server and client operations that take place. In the
session, the server is started, a number of clients connect, the session
is saved and then restored.
@subsubsection Starting up the server
Before all else, the user starts the server. It starts up and begins listening for
connections from clients. It doesn't do much else.
Before all else, the user starts the server. It starts up and begins
listening for connections from clients. It doesn't do much else.
To keep track of what is happening with LASH, the user can run the
@command{lash_panel} program (though this is not necessary, and it can
be started later at any time).
@subsubsection A client connection
The user then starts a JACK client program. It opens a connection to the server
and provides it with all information that the server will need to run the
application again. This information includes: the current directory that
the user was in when they ran the program, the command line that started the
application and the @emph{class} of the client (a character string that the
client application provides the initialisation routine that will never
change over all initialisations.)
The user then starts a JACK client program. It opens a connection
to the server and provides it with all information that the server
will need to run the application again. This information includes:
the current directory that the user was in when they ran the program,
the command line that started the application and the @emph{class} of
the client (a character string that the client application provides the
initialisation routine that will never change over all initialisations.)
With this information is included a set
of flags that describe the client to the server. This particular
client saves data to files and wants the server to tell it where to
save files when the project is saved, so it has the
@code{LASH_Config_File} flag set.
With this information is included a set of flags that describe the client
to the server. This particular client saves data to files and wants
the server to tell it where to save files when the project is saved,
so it has the @code{LASH_Config_File} flag set.
The client library starts two threads for communication with the server,
one for sending data and the other for recieving. It also sends, along with
the client supplied data, a number of parameters that were extracted from
the client's command line options before it checked them. This optionally includes the
name of the project that the client should initially be associated
with and a 128-bit, world-unique identifier for this particular client
instance (the @dfn{LASH ID}.)
one for sending data and the other for recieving. It also sends,
along with the client supplied data, a number of parameters that were
extracted from the client's command line options before it checked them.
This optionally includes the name of the project that the client should
initially be associated with and a 128-bit, world-unique identifier for
this particular client instance (the @dfn{LASH ID}.)
Server-side, the server wakes up to the fact that a new connection has
arrived and immediately adds it to a list of open connections and then
goes back to waiting. When the client sends the requisite information, the
server looks at it and decides what to do with the client. This client has
not requested a specific project to which it should be connected. However,
there are no existing projects so the server creates a new project with the
name @samp{project-1} in the directory
goes back to waiting. When the client sends the requisite information,
the server looks at it and decides what to do with the client.
This client has not requested a specific project to which it should
be connected. However, there are no existing projects so the server
creates a new project with the name @samp{project-1} in the directory
@file{/home/@var{user}/audio-projects/project-1} (assuming the user
didn't specify a different default directory when running configure.) It
also generates a new LASH ID for the client. It then adds the
client to the new project and goes back to listening.
didn't specify a different default directory when running configure.)
It also generates a new LASH ID for the client. It then adds the client
to the new project and goes back to listening.
The client then connects up to the JACK server and, after having done this,
sends a @code{LASH_Jack_Client_Name} event to the server with the name that
it registered to JACK with as the string. This notifies the server that it
is a JACK client and needs its JACK port connections saved and restored.
The server will now pay attention to any activity regarding the client
(ie, port creation and destruction and port connection and disconnection.)
If the user has the @command{lash_panel} client running, the new project
will appear as a tab with the title @samp{project-1}, and the new client
will appear in the client list for that project.
The client then connects up to the JACK server and, after having done
this, sends a @code{LASH_Jack_Client_Name} event to the server with the
name that it registered to JACK with as the string. This notifies the
server that it is a JACK client and needs its JACK port connections saved
and restored. The server will now pay attention to any activity regarding
the client (ie, port creation and destruction and port connection and
disconnection.)
@subsubsection Another client
The user then starts a second client that uses the ALSA sequencer interface
and wishes to save data on the server. It connects to the server with a
different class to the JACK client and with the
The user then starts a second client that uses the ALSA sequencer
interface and wishes to save data on the server. It connects to
the server with a different class to the JACK client and with the
@code{LASH_Config_Data_Set} flag set.
The server sees that this client also didn't specify a project, and so adds
it to the first available project; the same one as the previous project,
@samp{project-1}. It also sees that the client wants to store data on the
server, and so it creates a directory within the project directory for this
data to be stored in and creates a database-style object to manage the
client's data.
The server sees that this client also didn't specify a project, and so
adds it to the first available project; the same one as the previous
project, @samp{project-1}. It also sees that the client wants to store
data on the server, and so it creates a directory within the project
directory for this data to be stored in and creates a database-style
object to manage the client's data.
The client then connects to the ALSA sequencer and sends its client ID to
the server in the first character of the string of a
@code{LASH_Alsa_Client_Name} event. The server regards this similarly to
the other client's JACK client name.
If the user has the @command{lash_panel} client running, both clients
will now be visible in the clients list for @samp{project-1}.
The client then connects to the ALSA sequencer and sends its
client ID to the server in the first character of the string of a
@code{LASH_Alsa_Client_Name} event. The server regards this similarly
to the other client's JACK client name.
@subsubsection Saving the project
After the user has done some work in the two clients, they want to save
their work. They click a button on one of the clients (or something similar)
and the client sends a @code{LASH_Save} event to server. The server recieves
this and then iterates through each client in the project and checks its
flags. The JACK client saves data by itself (it has the
@code{LASH_Config_File} flag set,) so the server creates a
directory under the project directory for it to save in and then sends a
@code{LASH_Save_File} event to the client with a string containing the name
of the directory it made. The client recieves the event and saves its data into
the specified directory.
After the user has done some work in the two clients, they want to
save their work. They click the Save button in @command{lash_panel}
(or use the @command{save} command in @command{lash_control}), and a
@code{LASH_Save} event is sent to the server. The server recieves this
and then iterates through each client in the project and checks its flags.
The JACK client saves data by itself (it has the @code{LASH_Config_File}
flag set,) so the server creates a directory under the project directory
for it to save in and then sends a @code{LASH_Save_File} event to the
client with a string containing the name of the directory it made.
The client recieves the event and saves its data into the specified
directory.
Next, the server examines the ALSA client. It wishes to save data on the
server, so the server sends a @code{LASH_Save_Data_Set} to the client. With
all of the clients iterated through, it now saves all the information it
needs to be able to restore them; their working directory, command line
options, etc. In order to do this, it asks the JACK server
to find the connections for the JACK client, and asks the ALSA sequencer to
find the connections for the ALSA client. It uses the client name and ID
that both clients sent to the server after opening their connections to the
respective systems. All of this information is stored
in a file under the project's directory. When this is done, the server goes
back to listening for events and configs.
server, so the server sends a @code{LASH_Save_Data_Set} to the client.
With all of the clients iterated through, it now saves all the information
it needs to be able to restore them; their working directory, command
line options, etc. In order to do this, it asks the JACK server to
find the connections for the JACK client, and asks the ALSA sequencer to
find the connections for the ALSA client. It uses the client name and
ID that both clients sent to the server after opening their connections
to the respective systems. All of this information is stored in a file
under the project's directory. When this is done, the server goes back
to listening for events and configs.
The client, meanwhile,
has recieved the @code{LASH_Save_Data_Set} event and sends back a number of
configs to the server. When it has sent all the data it wishes to be saved,
it sends back a @code{LASH_Save_Data_Set} event. The server passes all of
the configs to the object managing the data store for the ALSA client.
When the server recieves the @code{LASH_Save_Data_Set} event
from the client, it tells the data store to write the data to
disk. The save is now complete.
The client, meanwhile, has recieved the @code{LASH_Save_Data_Set} event
and sends back a number of configs to the server. When it has sent all
the data it wishes to be saved, it sends back a @code{LASH_Save_Data_Set}
event. The server passes all of the configs to the object managing
the data store for the ALSA client. When the server recieves the
@code{LASH_Save_Data_Set} event from the client, it tells the data store
to write the data to disk. The save is now complete.
@subsubsection Client resumption
@ -409,59 +427,61 @@ Unfortunately for the user, the ALSA client crashes. The server detects
that the client has disconnected, and puts the client on a list of lost
clients for the project. The user then starts another copy of the client,
which connects to the server in the same way it did before. This time,
however, the server checks through the list of lost clients and finds that
the class of the new client matches the class of the lost client and so it
resumes the lost client using the new one. It gives it the 128-bit ID of
the lost client, adds it to the project, and then sends a
@code{LASH_Restore_Data_Set} event to the client. The client then cleans
itself up, ready to recieve the data set. The server sends the client the
configs, and then another @code{LASH_Restore_Data_Set} event. The client
recieves this data and its state has been restored that of the client that
crashed.
however, the server checks through the list of lost clients and finds
that the class of the new client matches the class of the lost client
and so it resumes the lost client using the new one. It gives it the
128-bit ID of the lost client, adds it to the project, and then sends
a @code{LASH_Restore_Data_Set} event to the client. The client then
cleans itself up, ready to recieve the data set. The server sends the
client the configs, and then another @code{LASH_Restore_Data_Set} event.
The client recieves this data and its state has been restored that of
the client that crashed.
The user can stop this behaviour by specifying the
@option{--lash-no-autoresume} option on the client's command line.
@subsubsection Restoring the project
The user has to go off and do other things, and so they close down
the clients and the server. Some time later, the user comes back and
wants to start working again so first, as always, they start up the server.
They then start the @command{lash_control} program. This is a text
interface command program for controlling the server. They get a command
prompt and into it type @kbd{restore
/home/@var{user}/audio-projects/project-1}. The lash_control client sends
a @code{LASH_Restore} event to the server with the specified directory as the
string. The server opens the file that it saved before, and reads in all
the information about the project and its clients. It creates a new project
with this information. The clients are created as lost clients, however.
The user has to go off and do other things, and so they close down the
clients and the server. Some time later, the user comes back and wants
to start working again so first, as always, they start up the server.
They then start the @command{lash_panel} program. Using the File->Open
menu item, the user selects the directory (not file!) where they saved
the project (by default @file{~/audio-projects/project-1}, but you
can save to a more descriptive name). The lash_panel client sends a
@code{LASH_Restore} event to the server with the specified directory as
the string. The server opens the file that it saved before, and reads
in all the information about the project and its clients. It creates
a new project with this information. The clients are created as lost
clients, however.
The server then iterates through each client and starts a new copy of it
using the information provided when the original client connected. It also
adds some command line options that are extracted by the client library.
These specify the LASH ID of the client, the project name that it should
be connecting to and the server's hostname and port. It then goes back to
waiting.
The server then iterates through each client and starts a new copy of
it using the information provided when the original client connected.
It also adds some command line options that are extracted by the client
library. These specify the LASH ID of the client, the project name
that it should be connecting to and the server's hostname and port.
It then goes back to waiting.
The new JACK client then connects to the server as normal. When the server
recieves it connection, it checks the client against the project's list of
lost clients. This time, however, it has its ID specified, so the server
will only resume a client with a matching ID. Lo and behold, such a client
exists. The server resumes the old JACK client, telling it to load its
state from the files in the project directory that the client previously
stored. It does so with a @code{LASH_Restore_File} event with the string as
the directory name. The ALSA client does exactly the same, except having
its data restored through @code{LASH_Restore_Data_Set} as described above.
The new JACK client then connects to the server as normal. When the
server recieves it connection, it checks the client against the project's
list of lost clients. This time, however, it has its ID specified, so
the server will only resume a client with a matching ID. Lo and behold,
such a client exists. The server resumes the old JACK client, telling it
to load its state from the files in the project directory that the client
previously stored. It does so with a @code{LASH_Restore_File} event with
the string as the directory name. The ALSA client does exactly the same,
except having its data restored through @code{LASH_Restore_Data_Set}
as described above.
Only one thing remains for the clients to be fully restored: the JACK and
ALSA sequencer connections. This happens when the clients send their
@code{LASH_Jack_Client_Name} and @code{LASH_Alsa_Client_ID} events. The
connections are stored with the LASH ID rather than the JACK
client name or ALSA client ID. When the client registers its name or ID,
the connections are converted from the LASH ID to the JACK client name or
ALSA client ID, and the connections are restored. It also pays attention to
connections to other clients within the same project, converting between JACK client
names, ALSA client IDs and LASH IDs as appropriate.
@code{LASH_Jack_Client_Name} and @code{LASH_Alsa_Client_ID} events.
The connections are stored with the LASH ID rather than the JACK client
name or ALSA client ID. When the client registers its name or ID, the
connections are converted from the LASH ID to the JACK client name or ALSA
client ID, and the connections are restored. It also pays attention to
connections to other clients within the same project, converting between
JACK client names, ALSA client IDs and LASH IDs as appropriate.
@node Types and functions, Event protocol, Operational overview, Client reference
@section Types and functions