track pending_jsonp requests

diff --git a/examples/selfcheck.js b/examples/selfcheck.js
index ce05385..250c547 100644 (file)
--- a/examples/selfcheck.js
+++ b/examples/selfcheck.js
@@ -15,7 +15,7 @@ if(!window.console) {
 
 var state;
 var scan_timeout;
-var scan_tags_active = true;
+var pending_jsonp = 0;
 
 function change_page(new_state) {
        if ( state != new_state ) {
@@ -68,6 +68,7 @@ function change_page(new_state) {
 function got_visible_tags(data,textStatus) {
        var html = 'No tags in range';
        if ( data.tags ) {
+               scan_tags_active = false;
                html = '<ul class="tags">';
                $.each(data.tags, function(i,tag) {
                        console.debug( i, tag );
@@ -104,6 +105,8 @@ function got_visible_tags(data,textStatus) {
                        }
                });
                html += '</ul>';
+
+               scan_tags_active = true;
        }
 
        var arrows = Array( 8592, 8598, 8593, 8599, 8594, 8600, 8595, 8601 );
@@ -115,18 +118,22 @@ function got_visible_tags(data,textStatus) {
                + html
                ;
        $('#tags').html( html );
-       scan_timeout = window.setTimeout(function(){
-               scan_tags();
-       },tag_rescan);  // re-scan every 200ms
+
+       pending_jsonp--;
 };
 
 function scan_tags() {
-       if ( scan_tags_active ) {
+       if ( pending_jsonp ) {
+               console.debug('scan_tags disabled ', pending_jsonp, ' requests waiting');
+       } else {
                console.info('scan_tags');
+               pending_jsonp++;
                $.getJSON("/scan?callback=?", got_visible_tags);
-       } else {
-               console.debug('scan_tags disabled');
        }
+
+       scan_timeout = window.setTimeout(function(){
+               scan_tags();
+       },tag_rescan);  // re-scan every 200ms
 }
 
 $(document).ready(function() {
@@ -166,7 +173,7 @@ function borrower_check() {
 
        fill_in( 'borrower_number', borrower_cardnumber );
 
-       scan_tags_active = false;
+       pending_jsonp++;
        $.getJSON('/sip2/patron_info/'+borrower_cardnumber)
        .done( function( data ) {
                console.info('patron', data);
@@ -174,10 +181,10 @@ function borrower_check() {
                fill_in( 'borrower_email', data['BE'] );
                fill_in( 'hold_items',    data['fixed'].substr( 2 + 14 + 3 + 18 + ( 0 * 4 ), 4 ) ) * 1;
                fill_in( 'overdue_items', data['fixed'].substr( 2 + 14 + 3 + 18 + ( 1 * 4 ), 4 ) ) * 1;
-               scan_tags_active = true;
+               pending_jsonp--;
                change_page('borrower_info');
        }).fail( function(data) {
-               scan_tags_active = true;
+               pending_jsonp--;
                change_page('error');
        });
 }
@@ -192,16 +199,16 @@ function circulation( barcode, sid ) {
                        && barcode.substr(0,3) == 130
                        && book_barcodes[barcode] != 1
        ) { // book, not seen yet
-               scan_tags_active = false;
+               book_barcodes[ barcode ] = 1;
+               pending_jsonp++;
                $.getJSON('/sip2/'+circulation_type+'/'+borrower_cardnumber+'/'+barcode+'/'+sid , function( data ) {
                        console.info( circulation_type, data );
                        $('ul#books').append('<li>' + ( data['AJ'] || barcode ) + ' <small>' + data['AF'] + '</small></li>');
-                       book_barcodes[ barcode ] = 1;
                        console.debug( book_barcodes );
-                       scan_tags_active = true;
+                       pending_jsonp--;
                }).fail( function() {
                        change_page('error');
-                       scan_tags_active = true;
+                       pending_jsonp--;
                });
        }
 }