git.sesse.net Git - nageru/blob - disk_space_estimator.cpp

   1 #include "disk_space_estimator.h"
   2
   3 #include <stdio.h>
   4 #include <sys/stat.h>
   5 #include <sys/statfs.h>
   6 #include <memory>
   7
   8 #include "metrics.h"
   9 #include "timebase.h"
  10
  11 DiskSpaceEstimator::DiskSpaceEstimator(DiskSpaceEstimator::callback_t callback)
  12         : callback(callback)
  13 {
  14         global_metrics.add("disk_free_bytes", &metric_disk_free_bytes, Metrics::TYPE_GAUGE);
  15 }
  16
  17 void DiskSpaceEstimator::report_write(const std::string &filename, uint64_t pts)
  18 {
  19         if (filename != last_filename) {
  20                 last_filename = filename;
  21                 measure_points.clear();
  22         }
  23
  24         // Reject points that are out-of-order (happens with B-frames).
  25         if (!measure_points.empty() && pts < measure_points.back().pts) {
  26                 return;
  27         }
  28
  29         // Remove too old points.
  30         while (measure_points.size() > 1 && measure_points.front().pts + window_length < pts) {
  31                 measure_points.pop_front();
  32         }
  33
  34         struct stat st;
  35         if (stat(filename.c_str(), &st) == -1) {
  36                 perror(filename.c_str());
  37                 return;
  38         }
  39
  40         struct statfs fst;
  41         if (statfs(filename.c_str(), &fst) == -1) {
  42                 perror(filename.c_str());
  43                 return;
  44         }
  45
  46         off_t free_bytes = off_t(fst.f_bavail) * fst.f_frsize;
  47         metric_disk_free_bytes = free_bytes;
  48
  49         if (!measure_points.empty()) {
  50                 double bytes_per_second = double(st.st_size - measure_points.front().size) /
  51                         (pts - measure_points.front().pts) * TIMEBASE;
  52                 double seconds_left = free_bytes / bytes_per_second;
  53
  54                 // Only report every second, since updating the UI can be expensive.
  55                 if (last_pts_reported == 0 || pts - last_pts_reported >= TIMEBASE) {
  56                         callback(free_bytes, seconds_left);
  57                         last_pts_reported = pts;
  58                 }
  59         }
  60
  61         measure_points.push_back({ pts, st.st_size });
  62 }
  63
  64 DiskSpaceEstimator *global_disk_space_estimator = nullptr;  // Created in MainWindow::MainWindow().