Fix loophole where Esc can cancel blocking a page

Closes proginosko#10

VERSIONS.md

@@ -1,3 +1,6 @@
+### Version 1.0.6 (26 Aug 2016)
+* Fixed loophole where blocking a page could be cancelled using <kbd>Escape</kbd> (issue 10)
+
 ### Version 1.0.5 (07 Aug 2016)
 * Minor code improvements (per AMO reviewer recommendation).
 

chrome/content/browser.js

@@ -425,6 +425,20 @@ LeechBlock.checkWindow = function (parsedURL, win, isRepeat) {
 					win.location.replace(blockURL);
 				}
 
+				// Prevent bypassing the block by pressing Escape to cancel the redirect to blockURL (issue #10)
+
+				// Remove old listener first
+				LeechBlock.preventEscapeListener && gBrowser.removeEventListener("keydown", LeechBlock.preventEscapeListener);
+
+				gBrowser.addEventListener("keydown",
+					LeechBlock.preventEscapeListener = // Assign for use with removeEventListener
+						evt => //Using an arrow function so the variable doc is available to it (thanks to autobinding)
+							evt.key === 'Escape' &&
+							gBrowser.getBrowserForTab(gBrowser.selectedTab).contentDocument === doc ? // Is this still the tab we're trying to redirect to the block page?
+								evt.preventDefault() : // Yes? Then block the default action of Escape, which is to cancel navigation
+								gBrowser.removeEventListener("keydown", LeechBlock.preventEscapeListener) //No? Then remove the eventListener
+				);
+
 				return; // nothing more to do
 			}
 

install.rdf

@@ -4,7 +4,7 @@
 		xmlns:em="http://www.mozilla.org/2004/em-rdf#">
 	<Description about="urn:mozilla:install-manifest">
 		<em:id>{a95d8332-e4b4-6e7f-98ac-20b733364387}</em:id>
-		<em:version>1.0.5</em:version>
+		<em:version>1.0.6</em:version>
 		<em:type>2</em:type>
 		<em:unpack>true</em:unpack>
 		<em:name>LeechBlock</em:name>