Utilities/top: Add sort-by and delay-time options

Add optional arguments to top so that the user can choose which field to
sort by and change the update frequency.

Userland/Utilities/top.cpp

@@ -11,6 +11,7 @@
 #include <AK/QuickSort.h>
 #include <AK/String.h>
 #include <AK/Vector.h>
+#include <LibCore/ArgsParser.h>
 #include <LibCore/ProcessStatisticsReader.h>
 #include <fcntl.h>
 #include <signal.h>
@@ -19,6 +20,23 @@
 #include <sys/ioctl.h>
 #include <unistd.h>
 
+struct TopOption {
+    enum class SortBy {
+        Pid,
+        Tid,
+        Priority,
+        UserName,
+        State,
+        Virt,
+        Phys,
+        Cpu,
+        Name
+    };
+
+    SortBy sort_by { SortBy::Cpu };
+    int delay_time { 1 };
+};
+
 struct ThreadData {
     int tid;
     pid_t pid;
@@ -114,7 +132,49 @@ static Snapshot get_snapshot()
 static bool g_window_size_changed = true;
 static struct winsize g_window_size;
 
-int main(int, char**)
+static void parse_args(int argc, char** argv, TopOption& top_option)
+{
+    Core::ArgsParser::Option sort_by_option {
+        true,
+        "Sort by field [pid, tid, pri, user, state, virt, phys, cpu, name]",
+        "sort-by",
+        's',
+        nullptr,
+        [&top_option](const char* s) {
+            StringView sort_by_option { s };
+            if (sort_by_option == "pid"sv)
+                top_option.sort_by = TopOption::SortBy::Pid;
+            else if (sort_by_option == "tid"sv)
+                top_option.sort_by = TopOption::SortBy::Tid;
+            else if (sort_by_option == "pri"sv)
+                top_option.sort_by = TopOption::SortBy::Priority;
+            else if (sort_by_option == "user"sv)
+                top_option.sort_by = TopOption::SortBy::UserName;
+            else if (sort_by_option == "state"sv)
+                top_option.sort_by = TopOption::SortBy::State;
+            else if (sort_by_option == "virt"sv)
+                top_option.sort_by = TopOption::SortBy::Virt;
+            else if (sort_by_option == "phys"sv)
+                top_option.sort_by = TopOption::SortBy::Phys;
+            else if (sort_by_option == "cpu"sv)
+                top_option.sort_by = TopOption::SortBy::Cpu;
+            else if (sort_by_option == "name"sv)
+                top_option.sort_by = TopOption::SortBy::Name;
+            else
+                return false;
+            return true;
+        }
+    };
+
+    Core::ArgsParser args_parser;
+
+    args_parser.set_general_help("Display information about processes");
+    args_parser.add_option(top_option.delay_time, "Delay time interval in seconds", "delay-time", 'd', nullptr);
+    args_parser.add_option(move(sort_by_option));
+    args_parser.parse(argc, argv);
+}
+
+int main(int argc, char** argv)
 {
     if (pledge("stdio rpath tty sigaction ", nullptr) < 0) {
         perror("pledge");
@@ -142,6 +202,9 @@ int main(int, char**)
         return 1;
     }
 
+    TopOption top_option;
+    parse_args(argc, argv, top_option);
+
     Vector<ThreadData*> threads;
     auto prev = get_snapshot();
     usleep(10000);
@@ -185,8 +248,28 @@ int main(int, char**)
             threads.append(&it.value);
         }
 
-        quick_sort(threads, [](auto* p1, auto* p2) {
-            return p2->times_scheduled_since_prev < p1->times_scheduled_since_prev;
+        quick_sort(threads, [&top_option](auto* p1, auto* p2) {
+            switch (top_option.sort_by) {
+            case TopOption::SortBy::Pid:
+                return p2->pid > p1->pid;
+            case TopOption::SortBy::Tid:
+                return p2->tid > p1->tid;
+            case TopOption::SortBy::Priority:
+                return p2->priority > p1->priority;
+            case TopOption::SortBy::UserName:
+                return p2->username > p1->username;
+            case TopOption::SortBy::State:
+                return p2->state > p1->state;
+            case TopOption::SortBy::Virt:
+                return p2->amount_virtual < p1->amount_virtual;
+            case TopOption::SortBy::Phys:
+                return p2->amount_resident < p1->amount_resident;
+            case TopOption::SortBy::Name:
+                return p2->name > p1->name;
+            case TopOption::SortBy::Cpu:
+            default:
+                return p2->times_scheduled_since_prev < p1->times_scheduled_since_prev;
+            }
         });
 
         int row = 0;
@@ -211,7 +294,7 @@ int main(int, char**)
         }
         threads.clear_with_capacity();
         prev = move(current);
-        sleep(1);
+        sleep(top_option.delay_time);
     }
     return 0;
 }