Merge pull request mathjax#40 from episodeyang/serverBusy

Server busy

Author: dpvc

lib/mj-page.js

@@ -1,11 +1,11 @@
 /*********************************************************************
  *
  *  mj-page-svg.js
- *  
+ *
  *  Implements an API to MathJax in node.js so that MathJax can be
  *  used server-side to generate SVG, MathML, or images (the latter
  *  requires an external library, batik, to do the svg to png
- *  conversion).  This API accepts HTML snippets that have their 
+ *  conversion).  This API accepts HTML snippets that have their
  *  math content converted to SVG's.
  *
  * ----------------------------------------------------------------------
@@ -65,6 +65,7 @@ var MathJaxConfig;         // configuration for when starting MathJax
 var MathJax;               // filled in once MathJax is loaded
 var serverStarted = false; // true when the MathJax DOM has been created
 var serverReady = false;   // true when MathJax has done its initial typeset (loaded all components)
+var serverBusy = false;    // true when MathJax is working on a job in the que
 var timer;                 // used to reset MathJax if it runs too long
 
 var document, window, content, html; // the DOM elements
@@ -130,11 +131,11 @@ function ConfigureMathJax() {
 
       delete MathJax.Hub.config.styles;               // don't need any styles
       MathJax.Hub.Startup.MenuZoom = function () {};  // don't load menu or zoom code
-      
+
       //
       //  When creating stylesheets, no need to wait for them
       //  to become active, so just do the callback
-      //  
+      //
       MathJax.Ajax.timer.create = function (callback,node) {
         callback = MathJax.Callback(callback);
         callback(this.STATUS.OK);
@@ -154,7 +155,7 @@ function ConfigureMathJax() {
       MathJax.Message.Clear = function () {};
       MathJax.Message.Remove = function () {};
       MathJax.Message.Init = function () {};
-      
+
       //
       //  Trap Math Processing Errors
       //
@@ -177,7 +178,7 @@ function ConfigureMathJax() {
       MathJax.Hub.Register.MessageHook("TeX Jax - parse error",function (message) {
         AddError("TeX parse error",message[1]);
       });
-      
+
       //
       //  Adjust the SVG output jax
       //
@@ -260,7 +261,7 @@ function ConfigureMathJax() {
             state.SVGdelay = false;
           }
         });
-        
+
         //
         //  TEXT boxes use getBBox, which isn't implemented, so
         //  use a monspace font and fake the size.  Since these
@@ -314,7 +315,7 @@ function ConfigureMathJax() {
         serverReady = true;
         MathJax.Hub.Queue(StartQueue);
       });
-      
+
     }
   };
 
@@ -398,7 +399,7 @@ function GetIMG() {
   var n = 0, nodes = document.getElementsByClassName("MathJax_SVG");
   for (var i = nodes.length-1; i >= 0; i--) {
     var svg = nodes[i].getElementsByTagName("svg")[0];
-    var css = svg.style.cssText + 
+    var css = svg.style.cssText +
          " width:"+svg.getAttribute("width") + "; height:"+svg.getAttribute("height");
     svg.style.cssText = ""; // this will be handled by the <img> tag instead
     svg.setAttribute("xmlns","http://www.w3.org/2000/svg");
@@ -440,6 +441,7 @@ function GetPreviews() {
 //    do the next queued expression
 //  
 function TypesetDone(result,selector) {
+  serverBusy = false;
   if (timer) {clearTimeout(timer); timer = null}
   if (errors.length) {result.errors = errors}
   if (data.renderer === "None") {content.innerHTML = "<p></p>"}
@@ -532,9 +534,13 @@ function TypesetDone(result,selector) {
 //  Start typesetting the queued expressions
 //  
 function StartQueue() {
+  serverBusy = true;
   data = callback = null;       //  clear existing equation, if any
   errors = [];                  //  clear any errors
-  if (!queue.length) return;    //  return if nothing to do
+  if (!queue.length) {         //  return if nothing to do
+    serverBusy = false;
+    return;
+  }
 
   var result = {}, $$ = window.Array;
 
@@ -546,7 +552,7 @@ function StartQueue() {
   data = item[0]; callback = item[1];
   content.innerHTML = data.html;  //  %%% disable <script> tags?
   html.setAttribute("xmlns:"+data.xmlns,"http://www.w3.org/1998/Math/MathML");
-  
+
   //
   //  Set the SVG and TeX parameters
   //  according to the requested data
@@ -564,14 +570,14 @@ function StartQueue() {
   SVG.config.useFontCache = data.useFontCache;
   SVG.config.useGlobalCache = data.useGlobalCache && !data.imgSVG;
   TEX.config.equationNumbers.autoNumber = data.equationNumbers;
-  
+
   //
   //  Set the TeX delimiters
   //
   var delimiters = $$($$('$','$'),$$('\\(','\\)'));
   if (!data.singleDollars) {delimiters.shift()}
   HUB.Config({tex2jax: {inlineMath: delimiters}});
-  
+
   //
   //  Register the preprocessors and get the jax selector
   //
@@ -625,6 +631,7 @@ function RestartMathJax() {
     serverReady = false;
   }
   serverStarted = true;
+  serverBusy = false;
   GetWindow();
   ConfigureMathJax();
   StartMathJax();
@@ -648,7 +655,7 @@ exports.typeset = function (data,callback) {
   }}
   queue.push([options,callback]);
   if (!serverStarted) {RestartMathJax()}
-  if (serverReady) StartQueue();
+  if (serverReady && !serverBusy) StartQueue();
 }
 
 //