Added CProcessStatisticsReader to avoid having to parse /proc/all (#35)

* Added CProcessStatisticsReader to avoid having to parse /proc/all

* Took @awesomekling's feedbacks into account

* Fixed indentation and replaced tabs by spaces

LibCore/CProcessStatisticsReader.cpp

@@ -0,0 +1,100 @@
+#include "CProcessStatisticsReader.h"
+#include "CFile.h"
+
+#include <stdio.h>
+#include <pwd.h>
+
+CProcessStatisticsReader::CProcessStatisticsReader()
+{
+    setpwent();
+    while (auto* passwd = getpwent())
+        m_usernames.set(passwd->pw_uid, passwd->pw_name);
+    endpwent();
+}
+
+HashMap<pid_t, CProcessStatistics> CProcessStatisticsReader::get_map()
+{
+    HashMap<pid_t, CProcessStatistics> res;
+    update_map(res);
+    return res;
+}
+
+void CProcessStatisticsReader::update_map(HashMap<pid_t, CProcessStatistics>& map)
+{
+    CFile file("/proc/all");
+    if (!file.open(CIODevice::ReadOnly)) {
+        fprintf(stderr, "CProcessHelper : failed to open /proc/all: %s\n", file.error_string());
+        return;
+    }
+
+    for (;;) {
+        auto line = file.read_line(1024);
+
+        if (line.is_empty())
+            break;
+
+        auto chomped = String((const char*)line.pointer(), line.size() - 1, Chomp);
+        auto parts = chomped.split_view(',');
+
+        if (parts.size() < 18)
+            break;
+
+        bool ok = false;
+        CProcessStatistics process;
+
+        process.pid = parts[0].to_uint(ok);
+        if (!ok) {
+            fprintf(stderr, "CProcessHelper : couldn't convert %s to a valid pid\n", parts[0].characters());
+            return;
+        }
+
+        process.nsched = parts[1].to_uint(ok);
+        if (!ok) {
+            fprintf(stderr, "CProcessHelper : couldn't convert %s to a valid nsched value\n", parts[1].characters());
+            return;
+        }
+
+        uid_t uid = parts[5].to_uint(ok);
+        if (!ok) {
+            fprintf(stderr, "CProcessHelper : couldn't convert %s to a valid uid value\n", parts[5].characters());
+            return;
+        }
+
+        process.uid = uid;
+        process.username = get_username_from_uid(uid);
+
+        process.priority = parts[16];
+        
+        process.syscalls = parts[17].to_uint(ok);
+        if (!ok) {
+            fprintf(stderr, "CProcessHelper : couldn't convert %s to a valid syscalls count value\n", parts[17].characters());
+            return;
+        }
+
+        process.state = parts[7];
+
+        process.name = parts[11];
+        process.linear = parts[12].to_uint(ok);
+        if (!ok) {
+            fprintf(stderr, "CProcessHelper : couldn't convert %s to a valid amount of linear address space used\n", parts[12].characters());
+            return;
+        }
+
+        process.physical = parts[13].to_uint(ok);
+        if (!ok) {
+            fprintf(stderr, "CProcessHelper : couldn't convert %s to a valid amount of physical address space used\n", parts[13].characters());
+            return;
+        }
+
+        map.set(process.pid, process);
+    }
+}
+
+String CProcessStatisticsReader::get_username_from_uid(const uid_t uid)
+{
+    auto it = m_usernames.find(uid);
+    if (it != m_usernames.end())
+        return (*it).value;
+    else
+        return String::format("%u", uid);
+}