ipc: implement events, cleanup the code a bit

include/i3/ipc.h

@@ -29,6 +29,9 @@
 /** Requests the current workspaces from i3 */
 #define I3_IPC_MESSAGE_TYPE_GET_WORKSPACES      1
 
+/** Subscribe to the specified events */
+#define I3_IPC_MESSAGE_TYPE_SUBSCRIBE           2
+
 /*
  * Messages from i3 to clients
  *
@@ -40,4 +43,14 @@
 /** Workspaces reply type */
 #define I3_IPC_REPLY_TYPE_WORKSPACES            1
 
+/** Subscription reply type */
+#define I3_IPC_REPLY_TYPE_SUBSCRIBE             2
+
+/*
+ * Events from i3 to clients
+ *
+ */
+
+#define I3_IPC_EVENT_WORKSPACE                  0
+
 #endif

include/ipc.h

@@ -3,7 +3,7 @@
  *
  * i3 - an improved dynamic tiling window manager
  *
- * © 2009 Michael Stapelberg and contributors
+ * © 2009-2010 Michael Stapelberg and contributors
  *
  * See file LICENSE for license information.
  *
@@ -16,6 +16,34 @@
 
 #include "i3/ipc.h"
 
+typedef struct ipc_client {
+        int fd;
+
+        /* The events which this client wants to receive */
+        int num_events;
+        char **events;
+
+        TAILQ_ENTRY(ipc_client) clients;
+} ipc_client;
+
+/*
+ * Callback type for the different message types.
+ *
+ * message is the raw packet, as received from the UNIX domain socket. size
+ * is the remaining size of bytes for this packet.
+ *
+ * message_size is the size of the message as the sender specified it.
+ * message_type is the type of the message as the sender specified it.
+ *
+ */
+typedef void(*handler_t)(int, uint8_t*, int, uint32_t, uint32_t);
+
+/* Macro to declare a callback */
+#define IPC_HANDLER(name) \
+        static void handle_ ## name (int fd, uint8_t *message, \
+                                     int size, uint32_t message_size, \
+                                     uint32_t message_type)
+
 /**
  * Handler for activity on the listening socket, meaning that a new client
  * has just connected and we should accept() him. Sets up the event handler
@@ -32,4 +60,12 @@ void ipc_new_client(EV_P_ struct ev_io *w, int revents);
  */
 int ipc_create_socket(const char *filename);
 
+/**
+ * Sends the specified event to all IPC clients which are currently connected
+ * and subscribed to this kind of event.
+ *
+ */
+void ipc_send_event(const char *event, uint32_t message_type, const char *payload);
+
+
 #endif

src/handlers.c

@@ -39,6 +39,7 @@
 #include "workspace.h"
 #include "log.h"
 #include "container.h"
+#include "ipc.h"
 
 /* After mapping/unmapping windows, a notify event is generated. However, we don’t want it,
    since it’d trigger an infinite loop of switching between the different windows when
@@ -573,8 +574,10 @@ int handle_unmap_notify_event(void *data, xcb_connection_t *conn, xcb_unmap_noti
                         break;
                 }
 
-        if (workspace_empty)
+        if (workspace_empty) {
                 client->workspace->output = NULL;
+                ipc_send_event("workspace", I3_IPC_EVENT_WORKSPACE, "{\"change\":\"empty\"}");
+        }
 
         /* Remove the urgency flag if set */
         client->urgent = false;

src/ipc.c

@@ -23,9 +23,10 @@
 #include <stdio.h>
 #include <ev.h>
 #include <yajl/yajl_gen.h>
+#include <yajl/yajl_parse.h>
 
 #include "queue.h"
-#include "i3/ipc.h"
+#include "ipc.h"
 #include "i3.h"
 #include "util.h"
 #include "commands.h"
@@ -36,12 +37,6 @@
 #define y(x, ...) yajl_gen_ ## x (gen, ##__VA_ARGS__)
 #define ystr(str) yajl_gen_string(gen, (unsigned char*)str, strlen(str))
 
-typedef struct ipc_client {
-        int fd;
-
-        TAILQ_ENTRY(ipc_client) clients;
-} ipc_client;
-
 TAILQ_HEAD(ipc_client_head, ipc_client) all_clients = TAILQ_HEAD_INITIALIZER(all_clients);
 
 /*
@@ -57,15 +52,6 @@ static void set_nonblock(int sockfd) {
                 err(-1, "Could not set O_NONBLOCK");
 }
 
-#if 0
-void broadcast(EV_P_ struct ev_timer *t, int revents) {
-        ipc_client *current;
-        TAILQ_FOREACH(current, &all_clients, clients) {
-                write(current->fd, "hi there!\n", strlen("hi there!\n"));
-        }
-}
-#endif
-
 static void ipc_send_message(int fd, const unsigned char *payload,
                              int message_type, int message_size) {
         int buffer_size = strlen("i3-ipc") + sizeof(uint32_t) +
@@ -95,12 +81,56 @@ static void ipc_send_message(int fd, const unsigned char *payload,
         }
 }
 
+/*
+ * Sends the specified event to all IPC clients which are currently connected
+ * and subscribed to this kind of event.
+ *
+ */
+void ipc_send_event(const char *event, uint32_t message_type, const char *payload) {
+        ipc_client *current;
+        TAILQ_FOREACH(current, &all_clients, clients) {
+                /* see if this client is interested in this event */
+                bool interested = false;
+                for (int i = 0; i < current->num_events; i++) {
+                        if (strcasecmp(current->events[i], event) != 0)
+                                continue;
+                        interested = true;
+                        break;
+                }
+                if (!interested)
+                        continue;
+
+                ipc_send_message(current->fd, (const unsigned char*)payload,
+                                 message_type, strlen(payload));
+        }
+}
+
+/*
+ * Executes the command and returns whether it could be successfully parsed
+ * or not (at the moment, always returns true).
+ *
+ */
+IPC_HANDLER(command) {
+        /* To get a properly terminated buffer, we copy
+         * message_size bytes out of the buffer */
+        char *command = scalloc(message_size);
+        strncpy(command, (const char*)message, message_size);
+        parse_command(global_conn, (const char*)command);
+        free(command);
+
+        /* For now, every command gets a positive acknowledge
+         * (will change with the new command parser) */
+        const char *reply = "{\"success\":true}";
+        ipc_send_message(fd, (const unsigned char*)reply,
+                         I3_IPC_REPLY_TYPE_COMMAND, strlen(reply));
+}
+
 /*
  * Formats the reply message for a GET_WORKSPACES request and sends it to the
  * client
  *
  */
-static void ipc_send_workspaces(int fd) {
+IPC_HANDLER(get_workspaces) {
         Workspace *ws;
 
         Client *last_focused = SLIST_FIRST(&(c_ws->focus_stack));
@@ -156,47 +186,86 @@ static void ipc_send_workspaces(int fd) {
 }
 
 /*
- * Decides what to do with the received message.
+ * Callback for the YAJL parser (will be called when a string is parsed).
- *
- * message is the raw packet, as received from the UNIX domain socket. size
- * is the remaining size of bytes for this packet.
- *
- * message_size is the size of the message as the sender specified it.
- * message_type is the type of the message as the sender specified it.
  *
  */
-static void ipc_handle_message(int fd, uint8_t *message, int size,
+static int add_subscription(void *extra, const unsigned char *s,
-                               uint32_t message_size, uint32_t message_type) {
+                            unsigned int len) {
-        DLOG("handling message of size %d\n", size);
+        ipc_client *client = extra;
-        DLOG("sender specified size %d\n", message_size);
-        DLOG("sender specified type %d\n", message_type);
-        DLOG("payload as a string = %s\n", message);
 
-        switch (message_type) {
+        DLOG("should add subscription to extra %p, sub %.*s\n", client, len, s);
-                case I3_IPC_MESSAGE_TYPE_COMMAND: {
+        int event = client->num_events;
-                        /* To get a properly terminated buffer, we copy
-                         * message_size bytes out of the buffer */
-                        char *command = scalloc(message_size);
-                        strncpy(command, (const char*)message, message_size);
-                        parse_command(global_conn, (const char*)command);
-                        free(command);
 
-                        /* For now, every command gets a positive acknowledge
+        client->num_events++;
-                         * (will change with the new command parser) */
+        client->events = realloc(client->events, client->num_events * sizeof(char*));
+        /* We copy the string because it is not null-terminated and strndup()
+         * is missing on some BSD systems */
+        client->events[event] = scalloc(len+1);
+        memcpy(client->events[event], s, len);
+
+        DLOG("client is now subscribed to:\n");
+        for (int i = 0; i < client->num_events; i++)
+                DLOG("event %s\n", client->events[i]);
+        DLOG("(done)\n");
+
+        return 1;
+}
+
+/*
+ * Subscribes this connection to the event types which were given as a JSON
+ * serialized array in the payload field of the message.
+ *
+ */
+IPC_HANDLER(subscribe) {
+        yajl_handle p;
+        yajl_callbacks callbacks;
+        yajl_status stat;
+        ipc_client *current, *client = NULL;
+
+        /* Search the ipc_client structure for this connection */
+        TAILQ_FOREACH(current, &all_clients, clients) {
+                if (current->fd != fd)
+                        continue;
+
+                client = current;
+                break;
+        }
+
+        if (client == NULL) {
+                ELOG("Could not find ipc_client data structure for fd %d\n", fd);
+                return;
+        }
+
+        /* Setup the JSON parser */
+        memset(&callbacks, 0, sizeof(yajl_callbacks));
+        callbacks.yajl_string = add_subscription;
+
+        p = yajl_alloc(&callbacks, NULL, NULL, (void*)client);
+        stat = yajl_parse(p, (const unsigned char*)message, message_size);
+        if (stat != yajl_status_ok) {
+                unsigned char *err;
+                err = yajl_get_error(p, true, (const unsigned char*)message,
+                                     message_size);
+                ELOG("YAJL parse error: %s\n", err);
+                yajl_free_error(p, err);
+
+                const char *reply = "{\"success\":false}";
+                ipc_send_message(fd, (const unsigned char*)reply,
+                                 I3_IPC_REPLY_TYPE_SUBSCRIBE, strlen(reply));
+                yajl_free(p);
+                return;
+        }
+        yajl_free(p);
         const char *reply = "{\"success\":true}";
         ipc_send_message(fd, (const unsigned char*)reply,
-                                         I3_IPC_REPLY_TYPE_COMMAND, strlen(reply));
+                         I3_IPC_REPLY_TYPE_SUBSCRIBE, strlen(reply));
+}
 
-                        break;
+handler_t handlers[3] = {
-                }
+        handle_command,
-                case I3_IPC_MESSAGE_TYPE_GET_WORKSPACES:
+        handle_get_workspaces,
-                        ipc_send_workspaces(fd);
+        handle_subscribe
-                        break;
+};
-                default:
-                        DLOG("unhandled ipc message\n");
-                        break;
-        }
-}
 
 /*
  * Handler for activity on a client connection, receives a message from a
@@ -227,11 +296,13 @@ static void ipc_receive_message(EV_P_ struct ev_io *w, int revents) {
                 close(w->fd);
 
                 /* Delete the client from the list of clients */
-                struct ipc_client *current;
+                ipc_client *current;
                 TAILQ_FOREACH(current, &all_clients, clients) {
                         if (current->fd != w->fd)
                                 continue;
 
+                        for (int i = 0; i < current->num_events; i++)
+                                free(current->events[i]);
                         /* We can call TAILQ_REMOVE because we break out of the
                          * TAILQ_FOREACH afterwards */
                         TAILQ_REMOVE(&all_clients, current, clients);
@@ -279,7 +350,12 @@ static void ipc_receive_message(EV_P_ struct ev_io *w, int revents) {
                 message += sizeof(uint32_t);
                 n -= sizeof(uint32_t);
 
-                ipc_handle_message(w->fd, message, n, message_size, message_type);
+                if (message_type >= (sizeof(handlers) / sizeof(handler_t)))
+                        DLOG("Unhandled message type: %d\n", message_type);
+                else {
+                        handler_t h = handlers[message_type];
+                        h(w->fd, message, n, message_size, message_type);
+                }
                 n -= message_size;
                 message += message_size;
         }
@@ -311,7 +387,7 @@ void ipc_new_client(EV_P_ struct ev_io *w, int revents) {
 
         DLOG("IPC: new client connected\n");
 
-        struct ipc_client *new = scalloc(sizeof(struct ipc_client));
+        ipc_client *new = scalloc(sizeof(ipc_client));
         new->fd = client;
 
         TAILQ_INSERT_TAIL(&all_clients, new, clients);

src/workspace.c

@@ -28,6 +28,7 @@
 #include "client.h"
 #include "log.h"
 #include "ewmh.h"
+#include "ipc.h"
 
 /*
  * Returns a pointer to the workspace with the given number (starting at 0),
@@ -57,6 +58,8 @@ Workspace *workspace_get(int number) {
                 workspace_set_name(ws, NULL);
 
                 TAILQ_INSERT_TAIL(workspaces, ws, workspaces);
+
+                ipc_send_event("workspace", I3_IPC_EVENT_WORKSPACE, "{\"change\":\"init\"}");
         }
         DLOG("done\n");
 
@@ -165,6 +168,8 @@ void workspace_show(xcb_connection_t *conn, int workspace) {
                         xcb_flush(conn);
                 }
 
+                ipc_send_event("workspace", I3_IPC_EVENT_WORKSPACE, "{\"change\":\"focus\"}");
+
                 return;
         }
 
@@ -178,6 +183,8 @@ void workspace_show(xcb_connection_t *conn, int workspace) {
         current_col = c_ws->current_col;
         DLOG("new current row = %d, current col = %d\n", current_row, current_col);
 
+        ipc_send_event("workspace", I3_IPC_EVENT_WORKSPACE, "{\"change\":\"focus\"}");
+
         workspace_map_clients(conn, c_ws);
 
         /* POTENTIAL TO IMPROVE HERE: due to the call to _map_clients first and