feat(data): buildStructTree 扁平→树（叶子=TM，含直挂/孤儿/空表）

src/data/dto/NavDto.cpp

@@ -2,6 +2,9 @@
 
 #include <QJsonValue>
 
+#include <functional>
+#include <set>
+
 namespace geopro::data::dto {
 
 namespace {
@@ -75,6 +78,35 @@ std::vector<DsNode> parseDatasets(const QJsonArray& arr) {
     return out;
 }
 
-std::vector<StructTreeNode> buildStructTree(const std::vector<StructNode>&) { return {}; }
+std::vector<StructTreeNode> buildStructTree(const std::vector<StructNode>& flat) {
+    std::set<std::string> ids;
+    std::set<std::string> hasChild;
+    for (const auto& n : flat) {
+        ids.insert(n.id);
+        if (!n.parentId.empty()) hasChild.insert(n.parentId);
+    }
+    // 叶子（无子节点）= TM。
+    auto isLeaf = [&](const std::string& id) { return hasChild.find(id) == hasChild.end(); };
+    // 根层节点：parentId 为空或 parentId 不在 id 集合内（孤儿）。
+    auto isRootLevel = [&](const StructNode& n) {
+        return n.parentId.empty() || ids.find(n.parentId) == ids.end();
+    };
+    std::function<std::vector<StructTreeNode>(const std::string&, bool)> build =
+        [&](const std::string& parentId, bool root) {
+            std::vector<StructTreeNode> out;
+            for (const auto& n : flat) {
+                const bool belongs = root ? isRootLevel(n) : (n.parentId == parentId);
+                if (!belongs) continue;
+                if (n.id == parentId) continue;  // 防自环
+                StructTreeNode t;
+                t.node = n;
+                t.isTm = isLeaf(n.id);
+                t.children = build(n.id, false);
+                out.push_back(std::move(t));
+            }
+            return out;
+        };
+    return build(std::string(), true);
+}
 
 }  // namespace geopro::data::dto

tests/data/test_nav_dto.cpp

@@ -74,3 +74,35 @@ TEST(NavDto, ParseDatasetsMapsDdCodeToDdType) {
     EXPECT_EQ(ds[0].name, "批次1");
     EXPECT_EQ(ds[0].ddType, "dd_section");
 }
+
+TEST(NavDto, BuildStructTreeNestsGsTmAndDirectTm) {
+    const std::vector<StructNode> flat = {
+        {"gs1", "工区1", "",    "GS", "", 1},
+        {"tm1", "测线1", "gs1", "TM", "", 2},
+        {"tm2", "测线2", "gs1", "TM", "", 2},
+        {"tmD", "直挂测线", "", "TM", "", 2},   // TM 直挂项目（无 GS）
+    };
+    const auto roots = dto::buildStructTree(flat);
+    ASSERT_EQ(roots.size(), 2u);                 // gs1 + tmD
+    EXPECT_EQ(roots[0].node.id, "gs1");
+    EXPECT_FALSE(roots[0].isTm);                 // 非叶 = GS
+    ASSERT_EQ(roots[0].children.size(), 2u);
+    EXPECT_EQ(roots[0].children[0].node.id, "tm1");
+    EXPECT_TRUE(roots[0].children[0].isTm);      // 叶 = TM
+    EXPECT_EQ(roots[1].node.id, "tmD");
+    EXPECT_TRUE(roots[1].isTm);                  // 直挂项目的叶子 = TM
+}
+
+TEST(NavDto, BuildStructTreeOrphanParentBecomesRoot) {
+    const std::vector<StructNode> flat = {
+        {"tmX", "孤儿测线", "ghost", "TM", "", 2},  // parentId 不在集合内
+    };
+    const auto roots = dto::buildStructTree(flat);
+    ASSERT_EQ(roots.size(), 1u);
+    EXPECT_EQ(roots[0].node.id, "tmX");
+    EXPECT_TRUE(roots[0].isTm);
+}
+
+TEST(NavDto, BuildStructTreeEmpty) {
+    EXPECT_TRUE(dto::buildStructTree({}).empty());
+}