Add file tree to file view page (#32721)

Resolve #29328

This pull request introduces a file tree on the left side when reviewing
files of a repository.

---------

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

web_src/js/components/ViewFileTreeItem.vue

@@ -0,0 +1,156 @@
+<script lang="ts" setup>
+import {SvgIcon} from '../svg.ts';
+import {ref} from 'vue';
+
+type Item = {
+  entryName: string;
+  entryMode: string;
+  fullPath: string;
+  submoduleUrl?: string;
+  children?: Item[];
+};
+
+const props = defineProps<{
+  item: Item,
+  navigateViewContent:(treePath: string) => void,
+  loadChildren:(treePath: string, subPath?: string) => Promise<Item[]>,
+  selectedItem?: string,
+}>();
+
+const isLoading = ref(false);
+const children = ref(props.item.children);
+const collapsed = ref(!props.item.children);
+
+const doLoadChildren = async () => {
+  collapsed.value = !collapsed.value;
+  if (!collapsed.value && props.loadChildren) {
+    isLoading.value = true;
+    try {
+      children.value = await props.loadChildren(props.item.fullPath);
+    } finally {
+      isLoading.value = false;
+    }
+  }
+};
+
+const doLoadDirContent = () => {
+  doLoadChildren();
+  props.navigateViewContent(props.item.fullPath);
+};
+
+const doLoadFileContent = () => {
+  props.navigateViewContent(props.item.fullPath);
+};
+
+const doGotoSubModule = () => {
+  location.href = props.item.submoduleUrl;
+};
+</script>
+
+<!--title instead of tooltip above as the tooltip needs too much work with the current methods, i.e. not being loaded or staying open for "too long"-->
+<template>
+  <div
+    v-if="item.entryMode === 'commit'" class="tree-item type-submodule"
+    :title="item.entryName"
+    @click.stop="doGotoSubModule"
+  >
+    <!-- submodule -->
+    <div class="item-content">
+      <SvgIcon class="text primary" name="octicon-file-submodule"/>
+      <span class="gt-ellipsis tw-flex-1">{{ item.entryName }}</span>
+    </div>
+  </div>
+  <div
+    v-else-if="item.entryMode === 'symlink'" class="tree-item type-symlink"
+    :class="{'selected': selectedItem === item.fullPath}"
+    :title="item.entryName"
+    @click.stop="doLoadFileContent"
+  >
+    <!-- symlink -->
+    <div class="item-content">
+      <SvgIcon name="octicon-file-symlink-file"/>
+      <span class="gt-ellipsis tw-flex-1">{{ item.entryName }}</span>
+    </div>
+  </div>
+  <div
+    v-else-if="item.entryMode !== 'tree'" class="tree-item type-file"
+    :class="{'selected': selectedItem === item.fullPath}"
+    :title="item.entryName"
+    @click.stop="doLoadFileContent"
+  >
+    <!-- file -->
+    <div class="item-content">
+      <SvgIcon name="octicon-file"/>
+      <span class="gt-ellipsis tw-flex-1">{{ item.entryName }}</span>
+    </div>
+  </div>
+  <div
+    v-else class="tree-item type-directory"
+    :class="{'selected': selectedItem === item.fullPath}"
+    :title="item.entryName"
+    @click.stop="doLoadDirContent"
+  >
+    <!-- directory -->
+    <div class="item-toggle">
+      <SvgIcon v-if="isLoading" name="octicon-sync" class="job-status-rotate"/>
+      <SvgIcon v-else :name="collapsed ? 'octicon-chevron-right' : 'octicon-chevron-down'" @click.stop="doLoadChildren"/>
+    </div>
+    <div class="item-content">
+      <SvgIcon class="text primary" :name="collapsed ? 'octicon-file-directory-fill' : 'octicon-file-directory-open-fill'"/>
+      <span class="gt-ellipsis">{{ item.entryName }}</span>
+    </div>
+  </div>
+
+  <div v-if="children?.length" v-show="!collapsed" class="sub-items">
+    <ViewFileTreeItem v-for="childItem in children" :key="childItem.entryName" :item="childItem" :selected-item="selectedItem" :navigate-view-content="navigateViewContent" :load-children="loadChildren"/>
+  </div>
+</template>
+<style scoped>
+.sub-items {
+  display: flex;
+  flex-direction: column;
+  gap: 1px;
+  margin-left: 14px;
+  border-left: 1px solid var(--color-secondary);
+}
+
+.tree-item.selected {
+  color: var(--color-text);
+  background: var(--color-active);
+  border-radius: 4px;
+}
+
+.tree-item.type-directory {
+  user-select: none;
+}
+
+.tree-item {
+  display: grid;
+  grid-template-columns: 16px 1fr;
+  grid-template-areas: "toggle content";
+  gap: 0.25em;
+  padding: 6px;
+}
+
+.tree-item:hover {
+  color: var(--color-text);
+  background: var(--color-hover);
+  border-radius: 4px;
+  cursor: pointer;
+}
+
+.item-toggle {
+  grid-area: toggle;
+  display: flex;
+  align-items: center;
+}
+
+.item-content {
+  grid-area: content;
+  display: flex;
+  align-items: center;
+  gap: 0.25em;
+  text-overflow: ellipsis;
+  min-width: 0;
+}
+</style>