Add basic flashlight support.

 Ported from UBPorts power indicator:

 commit efef6f25f378021c99b3078958482b3c4ffc43a2
 Author: Marius Gripsgard <mariogrip@ubuntu.com>
 Date:   Sun Aug 13 00:09:01 2017 +0200

    Add support for other flashlight sysfs paths

 commit 3f4339876ddb586b75a73fab51a54b1d4d54fdd1
 Author: Marius Gripsgard <mariogrip@ubuntu.com>
 Date:   Fri Jul 28 21:23:54 2017 +0200

    Add basic support for QCOM flashlight, Fixes https://github.com/ubports/ubports-touch/issues/79

    This does not work on non QCOM devices

 Ported-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>

1 files changed, 77 insertions, 0 deletions

diff --git a/src/flashlight.c b/src/flashlight.c
new file mode 100644
index 0000000..3c5e8b1
--- /dev/null
+++ b/src/flashlight.c
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2017 The UBports project
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *   Marius Gripsgard <marius@ubports.com>
+ */
+
+#include "flashlight.h"
+
+#include <gio/gio.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#define QCOM_ENABLE "255"
+#define QCOM_DISABLE "0"
+
+const size_t qcom_sysfs_size = 2;
+const char* const qcom_sysfs[] = {"/sys/class/leds/torch-light/brightness", "/sys/class/leds/led:flash_torch/brightness"};
+
+char* flash_sysfs_path = NULL;
+
+int
+set_sysfs_path()
+{
+  for (size_t i = 0; i < qcom_sysfs_size; i++) {
+    if (access(qcom_sysfs[i], F_OK ) != -1){
+        flash_sysfs_path = qcom_sysfs[i];
+        return 1;
+    }
+  }
+  return 0;
+}
+
+void
+toggle_flashlight_action(GAction *action,
+                         GVariant *parameter G_GNUC_UNUSED,
+                         gpointer data G_GNUC_UNUSED)
+{
+  GVariant *state;
+  gboolean b;
+  FILE* fd;
+
+  if (!set_sysfs_path())
+    return;
+
+  state = g_action_get_state(action);
+  b = g_variant_get_boolean(state);
+  g_variant_unref(state);
+  fd = fopen(flash_sysfs_path, "w");
+  if (fd != NULL){
+      if (b)
+        fprintf(fd, QCOM_DISABLE);
+      else
+        fprintf(fd, QCOM_ENABLE);
+      fclose(fd);
+      g_action_change_state(action, g_variant_new_boolean(!b));
+  }
+}
+
+int
+flashlight_supported()
+{
+  return set_sysfs_path();
+}