From ac8fe4b030754584cda9cb1707fc3d9f0d792366 Mon Sep 17 00:00:00 2001
From: Julian Andres Klode <jak@debian.org>
Date: Sat, 13 Apr 2024 23:59:41 +0200
Subject: apt: Use unicode install progress bar on UTF-8 locales

This produces a much more appealing progress bar and it can even
show parts of the progress being done.
---
 apt-pkg/install-progress.cc          | 12 +++++++++++-
 test/libapt/install_progress_test.cc | 20 ++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/apt-pkg/install-progress.cc b/apt-pkg/install-progress.cc
index 2b0dc21ea..fe3324426 100644
--- a/apt-pkg/install-progress.cc
+++ b/apt-pkg/install-progress.cc
@@ -13,6 +13,7 @@
 #include <sstream>
 #include <vector>
 #include <fcntl.h>
+#include <langinfo.h>
 #include <sys/ioctl.h>
 #include <unistd.h>
 
@@ -344,14 +345,23 @@ void PackageManagerFancy::Stop()
 std::string 
 PackageManagerFancy::GetTextProgressStr(float Percent, int OutputSize)
 {
+   bool Unicode = strcmp(nl_langinfo(CODESET), "UTF-8") == 0;
    std::string output;
    if (unlikely(OutputSize < 3))
       return output;
 
    int const BarSize = OutputSize - 2; // bar without the leading "[" and trailing "]"
    int const BarDone = std::max(0, std::min(BarSize, static_cast<int>(std::floor(Percent * BarSize))));
+   double dummy;
+   double const BarDoneFractional = std::modf(Percent * BarSize, &dummy);
+   const char *const BarDoneFractionalChar = (const char *[]){
+      " ", "▏", "▎", "▍", "▌", "▋", "▊", "▉"}[static_cast<int>(std::floor(BarDoneFractional * 8))];
    output.append("[");
-   std::fill_n(std::fill_n(std::back_inserter(output), BarDone, '#'), BarSize - BarDone, '.');
+   for (int i = 0; i < BarDone; i++)
+      output.append(Unicode ? "█" : "#");
+   if (BarDone + 1 <= BarSize)
+      output.append(Unicode ? BarDoneFractionalChar : ".");
+   std::fill_n(std::back_inserter(output), BarSize - BarDone - 1, Unicode ? ' ' : '.');
    output.append("]");
    return output;
 }
diff --git a/test/libapt/install_progress_test.cc b/test/libapt/install_progress_test.cc
index 68101af9b..7015c619c 100644
--- a/test/libapt/install_progress_test.cc
+++ b/test/libapt/install_progress_test.cc
@@ -2,6 +2,7 @@
 
 #include <apt-pkg/install-progress.h>
 
+#include <locale>
 #include <string>
 
 #include <gtest/gtest.h>
@@ -10,6 +11,7 @@ TEST(InstallProgressTest, FancyGetTextProgressStr)
 {
    APT::Progress::PackageManagerFancy p;
 
+   char *originalLocale = setlocale(LC_ALL, "C");
    EXPECT_EQ(60u, p.GetTextProgressStr(0.5, 60).size());
    EXPECT_EQ("[#.]", p.GetTextProgressStr(0.5, 4));
    EXPECT_EQ("[..........]", p.GetTextProgressStr(0.0, 12));
@@ -22,4 +24,22 @@ TEST(InstallProgressTest, FancyGetTextProgressStr)
    // deal with incorrect inputs gracefully (or should we die instead?)
    EXPECT_EQ("[..........]", p.GetTextProgressStr(-1.0, 12));
    EXPECT_EQ("[##########]", p.GetTextProgressStr(2.0, 12));
+
+   setlocale(LC_ALL, "C.UTF-8");
+
+   EXPECT_EQ("[█ ]", p.GetTextProgressStr(0.5, 4));
+   EXPECT_EQ("[          ]", p.GetTextProgressStr(0.0, 12));
+   EXPECT_EQ("[█         ]", p.GetTextProgressStr(0.1, 12));
+   EXPECT_EQ("[████      ]", p.GetTextProgressStr(0.4, 12));
+   EXPECT_EQ("[████▉     ]", p.GetTextProgressStr(0.4999, 12));
+   EXPECT_EQ("[█████     ]", p.GetTextProgressStr(0.5000, 12));
+   EXPECT_EQ("[█████     ]", p.GetTextProgressStr(0.5001, 12));
+   EXPECT_EQ("[█████████ ]", p.GetTextProgressStr(0.9001, 12));
+   EXPECT_EQ("[██████████]", p.GetTextProgressStr(1.0, 12));
+
+   // deal with incorrect inputs gracefully (or should we die instead?)
+   EXPECT_EQ("[          ]", p.GetTextProgressStr(-1.0, 12));
+   EXPECT_EQ("[██████████]", p.GetTextProgressStr(2.0, 12));
+
+   setlocale(LC_ALL, originalLocale);
 }
-- 
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