Add filetree on left of diff view (#21012)

This PR adds a filetree to the left side of the files/diff view.

Initially the filetree will not be shown and may be shown via a new
"Show file tree" button.

Showing and hiding is using the same icon as github. Folders are
collapsible. On small devices (max-width 991 PX) the file tree will be
hidden.

Close #18192

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/js/components/DiffFileList.vue

@@ -0,0 +1,81 @@
+<template>
+  <ol class="diff-detail-box diff-stats m-0" id="diff-files" v-if="fileListIsVisible">
+    <li v-for="file in files" :key="file.NameHash">
+      <div class="bold df ac pull-right">
+        <span v-if="file.IsBin" class="ml-1 mr-3">{{ binaryFileMessage }}</span>
+        {{ file.IsBin ? '' : file.Addition + file.Deletion }}
+        <span v-if="!file.IsBin" class="diff-stats-bar tooltip mx-3" :data-content="statisticsMessage.replace('%d', (file.Addition + file.Deletion)).replace('%d', file.Addition).replace('%d', file.Deletion)">
+          <div class="diff-stats-add-bar" :style="{ 'width': diffStatsWidth(file.Addition, file.Deletion) }" />
+        </span>
+      </div>
+      <!-- todo finish all file status, now modify, add, delete and rename -->
+      <span :class="['status', diffTypeToString(file.Type), 'tooltip']" :data-content="diffTypeToString(file.Type)" data-position="right center">&nbsp;</span>
+      <a class="file mono" :href="'#diff-' + file.NameHash">{{ file.Name }}</a>
+    </li>
+    <li v-if="isIncomplete" id="diff-too-many-files-stats" class="pt-2">
+      <span class="file df ac sb">{{ tooManyFilesMessage }}
+        <a :class="['ui', 'basic', 'tiny', 'button', isLoadingNewData === true ? 'disabled' : '']" id="diff-show-more-files-stats" @click.stop="loadMoreData">{{ showMoreMessage }}</a>
+      </span>
+    </li>
+  </ol>
+</template>
+
+<script>
+import {initTooltip} from '../modules/tippy.js';
+import {doLoadMoreFiles} from '../features/repo-diff.js';
+
+const {pageData} = window.config;
+
+export default {
+  name: 'DiffFileList',
+
+  data: () => {
+    return pageData.diffFileInfo;
+  },
+
+  watch: {
+    fileListIsVisible(newValue) {
+      if (newValue === true) {
+        this.$nextTick(() => {
+          for (const el of this.$el.querySelectorAll('.tooltip')) {
+            initTooltip(el);
+          }
+        });
+      }
+    }
+  },
+
+  mounted() {
+    document.getElementById('show-file-list-btn').addEventListener('click', this.toggleFileList);
+  },
+
+  unmounted() {
+    document.getElementById('show-file-list-btn').removeEventListener('click', this.toggleFileList);
+  },
+
+  methods: {
+    toggleFileList() {
+      this.fileListIsVisible = !this.fileListIsVisible;
+    },
+    diffTypeToString(pType) {
+      const diffTypes = {
+        1: 'add',
+        2: 'modify',
+        3: 'del',
+        4: 'rename',
+        5: 'copy',
+      };
+      return diffTypes[pType];
+    },
+    diffStatsWidth(adds, dels) {
+      return `${adds / (adds + dels) * 100}%`;
+    },
+    loadMoreData() {
+      this.isLoadingNewData = true;
+      doLoadMoreFiles(this.link, this.diffEnd, () => {
+        this.isLoadingNewData = false;
+      });
+    }
+  },
+};
+</script>