From d5c69a9d60a0bf9b6fbbaff7e122042410bfe44a Mon Sep 17 00:00:00 2001
From: johcgt <35880934+johcgt@users.noreply.github.com>
Date: Sun, 28 Jan 2018 14:37:51 +0000
Subject: Treat zero battery capacity as "not available" (#259)

`print_battery_info` computes `batt_info.percentage_remaining` by
dividing batt_info.remaining by `full`. If `full` is `0` then the
battery remaining will be reported as "inf".

Before this, it tries to set `full` to either the design capacity or to
the last known good charge. It determines if these values are available
by checking whether their fields in `batt_info` are non-negative. As it
initialized `batt_info` with values of `-1`, a non-negative value
implies that something has provided a value.

`slurp_all_batteries` and `add_battery_info` however initialize these
fields to zero, so if these functions are called then
`batt_info.full_design` will always be used.

This means that on systems that don't provide a value for design
capacity the percentage remaining will be reported as "inf", unless the
user has set `last_full_capacity` to `true` in their `i3status.conf`.

This patch changes `print_battery_info` to expect values for the battery
capacity to be strictly greater than zero. This seems reasonable as a
battery with a capacity of zero isn't useful.

An alternative solution would be to change `slurp_all_batteries` and
`add_battery_info` to initialize `batt_info` with `-1`, as
`print_battery_info` does. This is less appealing as `add_battery_info`
is accumulating the values, so using `-1` would introduce off-by-one
errors without additional code to avoid them.
---
 testcases/018-battery-capacity/1/uevent            |  2 ++
 testcases/018-battery-capacity/expected_output.txt |  1 +
 testcases/018-battery-capacity/i3status.conf       | 10 ++++++++++
 3 files changed, 13 insertions(+)
 create mode 100644 testcases/018-battery-capacity/1/uevent
 create mode 100644 testcases/018-battery-capacity/expected_output.txt
 create mode 100644 testcases/018-battery-capacity/i3status.conf

(limited to 'testcases/018-battery-capacity')

diff --git a/testcases/018-battery-capacity/1/uevent b/testcases/018-battery-capacity/1/uevent
new file mode 100644
index 0000000..00b1148
--- /dev/null
+++ b/testcases/018-battery-capacity/1/uevent
@@ -0,0 +1,2 @@
+POWER_SUPPLY_CHARGE_FULL=100
+POWER_SUPPLY_CHARGE_NOW=50
diff --git a/testcases/018-battery-capacity/expected_output.txt b/testcases/018-battery-capacity/expected_output.txt
new file mode 100644
index 0000000..ab07d0a
--- /dev/null
+++ b/testcases/018-battery-capacity/expected_output.txt
@@ -0,0 +1 @@
+50.00%
diff --git a/testcases/018-battery-capacity/i3status.conf b/testcases/018-battery-capacity/i3status.conf
new file mode 100644
index 0000000..7a3443c
--- /dev/null
+++ b/testcases/018-battery-capacity/i3status.conf
@@ -0,0 +1,10 @@
+general {
+        output_format = "none"
+}
+
+order += "battery all"
+
+battery all {
+        format = "%percentage"
+        path = "testcases/018-battery-capacity/%d/uevent"
+}
-- 
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