From b6e29656a16b2eacf446d156abc6d6126edb237a Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Mon, 27 Jul 2020 17:00:53 +0200
Subject: [PATCH] top: Limit printed process name characters to the available
 space

It looks much nicer if we don't break the line. You can resize the
terminal if you want to see the full process name.
---
 Userland/top.cpp | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/Userland/top.cpp b/Userland/top.cpp
index aca8ecec64..56d6db8e15 100644
--- a/Userland/top.cpp
+++ b/Userland/top.cpp
@@ -33,8 +33,10 @@
 #include <AK/Vector.h>
 #include <LibCore/ProcessStatisticsReader.h>
 #include <fcntl.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/ioctl.h>
 #include <unistd.h>
 
 struct ThreadData {
@@ -131,9 +133,12 @@ static Snapshot get_snapshot()
     return snapshot;
 }
 
+static bool g_window_size_changed = true;
+static struct winsize g_window_size;
+
 int main(int, char**)
 {
-    if (pledge("stdio rpath", nullptr) < 0) {
+    if (pledge("stdio rpath tty sigaction ", nullptr) < 0) {
         perror("pledge");
         return 1;
     }
@@ -150,10 +155,28 @@ int main(int, char**)
 
     unveil(nullptr, nullptr);
 
+    signal(SIGWINCH, [](int) {
+        g_window_size_changed = true;
+    });
+
+    if (pledge("stdio rpath tty", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
     Vector<ThreadData*> threads;
     auto prev = get_snapshot();
     usleep(10000);
     for (;;) {
+        if (g_window_size_changed) {
+            int rc = ioctl(STDOUT_FILENO, TIOCGWINSZ, &g_window_size);
+            if (rc < 0) {
+                perror("ioctl(TIOCGWINSZ)");
+                return 1;
+            }
+            g_window_size_changed = false;
+        }
+
         auto current = get_snapshot();
         auto sum_diff = current.sum_times_scheduled - prev.sum_times_scheduled;
 
@@ -189,7 +212,7 @@ int main(int, char**)
         });
 
         for (auto* thread : threads) {
-            printf("%6d %3d %2u   %-9s  %-10s  %6zu  %6zu  %2u.%1u  %s\n",
+            int nprinted = printf("%6d %3d %2u   %-9s  %-10s  %6zu  %6zu  %2u.%1u  ",
                 thread->pid,
                 thread->tid,
                 thread->priority,
@@ -198,8 +221,11 @@ int main(int, char**)
                 thread->amount_virtual / 1024,
                 thread->amount_resident / 1024,
                 thread->cpu_percent,
-                thread->cpu_percent_decimal,
-                thread->name.characters());
+                thread->cpu_percent_decimal);
+
+            int remaining = g_window_size.ws_col - nprinted;
+            fwrite(thread->name.characters(), 1, max(0, min(remaining, (int)thread->name.length())), stdout);
+            putchar('\n');
         }
         threads.clear_with_capacity();
         prev = move(current);