Add battery support to all Cygwin builds

It already exists in the Cygwin-w32 build.
* src/w32fns.c (Fw32_battery_status): Move to...
* src/w32cygwinx: New file, to be used for functions common to
the MS Windows and Cygwin builds.
(syms_of_w32cygwinx): New function.
* src/lisp.h: Add prototype of syms_of_w32cygwinx.
* src/emacs.c (main) [HAVE_NTGUI or CYGWIN]: Call syms_of_w32cygwinx.
* src/Makefile.in (SOME_MACHINE_OBJECTS):
* configure.ac (W32_OBJ) [HAVE_W32]: Add w32cygwinx.o.
(W32_LIBS) [CYGWIN]: Set equal to "-lkernel32" in non-w32 build.
(W32_OBJ) [CYGWIN]: Set equal to "w32cygwinx.o" in non-w32 build.
* etc/NEWS: Document the new battery support.

1 files changed, 140 insertions, 0 deletions

diff --git a/src/w32cygwinx.c b/src/w32cygwinx.c
new file mode 100644
index 00000000000..8d3ae164cf6
--- /dev/null
+++ b/src/w32cygwinx.c
@@ -0,0 +1,140 @@
+/* Common functions for the Microsoft Windows and Cygwin builds.
+
+Copyright (C) 2018 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include <stdio.h>
+
+#include "lisp.h"
+#include "w32common.h"
+
+DEFUN ("w32-battery-status", Fw32_battery_status, Sw32_battery_status, 0, 0, 0,
+       doc: /* Get power status information from Windows system.
+
+The following %-sequences are provided:
+%L AC line status (verbose)
+%B Battery status (verbose)
+%b Battery status, empty means high, `-' means low,
+   `!' means critical, and `+' means charging
+%p Battery load percentage
+%s Remaining time (to charge or discharge) in seconds
+%m Remaining time (to charge or discharge) in minutes
+%h Remaining time (to charge or discharge) in hours
+%t Remaining time (to charge or discharge) in the form `h:min'  */)
+  (void)
+{
+  Lisp_Object status = Qnil;
+
+  SYSTEM_POWER_STATUS system_status;
+  if (GetSystemPowerStatus (&system_status))
+    {
+      Lisp_Object line_status, battery_status, battery_status_symbol;
+      Lisp_Object load_percentage, seconds, minutes, hours, remain;
+
+      long seconds_left = (long) system_status.BatteryLifeTime;
+
+      if (system_status.ACLineStatus == 0)
+	line_status = build_string ("off-line");
+      else if (system_status.ACLineStatus == 1)
+	line_status = build_string ("on-line");
+      else
+	line_status = build_string ("N/A");
+
+      if (system_status.BatteryFlag & 128)
+	{
+	  battery_status = build_string ("N/A");
+	  battery_status_symbol = empty_unibyte_string;
+	}
+      else if (system_status.BatteryFlag & 8)
+	{
+	  battery_status = build_string ("charging");
+	  battery_status_symbol = build_string ("+");
+	  if (system_status.BatteryFullLifeTime != -1L)
+	    seconds_left = system_status.BatteryFullLifeTime - seconds_left;
+	}
+      else if (system_status.BatteryFlag & 4)
+	{
+	  battery_status = build_string ("critical");
+	  battery_status_symbol = build_string ("!");
+	}
+      else if (system_status.BatteryFlag & 2)
+	{
+	  battery_status = build_string ("low");
+	  battery_status_symbol = build_string ("-");
+	}
+      else if (system_status.BatteryFlag & 1)
+	{
+	  battery_status = build_string ("high");
+	  battery_status_symbol = empty_unibyte_string;
+	}
+      else
+	{
+	  battery_status = build_string ("medium");
+	  battery_status_symbol = empty_unibyte_string;
+	}
+
+      if (system_status.BatteryLifePercent > 100)
+	load_percentage = build_string ("N/A");
+      else
+	{
+	  char buffer[16];
+	  snprintf (buffer, 16, "%d", system_status.BatteryLifePercent);
+	  load_percentage = build_string (buffer);
+	}
+
+      if (seconds_left < 0)
+	seconds = minutes = hours = remain = build_string ("N/A");
+      else
+	{
+	  long m;
+	  double h;
+	  char buffer[16];
+	  snprintf (buffer, 16, "%ld", seconds_left);
+	  seconds = build_string (buffer);
+
+	  m = seconds_left / 60;
+	  snprintf (buffer, 16, "%ld", m);
+	  minutes = build_string (buffer);
+
+	  h = seconds_left / 3600.0;
+	  snprintf (buffer, 16, "%3.1f", h);
+	  hours = build_string (buffer);
+
+	  snprintf (buffer, 16, "%ld:%02ld", m / 60, m % 60);
+	  remain = build_string (buffer);
+	}
+
+      status = listn (CONSTYPE_HEAP, 8,
+		      Fcons (make_number ('L'), line_status),
+		      Fcons (make_number ('B'), battery_status),
+		      Fcons (make_number ('b'), battery_status_symbol),
+		      Fcons (make_number ('p'), load_percentage),
+		      Fcons (make_number ('s'), seconds),
+		      Fcons (make_number ('m'), minutes),
+		      Fcons (make_number ('h'), hours),
+		      Fcons (make_number ('t'), remain));
+    }
+  return status;
+}
+
+void
+syms_of_w32cygwinx (void)
+{
+  defsubr (&Sw32_battery_status);
+}