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[batteryviewer] / 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(
129 "com.scottworley.batteryviewer",
130 // G_APPLICATION_FLAGS_NONE is deprecated, but
131 // G_APPLICATION_DEFAULT_FLAGS isn't available on Stable Debian yet.
132 G_APPLICATION_FLAGS_NONE);
133 g_signal_connect(app, "activate", G_CALLBACK(activate), &state);
134 int status = g_application_run(G_APPLICATION(app), argc, argv);
135 g_object_unref(app);
136
137 return status;
138 }