text: /*
   * vim:ts=4:sw=4:expandtab
   *
   * i3bar - an xcb-based status- and ws-bar for i3
   * © 2010-2012 Axel Wagner and contributors (see also: LICENSE)
   *
   * ipc.c: Communicating with i3
   *
   */
  #include <stdlib.h>
  #include <stdio.h>
  #include <unistd.h>
  #include <stdint.h>
  #include <string.h>
  #include <errno.h>
  #include <sys/socket.h>
  #include <sys/un.h>
  #include <i3/ipc.h>
  #include <ev.h>
  
  #include "common.h"
  
  ev_io      *i3_connection;
  
  const char *sock_path;
  
  typedef void(*handler_t)(char*);
  
  /*
   * Called, when we get a reply to a command from i3.
   * Since i3 does not give us much feedback on commands, we do not much
   *
   */
  void got_command_reply(char *reply) {
      /* TODO: Error handling for command-replies */
  }
  
  /*
   * Called, when we get a reply with workspaces-data
   *
   */
  void got_workspace_reply(char *reply) {
      DLOG("Got Workspace-Data!\n");
      parse_workspaces_json(reply);
      draw_bars(false);
  }
  
  /*
   * Called, when we get a reply for a subscription.
   * Since i3 does not give us much feedback on commands, we do not much
   *
   */
  void got_subscribe_reply(char *reply) {
      DLOG("Got Subscribe Reply: %s\n", reply);
      /* TODO: Error handling for subscribe-commands */
  }
  
  /*
   * Called, when we get a reply with outputs-data
   *
   */
  void got_output_reply(char *reply) {
      DLOG("Parsing Outputs-JSON...\n");
      parse_outputs_json(reply);
      DLOG("Reconfiguring Windows...\n");
      realloc_sl_buffer();
      reconfig_windows(false);
  
      i3_output *o_walk;
      SLIST_FOREACH(o_walk, outputs, slist) {
          kick_tray_clients(o_walk);
      }
  
      draw_bars(false);
  }
  
  /*
   * Called when we get the configuration for our bar instance
   *
   */
  void got_bar_config(char *reply) {
      DLOG("Received bar config \"%s\"\n", reply);
      /* We initiate the main-function by requesting infos about the outputs and
       * workspaces. Everything else (creating the bars, showing the right workspace-
       * buttons and more) is taken care of by the event-drivenness of the code */
      i3_send_msg(I3_IPC_MESSAGE_TYPE_GET_OUTPUTS, NULL);
  
      free_colors(&(config.colors));
      parse_config_json(reply);
  
      /* Now we can actually use 'config', so let's subscribe to the appropriate
       * events and request the workspaces if necessary. */
      subscribe_events();
      if (!config.disable_ws)
          i3_send_msg(I3_IPC_MESSAGE_TYPE_GET_WORKSPACES, NULL);
  
      /* Initialize the rest of XCB */
      init_xcb_late(config.fontname);
  
      /* Resolve color strings to colorpixels and save them, then free the strings. */
      init_colors(&(config.colors));
  
      /* The name of this function is actually misleading. Even if no command is
       * specified, this function initiates the watchers to listen on stdin and
       * react accordingly */
      start_child(config.command);
      FREE(config.command);
  }
  
  /* Data-structure to easily call the reply-handlers later */
  handler_t reply_handlers[] = {
      &got_command_reply,
      &got_workspace_reply,
      &got_subscribe_reply,
      &got_output_reply,
      NULL,
      NULL,
      &got_bar_config,
  };
  
  /*
   * Called, when a workspace-event arrives (i.e. the user changed the workspace)
   *
   */
  void got_workspace_event(char *event) {
      DLOG("Got Workspace Event!\n");
      i3_send_msg(I3_IPC_MESSAGE_TYPE_GET_WORKSPACES, NULL);
  }
  
  /*
   * Called, when an output-event arrives (i.e. the screen-configuration changed)
   *
   */
  void got_output_event(char *event) {
      DLOG("Got Output Event!\n");
      i3_send_msg(I3_IPC_MESSAGE_TYPE_GET_OUTPUTS, NULL);
      if (!config.disable_ws) {
          i3_send_msg(I3_IPC_MESSAGE_TYPE_GET_WORKSPACES, NULL);
      }
  }
  
  /*
   * Called, when a mode-event arrives (i3 changed binding mode).
   *
   */
  void got_mode_event(char *event) {
      DLOG("Got Mode Event!\n");
      parse_mode_json(event);
      draw_bars(false);
  }
  
  /*
   * Called, when a barconfig_update event arrives (i.e. i3 changed the bar hidden_state or mode)
   *
   */
  void got_bar_config_update(char *event) {
      /* check whether this affect this bar instance by checking the bar_id */
      char *expected_id;
      sasprintf(&expected_id, "\"id\":\"%s\"", config.bar_id);
      char *found_id = strstr(event, expected_id);
      FREE(expected_id);
      if (found_id == NULL)
         return;
  
      /* update the configuration with the received settings */
      DLOG("Received bar config update \"%s\"\n", event);
      int old_mode = config.hide_on_modifier;
      parse_config_json(event);
      if (old_mode != config.hide_on_modifier) {
          reconfig_windows(true);
      }
  
      draw_bars(false);
  }
  
  /* Data-structure to easily call the event-handlers later */
  handler_t event_handlers[] = {
      &got_workspace_event,
      &got_output_event,
      &got_mode_event,
      NULL,
      &got_bar_config_update,
  };
  
  /*
   * Called, when we get a message from i3
   *
   */
  void got_data(struct ev_loop *loop, ev_io *watcher, int events) {
      DLOG("Got data!\n");
      int fd = watcher->fd;
  
      /* First we only read the header, because we know its length */
      uint32_t header_len = strlen(I3_IPC_MAGIC) + sizeof(uint32_t)*2;
      char *header = smalloc(header_len);
  
      /* We first parse the fixed-length IPC-header, to know, how much data
       * we have to expect */
      uint32_t rec = 0;
      while (rec < header_len) {
          int n = read(fd, header + rec, header_len - rec);
          if (n == -1) {
              ELOG("read() failed: %s\n", strerror(errno));
              exit(EXIT_FAILURE);
          }
          if (n == 0) {
              /* EOF received. Since i3 will restart i3bar instances as appropriate,
               * we exit here. */
              DLOG("EOF received, exiting...\n");
              clean_xcb();
              exit(EXIT_SUCCESS);
          }
          rec += n;
      }
  
      if (strncmp(header, I3_IPC_MAGIC, strlen(I3_IPC_MAGIC))) {
          ELOG("Wrong magic code: %.*s\n Expected: %s\n",
               (int) strlen(I3_IPC_MAGIC),
               header,
               I3_IPC_MAGIC);
          exit(EXIT_FAILURE);
      }
  
      char *walk = header + strlen(I3_IPC_MAGIC);
      uint32_t size;
      memcpy(&size, (uint32_t*)walk, sizeof(uint32_t));
      walk += sizeof(uint32_t);
      uint32_t type;
      memcpy(&type, (uint32_t*)walk, sizeof(uint32_t));
  
      /* Now that we know, what to expect, we can start read()ing the rest
       * of the message */
      char *buffer = smalloc(size + 1);
      rec = 0;
  
      while (rec < size) {
          int n = read(fd, buffer + rec, size - rec);
          if (n == -1) {
              ELOG("read() failed: %s\n", strerror(errno));
              exit(EXIT_FAILURE);
          }
          if (n == 0) {
              ELOG("Nothing to read!\n");
              exit(EXIT_FAILURE);
          }
          rec += n;
      }
      buffer[size] = '\0';
  
      /* And call the callback (indexed by the type) */
      if (type & (1 << 31)) {
          type ^= 1 << 31;
          event_handlers[type](buffer);
      } else {
          if (reply_handlers[type])
              reply_handlers[type](buffer);
      }
  
      FREE(header);
      FREE(buffer);
  }
  
  /*
   * Sends a Message to i3.
   * type must be a valid I3_IPC_MESSAGE_TYPE (see i3/ipc.h for further information)
   *
   */
  int i3_send_msg(uint32_t type, const char *payload) {
      uint32_t len = 0;
      if (payload != NULL) {
          len = strlen(payload);
      }
  
      /* We are a wellbehaved client and send a proper header first */
      uint32_t to_write = strlen (I3_IPC_MAGIC) + sizeof(uint32_t)*2 + len;
      /* TODO: I'm not entirely sure if this buffer really has to contain more
       * than the pure header (why not just write() the payload from *payload?),
       * but we leave it for now */
      char *buffer = smalloc(to_write);
      char *walk = buffer;
  
      strncpy(buffer, I3_IPC_MAGIC, strlen(I3_IPC_MAGIC));
      walk += strlen(I3_IPC_MAGIC);
      memcpy(walk, &len, sizeof(uint32_t));
      walk += sizeof(uint32_t);
      memcpy(walk, &type, sizeof(uint32_t));
      walk += sizeof(uint32_t);
  
      if (payload != NULL)
          strncpy(walk, payload, len);
  
      uint32_t written = 0;
  
      while (to_write > 0) {
          int n = write(i3_connection->fd, buffer + written, to_write);
          if (n == -1) {
              ELOG("write() failed: %s\n", strerror(errno));
              exit(EXIT_FAILURE);
          }
  
          to_write -= n;
          written += n;
      }
  
      FREE(buffer);
  
      return 1;
  }
  
  /*
   * Initiate a connection to i3.
   * socket-path must be a valid path to the ipc_socket of i3
   *
   */
  int init_connection(const char *socket_path) {
      sock_path = socket_path;
      int sockfd = ipc_connect(socket_path);
      i3_connection = smalloc(sizeof(ev_io));
      ev_io_init(i3_connection, &got_data, sockfd, EV_READ);
      ev_io_start(main_loop, i3_connection);
      return 1;
  }
  
  /*
   * Destroy the connection to i3.
   */
  void destroy_connection(void) {
      close(i3_connection->fd);
      ev_io_stop(main_loop, i3_connection);
  }
  
  /*
   * Subscribe to all the i3-events, we need
   *
   */
  void subscribe_events(void) {
      if (config.disable_ws) {
          i3_send_msg(I3_IPC_MESSAGE_TYPE_SUBSCRIBE, "[ \"output\", \"mode\", \"barconfig_update\" ]");
      } else {
          i3_send_msg(I3_IPC_MESSAGE_TYPE_SUBSCRIBE, "[ \"workspace\", \"output\", \"mode\", \"barconfig_update\" ]");
      }
  }
  