From 40fe74ef457d7070d45aa2fa77b7a1464c6f35da Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gina=20H=C3=A4u=C3=9Fge?= <osd@foosel.net>
Date: Fri, 27 Nov 2015 15:05:55 +0100
Subject: [PATCH] Cut off terminal after 3000 lines

When autoscroll was disabled, terminal could run on endlessly, eating
memory until the browser crashes. Now a hard upper limit ensures
that not more than 3000 lines are ever stored in the terminal. If autoscroll
is disabled and the limit is reached, no more log lines will be added. That
ensures that the log will not scroll and the current log excerpt will stay put.
---
 .../static/js/app/viewmodels/terminal.js      | 40 +++++++++++++++----
 src/octoprint/templates/tabs/terminal.jinja2  |  2 +-
 2 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/src/octoprint/static/js/app/viewmodels/terminal.js b/src/octoprint/static/js/app/viewmodels/terminal.js
index d7ec494d..7be593c6 100644
--- a/src/octoprint/static/js/app/viewmodels/terminal.js
+++ b/src/octoprint/static/js/app/viewmodels/terminal.js
@@ -7,6 +7,7 @@ $(function() {
 
         self.log = ko.observableArray([]);
         self.buffer = ko.observable(300);
+        self.upperLimit = ko.observable(3000);
 
         self.command = ko.observable(undefined);
 
@@ -52,13 +53,21 @@ $(function() {
 
         self.lineCount = ko.computed(function() {
             var total = self.log().length;
+            var filtered = _.filter(self.displayedLines(), function(entry) { return entry.type == "filtered" }).length;
             var displayed = _.filter(self.displayedLines(), function(entry) { return entry.type == "line" }).length;
-            var filtered = total - displayed;
 
-            if (total == displayed) {
-                return _.sprintf(gettext("showing %(displayed)d lines"), {displayed: displayed});
+            if (filtered > 0) {
+                if (total > self.upperLimit()) {
+                    return _.sprintf(gettext("showing %(displayed)d lines (%(filtered)d of %(total)d total lines filtered, buffer full)"), {displayed: displayed, total: total, filtered: filtered});
+                } else {
+                    return _.sprintf(gettext("showing %(displayed)d lines (%(filtered)d of %(total)d total lines filtered)"), {displayed: displayed, total: total, filtered: filtered});
+                }
             } else {
-                return _.sprintf(gettext("showing %(displayed)d lines (%(filtered)d of %(total)d total lines filtered)"), {displayed: displayed, total: total, filtered: filtered});
+                if (total > self.upperLimit()) {
+                    return _.sprintf(gettext("showing %(displayed)d lines (buffer full)"), {displayed: displayed});
+                } else {
+                    return _.sprintf(gettext("showing %(displayed)d lines"), {displayed: displayed});
+                }
             }
         });
 
@@ -84,10 +93,25 @@ $(function() {
         };
 
         self._processCurrentLogData = function(data) {
-            self.log(self.log().concat(_.map(data, function(line) { return self._toInternalFormat(line) })));
-            if (self.autoscrollEnabled()) {
-                self.log(self.log.slice(-self.buffer()));
+            var length = self.log().length;
+            if (length >= self.upperLimit()) {
+                var cutoff = "--- too many lines to buffer, cut off ---";
+                var last = self.log()[length-1];
+                if (!last || last.type != "cut" || last.line != cutoff) {
+                    self.log(self.log().concat(self._toInternalFormat(cutoff, "cut")));
+                }
+                return;
             }
+
+            var newLog = self.log().concat(_.map(data, function(line) { return self._toInternalFormat(line) }));
+            if (self.autoscrollEnabled()) {
+                // we only keep the last <buffer> entries
+                newLog = newLog.slice(-self.buffer());
+            } else if (newLog.length > self.upperLimit()) {
+                // we only keep the first <upperLimit> entries
+                newLog = newLog.slice(0, self.upperLimit());
+            }
+            self.log(newLog);
         };
 
         self._processHistoryLogData = function(data) {
@@ -232,4 +256,4 @@ $(function() {
         ["loginStateViewModel", "settingsViewModel"],
         "#term"
     ]);
-});
\ No newline at end of file
+});
diff --git a/src/octoprint/templates/tabs/terminal.jinja2 b/src/octoprint/templates/tabs/terminal.jinja2
index 18d2a30a..4389d725 100644
--- a/src/octoprint/templates/tabs/terminal.jinja2
+++ b/src/octoprint/templates/tabs/terminal.jinja2
@@ -1,5 +1,5 @@
 <div class="terminal">
-    <pre id="terminal-output" class="pre-scrollable" data-bind="foreach: displayedLines"><span data-bind="text: line, css: {muted: type == 'filtered'}"></span><br></pre>
+    <pre id="terminal-output" class="pre-scrollable" data-bind="foreach: displayedLines"><span data-bind="text: line, css: {muted: type == 'filtered' || type == 'cut'}"></span><br></pre>
     <small class="pull-left"><button class="btn btn-mini" data-bind="click: toggleAutoscroll, css: {active: autoscrollEnabled}">{{ _('Autoscroll') }}</button> <span data-bind="text: lineCount"></span></small>
     <small class="pull-right"><a href="#" data-bind="click: scrollToEnd">{{ _("Scroll to end") }}</a>&nbsp;|&nbsp;<a href="#" data-bind="click: selectAll">{{ _("Select all") }}</a></small>
 </div>