ui: one line per download -- the completion line only, with its size and time, in both modes (#734)

Output that is not a terminal printed a start line and a completion line for
every item; it now prints the completion line (or the line saying the item did
not complete). A terminal redraws the bar in place, as before, and ends it
with the same completion line, which now states the size and the time.

Author: speak-agent

CHANGELOG.md

@@ -31,6 +31,9 @@ SPEC-007 §9 与新的 SPEC-008。配套的 mcpp-plugins 0.17.0 以本版本为
 - **快路径看见 path 依赖的整棵源码树。** 此前只扫描依赖的 `src/`;依赖在别处的 host module
   (例如 mcpp-plugins 的 `deps/vcpkg.cppm`)编入消费方的构建程序,不在任何 ninja 边上,被编辑后
   构建报告"无事可做"。现在扫描依赖的整棵树,跳过隐藏目录、`target` 与嵌套的包(e2e 831)。
+- **每个下载只占一行。** 非终端输出此前在开始时写一行 `Downloading <item> (<size>)`,完成时再写一行
+  `... done, <size> in <time>`;现在只写完成的一行,失败时写 `did not complete` 的一行。终端上进度条
+  原地刷新,结束时换成同样带大小与耗时的完成行。
 - **MSVC ABI 上的 clang 找不到工具集时说明原因。** 默认的 `msvc@system` 在没有带 C++ 工具的
   Visual Studio 实例时,此前静默继续,随后在预编译 `mcpp` 模块时以 `'cstdio' file not found` 失败;
   现在解析时给出警告,写出安装与指定托管工具集的命令(在屏蔽 Visual Studio 的 runner 上测得)。

src/ui.cppm

@@ -149,9 +149,12 @@ private:
     void render_line(std::size_t percent, const std::string& info_text);
     void render_line_swept(std::size_t frame, const std::string& info_text);
 
-    // Not a terminal: one start line, then one finish line.
+    // One line per item in both modes (#734): a terminal redraws it in place
+    // and ends it with the completion line; elsewhere only the completion
+    // line is printed. `announce` records the size without printing.
     void announce(std::size_t total_bytes);
     void finish_plain(std::string_view final_message);
+    std::string completion(std::string_view final_message) const;
 
     std::string verb_;
     std::string label_;
@@ -608,20 +611,19 @@ ProgressBar::ProgressBar(std::string_view verb, std::string_view label)
 void ProgressBar::announce(std::size_t total_bytes) {
     if (announced_) return;
     announced_ = true;
-    if (total_bytes > 0)
-        info(verb_, std::format("{} ({})", label_, fmt_bytes(total_bytes)));
-    else
-        info(verb_, label_);
+    if (total_bytes > lastBytes_) lastBytes_ = total_bytes;
 }
 
-void ProgressBar::finish_plain(std::string_view final_message) {
+std::string ProgressBar::completion(std::string_view final_message) const {
     const auto secs = std::chrono::duration<double>(
         std::chrono::steady_clock::now() - start_).count();
     if (lastBytes_ > 0)
-        info(verb_, std::format("{} done, {} in {:.1f}s", final_message,
-                                fmt_bytes(lastBytes_), secs));
-    else
-        info(verb_, std::format("{} done in {:.1f}s", final_message, secs));
+        return std::format("{} done, {} in {:.1f}s", final_message, fmt_bytes(lastBytes_), secs);
+    return std::format("{} done in {:.1f}s", final_message, secs);
+}
+
+void ProgressBar::finish_plain(std::string_view final_message) {
+    info(verb_, completion(final_message));
 }
 
 ProgressBar::~ProgressBar() {
@@ -672,7 +674,8 @@ void ProgressBar::update(std::size_t percent) {
 void ProgressBar::update_bytes(std::size_t current, std::size_t total,
                                double elapsed_sec) {
     if (g_quiet || finished_) return;
-    if (!live_progress()) { announce(total); lastBytes_ = current; return; }
+    if (!live_progress()) { announce(total); if (current > lastBytes_) lastBytes_ = current; return; }
+    if (current > lastBytes_) lastBytes_ = current;
     auto now = std::chrono::steady_clock::now();
     auto pct = total ? (current * 100 / total) : 0;
     if (pct > 100) pct = 100;
@@ -696,6 +699,7 @@ void ProgressBar::update_indeterminate(std::size_t current_bytes,
                                        double elapsed_sec) {
     if (g_quiet || finished_) return;
     if (!live_progress()) { announce(0); lastBytes_ = current_bytes; return; }
+    lastBytes_ = current_bytes;
     auto now = std::chrono::steady_clock::now();
     // Same ~80ms throttle as update_bytes(); there is no "100%" early-out here
     // because there is no known total.
@@ -723,9 +727,9 @@ void ProgressBar::finish() {
         finish_plain(label_);
         return;
     }
-    // Clear the line and re-emit as a static info line.
+    // Clear the line and re-emit it as the completion line.
     std::print("\r\033[2K");
-    info(verb_, label_);
+    info(verb_, completion(label_));
 }
 
 void ProgressBar::finish_with(std::string_view final_message) {
@@ -738,7 +742,7 @@ void ProgressBar::finish_with(std::string_view final_message) {
         return;
     }
     std::print("\r\033[2K");
-    info(verb_, final_message);
+    info(verb_, completion(final_message));
 }
 
 void ProgressBar::finish_failed(std::string_view final_message) {

tests/unit/test_progress_render.cpp

@@ -6,7 +6,7 @@ import mcpp.fetcher.progress;
 import mcpp.platform.process;
 
 // W11: one renderer for every acquisition, with a terminal mode (redrawn in
-// place) and a plain mode (one start line and one finish line per item).
+// place) and a plain mode; either prints one line per item (#734).
 
 TEST(GitProgress, ParsesThePhaseAndThePercentage) {
     auto r = mcpp::fetcher::parse_git_progress(
@@ -25,7 +25,7 @@ TEST(GitProgress, ParsesThePhaseAndThePercentage) {
     EXPECT_FALSE(mcpp::fetcher::parse_git_progress("").has_value());
 }
 
-TEST(ProgressBarPlain, OneStartLineAndOneFinishLineWithoutRepaints) {
+TEST(ProgressBarPlain, OneCompletionLineWithoutRepaints) {
     mcpp::ui::disable_color();
     mcpp::ui::set_live_progress(false);
     testing::internal::CaptureStdout();
@@ -39,9 +39,9 @@ TEST(ProgressBarPlain, OneStartLineAndOneFinishLineWithoutRepaints) {
     auto out = testing::internal::GetCapturedStdout();
     EXPECT_EQ(out.find('\r'), std::string::npos) << out;
     EXPECT_EQ(out.find('\x1b'), std::string::npos) << out;
-    EXPECT_EQ(std::ranges::count(out, '\n'), 2) << out;
-    EXPECT_NE(out.find("Fetching example ("), std::string::npos) << out;
-    EXPECT_NE(out.find("done"), std::string::npos) << out;
+    // #734: one line per item, stating the size and the time.
+    EXPECT_EQ(std::ranges::count(out, '\n'), 1) << out;
+    EXPECT_NE(out.find("Fetching example done, 100 B in"), std::string::npos) << out;
 }
 
 TEST(ProgressBarPlain, AFailedItemIsNotReportedDone) {