[folks] inspect: Move readline() loop into the GLib main loop

[Philip Withnall <pwithnall src gnome org>]

commit 75c7fb1803a27a608d75ffda41306ef9082aa01c
Author: Philip Withnall <philip tecnocode co uk>
Date:   Fri Jan 13 16:29:22 2012 +0000

    inspect: Move readline() loop into the GLib main loop
    
    The readline() loop is more pain than itâs worth, so we now use readlineâs
    callback interface for command line handling, allowing us to use a single
    main loop and a single thread for both the aggregator and readline.
    
    This should make signal handling a lot easier.
    
    Note that this bumps our Vala requirement from 0.15.1 to 0.15.2.

 configure.ac               |    2 +-
 tools/inspect/inspect.vala |   95 ++++++++++++++++++++++++++++---------------
 2 files changed, 63 insertions(+), 34 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index c4b6f2e..012fe5b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -146,7 +146,7 @@ AM_CONDITIONAL([ENABLE_LIBSOCIALWEB],
 
 GLIB_REQUIRED=2.24.0
 TP_GLIB_REQUIRED=0.13.1
-VALA_REQUIRED=0.15.1
+VALA_REQUIRED=0.15.2
 VALADOC_REQUIRED=0.3.1
 TRACKER_SPARQL_MAJOR=0.14
 TRACKER_SPARQL_REQUIRED=0.13.1
diff --git a/tools/inspect/inspect.vala b/tools/inspect/inspect.vala
index 1e3eaed..f0c587f 100644
--- a/tools/inspect/inspect.vala
+++ b/tools/inspect/inspect.vala
@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2010 Collabora Ltd.
+ * Copyright (C) 2012 Philip Withnall
  *
  * This library is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Lesser General Public License as published by
@@ -32,7 +33,6 @@ public class Folks.Inspect.Client : Object
 {
   public HashMap<string, Command> commands;
   private MainLoop main_loop;
-  private unowned Thread folks_thread;
   public IndividualAggregator aggregator { get; private set; }
   public BackendStore backend_store { get; private set; }
   public SignalManager signal_manager { get; private set; }
@@ -112,6 +112,12 @@ public class Folks.Inspect.Client : Object
       this.aggregator = new IndividualAggregator ();
     }
 
+  public void quit ()
+    {
+      /* Kill the main loop. */
+      this.main_loop.quit ();
+    }
+
   private async void _wait_for_quiescence () throws GLib.Error
     {
       var has_yielded = false;
@@ -182,64 +188,87 @@ public class Folks.Inspect.Client : Object
       this.main_loop.run ();
     }
 
-  private void *folks_thread_main ()
-    {
-      this.aggregator.prepare ();
-      this.main_loop.run ();
-
-      return null;
-    }
-
   public void run_interactive ()
     {
       /* Interactive mode: have a little shell which allows the data from
-       * libfolks to be browsed and edited in real time. We do this by spawning
-       * a second thread which takes care of the main loop and aggregator. The
-       * main thread then sits in a readline loop. */
-
-      /* Spawn the folks worker thread. */
-      try
-        {
-          this.folks_thread = Thread<void*>.create<void*> (
-              this.folks_thread_main, true);
-        }
-      catch (ThreadError e)
+       * libfolks to be browsed and edited in real time. We do this by watching
+       * stdin in our main loop, and passing character notifications to
+       * readline. The main loop also processes all the folks events, thus
+       * preventing us having to run a second thread. */
+      var stdin_channel = new IOChannel.unix_new (stdin.fileno ());
+      stdin_channel.add_watch (IOCondition.IN, (source, cond) =>
         {
-          stdout.printf ("Couldn't create aggregator thread: %s", e.message);
-          Process.exit (1);
-        }
+          /* At least a single character is available on stdin, so let readline
+           * consume it. */
+          if ((cond & IOCondition.IN) != 0)
+            {
+              Readline.callback_read_char ();
+              return true;
+            }
+
+          assert_not_reached ();
+        });
 
       /* Allow things to be set for folks-inspect in ~/.inputrc, and install our
        * own completion function. */
       Readline.readline_name = "folks-inspect";
       Readline.attempted_completion_function = Client.completion_cb;
+      Readline.catch_signals = 0; /* go away, readline */
 
-      /* Main prompt loop */
-      while (true)
+      /* Callback for each character appearing on stdin. */
+      Readline.callback_handler_install ("> ", (_command_line) =>
         {
-          string command_line = Readline.readline ("> ");
+          if (_command_line == null)
+            {
+              /* EOF. If we've entered some text, don't do anything. Otherwise,
+               * quit. */
+              if (Readline.line_buffer != "")
+                {
+                  Readline.ding ();
+                  return;
+                }
+
+              /* Quit. */
+              Readline.crlf ();
+              Readline.callback_handler_remove ();
+              main_client.quit ();
+
+              return;
+            }
 
-          if (command_line == null)
-            continue;
+          var command_line = (!) _command_line;
 
           command_line = command_line.strip ();
           if (command_line == "")
-            continue;
+            {
+              /* If the user's entered a blank line, just display a new prompt
+               * without doing anything else. */
+              return;
+            }
 
           string subcommand;
           string command_name;
-          Command command = this.parse_command_line (command_line,
+          Command command = main_client.parse_command_line (command_line,
               out command_name, out subcommand);
 
           /* Run the command */
           if (command != null)
-            command.run (subcommand);
+            {
+              command.run (subcommand);
+            }
           else
-            stdout.printf ("Unrecognised command '%s'.\n", command_name);
+            {
+              stdout.printf ("Unrecognised command â%sâ.\n", command_name);
+            }
 
           /* Store the command in the history, even if it failed */
           Readline.History.add (command_line);
-        }
+        });
+
+      /* Run the aggregator and the main loop. */
+      this.aggregator.prepare ();
+
+      this.main_loop.run ();
     }
 
   private static Command? parse_command_line (string command_line,