Fix link to additional files during contests

modules/contest.js

@@ -337,6 +337,7 @@ app.get('/contest/:id/:pid', async (req, res) => {
 
     let problem_id = problems_id[pid - 1];
     let problem = await Problem.fromID(problem_id);
+    await problem.loadRelationships();
 
     contest.ended = await contest.isEnded();
     if (!(await contest.isRunning() || contest.ended)) {

modules/problem.js

@@ -749,7 +749,18 @@ app.get('/problem/:id/download/additional_file', async (req, res) => {
     let problem = await Problem.fromID(id);
 
     if (!problem) throw new ErrorMessage('无此题目。');
+
+    // XXX: Reduce duplication (see the '/problem/:id/submit' handler)
+    let contest_id = parseInt(req.query.contest_id);
+    if (contest_id) {
+      let contest = await Contest.fromID(contest_id);
+      if (!contest) throw new ErrorMessage('无此比赛。');
+      if (!await contest.isRunning()) throw new ErrorMessage('比赛未开始或已结束。');
+      let problems_id = await contest.getProblems();
+      if (!problems_id.includes(id)) throw new ErrorMessage('无此题目。');
+    } else {
       if (!await problem.isAllowedUseBy(res.locals.user)) throw new ErrorMessage('您没有权限进行此操作。');
+    }
 
     await problem.loadRelationships();
 

views/problem.ejs

@@ -91,7 +91,7 @@ div[class*=ace_br] {
           <a class="small ui orange button" href="<%= syzoj.utils.makeUrl(['problem', problem.id, 'statistics', problem.type === 'submit-answer' ? 'min' : 'fastest']) %>">统计</a>
           <a class="small ui yellow button" href="<%= syzoj.utils.makeUrl(['problem', problem.id, 'testdata']) %>">测试数据</a>
         <% } %>
-        <% if (problem.additional_file) { %><a class="small ui teal button" href="<%= syzoj.utils.makeUrl(['problem', problem.id, 'download', 'additional_file']) %>">附加文件</a><% } %>
+        <% if (problem.additional_file) { %><a class="small ui teal button" href="<%= syzoj.utils.makeUrl(['problem', problem.id, 'download', 'additional_file'], contest ? { contest_id: contest.id } : undefined) %>">附加文件</a><% } %>
       </div>
       <% if (!contest) { %>
         <div class="ui buttons right floated">