Support energy_now/power_now in battery_remaining

On some laptops (mostly thinkpads), the remaining time may be
expressed in µWh using energy_now and power_now files rather than µAh
for charge_now and current_now.

Add pick function to conditionally select appropriate one.

diff --git a/components/battery.c b/components/battery.c
index 50316086080c38a6f0caeb6eef26338ce94336aa..5d7a3855c046ffc18b057682cf1ce237f7aec84b 100644 (file)
--- a/components/battery.c
+++ b/components/battery.c
@@ -7,6 +7,26 @@
 
 #if defined(__linux__)
        #include <limits.h>
+       #include <unistd.h>
+
+       #define CHARGE_NOW    "/sys/class/power_supply/%s/charge_now"
+       #define ENERGY_NOW    "/sys/class/power_supply/%s/energy_now"
+       #define CURRENT_NOW   "/sys/class/power_supply/%s/current_now"
+       #define POWER_NOW     "/sys/class/power_supply/%s/power_now"
+
+       static const char *
+       pick(const char *bat, const char *f1, const char *f2, char *path, size_t length)
+       {
+               if (esnprintf(path, length, f1, bat) > 0 && access(path, R_OK) == 0) {
+                       return f1;
+               }
+
+               if (esnprintf(path, length, f2, bat) > 0 && access(path, R_OK) == 0) {
+                       return f2;
+               }
+
+               return NULL;
+       }
 
        const char *
        battery_perc(const char *bat)
@@ -72,21 +92,14 @@
                        return NULL;
                }
 
+               if (pick(bat, CHARGE_NOW, ENERGY_NOW, path, sizeof (path)) == NULL ||
+                   pscanf(path, "%d", &charge_now) < 0) {
+                       return NULL;
+               }
+
                if (!strcmp(state, "Discharging")) {
-                       if (esnprintf(path, sizeof(path),
-                                      "/sys/class/power_supply/%s/charge_now",
-                                     bat) < 0) {
-                               return NULL;
-                       }
-                       if (pscanf(path, "%d", &charge_now) != 1) {
-                               return NULL;
-                       }
-                       if (esnprintf(path, sizeof(path),
-                                     "/sys/class/power_supply/%s/current_now",
-                                     bat) < 0) {
-                               return NULL;
-                       }
-                       if (pscanf(path, "%d", &current_now) != 1) {
+                       if (pick(bat, CURRENT_NOW, POWER_NOW, path, sizeof (path)) == NULL ||
+                           pscanf(path, "%d", &current_now) < 0) {
                                return NULL;
                        }