Add API to access battery power state

Done:
- X11, server (tested)
- Windows (developed, would be nice to retest)
- OSX (not tested)
Prepared (not developed):
- Android (code is here, but may not compile)
- iphone
- winrt
- bb10
- haiku
- javascript

5 files changed, 187 insertions, 0 deletions

diff --git a/platform/windows/SCsub b/platform/windows/SCsub
index ae8c07384f..befbe00183 100644
--- a/platform/windows/SCsub
+++ b/platform/windows/SCsub
@@ -12,6 +12,7 @@ common_win = [
     "packet_peer_udp_winsock.cpp",
     "stream_peer_winsock.cpp",
     "joypad.cpp",
+	"power_windows.cpp",
 ]
 
 restarget = "godot_res" + env["OBJSUFFIX"]
diff --git a/platform/windows/os_windows.cpp b/platform/windows/os_windows.cpp
index 0ef964522b..8a347e5f32 100644
--- a/platform/windows/os_windows.cpp
+++ b/platform/windows/os_windows.cpp
@@ -1134,6 +1134,8 @@ void OS_Windows::initialize(const VideoMode& p_desired,int p_video_driver,int p_
 	input = memnew( InputDefault );
 	joypad = memnew (JoypadWindows(input, &hWnd));
 
+	power_manager = memnew( PowerWindows );
+
 	AudioDriverManager::get_driver(p_audio_driver)->set_singleton();
 
 	if (AudioDriverManager::get_driver(p_audio_driver)->init()!=OK) {
@@ -2393,6 +2395,18 @@ bool OS_Windows::is_vsync_enabled() const{
 	return true;
 }
 
+PowerState OS_Windows::get_power_state() {
+	return power_manager->get_power_state();
+}
+
+int OS_Windows::get_power_seconds_left() {
+	return power_manager->get_power_seconds_left();
+}
+
+int OS_Windows::get_power_percent_left() {
+	return power_manager->get_power_percent_left();
+}
+
 bool OS_Windows::check_feature_support(const String& p_feature) {
 
 	return VisualServer::get_singleton()->has_os_feature(p_feature);
diff --git a/platform/windows/os_windows.h b/platform/windows/os_windows.h
index 73a2d5f451..c8cacac7a2 100644
--- a/platform/windows/os_windows.h
+++ b/platform/windows/os_windows.h
@@ -31,6 +31,7 @@
 
 #include "os/input.h"
 #include "os/os.h"
+#include "power_windows.h"
 #include "context_gl_win.h"
 #include "servers/visual_server.h"
 #include "servers/visual/rasterizer.h"
@@ -125,6 +126,8 @@ class OS_Windows : public OS {
 	InputDefault *input;
 	JoypadWindows *joypad;
 
+	PowerWindows *power_manager;
+
 #ifdef RTAUDIO_ENABLED
 	AudioDriverRtAudio driver_rtaudio;
 #endif
@@ -285,6 +288,10 @@ public:
 	virtual void set_use_vsync(bool p_enable);
 	virtual bool is_vsync_enabled() const;
 
+	virtual PowerState get_power_state();
+	virtual int get_power_seconds_left();
+	virtual int get_power_percent_left();
+
 	virtual bool check_feature_support(const String& p_feature);
 
 	OS_Windows(HINSTANCE _hInstance);
diff --git a/platform/windows/power_windows.cpp b/platform/windows/power_windows.cpp
new file mode 100644
index 0000000000..a19472ab8f
--- /dev/null
+++ b/platform/windows/power_windows.cpp
@@ -0,0 +1,108 @@
+/*************************************************************************/
+/*  power_windows.cpp                                                    */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                    http://www.godotengine.org                         */
+/*************************************************************************/
+/* Copyright (c) 2007-2016 Juan Linietsky, Ariel Manzur.                 */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "power_windows.h"
+
+// CODE CHUNK IMPORTED FROM SDL 2.0
+
+bool PowerWindows::GetPowerInfo_Windows()
+{
+    SYSTEM_POWER_STATUS status;
+    bool need_details = FALSE;
+
+    /* This API should exist back to Win95. */
+    if (!GetSystemPowerStatus(&status))
+    {
+        /* !!! FIXME: push GetLastError() into GetError() */
+        power_state = POWERSTATE_UNKNOWN;
+    } else if (status.BatteryFlag == 0xFF) {    /* unknown state */
+        power_state = POWERSTATE_UNKNOWN;
+    } else if (status.BatteryFlag & (1 << 7)) { /* no battery */
+        power_state = POWERSTATE_NO_BATTERY;
+    } else if (status.BatteryFlag & (1 << 3)) { /* charging */
+        power_state = POWERSTATE_CHARGING;
+        need_details = TRUE;
+    } else if (status.ACLineStatus == 1) {
+        power_state = POWERSTATE_CHARGED;        /* on AC, not charging. */
+        need_details = TRUE;
+    } else {
+        power_state = POWERSTATE_ON_BATTERY;     /* not on AC. */
+        need_details = TRUE;
+    }
+
+    percent_left = -1;
+    nsecs_left = -1;
+    if (need_details) {
+        const int pct = (int) status.BatteryLifePercent;
+        const int secs = (int) status.BatteryLifeTime;
+
+        if (pct != 255) {       /* 255 == unknown */
+        	percent_left = (pct > 100) ? 100 : pct; /* clamp between 0%, 100% */
+        }
+        if (secs != 0xFFFFFFFF) {       /* ((DWORD)-1) == unknown */
+            nsecs_left = secs;
+        }
+    }
+
+    return TRUE;            /* always the definitive answer on Windows. */
+}
+
+PowerState PowerWindows::get_power_state() {
+	if (GetPowerInfo_Windows()) {
+		return power_state;
+	}
+	else {
+		return POWERSTATE_UNKNOWN;
+	}
+}
+
+int PowerWindows::get_power_seconds_left() {
+	if (GetPowerInfo_Windows()) {
+		return nsecs_left;
+	}
+	else {
+		return -1;
+	}
+}
+
+int PowerWindows::get_power_percent_left() {
+	if (GetPowerInfo_Windows()) {
+		return percent_left;
+	}
+	else {
+		return -1;
+	}
+}
+
+PowerWindows::PowerWindows() : nsecs_left(-1), percent_left(-1), power_state(POWERSTATE_UNKNOWN) {
+
+}
+
+PowerWindows::~PowerWindows() {
+}
\ No newline at end of file
diff --git a/platform/windows/power_windows.h b/platform/windows/power_windows.h
new file mode 100644
index 0000000000..a3a0b9568f
--- /dev/null
+++ b/platform/windows/power_windows.h
@@ -0,0 +1,57 @@
+/*************************************************************************/
+/*  power_windows.h                                                      */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                    http://www.godotengine.org                         */
+/*************************************************************************/
+/* Copyright (c) 2007-2016 Juan Linietsky, Ariel Manzur.                 */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef PLATFORM_WINDOWS_POWER_WINDOWS_H_
+#define PLATFORM_WINDOWS_POWER_WINDOWS_H_
+
+#include "os/dir_access.h"
+#include "os/file_access.h"
+#include "os/power.h"
+
+#include <windows.h>
+
+class PowerWindows {
+
+private:
+	int nsecs_left;
+	int percent_left;
+	PowerState power_state;
+
+	bool GetPowerInfo_Windows();
+
+public:
+	PowerWindows();
+	virtual ~PowerWindows();
+
+	PowerState get_power_state();
+	int get_power_seconds_left();
+	int get_power_percent_left();
+};
+
+#endif /* PLATFORM_WINDOWS_POWER_WINDOWS_H_ */
\ No newline at end of file