Crawler, second version

chrome/content/task_test_ui.js

Index: chrome/content/task_test_ui.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/chrome/content/task_test_ui.js
@@ -0,0 +1,109 @@
+/*
+ * This Source Code is subject to the terms of the Mozilla Public License
+ * version 2.0 (the "License"). You can obtain a copy of the License at
+ * http://mozilla.org/MPL/2.0/.
+ */
+
+var {Long_Task} = require( "task" );
+var {Counting_Task} = require( "counter_task" );
+let {Logger} = require( "logger" );
+
+var current_task = null;
+
+function update_status( s, perform_log )
+{
+  var status_field = document.getElementById( "task_status" );
+  if ( status_field.childNodes.length > 0 )
+  {
+    status_field.removeChild( status_field.childNodes[0] );
+  }
+  status_field.appendChild( document.createTextNode( s ) );
+  if ( arguments.length >= 2 && perform_log )
+  {
+    log( s );
+  }
+}
+
+function update_button( b )
+{
+  var button = document.getElementById( "task_go" );
+  if ( b )
+  {
+    button.label = "Cancel"
+  } else
+  {
+    button.label = "Start"
+  }
+
+}
+
+function task_finished()
+{
+  if ( current_task.cancelled )
+  {
+    var status = "Cancelled";
+  }
+  else
+  {
+    status = "Finished";
+  }
+  update_status( status );
+  update_button( false );
+  current_task = null;
+}
+
+function task_count( n )
+{
+  update_status( "Count " + n, false );
+}
+
+/*
+ * We're overloading the start button also to handle cancellation.
+ */
+function task_start_click()
+{
+  if ( !current_task )
+  {
+    log( "Clicked start" );
+    if ( !Counting_Task )
+    {
+      log( "No Counting_Task" );
+    }
+    if ( !Long_Task )
+    {
+      log( "No Long_Task" );
+    }
+    log( "require counter_task: " + require( "counter_task" ).toString() );
+
+    let count = document.getElementById( "task_count" ).value;
+    let limit = document.getElementById( "task_limit" ).value;
+    var variant;
+    switch ( document.getElementById( "counting_variant" ).selectedIndex )
+    {
+      case 0:
+        variant = { type: "continuous" };
+        break;
+      case 1:
+        variant = { type: "segmented fast" };
+        break;
+      case 2:
+        variant = { type: "segmented slow", interval: document.getElementById( "slow_interval" ).value};
+        break;
+      default:
+        log( "Unknown variant. This is an implementation defect." );
+        throw "bad variant";
+    }
+    current_task = new Long_Task( new Counting_Task( count, task_count, task_finished, variant ), false, limit );
+    update_status( "Started" );
+    update_button( true );
+    current_task.run();
+  }
+  else
+  {
+    current_task.cancel();
+    update_button( false );
+    // We have a running task, so cancel it.
+  }
+}
+
+var log = (new Logger( "task_ui" )).make_log();