git.scottworley.com Git - batteryviewer/blob - batteryviewer.c

   1 // For vasprintf
   2 #define _GNU_SOURCE
   3
   4 #include "chart.h"
   5 #include <ctype.h>
   6 #include <errno.h>
   7 #include <glob.h>
   8 #include <gtk/gtk.h>
   9 #include <math.h>
  10 #include <stdarg.h>
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14
  15 char *sasprintf(const char *fmt, ...) {
  16   char *result;
  17   va_list args;
  18   va_start(args, fmt);
  19   if (vasprintf(&result, fmt, args) == -1) {
  20     fprintf(stderr, "Can't allocate memory!?\n");
  21     abort();
  22   }
  23   va_end(args);
  24   return result;
  25 }
  26
  27 struct State {
  28   char *voltage_filename;
  29   char *current_filename;
  30   BVChart *voltage;
  31   BVChart *current;
  32 };
  33
  34 static float fatof(const char *filename) {
  35   FILE *f = fopen(filename, "r");
  36   if (f == NULL) {
  37     return NAN;
  38   }
  39
  40   const int bufsize = 1024;
  41   char buf[bufsize];
  42   const int read = fread(buf, sizeof(char), bufsize, f);
  43   if (read == 0 || read == bufsize || ferror(f)) {
  44     fclose(f);
  45     return NAN;
  46   }
  47   fclose(f);
  48
  49   char *end;
  50   errno = 0;
  51   float val = strtof(buf, &end);
  52   int parsed = end - buf;
  53   gboolean parsed_all = parsed == read;
  54   gboolean parsed_all_but_space = parsed == read - 1 && isspace(*end);
  55   gboolean parse_ok = parsed_all || parsed_all_but_space;
  56   if (errno != 0 || parsed == 0 || !parse_ok) {
  57     return NAN;
  58   }
  59   return val;
  60 }
  61
  62 static gboolean collect_data(struct State *state) {
  63   float now = g_get_monotonic_time() / 1e6;
  64   float voltage = fatof(state->voltage_filename);
  65   float current = fatof(state->current_filename);
  66   if (!isnan(voltage)) {
  67     bv_chart_add_point(state->voltage, now, voltage);
  68     gtk_widget_queue_draw(GTK_WIDGET(state->voltage));
  69   }
  70   if (!isnan(current)) {
  71     bv_chart_add_point(state->current, now, current);
  72     gtk_widget_queue_draw(GTK_WIDGET(state->current));
  73   }
  74   return TRUE;
  75 }
  76
  77 static void activate(GtkApplication *app, gpointer user_data) {
  78
  79   GtkWidget *window = gtk_application_window_new(app);
  80   gtk_window_set_title(GTK_WINDOW(window), "BatteryViewer");
  81   gtk_window_set_default_size(GTK_WINDOW(window), 200, 200);
  82
  83   GtkWidget *box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 1);
  84   gtk_container_add(GTK_CONTAINER(window), box);
  85
  86   struct State *state = (struct State *)user_data;
  87   state->voltage = BV_CHART(bv_chart_new());
  88   gboolean expand = TRUE;
  89   gboolean fill = TRUE;
  90   guint padding = 0;
  91   gtk_box_pack_start(GTK_BOX(box), GTK_WIDGET(state->voltage), expand, fill,
  92                      padding);
  93
  94   state->current = BV_CHART(bv_chart_new());
  95   gtk_box_pack_end(GTK_BOX(box), GTK_WIDGET(state->current), expand, fill,
  96                    padding);
  97
  98   gtk_widget_show_all(window);
  99
 100   g_timeout_add_seconds(1, (GSourceFunc)collect_data, user_data);
 101 }
 102
 103 char *find_battery_dir() {
 104   glob_t globbuf = {.gl_offs = 0};
 105   char pattern[] = "/sys/class/power_supply/*[Bb][Aa][Tt]*";
 106   if (glob(pattern, GLOB_ERR, NULL, &globbuf) != 0 || globbuf.gl_pathc == 0) {
 107     fprintf(stderr, "Could not find battery dir %s\n", pattern);
 108     exit(1);
 109   }
 110   if (globbuf.gl_pathc != 1) {
 111     // TODO: Filter for directories that have {voltage,current}_now files.
 112     // TODO: Support multiple batteries
 113     fprintf(stderr, "Multiple batteries found. Arbitrarily choosing %s\n",
 114             globbuf.gl_pathv[0]);
 115   }
 116   char *dir = strdup(globbuf.gl_pathv[0]);
 117   globfree(&globbuf);
 118   return dir;
 119 }
 120
 121 int main(int argc, char **argv) {
 122   char *battery_dir = find_battery_dir();
 123   struct State state = {
 124       .voltage_filename = sasprintf("%s/voltage_now", battery_dir),
 125       .current_filename = sasprintf("%s/current_now", battery_dir),
 126   };
 127
 128   GtkApplication *app = gtk_application_new("com.scottworley.batteryviewer",
 129                                             G_APPLICATION_DEFAULT_FLAGS);
 130   g_signal_connect(app, "activate", G_CALLBACK(activate), &state);
 131   int status = g_application_run(G_APPLICATION(app), argc, argv);
 132   g_object_unref(app);
 133
 134   return status;
 135 }