optimize getUserGroups to work with multiple user ids

src/groups.js

@@ -438,7 +438,7 @@
 		});
 	};
 
-	Groups.getUserGroups = function(uid, callback) {
+	Groups.getUserGroups = function(uids, callback) {
 		var ignoredGroups = ['registered-users'];
 
 		db.getSetMembers('groups', function(err, groupNames) {
@@ -466,19 +466,22 @@
 					return 'group:' + group.name + ':members';
 				});
 
-				db.isMemberOfSets(groupSets, uid, function(err, isMembers) {
-					if (err) {
-						return callback(err);
-					}
-
-					for(var i=isMembers.length - 1; i>=0; --i) {
-						if (!isMembers[i]) {
-							groupData.splice(i, 1);
+				async.map(uids, function(uid, next) {
+					db.isMemberOfSets(groupSets, uid, function(err, isMembers) {
+						if (err) {
+							return next(err);
 						}
-					}
 
-					callback(null, groupData);
-				});
+						var memberOf = [];
+						isMembers.forEach(function(isMember, index) {
+							if (isMember) {
+								memberOf.push(groupData[index]);
+							}
+						});
+
+						next(null, memberOf);
+					});
+				}, callback);
 			});
 		});
 	};

src/posts.js

@@ -222,21 +222,31 @@ var async = require('async'),
 	};
 
 	Posts.getUserInfoForPosts = function(uids, callback) {
-		user.getMultipleUserFields(uids, ['uid', 'username', 'userslug', 'reputation', 'postcount', 'picture', 'signature', 'banned'], function(err, userData) {
+		async.parallel({
+			groups: function(next) {
+				groups.getUserGroups(uids, next);
+			},
+			userData: function(next) {
+				user.getMultipleUserFields(uids, ['uid', 'username', 'userslug', 'reputation', 'postcount', 'picture', 'signature', 'banned'], next);
+			}
+		}, function(err, results) {
 			if (err) {
 				return callback(err);
 			}
 
+			var userData = results.userData;
+			for(var i=0; i<userData.length; ++i) {
+				userData[i].groups = results.groups[i];
+			}
+
 			async.map(userData, function(userData, next) {
-				var userInfo = {
-					uid: userData.uid || 0,
-					username: userData.username || '[[global:guest]]',
-					userslug: userData.userslug || '',
-					reputation: userData.reputation || 0,
-					postcount: userData.postcount || 0,
-					banned: parseInt(userData.banned, 10) === 1,
-					picture: userData.picture || user.createGravatarURLFromEmail('')
-				};
+				userData.uid = userData.uid || 0;
+				userData.username = userData.username || '[[global:guest]]';
+				userData.userslug = userData.userslug || '';
+				userData.reputation = userData.reputation || 0;
+				userData.postcount = userData.postcount || 0;
+				userData.banned = parseInt(userData.banned, 10) === 1;
+				userData.picture = userData.picture || user.createGravatarURLFromEmail('');
 
 				async.parallel({
 					signature: function(next) {
@@ -247,18 +257,14 @@ var async = require('async'),
 					},
 					customProfileInfo: function(next) {
 						plugins.fireHook('filter:posts.custom_profile_info', {profile: [], uid: userData.uid}, next);
-					},
-					groups: function(next) {
-						groups.getUserGroups(userData.uid, next);
 					}
 				}, function(err, results) {
 					if (err) {
 						return next(err);
 					}
-					userInfo.signature = results.signature;
-					userInfo.custom_profile_info = results.customProfileInfo.profile;
-					userInfo.groups = results.groups;
-					next(null, userInfo);
+					userData.signature = results.signature;
+					userData.custom_profile_info = results.customProfileInfo.profile;
+					next(null, userData);
 				});
 			}, callback);
 		});