Extract EINTR handling for Os.write()

Expose a function which retries automatically on EINTR, and throws an
IOException on other errors.

server/src/main/java/com/genymobile/scrcpy/util/IO.java

@@ -17,24 +17,30 @@ public final class IO {
         // not instantiable
     }
 
+    private static int write(FileDescriptor fd, ByteBuffer from) throws IOException {
+        while (true) {
+            try {
+                return Os.write(fd, from);
+            } catch (ErrnoException e) {
+                if (e.errno != OsConstants.EINTR) {
+                    throw new IOException(e);
+                }
+            }
+        }
+    }
+
     public static void writeFully(FileDescriptor fd, ByteBuffer from) throws IOException {
         // ByteBuffer position is not updated as expected by Os.write() on old Android versions, so
         // count the remaining bytes manually.
         // See <https://github.com/Genymobile/scrcpy/issues/291>.
         int remaining = from.remaining();
         while (remaining > 0) {
-            try {
+            int w = write(fd, from);
-                int w = Os.write(fd, from);
+            if (BuildConfig.DEBUG && w < 0) {
-                if (BuildConfig.DEBUG && w < 0) {
+                // w should not be negative, since an exception is thrown on error
-                    // w should not be negative, since an exception is thrown on error
+                throw new AssertionError("Os.write() returned a negative value (" + w + ")");
-                    throw new AssertionError("Os.write() returned a negative value (" + w + ")");
-                }
-                remaining -= w;
-            } catch (ErrnoException e) {
-                if (e.errno != OsConstants.EINTR) {
-                    throw new IOException(e);
-                }
             }
+            remaining -= w;
         }
     }