feat(noent): add pids

src/linux_parser.cpp

@@ -1,15 +1,20 @@
+#include "linux_parser.h"
+
 #include <dirent.h>
 #include <unistd.h>
+
+#include <filesystem>
+#include <set>
 #include <string>
 #include <vector>
 
-#include "linux_parser.h"
-
 using std::stof;
 using std::string;
 using std::to_string;
 using std::vector;
 
+namespace fs = std::filesystem;
+
 // DONE: An example of how to read data from the filesystem
 string LinuxParser::OperatingSystem() {
   string line;
@@ -48,21 +53,27 @@ string LinuxParser::Kernel() {
 
 // BONUS: Update this to use std::filesystem
 vector<int> LinuxParser::Pids() {
-  vector<int> pids;
-  DIR* directory = opendir(kProcDirectory.c_str());
-  struct dirent* file;
-  while ((file = readdir(directory)) != nullptr) {
-    // Is this a directory?
-    if (file->d_type == DT_DIR) {
-      // Is every character of the name a digit?
-      string filename(file->d_name);
-      if (std::all_of(filename.begin(), filename.end(), isdigit)) {
-        int pid = stoi(filename);
-        pids.push_back(pid);
+  std::set<int> pids_as_set;
+  const string &proc_dir = LinuxParser::kProcDirectory;
+
+  auto is_convertible = [](const std::string str) -> bool {
+    for (int i = 0; i < str.length(); i++) {
+      if (!isdigit(str[i])) return false;
+    }
+    return true;
+  };
+
+  if (fs::exists(proc_dir)) {
+    for (auto const &entry : fs::directory_iterator(proc_dir)) {
+      auto path = entry.path();
+      auto relative = path.lexically_relative(proc_dir);
+      if (fs::is_directory(path) && is_convertible(relative)) {
+        int pid = std::stoi(relative);
+        pids_as_set.insert(pid);
       }
     }
   }
-  closedir(directory);
+  vector<int> pids{pids_as_set.begin(), pids_as_set.end()};
   return pids;
 }
 
@@ -77,7 +88,7 @@ long LinuxParser::Jiffies() { return 0; }
 
 // TODO: Read and return the number of active jiffies for a PID
 // REMOVE: [[maybe_unused]] once you define the function
-long LinuxParser::ActiveJiffies(int pid[[maybe_unused]]) { return 0; }
+long LinuxParser::ActiveJiffies(int pid [[maybe_unused]]) { return 0; }
 
 // TODO: Read and return the number of active jiffies for the system
 long LinuxParser::ActiveJiffies() { return 0; }
@@ -96,20 +107,20 @@ int LinuxParser::RunningProcesses() { return 0; }
 
 // TODO: Read and return the command associated with a process
 // REMOVE: [[maybe_unused]] once you define the function
-string LinuxParser::Command(int pid[[maybe_unused]]) { return string(); }
+string LinuxParser::Command(int pid [[maybe_unused]]) { return string(); }
 
 // TODO: Read and return the memory used by a process
 // REMOVE: [[maybe_unused]] once you define the function
-string LinuxParser::Ram(int pid[[maybe_unused]]) { return string(); }
+string LinuxParser::Ram(int pid [[maybe_unused]]) { return string(); }
 
 // TODO: Read and return the user ID associated with a process
 // REMOVE: [[maybe_unused]] once you define the function
-string LinuxParser::Uid(int pid[[maybe_unused]]) { return string(); }
+string LinuxParser::Uid(int pid [[maybe_unused]]) { return string(); }
 
 // TODO: Read and return the user associated with a process
 // REMOVE: [[maybe_unused]] once you define the function
-string LinuxParser::User(int pid[[maybe_unused]]) { return string(); }
+string LinuxParser::User(int pid [[maybe_unused]]) { return string(); }
 
 // TODO: Read and return the uptime of a process
 // REMOVE: [[maybe_unused]] once you define the function
-long LinuxParser::UpTime(int pid[[maybe_unused]]) { return 0; }
+long LinuxParser::UpTime(int pid [[maybe_unused]]) { return 0; }