gitweb.js: Introduce code to handle cookies from JavaScript

Introduced gitweb/static/js/cookies.js file provides functions for
setting, getting and deleting cookies.

Code taken from subsection "Cookies in JavaScript" of "Professional
JavaScript for Web Developers" by Nicholas C. Zakas and from cookie
plugin for jQuery (dual licensed under the MIT and GPL licenses).

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gitweb/Makefile

@@ -118,6 +118,7 @@ GITWEB_FILES += static/git-logo.png static/git-favicon.png
 # then the rest of files; js/gitweb.js should be last (if it exists)
 GITWEB_JSLIB_FILES += static/js/lib/common-lib.js
 GITWEB_JSLIB_FILES += static/js/lib/datetime.js
+GITWEB_JSLIB_FILES += static/js/lib/cookies.js
 GITWEB_JSLIB_FILES += static/js/javascript-detection.js
 GITWEB_JSLIB_FILES += static/js/blame_incremental.js
 

gitweb/static/js/lib/cookies.js

@@ -0,0 +1,114 @@
+/**
+ * @fileOverview Accessing cookies from JavaScript
+ * @license GPLv2 or later
+ */
+
+/*
+ * Based on subsection "Cookies in JavaScript" of "Professional
+ * JavaScript for Web Developers" by Nicholas C. Zakas and cookie
+ * plugin from jQuery (dual licensed under the MIT and GPL licenses)
+ */
+
+
+/**
+ * Create a cookie with the given name and value,
+ * and other optional parameters.
+ *
+ * @example
+ *   setCookie('foo', 'bar'); // will be deleted when browser exits
+ *   setCookie('foo', 'bar', { expires: new Date(Date.parse('Jan 1, 2012')) });
+ *   setCookie('foo', 'bar', { expires: 7 }); // 7 days = 1 week
+ *   setCookie('foo', 'bar', { expires: 14, path: '/' });
+ *
+ * @param {String} sName:    Unique name of a cookie (letters, numbers, underscores).
+ * @param {String} sValue:   The string value stored in a cookie.
+ * @param {Object} [options] An object literal containing key/value pairs
+ *                           to provide optional cookie attributes.
+ * @param {String|Number|Date} [options.expires] Either literal string to be used as cookie expires,
+ *                            or an integer specifying the expiration date from now on in days,
+ *                            or a Date object to be used as cookie expiration date.
+ *                            If a negative value is specified or a date in the past),
+ *                            the cookie will be deleted.
+ *                            If set to null or omitted, the cookie will be a session cookie
+ *                            and will not be retained when the the browser exits.
+ * @param {String} [options.path] Restrict access of a cookie to particular directory
+ *                               (default: path of page that created the cookie).
+ * @param {String} [options.domain] Override what web sites are allowed to access cookie
+ *                                  (default: domain of page that created the cookie).
+ * @param {Boolean} [options.secure] If true, the secure attribute of the cookie will be set
+ *                                   and the cookie would be accessible only from secure sites
+ *                                   (cookie transmission will require secure protocol like HTTPS).
+ */
+function setCookie(sName, sValue, options) {
+	options = options || {};
+	if (sValue === null) {
+		sValue = '';
+		option.expires = 'delete';
+	}
+
+	var sCookie = sName + '=' + encodeURIComponent(sValue);
+
+	if (options.expires) {
+		var oExpires = options.expires, sDate;
+		if (oExpires === 'delete') {
+			sDate = 'Thu, 01 Jan 1970 00:00:00 GMT';
+		} else if (typeof oExpires === 'string') {
+			sDate = oExpires;
+		} else {
+			var oDate;
+			if (typeof oExpires === 'number') {
+				oDate = new Date();
+				oDate.setTime(oDate.getTime() + (oExpires * 24 * 60 * 60 * 1000)); // days to ms
+			} else {
+				oDate = oExpires;
+			}
+			sDate = oDate.toGMTString();
+		}
+		sCookie += '; expires=' + sDate;
+	}
+
+	if (options.path) {
+		sCookie += '; path=' + (options.path);
+	}
+	if (options.domain) {
+		sCookie += '; domain=' + (options.domain);
+	}
+	if (options.secure) {
+		sCookie += '; secure';
+	}
+	document.cookie = sCookie;
+}
+
+/**
+ * Get the value of a cookie with the given name.
+ *
+ * @param {String} sName: Unique name of a cookie (letters, numbers, underscores)
+ * @returns {String|null} The string value stored in a cookie
+ */
+function getCookie(sName) {
+	var sRE = '(?:; )?' + sName + '=([^;]*);?';
+	var oRE = new RegExp(sRE);
+	if (oRE.test(document.cookie)) {
+		return decodeURIComponent(RegExp['$1']);
+	} else {
+		return null;
+	}
+}
+
+/**
+ * Delete cookie with given name
+ *
+ * @param {String} sName:    Unique name of a cookie (letters, numbers, underscores)
+ * @param {Object} [options] An object literal containing key/value pairs
+ *                           to provide optional cookie attributes.
+ * @param {String} [options.path]   Must be the same as when setting a cookie
+ * @param {String} [options.domain] Must be the same as when setting a cookie
+ */
+function deleteCookie(sName, options) {
+	options = options || {};
+	options.expires = 'delete';
+
+	setCookie(sName, '', options);
+}
+
+/* end of cookies.js */