GPU (Android): adds GPU temp detection support

src/detection/gpu/gpu_android.c

@@ -0,0 +1,53 @@
+#include "gpu.h"
+#include "common/io/io.h"
+#include "util/stringUtils.h"
+
+#include <fcntl.h>
+
+static double parseTZDir(int dfd, FFstrbuf* buffer)
+{
+    if(!ffReadFileBufferRelative(dfd, "temp", buffer))
+        return FF_GPU_TEMP_UNSET;
+
+    double value = ffStrbufToDouble(buffer, FF_GPU_TEMP_UNSET);// millidegree Celsius
+    if(value == FF_GPU_TEMP_UNSET)
+        return FF_GPU_TEMP_UNSET;
+
+    if (!ffReadFileBufferRelative(dfd, "type", buffer) || ffStrbufStartsWithS(buffer, "gpu"))
+        return FF_GPU_TEMP_UNSET;
+
+    return value / 1000.;
+}
+
+double ffGPUDetectTempFromTZ(void)
+{
+    FF_AUTO_CLOSE_DIR DIR* dirp = opendir("/sys/class/thermal/");
+    if(dirp)
+    {
+        FF_STRBUF_AUTO_DESTROY buffer = ffStrbufCreate();
+        int dfd = dirfd(dirp);
+        struct dirent* entry;
+        while((entry = readdir(dirp)) != NULL)
+        {
+            if(entry->d_name[0] == '.')
+                continue;
+            if(!ffStrStartsWith(entry->d_name, "thermal_zone"))
+                continue;
+
+            FF_AUTO_CLOSE_FD int subfd = openat(dfd, entry->d_name, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+            if(subfd < 0)
+                continue;
+
+            double result = parseTZDir(subfd, &buffer);
+            if (result != FF_GPU_TEMP_UNSET)
+                return result;
+        }
+    }
+    return FF_GPU_TEMP_UNSET;
+}
+
+const char* ffDetectGPUImpl(const FFGPUOptions* options, FFlist* gpus)
+{
+    FF_UNUSED(options, gpus);
+    return "No permission. Fallbacks to Vulkan, OpenCL or OpenGL instead";
+}